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DR ANTHONY MELVIN CRASTO Ph.D

DR ANTHONY MELVIN CRASTO Ph.D

DR ANTHONY MELVIN CRASTO, Born in Mumbai in 1964 and graduated from Mumbai University, Completed his Ph.D from ICT, 1991,Matunga, Mumbai, India, in Organic Chemistry, The thesis topic was Synthesis of Novel Pyrethroid Analogues, Currently he is working with GLENMARK PHARMACEUTICALS LTD, Research Centre as Principal Scientist, Process Research (bulk actives) at Mahape, Navi Mumbai, India. Total Industry exp 30 plus yrs, Prior to joining Glenmark, he has worked with major multinationals like Hoechst Marion Roussel, now Sanofi, Searle India Ltd, now RPG lifesciences, etc. He has worked with notable scientists like Dr K Nagarajan, Dr Ralph Stapel, Prof S Seshadri, Dr T.V. Radhakrishnan and Dr B. K. Kulkarni, etc, He did custom synthesis for major multinationals in his career like BASF, Novartis, Sanofi, etc., He has worked in Discovery, Natural products, Bulk drugs, Generics, Intermediates, Fine chemicals, Neutraceuticals, GMP, Scaleups, etc, he is now helping millions, has 9 million plus hits on Google on all Organic chemistry websites. His friends call him Open superstar worlddrugtracker. His New Drug Approvals, Green Chemistry International, All about drugs, Eurekamoments, Organic spectroscopy international, etc in organic chemistry are some most read blogs He has hands on experience in initiation and developing novel routes for drug molecules and implementation them on commercial scale over a 30 year tenure till date Dec 2017, Around 35 plus products in his career. He has good knowledge of IPM, GMP, Regulatory aspects, he has several International patents published worldwide . He has good proficiency in Technology transfer, Spectroscopy, Stereochemistry, Synthesis, Polymorphism etc., He suffered a paralytic stroke/ Acute Transverse mylitis in Dec 2007 and is 90 %Paralysed, He is bound to a wheelchair, this seems to have injected feul in him to help chemists all around the world, he is more active than before and is pushing boundaries, He has 9 million plus hits on Google, 2.5 lakh plus connections on all networking sites, 50 Lakh plus views on dozen plus blogs, He makes himself available to all, contact him on +91 9323115463, email amcrasto@gmail.com, Twitter, @amcrasto , He lives and will die for his family, 90% paralysis cannot kill his soul., Notably he has 19 lakh plus views on New Drug Approvals Blog in 216 countries......https://newdrugapprovals.wordpress.com/ , He appreciates the help he gets from one and all, Friends, Family, Glenmark, Readers, Wellwishers, Doctors, Drug authorities, His Contacts, Physiotherapist, etc

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Cladribine, クラドリビン


Cladribine.svgChemSpider 2D Image | Cladribine | C10H12ClN5O3

Cladribine

クラドリビン

Leustatin

クラドリビン

RWJ 26251 / RWJ-26251

  • Molecular FormulaC10H12ClN5O3
  • Average mass285.687 Da
2-chloro-6-amino-9-(2-deoxy-β-D-erythro-pentofuranosyl)purine
2-Chlorodeoxyadenosine
4291-63-8 [RN]
6997
adenosine, 2-chloro-2′-deoxy- [ACD/Index Name]
AU7357560
CDA
(2R,3S,5R)-5-(6-Amino-2-chlor-9H-purin-9-yl)-2-(hydroxymethyl)tetrahydrofuran-3-ol
Leustatin (Trade name)
Litak (Trade name)
MLS000759397
Movectro (Trade name)
Mylinax
QA-1968
LAUNCHED, 1993, USA Ortho Biotech, Janssen Biotech

Cladribine, sold under the brand name Leustatin and Mavenclad among others, is a medication used to treat hairy cell leukemia(HCL, leukemic reticuloendotheliosis), B-cell chronic lymphocytic leukemia and relapsing-remitting multiple sclerosis.[4][5] Its chemical name is 2-chloro-2′-deoxyadenosine (2CdA).

Cladribine, a deoxyadenosine derivative developed by Ortho Biotech (currently Janssen), was first launched in the U.S. in 1993 as an intravenous treatment for hairy cell leukemia

Cladribine has been granted orphan drug designation in the U.S. in 1990 for the treatment of acute myeloid leukemia (AML) and hairy cell leukemia

As a purine analog, it is a synthetic chemotherapy agent that targets lymphocytes and selectively suppresses the immune system. Chemically, it mimics the nucleoside adenosine. However, unlike adenosine it is relatively resistant to breakdown by the enzyme adenosine deaminase, which causes it to accumulate in cells and interfere with the cell’s ability to process DNA. Cladribine is taken up cells via a transporter. Once inside a cell cladribine is activated mostly in lymphocytes, when it is triphosphorylated by the enzyme deoxyadenosine kinase (dCK). Various phosphatases dephosphorylate cladribine. Activated, triphosphorylated, cladribine is incorporated into mitochondrial and nuclear DNA, which triggers apoptosis. Non-activated cladribine is removed quickly from all other cells. This means that there is very little non-target cell loss.[4][6]

Medical uses

Cladribine is used for as a first and second-line treatment for symptomatic hairy cell leukemia and for B-cell chronic lymphocytic leukemia and is administered by intravenous or subcutaneous infusion.[5][7]

Since 2017, cladribine is approved as an oral formulation (10 mg tablet) for the treatment of RRMS in Europe, UAE, Argentina, Chile, Canada and Australia. Marketing authorization in the US was obtained in March 2019[8].

Some investigators have used the parenteral formulation orally to treat patients with HCL. It is important to note that approximately 40% of oral cladribine in bioavailable orally. It used, often in combination with other cytotoxic agents, to treat various kinds of histiocytosis, including Erdheim–Chester disease[9] and Langerhans cell histiocytosis,[10]

Cladribine can cause fetal harm when administered to a pregnant woman and is listed by the FDA as Pregnancy Category D; safety and efficacy in children has not been established.[7]

Adverse effects

Injectable cladribine suppresses the body’s ability to make new lymphocytesnatural killer cells and neutrophils (called myelosuppression); data from HCL studies showed that about 70% of people taking the drug had fewer white blood cells and about 30% developed infections and some of those progressed to septic shock; about 40% of people taking the drug had fewer red blood cells and became severely anemic; and about 10% of people had too few platelets.[7]

At the dosage used to treat HCL in two clinical trials, 16% of people had rashes and 22% had nausea, the nausea generally did not lead to vomiting.[7]

In comparison, in MS, cladribine is associated with a 6% rate of severe lymphocyte suppression (lymphopenia) (levels lower than 50% of normal). Other common side effects include headache (75%), sore throat (56%), common cold-like illness (42%) and nausea (39%)[11]

Mechanism of Action

As a purine analogue, it is taken up into rapidly proliferating cells like lymphocytes to be incorporated into DNA synthesis. Unlike adenosine, cladribine has a chlorine molecule at position 2, which renders it partially resistant to breakdown by adenosine deaminase (ADA). In cells it is phosphorylated into its toxic form, deoxyadenosine triphosphate, by the enzyme deoxycytidine kinase (DCK). This molecule is then incorporated into the DNA synthesis pathway, where it causes strand breakage. This is followed by the activation of transcription factor p53, the release of cytochrome c from mitochondria and eventual programmed cell death (apoptosis).[12] This process occurs over approximately 2 months, with a peak level of cell depletion 4–8 weeks after treatment[13]

Within the lymphocyte pool, cladribine targets B cells more than T cells. Both HCL and B-cell chronic lymphocytic leukaemia are types of B cell blood cancers. In MS, its effectiveness may be due to its ability to effectively deplete B cells, in particular memory B cells[14] In the pivotal phase 3 clinical trial of oral cladribine in MS, CLARITY, cladribine selectively depleted 80% of peripheral B cells, compared to only 40-50% of total T cells.[15] More recently, cladribine has been shown to induce long term, selective suppression of certain subtypes of B cells, especially memory B cells.[16]

Another family of enzymes, the 5´nucleotidase (5NCT) family, is also capable of dephosphorylating cladribine, making it inactive. The most important subtype of this group appears to be 5NCT1A, which is cytosolically active and specific for purine analogues. When DCK gene expression is expressed as a ratio with 5NCT1A, the cells with the highest ratios are B cells, especially germinal centre and naive B cells.[16] This again helps to explain which B cells are more vulnerable to cladribine-mediated apoptosis.

Although cladribine is selective for B cells, the long term suppression of memory B cells, which may contribute to its effect in MS, is not explained by gene or protein expression. Instead, cladribine appears to deplete the entire B cell department. However, while naive B cells rapidly move from lymphoid organs, the memory B cell pool repopulates very slowly from the bone marrow.

History

Ernest Beutler and Dennis A. Carson had studied adenosine deaminase deficiency and recognized that because the lack of adenosine deaminase led to the destruction of B cell lymphocytes, a drug designed to inhibit adenosine deaminase might be useful in lymphomas. Carson then synthesized cladribine, and through clinical research at Scripps starting in the 1980s, Beutler tested it as intravenous infusion and found it was especially useful to treat hairy cell leukemia (HCL). No pharmaceutical companies were interested in selling the drug because HCL was an orphan disease, so Beutler’s lab synthesized and packaged it and supplied it to the hospital pharmacy; the lab also developed a test to monitor blood levels. This was the first treatment that led to prolonged remission of HCL, which was previously untreatable.[17]:14–15

In February 1991 Scripps began a collaboration with Johnson & Johnson to bring intravenous cladribine to market and by December of that year J&J had filed an NDA; cladrabine was approved by the FDA in 1993 for HCL as an orphan drug,[18] and was approved in Europe later that year.[19]:2

The subcutaneous formulation was developed in Switzerland in the early 1990s and it was commercialized by Lipomed GmbH in the 2000s.[19]:2[20]

Multiple sclerosis

In the mid-1990s Beutler, in collaboration with Jack Sipe, a neurologist at Scripps, ran several clinical trials exploring the utility of cladribine in multiple sclerosis, based on the drug’s immunosuppressive effects. Sipe’s insight into MS, and Beutler’s interest in MS due to his sister’s having had it, led a very productive collaboration.[17]:17[21] Ortho-Clinical, a subsidiary of J&J, filed an NDA for cladribine for MS in 1997 but withdrew it in the late 1990s after discussion with the FDA proved that more clinical data would be needed.[22][23]

Ivax acquired the rights for oral administration of cladribine to treat MS from Scripps in 2000,[24] and partnered with Serono in 2002.[23] Ivax was acquired by Teva in 2006,[25][26] and Merck KGaA acquired control of Serono’s drug business in 2006.[27]

An oral formulation of the drug with cyclodextrin was developed[28]:16 and Ivax and Serono, and then Merck KGaA conducted several clinical studies. Merck KGaA submitted an application to the European Medicines Agency in 2009, which was rejected in 2010, and an appeal was denied in 2011.[28]:4–5 Likewise Merck KGaA’s NDA with the FDA rejected in 2011.[29] The concerns were that several cases of cancer had arisen, and the ratio of benefit to harm was not clear to regulators.[28]:54–55 The failures with the FDA and the EMA were a blow to Merck KGaA and were one of a series of events that led to a reorganization, layoffs, and closing the Swiss facility where Serono had arisen.[30][31] However, several MS clinical trials were still ongoing at the time of the rejections, and Merck KGaA committed to completing them.[29] A meta-analysis of data from clinical trials showed that cladiribine did not increase the risk of cancer at the doses used in the clinical trials.[32]

In 2015 Merck KGaA announced it would again seek regulatory approval with data from the completed clinical trials in hand,[30] and in 2016 the EMA accepted its application for review.[33] On June 22, 2017, the EMA’s Committee for Medicinal Products for Human Use (CHMP) adopted a positive opinion, recommending the granting of a marketing authorisation for the treatment of relapsing forms of multiple sclerosis.[34]

Finally, after all these problems it was approved in Europe on August 2017 for highly active RRMS.[35]

Efficacy

Cladribine is an effective treatment for relapsing remitting MS, with a reduction in the annual rate of relapses of 54.5%.[11] These effects may be sustained up to 4 years after initial treatment, even if no further doses are given.[36] Thus, cladribine is considered to be a highly effective immune reconstitution therapy in MS. Similar to alemtuzumab, cladribine is given as two courses approximately one year apart. Each course consists of 4-5 tablets given over a week in the first month, followed by a second dosing of another 4-5 tablets the following month[37] During this time and after the final dose patients are monitored for adverse effects and signs of relapse.

https://www.merckneurology.co.uk/wp-content/uploads/2017/08/mavenclad-table-1.jpg

Safety

Compared to alemtuzumab, cladribine is associated with a lower rate of severe lymphopenia. It also appears to have a lower rate of common adverse events, especially mild to moderate infections[11][36] As cladribine is not a recombinant biological therapy, it is not associated with the development of antibodies against the drug, which might reduce the effectiveness of future doses. Also, unlike alemtuzumab, cladribine is not associated with secondary autoimmunity.[38]

This is probably due to the fact cladribine more selectively targets B cells. Unlike alemtuzumab, cladribine is not associated with a rapid repopulation of the peripheral blood B cell pool, which then ´overshoots´ the original number by up to 30%.[39] Instead, B cells repopulate more slowly, reaching near normal total B cells numbers at 1 year. This phenomenon and the relative sparing of T cells, some of which might be important in regulating the system against other autoimmune reactions, is thought to explain the lack of secondary autoimmunity.

Use in clinical practice

The decision to start cladribine in MS depends on the degree of disease activity (as measured by number of relapses in the past year and T1 gadolinium-enhancing lesions on MRI), the failure of previous disease-modifying therapies, the potential risks and benefits and patient choice.

In the UK, the National Institute for Clinical Excellence (NICE) recommends cladribine for treating highly active RRMS in adults if the persons has:

rapidly evolving severe relapsing–remitting multiple sclerosis, that is, at least 2 relapses in the previous year and at least 1 T1 gadolinium-enhancing lesion at baseline MRI or

relapsing–remitting multiple sclerosis that has responded inadequately to treatment with disease-modifying therapy, defined as 1 relapse in the previous year and MRI evidence of disease activity.[40]

People with MS require counselling on the intended benefits of cladribine in reducing the risk of relapse and disease progression, versus the risk of adverse effects such as headaches, nausea and mild to moderate infections. Women of childbearing age also require counselling that they should not conceive while taking cladribine, due to the risk of harm to the fetus.

Cladribine, as the 10 mg oral preparation Mavenclad, is administered as two courses of tablets approximately one year apart. Each course consists of four to five treatment days in the first month, followed by an additional four to five treatment days in the second month. The recommended dose of Mavenclad is 3.5 mg/kg over 2 years, given in two treatment courses of 1.75 mg/kg/year. Therefore, the number of tablets administered on each treatment day depends on the person’s weight. A full guide to the dosing strategy can be found below:

https://www.merckneurology.co.uk/mavenclad/mavenclad-efficacy/

After treatment, people with MS are monitored with regular blood tests, looking specifically at the white cell count and liver function. Patients should be followed up regularly by their treating neurologist to assess efficacy, and should be able to contact their MS service in the case of adverse effects or relapse. After the first two years of active treatment no further therapy may need to be given, as cladribine has been shown to be efficacious for up to last least four years after treatment. However, if patients fail to respond, options include switching to other highly effective disease-modifying therapies such as alemtuzumab, fingolimod or natalizumab.

Research directions

Cladribine has been studied as part of a multi-drug chemotherapy regimen for drug-resistant T-cell prolymphocytic leukemia.[41]

REF

A universal biocatalyst for the preparation of base- and sugar-modified nucleosides via an enzymatic transglycosylation
Helv Chim Acta 2002, 85(7): 1901

Synthesis of 2-chloro-2′-deoxyadenosine by microbiological transglycosylation
Nucleosides Nucleotides 1993, 12(3-4): 417

Synthesis of 2-chloro-2′-deoxyadenosine by washed cells of E. coli
Biotechnol Lett 1992, 14(8): 669

Efficient syntheses of 2-chloro-2′-deoxyadenosine (cladribine) from 2′-deoxyguanosine
J Org Chem 2003, 68(3): 989

WO 2004028462

Synthesis of 2′-deoxytubercidin, 2′-deoxyadenosine, and related 2′-deoxynucleosides via a novel direct stereospecific sodium salt glycosylation procedure
J Am Chem Soc 1984, 106(21): 6379

WO 2011113476

A stereoselective process for the manufacture of a 2′-deoxy-beta-D-ribonucleoside using the vorbruggen glycosylation
Org Process Res Dev 2013, 17(11): 1419

A new synthesis of 2-chloro-2′-deoxyadenosine (Cladribine), CdA)
Nucleosides Nucleotides Nucleic Acids 2011, 30(5): 353

A dramatic concentration effect on the stereoselectivity of N-glycosylation for the synthesis of 2′-deoxy-beta-ribonucleosides
Chem Commun (London) 2012, 48(56): 7097

CN 105367616

PATENT

https://patents.google.com/patent/EP2891660A1/en

Previously Robins and Robins (Robins, M. J. and Robins, R. K., J. Am. Chem. Soc. 1965, 87, 4934-4940) reported that acid-catalyzed fusion of 1,3,5-tri-O-acety-2-deoxy-D-ribofuranose and 2,6-dichloropurine gave a 65% yield of an anomeric mixture 2,6-dichloro-9-(3′,5′-di-O-acetyl-2′-deoxy-α-,β-D-ribofuranosyl)-purines from which the α-anomer was obtained as a pure crystalline product by fractional crystallization from ethanol in 32% yield and the equivalent β-anomer remained in the mother liquor (see Scheme 1). The β-anomer, which could have been used to synthesize cladribine, wasn’t isolated further. The α-anomer was treated with methanolic ammonia which resulted in simultaneous deacetylation and amination to give 6-amino-2-chloro-9-(2′-deoxy-α-D-ribofuranosyl)-purine, which is a diastereomer of cladribine.

Figure imgb0001

[0004]

Broom et al. (Christensen, L. F., Broom, A. D., Robins, M. J., and Bloch, A., J. Med. Chem. 1972, 15, 735-739) adapted Robins et al.’s method by treating the acetylated mixture (viz., 2,6-dichloro-9-(3′,5′-di-O-acety-2′-deoxy-α,β-D-ribofuranosyl)-purine) with liquid ammonia and reacylating the resulting 2′-deoxy-α-and –β-adenosines with p-toluoyl chloride (see Scheme 2). The desired 2-chloro-9-(3′,5′-di-Op-toluoyl-2′-deoxy-β-D-ribofuranosyl)-adenine was then separated by chromatography and removal of the p-toluoyl group resulted in cladribine in 9% overall yield based on the fusion of 1,3,5-tri-O-acety-2-deoxy-D-ribofuranose and 2,6-dichloropurine.

Figure imgb0002
[0005]

To increase the stereoselectivity in favour of the β-anomer, Robins et al.(Robins, R. L. et al., J. Am. Chem. Soc. 1984, 106, 6379-6382US4760137 EP0173059 ) provided an improved method in which the sodium salt of 2,6-dichloropurine was coupled with 1-chloro-2-deoxy-3,5-di-Op-toluoyl-α-D-ribofuranose in acetonitrile (MeCN) to give the protected β-nucleoside in 59% isolated yield, following chromatography and crystallisation, in addition to 13% of the undesired N-7 regioisomer (see Scheme 3). The apparently higher selectivity in this coupling reaction is attributed to it being a direct SN2 displacement of the chloride ion by the purine sodium salt. The protected N-9 2′-deoxy-β-nucleoside was treated with methanolic ammonia at 100°C to give cladribine in an overall 42% yield. The drawback of this process is that the nucleophilic 7- position nitrogen competes in the SN2 reaction against the nucleophilic 9- position, leading to a mixture of the N-7 and N-9 glycosyl isomers as well as the need for chromatography and crystallisation to obtain the pure desired isomer.

Figure imgb0003
[0006]

Gerszberg and Alonso (Gerszberg S. and Alonso, D. WO0064918 , and US20020052491 ) also utilised an SN2 approach with 1-chloro-2-deoxy-3,5-di-Op-toluoyl-α-D-ribofuranose but instead coupled it with the sodium salt of 2-chloroadenine in acetone giving the desired β-anomer of the protected cladribine in 60% yield following crystallisation from ethanol (see Scheme 4). After the deprotection step using ammonia in methanol (MeOH), the β-anomer of cladribine was isolated in an overall 42% yield based on the 1-chlorosugar, and 30% if calculated based on the sodium salt since this was used in a 2.3 molar excess.

Figure imgb0004
[0007]

To increase the regioselectivity towards glycosylation of the N-9 position, Gupta and Munk recently ( Gupta, P. K. and Munk, S. A., US20040039190 WO2004018490 and CA2493724 ) conducted an SN2 reaction using the anomerically pure α-anomer, 1-chloro-2-deoxy-3,5-di-Op-toluoyl-α-D-ribofuranose but coupling it with the potassium salt of a 6-heptanoylamido modified purine (see Scheme 5). The bulky alkyl group probably imparted steric hindrance around the N-7 position, resulting in the reported improved regioselectivity. Despite this, following deprotection, the overall yield of cladribine based on the 1-chlorosugar was 43%, showing no large improvement in overall yield on related methods. Moreover 2-chloroadenine required prior acylation with heptanoic anhydride at high temperature (130°C) in 72% yield, and the coupling required cryogenic cooling (-30°C) and the use of the strong base potassium hexamethyldisilazide and was followed by column chromatography to purify the product protected cladribine.

Figure imgb0005
[0008]

More recently Robins et al. (Robins, M. J. et al., J. Org. Chem. 2006, 71, 7773-7779US20080207891 ) published a procedure for synthesis of cladribine that purports to achieve almost quantitative yields in the N-9-regioselective glycosylation of 6-(substituted-imidazol-1-yl)-purine sodium salts with 1-chloro-2-deoxy-3,5-di-Op-toluoyl-α-D-ribofuranose in MeCN/dichloromethane (DCM) mixtures to give small or no detectable amounts of the undesired α-anomer (see Scheme 6). In actuality this was only demonstrated on the multi-milligram to several grams scale, and whilst the actual coupling yield following chromatography of the desired N-9-β-anomer was high (83% to quantitative), the protected 6-(substituted-imidazol-1-yl)-products were obtained in 55% to 76% yield after recrystallisation. Following this, toxic benzyl iodide was used to activate the 6-(imidazole-1-yl) groups which were then subsequently displaced by ammonia at 60-80°C in methanolic ammonia to give cladribine in 59-70% yield following ion exchange chromatography and multiple crystallisations, or following extraction with DCM and crystallisation. Although high anomeric and regioselective glycosylation was demonstrated the procedure is longer than the prior arts, atom uneconomic and not readily applicable to industrial synthesis of cladribine such as due to the reliance on chromatography and the requirement for a pressure vessel in the substitution of the 6-(substituted-imidazole-1-yl) groups.

Figure imgb0006
[0009]
Therefore, there is a need for a more direct, less laborious process, which will produce cladribine in good yield and high purity that is applicable to industrial scales.

EXAMPLE 1 Preparation of 2-chloro-6-trimethylsilylamino-9-[3,5-di-O-(4-chlorobenzoyl)-2-deoxy-β-D-ribofuranosyl]-purine

  • [0052]
    2-Chloroadenine (75 g, 0.44 mol, 1.0 eq.), MeCN (900 mL, 12 P), and BSTFA (343.5 g, 1.33 mol, 3.0 eq.) were stirred and heated under reflux until the mixture was almost turned clear. The mixture was cooled to 60°C and TfOH (7.9 mL, 0.089 mol, 0.2 eq.) and then 1-O-acetyl-3,5-di-O-(4-chlorobenzoyl)-2-deoxy-D-ribofuranose (III; 200.6 g, 1.0 eq.) were added into the mixture, and then the mixture was stirred at 60°C. After 1 hour, some solid precipitated from the solution and the mixture was heated for at least a further 10 hours. The mixture was cooled to r.t. and stirred for 2 hours. The solid was filtered and dried in vacuo at 60°C to give 180.6 g in 64% yield of a mixture of 2-chloro-6-trimethylsilylamino-9-[3,5-di-O-(4-chlorobenzoyl)-2-deoxy-β-D-ribofurano syl]-purine (IVa) with 95.4% HPLC purity and its non-silylated derivative 2-chloro-6-amino-9-[3,5-di-O-(4-chlorobenzoyl)-2′-deoxy-β-D-ribofuranosyl]-purine (IVb) with 1.1 % HPLC purity.

EXAMPLE 2 Preparation of 2-chloro-6-trimethylsilylamino-9-[3,5-di-O-(4-chlorobenzoyl)-2-deoxy-β-D-ribofuranosyl]-purine by isomerisation of a mixture of 2-chloro-6-amino-9-[3,5-di-O-(4-chlorobenzoyl)-2-deoxy-α,β-D-ribofuranosyl]-purine mixture

  • [0053]
    50.0 g of 2-chloro-6-amino-9-[3,5-di-O-(4-chlorobenzoyl)-2-deoxy-α,β-D-ribofuranosyl]-purine as a 0.6:1.0 mixture of the β-anomer IVb and α-anomer Vb(83.16 mmol, assay of α-anomer was 58.6% (52.06 mmol) and β-anomer was 34.3% (31.10 mmol, 17.15 g)), 68.6 g BSTFA (266.5 mmol) and 180 mL of MeCN (3.6 P) were charged into a dried 4-necked flask. The mixture was heated to 60°C under N2 for about 3 h and then 2.67 g of TfOH (17.8 mmol) was added. The mixture was stirred at 60°C for 15 h and was then cooled to about 25°C and stirred for a further 2 h, and then filtered. The filter cake was washed twice with MeCN (20 mL each) and dried at 60°C in vacuo for 6 h to give 24 g of off-white solid (the assay of 2-chloro-6-amino-9-[3,5-di-O-(4-chlorobenzoyl)-2-deoxy-α-D-ribofuranosyl]-purine was 1.4% (0.60 mmol, 0.34 g),
    2-chloro-6-amino-9-[3,5-di-O-(4-chlorobenzoyl)-2-deoxy-β-D-ribofuranosyl]-purine was 8.4% (3.18 mmol, 2.02 g) and
    2-chloro-6-trimethylsilylamino-9-[3,5-di-O-(4-chlorobenzoyl)-2-deoxy-β-D-ribofuranosyl]-purine was 86.6% (32.73 mmol, 20.78 g)).
    Analysis of the 274.8 g of the mother liquor by assay showed that it in addition to the α-anomer it contained 0.5% (1.37 g, 2.43 mmol) of
    2-chloro-6-amino-9-[3,5-di-O-(4-chlorobenzoyl)-2-deoxy-β-D-ribofuranosyl]-purine and 0.01% (0.027 g, 0.05 mmol) of
    2-chloro-6-trimethylsilylamino-9-[3,5-di-O-(4-chlorobenzoyl)-2-deoxy-β-D-ribofuranosyl]-purine.

EXAMPLE 3 Preparation of 2-chloro-2′-deoxy-adenosine (cladribine)

  • [0054]
    To the above prepared mixture of 2-chloro-6-trimethylsilylamino-9-[3,5-di-O-(4-chlorobenzoyl)-2-deoxy-β-D-ribofurano syl]- purine (IVa) and 2-chloro-6-amino-9-[3,5-di-O-(4-chlorobenzoyl)-2′-deoxy-β-D-ribofuranosyl]-purine (IVb) (179 g, >95.4% HPLC purity) in MeOH (895 mL, 5 P) was added 29% MeONa/MeOH solution (5.25 g, 0.1 eq.) at 20-30°C. The mixture was stirred at 20-30°C for 6 hours, the solid was filtered, washed with MeOH (60 mL, 0.34 P) and then dried in vacuo at 50°C for 6 hour to give 72 g white to off-white crude cladribine with 98.9% HPLC purity in ca. 93% yield.

EXAMPLE 4 Recrystallisation

  • [0055]
    Crude cladribine (70 g), H2O (350 mL, 5 P), MeOH (350 mL, 5 P) and 29% MeONa/MeOH solution (0.17 g) were stirred and heated under reflux until the mixture turned clear. The mixture was stirred for 3 hour and was then filtered to remove the precipitates at 74-78°C. The mixture was stirred and heated under reflux until the mixture turned clear and was then cooled. Crystals started to form at ca. 45°C. The slurry was stirred for 2 hour at the cloudy point. The slurry was cooled slowly at a rate of 5°C/0.5 hour. The slurry was stirred at 10-20°C for 4-8 hours and then filtered. The filter cake was washed three times with MeOH (50 mL each) and dried at 50°C in vacuo for 6 hours to give 62.7 g of 99.9% HPLC pure cladribine in ca. 90% yield.

EXAMPLE 5 Preparation of 2-chloro-6-trimethylsilylamino-9-[3,5-di-O-(4-chlorobenzoyl)-2-deoxy-β-D-ribofuranosyl]-purine

  • [0056]
    2-Chloroadenine (2.2 Kg, 13.0 mol, 1.0 eq.), MeCN (20.7 Kg, 12 P), and BSTFA (10.0 Kg, 38.9 mol, 3.0 eq.) were stirred and heated under reflux for 3 hours and then filtered through celite and was cooled to about 60°C. TfOH (0.40 Kg, 2.6 mol, 0.2 eq.) and 1-O-acetyl-3,5-di-O-(4-chlorobenzoyl)-2-deoxy-D-ribofuranose (III; 5.87 Kg, 13.0 mol, 1.0 eq.) were added into the filtrate and the mixture was stirred at about 60°C for 29.5 hours. The slurry was cooled to about 20°C and stirred for 2 hours. The solids were filtered and washed with MeCN (2.8 Kg) twice and dried in vacuo at 60°C to give 5.17 Kg with a 96.5% HPLC purity in 62% yield of a mixture of 2-chloro-6-trimethylsilylamino-9-[3,5-di-O-(4-chlorobenzoyl)-2-deoxy-β-D-ribofurano syl]-purine (IVa), and non-silylated derivative 2-chloro-6-amino-9-[3,5-di-O-(4-chlorobenzoyl)-2′-deoxy-β-D-ribofuranosyl]-purine (IVb).

EXAMPLE 6 Preparation of 2-chloro-2′-deoxy-adenosine (cladribine)

  • [0057]
    To a mixture of 25% sodium methoxide in MeOH (0.11 Kg, 0.5 mol, 0.1 eq.) and MeOH (14.8 Kg, 5 P) at about at 25°C was added 2-chloro-6-trimethylsilylamino-9-[3,5-di-O-(4-chlorobenzoyl)-2-deoxy-β-D-ribofurano syl]-purine (IVa) and non-silylated derivative 2-chloro-6-amino-9-[3,5-di-O-(4-chlorobenzoyl)-2′-deoxy-β-D-ribofuranosyl]-purine (IVb) (3.70 Kg, combined HPLC purity of >96.3%) and the mixture was agitated at about 25°C for 2 hours. The solids were filtered, washed with MeOH (1.11 Kg, 0.4 P) and then dried in vacuo at 60°C for 4 hours to give 1.43 Kg of a crude cladribine with 97.8% HPLC purity in ca. 87% yield.

EXAMPLE 7 Recrystallisation of crude cladribine

  • [0058]
    A mixture of crude cladribine (1.94 Kg, >96.0% HPLC purity), MeOH (7.77 Kg, 5 P), process purified water (9.67 Kg, 5 P) and 25% sodium methoxide in MeOH (32 g, 0.15 mol) were stirred and heated under reflux until the solids dissolved. The solution was cooled to about 70°C and treated with activated carbon (0.16 Kg) and celite for 1 hour at about 70°C, rinsed with a mixture of preheated MeOH and process purified water (W/W = 1:1.25, 1.75 Kg). The filtrate was cooled to about 45°C and maintained at this temperature for 1 hours, and then cooled to about 15°C and agitated at this temperature for 2 hours. The solids were filtered and washed with MeOH (1.0 Kg, 0.7 P) three times and were then dried in vacuo at 60°C for 4 hours giving API grade cladribine (1.5 Kg, 5.2 mol) in 80% yield with 99.84% HPLC purity.

EXAMPLE 8 Recrystallisation of crude cladribine

  • [0059]
    A mixture of crude cladribine (1.92 Kg, >95.7% HPLC purity), MeOH (7.76 Kg, 5 P), process purified water (9.67 Kg, 5 P) and 25% sodium methoxide in MeOH (36 g, 0.17 mol) were stirred and heated under reflux until the solids dissolved. The solution was cooled to about 70°C and treated with activated carbon (0.15 Kg) and celite for 1 hour at about 70°C, rinsed with a mixture of preheated MeOH and process purified water (1:1.25, 1.74 Kg). The filtrate was cooled to about 45°C and maintained at this temperature for 1 hour, and then cooled to about 15°C and agitated at this temperature for 2 hours. The solids were filtered and washed with MeOH (1.0 Kg, 0.7 P) three times and were giving damp cladribine (1.83 Kg). A mixture of this cladribine (1.83 Kg), MeOH (7.33 Kg, 5 P) and process purified water (9.11 Kg, 5 P) were stirred and heated under reflux until the solids dissolved and was then cooled to about 45°C and maintained at this temperature for 1 hours. The slurry was further cooled to about 15°C and agitated at this temperature for 2 hours. The solids were filtered and washed with MeOH (0.9 Kg, 0.7 P) three times and were then dried in vacuo at 60°C for 4 hours giving API grade cladribine (1.38 Kg, 4.8 mol) in 75% yield with 99.86% HPLC purity.

SYN

Image result for cladribine

Cladribine can be got from 2-Deoxy-D-ribose. The detail is as follows:

Production of Cladribine

SYN

https://www.tandfonline.com/doi/abs/10.1080/15257770.2015.1071848?journalCode=lncn20

clip
FDA approves new oral treatment for multiple sclerosis, Mavenclad (cladribine)
The U.S. Food and Drug Administration today approved Mavenclad (cladribine) tablets to treat
relapsing forms of multiple sclerosis (MS) in adults, to include relapsing-remitting disease and active secondary progressive disease. Mavenclad is not recommended for MS patients with clinically isolated syndrome. Because of its safety profile, the use of Mavenclad is generally recommended for patients who have had an inadequate response to…

March 29, 2019

Release

The U.S. Food and Drug Administration today approved Mavenclad (cladribine) tablets to treat relapsing forms of multiple sclerosis (MS) in adults, to include relapsing-remitting disease and active secondary progressive disease. Mavenclad is not recommended for MS patients with clinically isolated syndrome. Because of its safety profile, the use of Mavenclad is generally recommended for patients who have had an inadequate response to, or are unable to tolerate, an alternate drug indicated for the treatment of MS.

“We are committed to supporting the development of safe and effective treatments for patients with multiple sclerosis,” said Billy Dunn, M.D., director of the Division of Neurology Products in the FDA’s Center for Drug Evaluation and Research. “The approval of Mavenclad represents an additional option for patients who have tried another treatment without success.”

MS is a chronic, inflammatory, autoimmune disease of the central nervous system that disrupts communications between the brain and other parts of the body. Most people experience their first symptoms of MS between the ages of 20 and 40. MS is among the most common causes of neurological disability in young adults and occurs more frequently in women than in men.

For most people, MS starts with a relapsing-remitting course, in which episodes of worsening function (relapses) are followed by recovery periods (remissions). These remissions may not be complete and may leave patients with some degree of residual disability. Many, but not all, patients with MS experience some degree of persistent disability that gradually worsens over time. In some patients, disability may progress independent of relapses, a process termed secondary progressive multiple sclerosis (SPMS). In the first few years of this process, many patients continue to experience relapses, a phase of the disease described as active SPMS. Active SPMS is one of the relapsing forms of MS, and drugs approved for the treatment of relapsing forms of MS can be used to treat active SPMS.

The efficacy of Mavenclad was shown in a clinical trial in 1,326 patients with relapsing forms of MS who had least one relapse in the previous 12 months. Mavenclad significantly decreased the number of relapses experienced by these patients compared to placebo. Mavenclad also reduced the progression of disability compared to placebo.

Mavenclad must be dispensed with a patient Medication Guide that describes important information about the drug’s uses and risks. Mavenclad has a Boxed Warning for an increased risk of malignancy and fetal harm. Mavenclad is not to be used in patients with current malignancy. In patients with prior malignancy or with increased risk of malignancy, health care professionals should evaluate the benefits and risks of the use of Mavenclad on an individual patient basis. Health care professionals should follow standard cancer screening guidelines in patients treated with Mavenclad. The drug should not be used in pregnant women and in women and men of reproductive potential who do not plan to use effective contraception during treatment and for six months after the course of therapy because of the potential for fetal harm. Mavenclad should be stopped if the patient becomes pregnant.

Other warnings include the risk of decreased lymphocyte (white blood cell) counts; lymphocyte counts should be monitored before, during and after treatment. Mavenclad may increase the risk of infections; health care professionals should screen patients for infections and treatment with Mavenclad should be delayed if necessary. Mavenclad may cause hematologic toxicity and bone marrow suppression so health care professionals should measure a patient’s complete blood counts before, during and after therapy. The drug has been associated with graft-versus-host-disease following blood transfusions with non-irradiated blood. Mavenclad may cause liver injury and treatment should be interrupted or discontinued, as appropriate, if clinically significant liver injury is suspected.

The most common adverse reactions reported by patients receiving Mavenclad in the clinical trials include upper respiratory tract infections, headache and decreased lymphocyte counts.

The FDA granted approval of Mavenclad to EMD Serono, Inc.

References

  1. ^ Drugs.com International trade names for Cladribine Page accessed Jan 14, 2015
  2. Jump up to:a b c d “PRODUCT INFORMATION LITAK© 2 mg/mL solution for injection” (PDF)TGA eBusiness Services. St Leonards, Australia: Orphan Australia Pty. Ltd. 10 May 2010. Retrieved 27 November 2014.
  3. ^ Liliemark, Jan (1997). “The Clinical Pharmacokinetics of Cladribine”. Clinical Pharmacokinetics32 (2): 120–131. doi:10.2165/00003088-199732020-00003PMID 9068927.
  4. Jump up to:a b “European Medicines Agency – – Litak”http://www.ema.europa.eu.
  5. Jump up to:a b “Leustat Injection. – Summary of Product Characteristics (SPC) – (eMC)”http://www.medicines.org.uk.
  6. ^ Leist, TP; Weissert, R (2010). “Cladribine: mode of action and implications for treatment of multiple sclerosis”. Clinical Neuropharmacology34 (1): 28–35. doi:10.1097/wnf.0b013e318204cd90PMID 21242742.
  7. Jump up to:a b c d Cladribine label, last updated July 2012. Page accessed January 14, 2015
  8. ^ https://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm634837.htm
  9. ^ Histiocytosis Association Erdheim-Chester Disease Page accessed Aug 20, 2016
  10. ^ Aricò M (2016). “Langerhans cell histiocytosis in children: from the bench to bedside for an updated therapy”. Br J Haematol173 (5): 663–70. doi:10.1111/bjh.13955PMID 26913480The combination of cytarabine and cladribine is the current standard for second-line therapy of refractory cases with vital organ dysfunction.
  11. Jump up to:a b c Giovannoni, G; Comi, G; Cook, S; Rammohan, K; Rieckmann, P; Soelberg Sørensen, P; Vermersch, P; Chang, P; Hamlett, A; Musch, B; Greenberg, SJ; CLARITY Study, Group. (4 February 2010). “A placebo-controlled trial of oral cladribine for relapsing multiple sclerosis”. The New England Journal of Medicine362 (5): 416–26. doi:10.1056/NEJMoa0902533PMID 20089960.
  12. ^ Johnston, JB (June 2011). “Mechanism of action of pentostatin and cladribine in hairy cell leukemia”. Leukemia & Lymphoma. 52 Suppl 2: 43–5. doi:10.3109/10428194.2011.570394PMID 21463108.
  13. ^ Beutler, E; Piro, LD; Saven, A; Kay, AC; McMillan, R; Longmire, R; Carrera, CJ; Morin, P; Carson, DA (1991). “2-Chlorodeoxyadenosine (2-CdA): A Potent Chemotherapeutic and Immunosuppressive Nucleoside”. Leukemia & Lymphoma5 (1): 1–8. doi:10.3109/10428199109068099PMID 27463204.
  14. ^ Baker, D; Marta, M; Pryce, G; Giovannoni, G; Schmierer, K (February 2017). “Memory B Cells are Major Targets for Effective Immunotherapy in Relapsing Multiple Sclerosis”EBioMedicine16: 41–50. doi:10.1016/j.ebiom.2017.01.042PMC 5474520PMID 28161400.
  15. ^ Baker, D; Herrod, SS; Alvarez-Gonzalez, C; Zalewski, L; Albor, C; Schmierer, K (July 2017). “Both cladribine and alemtuzumab may effect MS via B-cell depletion”Neurology: Neuroimmunology & Neuroinflammation4 (4): e360. doi:10.1212/NXI.0000000000000360PMC 5459792PMID 28626781.
  16. Jump up to:a b Ceronie, B; Jacobs, BM; Baker, D; Dubuisson, N; Mao, Z; Ammoscato, F; Lock, H; Longhurst, HJ; Giovannoni, G; Schmierer, K (May 2018). “Cladribine treatment of multiple sclerosis is associated with depletion of memory B cells”Journal of Neurology265 (5): 1199–1209. doi:10.1007/s00415-018-8830-yPMC 5937883PMID 29550884.
  17. Jump up to:a b Marshall A. Lichtman Biographical Memoir: Ernest Beutler 1928–2008 National Academy of Sciences, 2012
  18. ^ Staff, The Pink Sheet Mar 8, 1993 Ortho Biotech’s Leustatin For Hairy Cell Leukemia
  19. Jump up to:a b EMA 2004 Litak EMA package: Scientific Discussion
  20. ^ EMA 2004 Litak: Background Information one the Procedure
  21. ^ Eric Sauter and Mika Ono for Scripps News and Views. Vol 9. Issue 18. June 1, 2009 A Potential New MS Treatment’s Long and Winding Road
  22. ^ Tortorella C, Rovaris M, Filippi M (2001). “Cladribine. Ortho Biotech Inc”. Curr Opin Investig Drugs2 (12): 1751–6. PMID 11892941.
  23. Jump up to:a b Carey Sargent for Dow Jones Newswires in the Wall Street Journal. Oct. 31, 2002 Serono Purchases Rights To Experimental MS Drug
  24. ^ Reuters. Dec 4, 2000. Ivax to Develop Cladribine for Multiple Sclerosis
  25. ^ Jennifer Bayot for the New York Times. July 26, 2005 Teva to Acquire Ivax, Another Maker of Generic Drugs
  26. ^ Teva Press Release, 2006. Teva Completes Acquisition of Ivax
  27. ^ Staff, First Word Pharma. Sept 21, 2006 Merck KGaA to acquire Serono
  28. Jump up to:a b c EMA. 2011 Withdrawal Assessment Report for Movectro Procedure No. EMEA/H/C/001197
  29. Jump up to:a b John Gever for MedPage Today June 22, 2011 06.22.2011 0 Merck KGaA Throws in Towel on Cladribine for MS
  30. Jump up to:a b John Carroll for FierceBiotech Sep 11, 2015 Four years after a transatlantic slapdown, Merck KGaA will once again seek cladribine OK
  31. ^ Connolly, Allison (24 April 2012). “Merck KGaA to Close Merck Serono Site in Geneva, Cut Jobs”Bloomberg.
  32. ^ Pakpoor, J; et al. (December 2015). “No evidence for higher risk of cancer in patients with multiple sclerosis taking cladribine”Neurology: Neuroimmunology & Neuroinflammation2 (6): e158. doi:10.1212/nxi.0000000000000158PMC 4592538PMID 26468472.
  33. ^ Press release
  34. ^ Merck. “Cladribine Tablets Receives Positive CHMP Opinion for Treatment of Relapsing Forms of Multiple Sclerosis”http://www.prnewswire.co.uk. Retrieved 2017-08-22.
  35. ^ Cladribine approved in Europe, Press Release
  36. Jump up to:a b Giovannoni, G; Soelberg Sorensen, P; Cook, S; Rammohan, K; Rieckmann, P; Comi, G; Dangond, F; Adeniji, AK; Vermersch, P (1 August 2017). “Safety and efficacy of cladribine tablets in patients with relapsing-remitting multiple sclerosis: Results from the randomized extension trial of the CLARITY study”. Multiple Sclerosis (Houndmills, Basingstoke, England): 1352458517727603. doi:10.1177/1352458517727603PMID 28870107.
  37. ^ “Sustained Efficacy – Merck Neurology”Merck Neurology. Retrieved 28 September2018.
  38. ^ Guarnera, C; Bramanti, P; Mazzon, E (2017). “Alemtuzumab: a review of efficacy and risks in the treatment of relapsing remitting multiple sclerosis”Therapeutics and Clinical Risk Management13: 871–879. doi:10.2147/TCRM.S134398PMC 5522829PMID 28761351.
  39. ^ Baker, D; Herrod, SS; Alvarez-Gonzalez, C; Giovannoni, G; Schmierer, K (1 August 2017). “Interpreting Lymphocyte Reconstitution Data From the Pivotal Phase 3 Trials of Alemtuzumab”JAMA Neurology74 (8): 961–969. doi:10.1001/jamaneurol.2017.0676PMC 5710323PMID 28604916.
  40. ^ “Cladribine tablets for treating relapsing–remitting multiple sclerosis”National Institute for Clinical Excellence. Retrieved 23 September 2018.
  41. ^ Hasanali, Zainul S.; Saroya, Bikramajit Singh; Stuart, August; Shimko, Sara; Evans, Juanita; Shah, Mithun Vinod; Sharma, Kamal; Leshchenko, Violetta V.; Parekh, Samir (24 June 2015). “Epigenetic therapy overcomes treatment resistance in T cell prolymphocytic leukemia”Science Translational Medicine7 (293): 293ra102. doi:10.1126/scitranslmed.aaa5079ISSN 1946-6234PMC 4807901PMID 26109102.
Cladribine
Cladribine.svg
Clinical data
Trade names Leustatin, others[1]
AHFS/Drugs.com Monograph
MedlinePlus a693015
License data
Pregnancy
category
  • AU:D
  • US:D (Evidence of risk)
Routes of
administration
Intravenoussubcutaneous(liquid)
ATC code
Legal status
Legal status
  • AU:S4 (Prescription only)
  • CA℞-only
  • UK:POM (Prescription only)
Pharmacokinetic data
Bioavailability 100% (i.v.); 37 to 51% (orally)[3]
Protein binding 25% (range 5-50%)[2]
Metabolism Mostly via intracellularkinases; 15-18% is excreted unchanged[2]
Elimination half-life Terminal elimination half-life: Approximately 10 hours after both intravenous infusion an subcutaneous bolus injection[2]
Excretion Urinary[2]
Identifiers
CAS Number
PubChemCID
IUPHAR/BPS
DrugBank
ChemSpider
UNII
KEGG
ChEBI
ChEMBL
ECHA InfoCard 100.164.726Edit this at Wikidata
Chemical and physical data
Formula C10H12ClN5O3
Molar mass 285.687 g/mol g·mol−1
3D model (JSmol)
Cladribine
CAS Registry Number: 4291-63-8
CAS Name: 2-Chloro-2¢-deoxyadenosine
Additional Names: 2-chloro-6-amino-9-(2-deoxy-b-D-erythro-pentofuranosyl)purine; 2-chlorodeoxyadenosine; 2-CdA; CldAdo
Manufacturers’ Codes: NSC-105014-F
Trademarks: Leustatin (Ortho Biotech)
Molecular Formula: C10H12ClN5O3
Molecular Weight: 285.69
Percent Composition: C 42.04%, H 4.23%, Cl 12.41%, N 24.51%, O 16.80%
Literature References: Substituted purine nucleoside with antileukemic activity. Prepn as intermediate in synthesis of 2-deoxynucleosides: H. Venner, Ber. 93, 140 (1960); M. Ikehara, H. Tada, J. Am. Chem. Soc. 85, 2344 (1963); eidem, ibid. 87, 606 (1965). Synthesis and biological activity: L. F. Christensen et al., J. Med. Chem. 15, 735 (1972). Stereospecific synthesis: Z. Kazimierczuk et al., J. Am. Chem. Soc. 106, 6379 (1984); R. K. Robins, G. R. Revankar, EP 173059eidem, US 4760137 (1986, 1988 both to Brigham Young Univ.). Specific toxicity to lymphocytes: D. A. Carson et al., Proc. Natl. Acad. Sci. USA 77, 6865 (1980); eidem, Blood 62, 737 (1983). Mechanism of action: S. Seto et al., J. Clin. Invest. 75, 377 (1985). Clinical evaluation in chronic lymphocytic leukemia: L. D. Piro et al., Blood 72, 1069 (1988); in hairy cell leukemia: eidem, N. Engl. J. Med. 322, 1117 (1990).
Properties: Crystals from water, softens at 210-215°, solidifies and turns brown (Christensen). Also reported as crystals from ethanol, mp 220° (softens), resolidifies, turns brown and does not melt below 300° (Kazimierczuk). [a]D25 -18.8° (c = 1 in DMF). uv max in 0.1N NaOH: 265 nm; in 0.1N HCl: 265 nm.
Melting point: mp 220° (softens), resolidifies, turns brown and does not melt below 300°
Optical Rotation: [a]D25 -18.8° (c = 1 in DMF)
Absorption maximum: uv max in 0.1N NaOH: 265 nm; in 0.1N HCl: 265 nm
Therap-Cat: Antineoplastic.
Keywords: Antineoplastic; Antimetabolites; Purine Analogs.
////////////fda 2019, Mavenclad, cladribine, multiple sclerosis, EMD Serono, クラドリビン , Leustatin, クラドリビン , orphan drug designation
NC1=C2N=CN([C@H]3C[C@H](O)[C@@H](CO)O3)C2=NC(Cl)=N1

FDA approves new oral treatment for multiple sclerosis, Mavenclad (cladribine)


FDA approves new oral treatment for multiple sclerosis, Mavenclad (cladribine)
The U.S. Food and Drug Administration today approved Mavenclad (cladribine) tablets to treat
relapsing forms of multiple sclerosis (MS) in adults, to include relapsing-remitting disease and active secondary progressive disease. Mavenclad is not recommended for MS patients with clinically isolated syndrome. Because of its safety profile, the use of Mavenclad is generally recommended for patients who have had an inadequate response to…

March 29, 2019

Release

The U.S. Food and Drug Administration today approved Mavenclad (cladribine) tablets to treat relapsing forms of multiple sclerosis (MS) in adults, to include relapsing-remitting disease and active secondary progressive disease. Mavenclad is not recommended for MS patients with clinically isolated syndrome. Because of its safety profile, the use of Mavenclad is generally recommended for patients who have had an inadequate response to, or are unable to tolerate, an alternate drug indicated for the treatment of MS.

“We are committed to supporting the development of safe and effective treatments for patients with multiple sclerosis,” said Billy Dunn, M.D., director of the Division of Neurology Products in the FDA’s Center for Drug Evaluation and Research. “The approval of Mavenclad represents an additional option for patients who have tried another treatment without success.”

MS is a chronic, inflammatory, autoimmune disease of the central nervous system that disrupts communications between the brain and other parts of the body. Most people experience their first symptoms of MS between the ages of 20 and 40. MS is among the most common causes of neurological disability in young adults and occurs more frequently in women than in men.

For most people, MS starts with a relapsing-remitting course, in which episodes of worsening function (relapses) are followed by recovery periods (remissions). These remissions may not be complete and may leave patients with some degree of residual disability. Many, but not all, patients with MS experience some degree of persistent disability that gradually worsens over time. In some patients, disability may progress independent of relapses, a process termed secondary progressive multiple sclerosis (SPMS). In the first few years of this process, many patients continue to experience relapses, a phase of the disease described as active SPMS. Active SPMS is one of the relapsing forms of MS, and drugs approved for the treatment of relapsing forms of MS can be used to treat active SPMS.

The efficacy of Mavenclad was shown in a clinical trial in 1,326 patients with relapsing forms of MS who had least one relapse in the previous 12 months. Mavenclad significantly decreased the number of relapses experienced by these patients compared to placebo. Mavenclad also reduced the progression of disability compared to placebo.

Mavenclad must be dispensed with a patient Medication Guide that describes important information about the drug’s uses and risks. Mavenclad has a Boxed Warning for an increased risk of malignancy and fetal harm. Mavenclad is not to be used in patients with current malignancy. In patients with prior malignancy or with increased risk of malignancy, health care professionals should evaluate the benefits and risks of the use of Mavenclad on an individual patient basis. Health care professionals should follow standard cancer screening guidelines in patients treated with Mavenclad. The drug should not be used in pregnant women and in women and men of reproductive potential who do not plan to use effective contraception during treatment and for six months after the course of therapy because of the potential for fetal harm. Mavenclad should be stopped if the patient becomes pregnant.

Other warnings include the risk of decreased lymphocyte (white blood cell) counts; lymphocyte counts should be monitored before, during and after treatment. Mavenclad may increase the risk of infections; health care professionals should screen patients for infections and treatment with Mavenclad should be delayed if necessary. Mavenclad may cause hematologic toxicity and bone marrow suppression so health care professionals should measure a patient’s complete blood counts before, during and after therapy. The drug has been associated with graft-versus-host-disease following blood transfusions with non-irradiated blood. Mavenclad may cause liver injury and treatment should be interrupted or discontinued, as appropriate, if clinically significant liver injury is suspected.

The most common adverse reactions reported by patients receiving Mavenclad in the clinical trials include upper respiratory tract infections, headache and decreased lymphocyte counts.

The FDA granted approval of Mavenclad to EMD Serono, Inc.

////////////fda 2019, Mavenclad, cladribine, multiple sclerosis, EMD Serono,

Omecamtiv mecarbil オメカムティブメカビル


Omecamtiv mecarbil.svg

ChemSpider 2D Image | omecamtiv mecarbil | C20H24FN5O3

Image result for OMECAMTIV

Omecamtiv mecarbil

  • Molecular FormulaC20H24FN5O3
  • Average mass401.435 Da
4-[2-fluoro-3-[(6-methyl-3-pyridyl)carbamoylamino]benzyl]piperazine-1-carboxylic acid methyl ester
AMG 423
AMG-423
CK1827452
CK-1827452; CK1827452
Cladribine [BAN] [INN] [JAN] [USAN] [Wiki]
methyl 4-(2-fluoro-3-(3-(6-methylpyridin-3-yl)ureido)benzyl)piperazine-1-carboxylate
1-Piperazinecarboxylic acid, 4-[[2-fluoro-3-[[[(6-methyl-3-pyridinyl)amino]carbonyl]amino]phenyl]methyl]-, methyl ester
2M19539ERK
オメカムティブメカビル
873697-71-3 [RN]
9088
Methyl 4-(2-fluoro-3-{[(6-methyl-3-pyridinyl)carbamoyl]amino}benzyl)-1-piperazinecarboxylate

In January 2019, Cytokinetics and licensees Amgen and Servier are developing oral modified- and immediate-release formulations of the cardiac myosin activator omecamtiv mecarbil (phase III), the lead from a series of small-molecule, sarcomere-directed compounds, for the treatment of chronic heart diseases including high risk heart failure, stable heart failure and ischemic cardiomyopathy

Omecamtiv Mecarbil has been used in trials studying the treatment and basic science of Heart Failure, Echocardiogram, Pharmacokinetics, Chronic Heart Failure, and History of Chronic Heart Failure, among others.

Omecamtiv mecarbil, a small-molecule activator of cardiac myosin, is developed in phase III clinical trials by originator Cytokinetics and Amgen for the oral treatment of chronic heart failure.

WO2006009726 product patent of omecamtiv mecarbil expire in EU states until June 2025 and expire in the US in September 2027 with US154 extension.

  • Originator Cytokinetics
  • Developer Amgen; Cytokinetics; Servier
  • Class Esters; Heart failure therapies; Organic chemicals; Piperazines; Pyridines; Small molecules
  • Mechanism of Action Cardiac myosin stimulants
  • Phase III Chronic heart failure
  • Phase II Acute heart failure; Heart failure
  • No development reported Angina pectoris; Cardiomyopathies
  • 26 Apr 2018 Amgen and Cytokinetics plan the phase III METEORIC-HF trial in Heart failure by the end of 2018 (NCT03759392)
  • 18 Sep 2017 Pharmacodynamics data from the phase III COSMIC-HF trial Chronic heart failure released by Cytokinetics
  • 08 May 2017 Amgen completes the phase II trial in Heart failure in Japan (NCT02695420)

Omecamtiv mecarbil (INN), previously referred to as CK-1827452, is a cardiac-specific myosin activator. It is being studied for a potential role in the treatment of left ventricular systolic heart failure.[1]

Systolic heart failure involves a loss of effective actin-myosin cross bridges in the myocytes (heart muscle cells) of the left ventricle, which leads to a decreased ability of the heart to move blood through the body. This causes peripheral edema (blood pooling), which the sympathetic nervous system tries to correct[2] by overstimulating the cardiac myocytes, leading to left ventricular hypertrophy, another characteristic of chronic heart failure.

Current inotropic therapies work by increasing the force of cardiac contraction, such as through calcium conduction or modulating adrenoreceptors. But these are limited by adverse events, including arrhythmias related to increased myocardical oxygen consumption, desensitization of adrenergic receptors, and altering intracellular calcium levels.[3] Inotropes are also thought to be associated with worse prognosis.[4] Therefore, the novel mechanism of omecamtiv mecarbil may offer a useful new option for heart failure.

Mechanism of action

Cardiac myocytes contract through a cross-bridge cycle between the myofilaments, actin and myosin. Chemical energy in the form of ATP is converted into mechanical energy which allows myosin to strongly bind to actin and produce a power stroke resulting in sarcomere shortening/contraction.[5] Omecamtiv mecarbil specifically targets and activates myocardial ATPase and improves energy utilization. This enhances effective myosin cross-bridge formation and duration, while the velocity of contraction remains the same.[6]Specifically, it increases the rate of phosphate release from myosin, thereby accelerating the rate-determining step of the cross-bridge cycle, which is the transition of the actin-myosin complex from the weakly bound to the strongly bound state.[7][1] Furthermore, once myosin is bound to actin, it stays bound dramatically longer in the presence of omecamtiv mecarbil.[8][9] The combination of increased and prolonged cross-bridge formation prolongs myocardial contraction. Thus, the overall clinical result of omecamtiv mecarbil is an increase in left ventricular systolic ejection time and ejection fraction.[6][7]

There is a slight decrease in heart rate while myocardial oxygen consumption is unaffected. The increased cardiac output is independent of intracellular calcium and cAMP levels.[3][10] Thus omecamtiv mecarbil improves systolic function by increasing the systolic ejection duration and stroke volume, without consuming more ATP energy, oxygen or altering intracellular calcium levels causing an overall improvement in cardiac efficiency.[6]

Clinical trials

Experimental studies on rats and dogs, proved the efficacy and mechanism of action of omecamtiv mecarbil.[3] Current clinical studies on humans have shown there is a direct linear relationship between dose and systolic ejection time.[1][11][12] The dose-dependent effects persisted throughout the entire trial, suggesting that desensitization does not occur. The maximum tolerated dose was observed to be an infusion of 0.5 mg/kg/h. Adverse effects, such as ischemia, were only seen at doses beyond this level, due to extreme lengthening of systolic ejection time.[1] Thus due to the unique cardiac myosin activation mechanism, omecamtiv mecarbil could safely improve cardiac function within tolerated doses. Omecamtiv mecarbil effectively relieves symptoms and enhances the quality of life of systolic heart failure patients. It drastically improves cardiac performance in the short term; however, the hopeful long-term effects of reduced mortality have yet to be studied.[1][2]

PATENT

WO2006009726

PAPER

Synthesis of unsymmetrical diarylureas via pd-catalyzed C-N cross-coupling reactions
Org Lett 2011, 13(12): 3262

Synthesis of Unsymmetrical Diarylureas via Pd-Catalyzed C–N Cross-Coupling Reactions

Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
Org. Lett.201113 (12), pp 3262–3265
DOI: 10.1021/ol201210t

Abstract

Abstract Image

A facile synthesis of unsymmetrical N,N′-diarylureas is described. The utilization of the Pd-catalyzed arylation of ureas enables the synthesis of an array of diarylureas in good to excellent yields from benzylurea via a one-pot arylation–deprotection protocol, followed by a second arylation.

Click to access ol201210t_si_001.pdf

Methyl 4-(2-fluoro-3-(3-(6-methylpyridin-3-yl)ureido)benzyl)piperazine-1- carboxylate (Omecamtiv Mecarbil).11 Following general procedure C, a mixture of methyl 4-(3-chloro-2-fluorobenzyl)piperazine-1-carboxylate (143.1 mg, 0.5 mmol), (2- Methylpyridin-5-yl)urea (90.6 mg, 0.6 mmol), Pd(OAc)2 (5 mol %), t-BuBrettPhos (15 mol %), Cs2CO3 (456.2 mg, 0.7 mmol), degassed water (4 mol %) and THF (1 mL) was heated to 65 °C for 6 h. The crude product was purified via flash chromatography (5-10% MeOH/DCM) to provide the title compound as a slightly brownish solid (164 mg, 82%),

mp = 180 °C.

1 H NMR (400 MHz, DMSO-d6 ) δ: 9.13 (s, 1H), 8.59 (d, J = 1.5 Hz, 1H), 8.47 (d, J = 2.3 Hz, 1H), 8.05 (t, J = 7.6 Hz, 1H), 7.83 (dd, J = 8.4, 2.4 Hz, 1H), 7.16 (d, J = 8.4 Hz, 1H), 7.09 (t, J = 7.9 Hz, 1H), 7.00 (t, J = 6.7 Hz, 1H), 3.57 (s, 3H), 3.55 (s, 2H), 3.35 (br, 4H), 2.40 (s, 3H), 2.36 (br, 4H) ppm.

13C NMR (101 MHz, DMSO-d6 ) δ: 155.0, 152.3, 151.1, 150.7 (d, J = 242.5 Hz), 139.2, 133.6, 127.3 (d, J = 10.9 Hz), 125.8, 124.1 (d, J = 13.3 Hz), 124.0 (d, J = 4.0 Hz), 123.8 (d, J = 3.8 Hz), 122.8, 119.5, 54.6, 52.2, 52.1, 43.4, 23.2 ppm (observed complexity is due to C–F splitting).

19F NMR (376 MHz, DMSO-d6 ) δ: -135.09.

IR (neat, cm-1 ): 3297, 2920, 2823, 1705, 1638, 1557, 1476, 1450, 1233, 1189, 1129, 779, 765.

Anal. Calcd. for C20H24FN5O3: C, 59.84; H, 6.03. Found: C, 59.64; H, 5.92.

PAPER

Morgan et al. ACS Med. Chem. Lett. 2010, 1, 472

Discovery of Omecamtiv Mecarbil the First, Selective, Small Molecule Activator of Cardiac Myosin

Abstract Image

We report the design, synthesis, and optimization of the first, selective activators of cardiac myosin. Starting with a poorly soluble, nitro-aromatic hit compound (1), potent, selective, and soluble myosin activators were designed culminating in the discovery of omecamtiv mecarbil (24). Compound 24 is currently in clinical trials for the treatment of systolic heart failure.

omecamtiv mecarbil as a white powder (3.64 kg, 90% yield).

IR (KBR) 3292, 2950, 2866, 2833, 1720, 1640, 1550, 1600, 1490, 1455, 1406, 1378, 1352, 1274, 1244, 1191, 1125, 815, 769, 725, 668 cm-1 ;

1H NMR (400 MHz, DMSO-d6) δ 9.12 (s, 1 H, 2-pyridyl H), 8.59 (d, 1 H, J = 2.5 Hz, Urea N-H), 8.47 (d, 1 H, J = 2.6 Hz, Urea N-H), 8.04 (dt, 1 H, J = 1.5 Hz, 7.8 Hz, phenyl H), 7.83 (dd, 1 H, J = 2.6 Hz, 8.4 Hz, 4-pyridyl H), 7.18 (d, 1 H, J = 8.4 Hz, 5-pyridyl H), 7.10 (app t, 1 H, J = 7.8 Hz, phenyl H), 7.02 (app p, 1 H, J = 1.5 Hz, 6.3 Hz, 7.8 Hz, phenyl H), 3.58 (s, 3 H, OCH3), 3.56 (m, 4 H, piperazine Hs), 2.41 (s, 3 H, pyridineCH3), 2.37 (br m, 4 H, piperazine Hs); 13C NMR (100 MHz, DMSO-d6) δ 155.0,152.3, 151.1 150.7, 139.1, 133.6, 127.3, 127.2, 125.8, 124.1, 123.7, 122.8, 119.5, 54.5, 52.2, 52.0, 43.4, 23.2;

Exact mass calcd for C20H24FN5O3 requires m/z 402.1926. Found m/z 402.1940.

Anal. Calcd. For C20H24FN5O3: C, 59.84; H, 6.03; N, 17.45. Found: C, 59.99; H, 6.07; N, 17.41.

PATENT

WO2016210240

PATENT

WO-2019006231

https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2019006231&tab=PCTDESCRIPTION&maxRec=1000

Process for the preparation of omecamtiv mecarbil and its new intermediates. Useful for the treatment of heart failure..

Scheme 1 :

Scheme 2

I

Scheme 3

I

Piper 


Scheme 5

Aminopyridine

(APYR) Commercially Available

Scheme 6


IPAc Reaction

.

Scheme 7

Scheme 8

Pi 
(PIPA)

[0043] Thus, provided herein is a method of synthesizing PIPA comprising admixing PIPN (which can comprise PIPN hydrochloride salt), an aqueous solution of an inorganic base, and toluene to form a PIPN freebase solution. The inorganic base can be sodium bicarbonate or sodium hydroxide, for example. In some embodiments, the inorganic base comprises sodium hydroxide. The PIPN freebase solution is then hydrogenated in the presence of a palladium catalyst in toluene and an alcohol solvent to form crude PIPA. The alcohol solvent can comprise ethanol or isopropanol. PIPA is then crystallized from a heptane and toluene solvent mixture.

[0044] In some specific embodiments, to a mixture of 1 equiv. PIPN-HCI and toluene (4V) is added 1 M aq. NaOH (3.3V) at 20 °C. Stirring is continued for 1 hour before the phases are separated. The organic layer is washed twice with a mixture of water (2.4V) and saturated brine (0.6V), then the organic layer is distilled to 3.8V. The solution is filtered, the reactor rinsed with toluene (1V) and the rinse solution filtered before the organic layers are combined. To the toluene layer is added Pd/C (0.7 wt%) and the heterogeneous mixture is charged into a hydrogenation vessel. Ethanol (1V) is added to the mixture. Hydrogenation is performed at 20 °C under 60 psig of hydrogen. After the reaction is complete, the mixture is filtered and rinsed with toluene (1V). The mixture is distilled to 2.4V, seeded with 1 mol% PIPA in heptane (0.1V) at 35 °C and then cooled to 20 °C. The addition of heptane (5.6V) is completed in 3 hours. The mixture is filtered and dried under vacuum and nitrogen to afford PIPA (90% yield, > 97.0 wt%, > 98.0 LCAP).

[0045] In some other specific embodiments, 1 N aqueous sodium hydroxide (3.3 volumes) is added to 1 equiv. of PIPN (hydrochloride salt) suspended in toluene (4 volumes). The biphasic mixture is agitated at 20 °C for 1 hour and the phases are allowed to separate. The organic layer is washed twice with a 0.9 M aqueous sodium chloride solution (3 volumes). The reaction mixture is azeotropically dried by concentration to approximately 3.8 volumes and polish filtered. The transfer line is rinsed with toluene (1 volume) and the rinse solution is combined with the PIPN solution.

Ethanol (1 volume) is added to the PIPN solution and hydrogenation of the starting material is carried out in the presence of 5% Pd/C (on activated carbon sold by BASF as Escat 1421, 0.7 wt% catalyst loading) using a pressure of 4 bars of hydrogen at 15 °C. Upon reaction completion, the mixture is filtered. The hydrogenation autoclave and filtered catalyst are rinsed with toluene (1V) and the rinse solution is combined with the reaction mixture. The solution is concentrated to 2.4 volumes and seeded with 1 mol% PIPA in heptane (0.1 volume) at 38 °C. The mixture is agitated for 30 minutes at 38 °C, cooled to 20 °C over the course of 2 hours, and agitated at that temperature for 30 minutes. Heptane is added (5.6 volumes) over the course of 3 hours and the mixture is agitated for 30 minutes. The mixture is filtered and dried on filter/drier. The cake is washed once with

heptane:toluene (7:3, 2 total volumes) and once with heptane (2 volumes). PIPA is isolated in 88% yield with > 98.0 wt% assay and > 98.0 LC area%.

[0046] Preparation of omecamtiv mecarbil dihvdrochloride hydrate: The prior process to prepare omecamtiv mecarbil dihydrochloride hydrate involved a telescoped procedure by which the

omecamtiv mecarbil is prepared as a solution in THF, and the solvent is subsequently exchanged for isopropanol. However, considering that the solubility of omecamtiv mecarbil in isopropanol at 20°C is about 10 mg/mL and the total volume of isopropanol at the end of the solvent exchange, 95% of the material is out of solution at the end of the solvent exchange, leading to the formation of a slurry that is difficult or impossible to stir. Distillation can no longer be performed once this slurry is formed due to poor mass transfer, leaving behind THF levels in the slurry that are above the in-process control (IPC) specification, e.g., greater than or equal to 1 GC area%. In practice, this leads to delays in the manufacturing due to necessary recharging of isopropanol until the mixture can be stirred, followed by additional distillation and analysis of residual THF. In addition, the ratio of isopropanol and water has to be verified using an in-process control considering the variable amounts of isopropanol at the end of the distillation and the influence of the solvent ratio (isopropanol/water) on the mother liquor losses upon filtration.

Scheme 9

95% yield

[0048] Thus, provided herein is a method of preparing omecamtiv mecarbil dihydrochloride hydrate via admixing PIPA, PCAR, and a trialkylamine (e.g., triethylamine or diisopropylethylamine) in acetonitrile and THF to form omecamtiv mecarbil. The omecamtiv mecarbil is isolated as the free base and then admixed with 2 to 3 molar equivalents of hydrochloric acid in isopropanol and water to form omecamtiv mecarbil dihydrochloride hydrate, which can optionally be crystallized from isopropanol and water. Isolation of the omecamtiv mecarbil free base can be performed via crystallization by addition of water and filtration. PIPA and PCAR can be prepared as disclosed above.

[0049] In some embodiments, PIPA (2.1 kg, 1 equiv) is charged to a reactor, followed by PCAR (1.1 equiv), then THF (2.5 V), and finally acetonitrile (2.5 V). To the resulting slurry is added N,N-diisopropylethylamine (1.2 equiv) and the batch is heated to 55 °C for 16 h. Water (5 V) is then added over 15 minutes and omecamtiv mecarbil freebase seeds (0.05 equiv) are charged to the reactor. The batch is agitated for 15 minutes and water (10 V) is added over 3 h. The batch is cooled to 20 °C over 1 h and filtered. The cake is washed with 3:1 watenacetonitrile (3 V) and then acetonitrile (3 x 3 V). The cake is dried in a filter/drier. Omecamtiv mecarbil freebase is isolated as a solid in 80% yield, with 99.9 LC area%, and 99.3 wt% assay.

[0050] Omecamtiv mecarbil freebase (2.6 kg, 1 equiv) is charged to a reactor followed by 2-propanol (2.6 V) and water (1.53 V). The batch is then heated to 45 °C. 6 M aqueous HCI (2.2 equiv) is added at a rate to keep batch temperature below 60 °C. The batch is heated to 60 °C for 30 minutes and filtered into a clean reactor at 60 °C. The original vessel is rinsed with an

isopropanokwater mixture (1 :1 , 0.1 volume total) and the rinse volume is added to the reaction mixture. The solution is cooled to 45 °C and a slurry of omecamtiv mecarbil dihydrochloride hydrate seed (0.05 or 0.03 equiv) in isopropanol (0.14 or 0.1 V) is charged to the reactor. The suspension is agitated for 1 h. Isopropanol (3.68 V) is charged to the reactor over 2 h. The mixture is warmed to 55 °C over 1 h and held for 30 minutes at that temperature. The mixture is cooled to 45 °C over 1 h. The mixture is agitated for 2 h and then isopropanol (7.37 V) is added to the reactor over 3 h. The mixture is agitated for 1 h and then cooled to 20 °C over 2 h. The mixture is wet milled until d90 specifications are met (e.g., < 110 μιτι) and the suspension is filtered. The wet cake is washed twice with isopropanokwater (95:5, 2V) . The wet cake is dried under vacuum until isopropanol levels are below 1000 ppm. The cake is optionally re-hydrated if necessary using e.g., a stream of humidified nitrogen, until the water content of the solids are between 3.0 and 4.2 wt%. The material can be recrystallized if it doesn’t meet specification. Omecamtiv mecarbil dihydrochloride hydrate is isolated as a solid in 91.3% yield, with 99.96 LC area%, and 100.1 wt% assay.

[0051] Omecamtiv Mecarbil Dihydrochloride Hydrate Preparation using Continuous Manufacturing: Provided herein is a method of preparing omecamtiv mecarbil dihydrochloride hydrate using a continuous manufacturing process. The general synthetic procedure is outlined in Scheme 10 below.

Scheme 10

Conditions For 100 a Demo Run

CH3CN (6 V), 21 °C

Assay Yield = 95.2 %

Conversion = 98.2 %

L-Urea LCAP = 0 %

PIPA Methyl Carbamate LCAP = 1.49 %

Production Rate of Omecamtiv Mecarbil = 15.29 g/h

PATENT

WO2019006235

PATENT

https://patents.google.com/patent/WO2014152270A1

The cardiac sarcomere is the basic unit of muscle contraction in the heart. The cardiac sarcomere is a highly ordered cytoskeletal structure composed of cardiac muscle myosin, actin and a set of regulatory proteins. The discovery and development of small molecule cardiac muscle myosin activators would lead to promising treatments for acute and chronic heart failure. Cardiac muscle myosin is the cytoskeletal motor protein in the cardiac muscle cell. It is directly responsible for converting chemical energy into the mechanical force, resulting in cardiac muscle contraction.

[0004] Current positive inotropic agents, such as beta-adrenergic receptor agonists or inhibitors of phosphodiesterase activity, increase the concentration of intracellular calcium, thereby increasing cardiac sarcomere contractility. However, the increase in calcium levels increase the velocity of cardiac muscle contraction and shortens systolic ejection time, which has been linked to potentially life-threatening side effects. In contrast, cardiac muscle myosin activators work by a mechanism that directly stimulates the activity of the cardiac muscle myosin motor protein, without increasing the intracellular calcium concentration. They accelerate the rate-limiting step of the myosin enzymatic cycle and shift it in favor of the force-producing state. Rather than increasing the velocity of cardiac contraction, this mechanism instead lengthens the systolic ejection time, which results in increased cardiac muscle contractility and cardiac output in a potentially more oxygen-efficient manner. [0005] U.S. Patent No. 7,507,735, herein incorporated by reference, discloses a genus of com ounds, including omecamtiv mecarbil (AMG 423, CK- 1827452), having the structure:

Figure imgf000003_0001

[0006] Omecamtiv mecarbil is a first in class direct activator of cardiac myosin, the motor protein that causes cardiac contraction. It is being evaluated as a potential treatment of heart failure in both intravenous and oral formulations with the goal of establishing a new continuum of care for patients in both the in-hospital and outpatient settings.

Manufacture of Omecamtiv Mecarbil dihydrochloride hydrate Synthetic Route to Omecamtiv Mecarbil

Figure imgf000016_0001

PiE§razine_Nitro^!C Piperazine Aniline

to IPA

Figure imgf000016_0002

omecamtiv mecarbil-2HCI-H20

Synthesis of the API SM Piperazine Nitro-HCl

Figure imgf000016_0003

Piperazine Carboxylate

Figure imgf000016_0004

88% overall [0081] In a 60 L reactor (containing no exposed Stainless steel, Hastelloy®, or other metal parts) equipped with a reflux/return condenser and scrubber charged with a 5N NaOH solution, a mechanically stirred mixture of FN-Toluene (2.0 kg, 12.89 mol, 1.0 equiv.), N- Bromosuccinimide (3.9 kg, 21.92 mol, 1.70 equiv.), benzoyl peroxide (125.0 g, 0.03 equiv., 0.39 mol, containing 25 wt% water), and acetic acid (7.0 L, 3.5 volumes) was heated to 85 °C under an atmosphere of nitrogen for 7 hours. A solution of H3PO3 (106.0 g, 1.29 mol, 0.1 equiv.) and acetic acid (200 mL, 0.1 volume), prepared in separate vessel, was added. The reaction mixture was agitated for 0.5 h and analysis of an aliquot confirmed complete decomposition of benzoyl peroxide (not detected, HPLC254 nm)- The reaction mixture was cooled to 22 °C. DI Water (8.0 L, 4 volumes) and toluene (16.0 L, 8 volumes) were charged, the biphasic mixture was agitated (20 min), and the layers were separated. Aqueous 1.6N NaOH (14.0 L, 7.0 volumes) was added to the organic layer at a rate allowing the batch temperature to stay under 25 °C and the pH of the resultant aqueous phase was measured (> 11). The biphasic mixture was filtered through a 5 μιη Teflon® cartridge line and the layers were separated. The filter line was washed with another 2L of toluene.

[0082] The assay yields were 2.5 % of FN-Toluene, 62.3 % of FN-Bromide and 30.0 % of Di-Bromide. The toluene solution contained no benzoyl peroxide, succinimide, or cc- bromoacetic acid and water content by KF titration was 1030 ppm (This solution could be held under nitrogen at room temperature for > 12 h without any change in the assay yield).

[0083] To this solution at room temperature was added diisopropylethylamine (880.0 g, 6.63 mol, 0.53 equiv.) followed by methanol (460 mL, 11.28 mol, 0.88 equiv.) and heated to 40 °C. A solution of diethylphosphite (820.0 g, 5.63 mol, 0.46 equiv.) in methanol (460 mL, 11.28 mol, 0.88 equiv.) was prepared and added to the reaction mixture at 40 °C through an addition funnel over a period of 1 hour at such a rate that the batch temperature was within 40 + 5 °C. The contents were stirred for a period of 3h at 40 °C from the start of addition and cooled to room temperature and held under nitrogen atmosphere for 12 hours. The assay yield of the reaction mixture was 2.5 % FN-Toluene 92.0% FN-Bromide and 0.2% Di-Bromide. This solution is used as such for the alkylation step.

[0084] Characterization for components of final product mixture (collected for pure compounds).

[0085] 2-Fluoro-3-Nitrotoluene (FN-Toluene): 1H NMR (400 MHz, CHLOROFORM- J) δ ppm 2.37 (s, 1 H), 7.13-7.20 (m, 1 H), 7.45-7.51 (m, 1 H), 7.79-7.85 (m, 1 H). 13C NMR (100 MHz, CHLOROFORM- d) δ ppm 14.3 (d, J = 5 Hz), 123.3 (d, J = 3 Hz), 123.6 (d, J = 5 Hz), 128.2 (d, J = 16 Hz), 136.7 (d, J = 5 Hz), 137.5 (broad), 153.7 (d, J = 261 Hz); 1- (bromomethyl)-2-fluoro-3-nitrobenzene (FN-Bromide): 1H NMR (400 MHz,

CHLOROFORM-J) δ ppm 4.56 (s, 1 H), 7.28-7.34 (m, 1 H), 7.69-7.76 (m, 1 H), 7.98-8.05 (m, 1 H). 13C NMR (100 MHz, CHLOROFORM- J) δ ppm 23.6 (d, / = 5 Hz), 124.5 (d, / = 5 Hz), 126.1 (d, / = 3 Hz), 128.5 (d, / = 14 Hz), 136.5 (d, / = 4 Hz), 137.7 (broad), 153.3 (d, / = 265 Hz). DSC: single melt at 53.59 °C. Exact Mass [C7H5BrFN02 + H]+: calc. = 233.9566, measured = 233.9561; l-(dibromomethyl)-2-fluoro-3-nitrobenzene (Dibromide): 1H NMR (400 MHz, CHLOROFORM- d) δ ppm 6.97 (s, 1 H), 7.39-7.45 (m, 1 H), 8.03-8.10 (m, 1 H), 8.16-8.21 (m, 1 H). 13C NMR (100 MHz, CHLOROFORM-J) δ ppm 29.2 (d, / = 7 Hz), 124.9 (d, / = 5 Hz), 127.1 (d, / = 2 Hz), 132.1 (d, / = 11 Hz), 135.7 (d, / = 2 Hz), 137.2 (broad), 149.8 (d, / = 266 Hz). DSC: single melt at 49.03 °C. Exact Mass [C7H4Br2FN02 + H]+: calc. = 311.8671, measured = 311.8666.

Piperazine Nitro-HCl:

[0086] To a mechanically stirred toluene solution (9 volumes) of FN-Bromide (prepared from previous step) in a 60 L reactor at 22 °C under an atmosphere of nitrogen,

diisopropylethylamine was charged (1.90 kg, 14.69 mol, 1.14 equiv.). To this mixture a solution of piperazine carboxylate methylester (Piperazine Carboxylate) (2.03 kg, 14.05 mol, 1.09 equiv.) in toluene (1.0 L, 0.5 volumes) was added at a rate allowing the batch temperature to stay under 30.0 °C (Exothermic. During the addition, jacket temperature was adjusted to 5 °C in order to maintain batch temperature below 30 °C. The mixture was agitated at 22 °C for 3 hours and analysis of an aliquot confirmed completion of the alkylation reaction (<1.0 LCAP FN-Bromide, HPLC254 nm). The reaction mixture was treated with aqueous NH4C1 (20 wt%, 10.0 L, 5 volumes; prepared from 2.0 kg of NH4C1 and 10.0 L of DI water), the biphasic mixture was agitated (30 min), and the layers were separated. The organic layer was sequentially washed with aqueous NaHC03 (9 wt%, 10.0 L, 5 volumes; prepared from 0.90 kg of NaHC03 and 10.0 L of DI water). The organic layer was filtered through a 5 μιη Teflon® cartridge line and transferred in a drum, washed the filter line with another 1.0 L toluene and the combined toluene solution (10.0 volumes) weighed, and assayed (HPLC) to quantify Piperazine Nitro free base. The assay yield for the Piperazine Nitro-freebase is 89.0%, FN-Toluene 2.5% and FN-Bromide 0.2% with FN-Bromide undetected. The total loss of product to the aqueous washes is < 1.0 %. This solution under nitrogen atmosphere is stable for more than 12h.

[0087] To a mechanically stirred toluene solution of Piperazine Nitro free base, prepared as described above, at 22 °C in a 60 L reactor under an atmosphere of nitrogen, IPA (19.4 L, 9.7 volumes) and DI water (1.0 L, 0.5 volume) were charged. The mixture was heated to 55 °C and 20% of the 1.4 equiv. of cone. HCl (Titrated prior to use and charge based on titer value; 276.0 mL, 3.21 mol) was charged. The contents were agitated for 15 min and

Piperazine Nitro-HCl seed (130.0 g, 0.39 mol, 0.03 equiv.) was charged as slurry in IPA (400 mL, 0.2 volume). The mixture was agitated for 30 min and the remaining cone. HCl (80% of the charge, 1.10 L, 12.82 mol) was added over a period of 4 hours. The mixture was stirred at 55 °C for 1 h, cooled to 20 °C in a linear manner over 1.5 hours, and agitated at this temperature for 12 hours. The supernatant concentration of Piperazine Nitro-HCl was measured (2.8 mg/g). The mixture was filtered through an aurora filter equipped with a 5 μιη Teflon® cloth. The mother liquor were transferred to a clean drum and assayed. The filter cake was washed twice with IPA (11.2 L, 5.6 volumes) and dried to constant weight (defined as < 1.0% weight loss for 2 consecutive TGA measurements over a period of 2 hours) on filter with vacuum and a nitrogen sweep (14 h). The combined losses of Piperazine Nitro- HCl in the mother liquors and the washes were 2.5 %. Piperazine Nitro-HCl was isolated 3.59 kg in 87.6% corrected yield with >99.5 wt% and 99.0% LCAP purity.

[0088] Methyl 4-(2-fluoro-3-nitrobenzyl)piperazine-l-carboxylate hydrochloride

(Piperazine Nitro-HCl): 1H NMR (300 MHz, DMSO-J) δ ppm 3.25 (br. s, 3 H), 3.52-3.66 (m, 8 H), 4.47 (s, 2 H), 7.44-7.63 (t, 1 H, J = 8 Hz), 7.98-8.15 (m, 1 H), 8.17-8.34 (m, 1 H). 13C NMR (75 MHz, DMSO-J) 5 ppm 50.3, 51.4, 52.8, 119.6 (d, J = 14 Hz), 125.1 (d, J = 5 Hz), 127.9, 137.4 (d, J = 8 Hz), 139.8 (d, J = 3 Hz), 152.2, 154.7, 155.7. DSC: melt onset at 248.4 °C. Exact Mass [Q3H16FN3O4 + H]+: calculated = 298.1203, measured = 298.1198. lternative processes for the synthesis of Piperazine Nitro:

Figure imgf000020_0001

2-fluoro-3-nitrobenzoic acid (2-fluoro-3-nitrophenyl)metlianol 2-fluoro-3-nitrobenzy? methanesulfonate

Figure imgf000020_0002

methyl 4-(2-fluoro-3-nitrobenzyl)piperazine-l -carboxylate hydrochloride

[0089] A mixture of NaBH4 ( 1.7 g, 44 mmol) in THF (68 mL) was treated 2-fluoro-3- nitrobenzoic acid (3.4 g, 18.4 mmol) and cooled to 0-5 °C. A solution of iodine (4.7 g, 18.4 mmol) in THF (12 mL) was then added drop wise at a rate to control off-gassing. The progress of the reaction was assessed by HPLC. After 2 hours HPLC assay indicated 4% AUC of 2-fluoro-3-nitrobenzoic acid remained. The mixture was quenched into 1 M HCl (30 mL) and extracted with MTBE (5 mL). The organics were then washed with 20% aqueous KOH solution and 10% sodium thiosulfate. The organics were dried with Na2S04, filtered over Celite and concentrated to afford (2-fluoro-3-nitrophenyl)methanol (2.8 g, 88%, 89% AUC by HPLC).

[0090] A solution of (2-fluoro-3-nitrophenyl)methanol (2.8 g, 16 mmol) in 2-MeTHF (26 mL) was treated with triethylamine (4.5 mL, 32 mmol) and cooled to 0-5 °C. The solution was then treated with methanesulfonyl chloride (1.6 mL, 21 mmol). The progress of the reaction was assessed by HPLC. After 30 minutes at 0-5 °C, the reaction was deemed complete. The mixture was quenched with water (14 mL) and the phases were separated. The organics were washed with brine, dried with Na2S04, filtered over Celite and

concentrated to afford 2-fluoro-3-nitrobenzyl methanesulfonate (3.3 g, 83.1%, 81% AUC by HPLC) as a yellow oil.

[0091] A solution of 2-fluoro-3-nitrobenzyl methanesulfonate (3.3 g, 13 mmol, AMRI lot # 46DAT067B) in toluene (33 mL), was treated with diisopropylethylamine (2.7 mL, 15 mmol) in one portion. A solution of methylpiperazine- 1 -carboxylate (2.1 g, 15 mmol) in toluene (1.1 mL) was added slowly via syringe to maintain between 23-29 °C. The reaction was stirred for 16 hours following the addition. An HPLC assay after this time showed that the reaction was complete. 20% Aqueous NH4C1 (11 mL) was added at 20-25 °C. The biphasic mixture was stirred for 15 minutes, and the phases were separated. This process was repeated using 9% aqueous sodium bicarbonate (11 mL). The toluene layer was then filtered over Celite at 20-25 °C. 2-propanol (50 mL) and water (1.1 mL) were added to the toluene solution and the mixture heated to 55-60 °C. The mixture was then treated with 37wt% HC1 (1.6 mL, 18.7 mmol) over 20 minutes. A precipitate was noted following the addition. When the addition was complete, the mixture was allowed to cool gradually to 20-25 °C and was stirred for hours before filtering and washing with IPA (2 bed volumes).

[0092] The cake was then dried at under vacuum to afford 4-(2-fluoro-3- nitrobenzyl)piperazine-l-carboxylate hydrochloride (2.41 g, 54%, 90% AUC by HPLC, 88 wt% by HPLC).

Piperazine Nitro Freebase:

[0093] In a 60 L reactor equipped with a reflux/return condenser, a mixture of Piperazine Nitro-HCl (2.0 kg, 5.99 mol, 1.0 equiv.) and isopropyl acetate (6.0 L, 3.0 volumes) was mechanically agitated at ambient temperature under an atmosphere of nitrogen. A solution of sodium bicarbonate (629 g, 7.49 mol, 1.25 equiv.) and water (7.5 L, 3.75 volume), prepared in separate vessel, was added. The biphasic mixture was agitated (15 min), and the layers were separated. The upper organic layer (containing product) was transferred to a separate vessel while the reactor was rinsed with water and isopropanol. The organic layer was then transferred through an inline 5 μιη Teflon® cartridge back into the clean 60 L reactor. The filter line was washed with 4.0 L (2.0 volumes) of isopropanol into the 60 L reactor. An additional 12.0 L (6.0 volumes) of isoproponal was added to the 60 L reactor and heated to 40 °C. Under reduced pressure (50 torr) the batch was concentrated down to approximately 6 L (3.0 volumes). The solution was cooled from 27 °C to 20 °C in a linear manner over 10 minutes. Water (4.0 L, 2.0 volumes) was added at 20 °C over 30 minutes followed by Piperazine Nitro Freebase seed (18 g, 0.06 mol, 0.01 equiv). The mixture was aged for 5 minutes and the remaining water (24.0 L, 12.0 volumes) was added over 90 minutes. After holding overnight at 20 °C, the supernatant concentration of Piperazine Nitro Freebase was measured (< 10 mg/mL). The mixture was filtered through an aurora filter equipped with a 12 μιη Teflon® cloth. The filter cake was washed with a mixture of water (3.3 L, 1.65 volumes) and isopropanol (700 mL, 0.35 volumes) and dried to constant weight (defined as < 1.0% weight loss for 2 consecutive TGA measurements over a period of 2 hours) on filter with vacuum and a nitrogen sweep (48 h). The combined losses of Piperazine Nitro Freebase in the mother liquors and the wash were aproximately 7.5 %. Piperazine Nitro Freebase was isolated 1.67 kg in 92.5% corrected yield with 100.0 wt% and 99.4% LCAP purity.

Synthesis of the API SM Phenyl Carbamate-HCl

Figure imgf000022_0001

Amino Pyridine Phenyl Carbamate-HCl

[0094] A 60 L, glass-lined, jacketed reactor set at 20 °C under nitrogen atmosphere and vented through a scrubber (containing 5N NaOH) was charged with 2.5 kg of Amino

Pyridine (1.0 equiv, 23.1 moles), followed by 25 L (19.6 kg, 10 vol) acetonitrile. After initiating agitation and (the endothermic) dissolution of the Amino Pyridine, the vessel was charged with 12.5 L of N-methyl-2-pyrolidinone (12.8 kg, 5 vol). An addition funnel was charged with 1.8 L (0.6 equiv, 13.9 moles) phenyl chloroformate which was then added over 68 minutes to the solution of the Amino Pyridine keeping the internal temperature < 30°C. The reaction was agitated for > 30 minutes at an internal temperature of 20 ± 5 °C. The vessel was then charged with 61 ± 1 g of seed as a slurry in 200 mL acetonitrile and aged for > 30 min. The addition funnel was charged with 1.25 L (0.45 equiv, 9.7 moles) of phenyl chloroformate which was then added over 53 minutes to the reaction suspension while again keeping the temperature < 30°C. The contents of the reactor were aged > 30 hours at 20 ± 5°C. After assaying the supernatant (< 15mg/g for both product and starting material), the solids were filtered using an Aurora filter equipped with a 12μιη Teflon cloth. The mother liquor was forwarded to a 2nd 60 L, glass-lined, jacketed reactor. The reactor and cake were rinsed with l x lO L of 5: 10 NMP/ ACN and 1 x 10 L ACN. The washes were forwarded to the 2nd reactor as well. The cake was dried under vacuum with a nitrogen bleed for > 24 hours to afford 5.65 kg (90.2% yield) of the product, Phenyl Carbamate-HCl as an off-white solid in 98.8 wt% with 99.2% LCAP purity.

[0095] Phenyl (6-methylpyridin-3-yl)carbamate hydrochloride (Phenyl Carbamate-HCl) 1H NMR (400 MHz, DMSO-J6) 5 ppm 11.24 (s, 1 H), 8.81 (s, 1 H), 8.41 (d, 1 Η, / = 8.8 Hz), 7.85 (d, l H, / = 8.8 Hz), 7.48 – 7.44 (m, 2 H), 7.32 – 7.26 (m, 3 H), 2.69 (s, 3 H); 13C NMR (100 MHz, DMSO- ) δ ppm 151.66, 150.01, 147.51, 136.14, 133.79, 129.99, 129.49, 127.75, 125.87, 121.70, 18.55: HR-MS : Calculated for Cuii W . 228.0899, M + H+ = 229.0972; Observed mass: 229.0961

Alternative Synthesis of Phenyl Carbamate HC1

[0096] 5-Amino-2-methylpyridine (53.2 kg, 1.0 equiv) and acetonitrile (334 kg, 8.0 mL/g) were charged to a nitrogen flushed glass-lined reactor. The contents of the reactor were stirred while warming to 25-30 °C. The mixture was then recirculated through a filter packed with activated carbon (11 kg, 20 wt ) for 3 h intervals while maintaining 25-30 °C.

Following each 3 h interval, a sample of the mixture was analyzed for color by comparison to a color standard and UV Absorbance at 440nm. Once a satisfactory result was achieved, the filter was blown out into the reactor and the filter was rinsed with acetonitrile (85 kg, 2.0 mL/g). The acetonitrile rinse was transferred into the reaction mixture. l-Methyl-2- pyrrolidinone (274 kg, 5.0 mL/g) was charged to the reaction mixture in the glass-lined reactor. Phenyl chloroformate (46.6 kg, 0.6 equiv) was slowly added to the mixture while maintaining 15-30 °C (typically 60-70 min). The reaction mixture was stirred for approximatly 60 minutes while maintaining 20-25 °C. Phenyl(6-methylpyridin-3- yl)carbamate hydrochloride (0.58 kg, 0.010 equiv) seed crystals were charged to the stirring mixture. The slurry was then stirred for approximatly 4 h at 20+ 5°C. Phenyl chloroformate (33.4 kg, 0.45 equiv) was slowly added to the slurry while maintaining 15-30 °C. The mixture was then allowed to age while stirring for 8+1 h whereupon concentration of 5- amino-2-methylpyridine (target <15 mg/mL) and phenyl (6-methylpyridin-3-yl)carbamate hydrochloride (target <15 mg/mL) were checked by HPLC. The batch was then filtered under vacuum and washed with a mixture of acetonitrile (112 kg, 2.68 mL/g) and l-methyl-2- pyrrolidinone (72 kg, 1.32 mL/g) followed by washing thrise with acetonitrile (167 kg, 4.0 mL/g). The solids were deliquored followed by transfering to a tray dryer maintained between 20-40°C and 1.3-0.65 psia until an LOD of <lwt was achieved, whereupon phenyl(6-methylpyridin-3-yl)carbamate hydrochloride 106.3 kg (81.6% yield) was isolated from the dryer. Methyl 4-(3-amino-2-fluorobenzyl)piperazine-l-carboxylate (Piperazine Aniline)

Neutralization

Figure imgf000024_0001

Piperazine NitrcHCI

+ NaCI (1 equiv)

+ C02 (1 equiv)

+ H20 (1 equiv)

+ NaHC03 (0.25 equiv)

Figure imgf000024_0002

[0097] To a 100-L jacketed glass-lined reactor were added methyl 4-(2-fluoro-3- nitrobenzyl)piperazine-l-carboxylate hydrochloride (2.00 kg, 1.00 equiv) and isopropyl acetate (6.00 L, 3.00 Vol with-respect to starting material). The resulting slurry was agitated under a nitrogen sweep. To the mixture was added dropwise over 45 + 30 min: 7.7 % w/w aqueous sodium bicarbonate solution (629 g, 1.25 equiv of sodium bicarbonate dissolved in 7.50 L water), maintaining an internal temperature of 20 + 5 °C by jacket control (NOTE: addition is endo thermic, and may evolve up to 1 equiv of carbon dioxide gas). The mixture was stirred for > 15 min, resulting in a clear biphasic mixture. Agitation was stopped and the layers were allowed to settle.

[0098] The bottom (aqueous) layer was drained and analyzed by pH paper to ensure that the layer is pH > 6. Quantititative HPLC analysis of the upper (organic) layer revealed 97- 100% assay yield of the methyl 4-(2-fluoro-3-nitrobenzyl)piperazine-l-carboxylate freebase (1.73 – 1.78 kg). The upper (organic) layer was transferred through an in-line filter into a 20- L Hastelloy® hydro genator, and the 100-L reactor and lines were rinsed with an additional aliquot of isopropyl acetate (2.00 L, 1.00 Vol). The hydrogenator was purged with nitrogen and vented to atmospheric pressure. To the reaction mixture was added a slurry of 5.0 wt% palladium on carbon (20.0 g, Strem/BASF Escat™ 1421, approx 50% water) in isopropyl acetate (400 mL), followed by a 400 mL rinse. The resulting reaction mixture was diluted with an additional aliquot of isopropyl acetate (1.2 L; total isopropyl acetate amount is 10.0 L, 5.00 Vol). The hydrogenator was purged three times with nitrogen (pressurized to 60 + 10 psig, then vented to atmospheric pressure), then pressurized to 60 + 5 psig with hydrogen. The reaction mixture was stirred at < 100 rpm at 30 + 5 °C while maintaining 60 + 5 psig hydrogen, for >2 hours until reaction was deemed complete. This temperature and pressure correspond to a measured kLa value of approx 0.40 in a 20-L Hydrogenator. End of reaction is determined by dramatic decrease in hydrogen consumption accompanied by a relief in the heat evolution of the reaction. To control potential dimeric impurities, the reaction is continued for at least 30 minutes after this change in reaction profile, and HPLC analysis is performed to confirm that >99.5% conversion of the hydroxyl-amine to the aniline is achieved.

[0099] At the end of reaction, the hydrogenator was purged with nitrogen twice

(pressurized to 60 + 10 psig, then vented to atmospheric pressure). The crude reaction mixture was filtered through a 5 μιη filter followed by a 0.45 μιη filter in series, into a 40-L glass-lined reactor. The hydrogenator and lines were washed with an additional aliquot of isopropyl acetate (2.00 L). Quantitative HPLC analysis of the crude reaction mixture revealed 95-100% assay yield (1.52 – 1.60 kg aniline product). The reaction mixture was distilled under reduced pressure (typically 250 – 300 mbar) at a batch temperature of 50 + 5 °C until the total reaction volume was approximately 8.00 L (4.00 Vol). The batch was subjected to a constant-volume distillation at 50 + 5 °C, 250 – 300 mbar, by adding heptane to control the total batch volume. After approximately 8.00 L (4.00 Vol) of heptane were added, GC analysis indicated that the solvent composition was approximately 50 % isopropyl acetate, 50% heptane. Vacuum was broken, and the internal batch temperature was maintained at 50 + 5 °C. To the reaction mixture was added a slurry of seed (20.0 grams of product methyl 4-(3-amino-2-fluorobenzyl)piperazine-l-carboxylate, in a solvent mixture of 80 mL heptane and 20 mL isopropyl acetate). The resulting slurry was allowed to stir at 50 + 5 °C for 2 + 1 hours, then cooled to 20 + 5 °C over 2.5 + 1.0 h. Additional heptane (24.0 L, 12.0 Vol) was added dropwise over 2 hours, and the batch was allowed to stir at 20 + 5 °C for > 1 hours (typically overnight). Quantitative HPLC analysis of this filtered supernatant revealed < 5 mg/mL product in solution, and the product crystals were 50 – 400 μιη birefringent rods. The reaction slurry was filtered at 20 °C onto a filter cloth, and the cake was displacement-washed with heptane (6.00 L, 2.00 Vol). The cake was dried on the filter under nitrogen sweep at ambient temperature for > 4 hours, until sample dryness was confirmed by LOD analysis (indicated <1.0 wt% loss). The product methyl 4-(3-amino-2- fluorobenzyl)piperazine-l-carboxylate (1.56 kg) was isolated as a pale-yellow powder in 86% yield at 99.8 wt% by HPLC with 100.0 LCAP2i0. [Analysis of the combined filtrates and washes revealed 108 grams (7.0%) of product lost to the mother liquors. The remaining mass balance is comprised of product hold-up in the reactor (fouling).] 1H NMR (DMSO-Jg, 400 MHz) δ: 6.81 (dd, J = 7.53, 7.82 Hz, 1H), 6.67 (m, 1H), 6.49 (m, 1H), 5.04 (s, 2H), 3.58 (s, 3H), 3.45 (m, 2H), 3.34 (m, 4H), 2.33 (m, 4H). 19F NMR (d6-DMSO, 376 MHz) δ: – 140.2. 13C NMR (d6-DMSO, 125 MHz) δ: 155.0, 150.5, 148.2, 136.2 (m), 123.7 (m), 117.6, 115.1, 73.7, 54.9 (m), 52.1 (m), 43.4. mp = 89.2 °C.

Alternate route to Piperazine Aniline

[00100] To a jacketed glass-lined reactor were added methyl 4-(2-fluoro-3- nitrobenzyl)piperazine-l-carboxylate hydrochloride (46.00 kg, 1.00 equiv) and isopropyl acetate (200 kg, 5.0 mL/g). The resulting slurry was agitated under a nitrogen sweep. To the mixture was added 7.4 % w/w aqueous sodium bicarbonate solution (1.25 equiv) while maintaining an internal temperature of 25 + 5 °C. The mixture was agitated for > 30 min, resulting in a clear biphasic mixture. Agitation was stopped and the bottom (aqueous) layer was discharged. Analysis of aqueous layer indicates pH >6. Water (92 kg, 2.0 mL/g) was charged the organic layer and agitated for >15 min. Agitation was then stopped and the bottom (water wash) layer was discharged. Water (92 kg, 2.0 mL/g) was charged the organic layer and agitated for > 15 min. Agitation was then stopped and the bottom (water wash) layer was discharged. The batch was distilled under reduced pressure while maintaining the batch temperature between 40-50 °C. The batch volume was held constant throughout the distillation by the continuous addition of isopropyl acetate. Once the water content of the batch was < 1,500 ppm, the solution was passed through an inline filter into a Hastelloy reactor containing 5.0 wt% palladium on carbon (BASF Escat 1421, 0.69 kg, 1.5 wt%). The jacketed glass-lined reactor was rinsed with isopropyl acetate (100 kg, 2.5 mL/g) and added to the Hastelloy reactor though the inline filter.

[00101] The batch was adjusted to approximately 25-35 °C (preferably 30 °C) and hydrogen gas was added to maintain about 4 barg with vigorous agitation. Hydrogenation was continued for 1 h after hydrogen uptake has ceased, and >99.0% conversion by HPLC were achieved. The palladium on carbon catalyst was collected by filtration and the supernatant was collected in a reactor. Isopropyl acetate (40 kg, 1.0 mL/g) was charged to the Hastelloy reactor and transferred through the filter and collected in the jacketed glass-lined reactor.

[00102] The batch was concentrated under reduced pressure while maintaining the batch temperature between 35-55 °C until the final volume was approximately 4.0 mL/g. Heptane (219 kg, 7.0 mL/g) was added to the jacketed glass-lined reactor while maintaining the batch between 50-60 °C, until 20-25% isopropyl acetate in heptane was achieved as measured by GC. The solution was cooled to between 40-50 °C and seeded with methyl 4-(3-amino-2- fluorobenzyl)piperazine-l-carboxylate (0.46 kg, 1.0 wt%) as a slurry in heptane (6.4 kg, 0.20 mL/g). The slurry was aged for approximately 2 h, whereupon, the batch was distilled under reduced pressure while maintaining the batch temperature between 35-45 °C. The batch volume was held constant throughout the distillation by the continuous addition of heptane (219 kg, 7.0 mL/g). The batch was then cooled to between 15-25 °C over approximately 3 h. Concentration of the supernatant was measured to be <5 mg/mL methyl 4-(3-amino-2- fluorobenzyl)piperazine-l-carboxylate by HPLC.

[00103] The batch was filtered and the resulting solids were successively washed with heptane (63 kg, 2.0 mL/g) then heptane (94 kg, 3.0 mL/g). The solids were dried on the filter with a stream of dry nitrogen with vacuum until an LOD of <_lwt% was achieved whereupon 33.88 kg (90.7% yield) was isolated from the filter dryer.

Omecamtiv Mecarbil Dihydrochloride Hydrate procedure

f lu

Figure imgf000027_0001

1) 2-PrOH (11 V)

2) Distill to 4V

3) Water (2.30 V)

4) 6N HCI (2.4 equiv)

5) 2-PrOH (16.5V)

6) Wet Mill

Figure imgf000027_0002

[00104] To a 15L glass lined reactor were charged methyl 4-(3-amino-2-fluoro- benzyl)piperazine-l-carboxylate (1,202 g, 4.50 mol), phenyl (6-methylpyridin-3- yl)carbamate hydrochloride (1,444 g, 5.40 mol), and tetrahydrofuran (4.81 L). The resulting slurry was agitated under a nitrogen sweep and N,N-diisopropylethylamine (1,019 L, 5.85 mol) was then charged to the slurry which resulted in a brown solution. The temperature of the solution was increased to 65 °C and agitated for 22 h, until <1% AUC piperazine aniline remained by HPLC analysis.

[0100] The batch was cooled to 50 °C and distilled under reduced pressure while maintaining the internal temperature of the vessel below 50 °C by adjusting vacuum pressure. 2-Propanol was added with residual vacuum at a rate to maintain a constant volume in the 15 L reactor. A total of 10.5 kg of 2-propanol was required to achieve <5% THF by GC. Water (2.77 kg) was then charged to the reactor followed by the addition of 6N HC1 (1.98 kg) at a rate to maintain the internal temperature below 60 °C. The reactor was brought to ambient pressure under a nitrogen sweep. The solution was then heated to 60 °C, and transferred to a 60L glass lined reactor through an inline filter. The 15L reactor was then rinsed with 1: 1 water/2-propanol (1.2L) which was sent through the inline filter to the 60L reactor.

[0101] The 60L reactor was adjusted to 45 °C and a slurry of seed (114 g, 0.23 mol) in 2- propanol (0.35 L) was added to the reactor resulting in a slurry. The batch was aged at 45 °C for 1 h, followed by the addition of 2-propanol (3.97 kg) through an inline filter over 2 h. The batch was heated to 55°C over 1 h and held for 0.25 h, then cooled back to 45°C over 1 h and held overnight at 45 °C. 2-propanol (11.71 kg) was then added through an inline filter to the batch over 3 h. The batch was aged for 1 h and then cooled to 20°C over 2 h and held at 20 °C for 0.5 h. The batch was then recirculated though a wet mill affixed with 1-medium and 2- fine rotor-stators operating at 56 Hz for 2.15 h, until no further particle size reduction was observed by microscopy.

[0102] The batch was then filtered through a 20″ Hastelloy® filter fitted with a 12 urn filter cloth under 500 torr vacuum. A wash solution of 95:5 2-propanol:water (1.82 L) was charged through an inline filter to the 60L reactor, then onto the filter. A second wash of 2- propanol (2.85L) was charged through an inline filter to the 60L reactor, then onto the filter. The batch was then dried under 5 psi humidified nitrogen pressure until <5,000 ppm 2- propanol, and 2.5-5% water remained. The final solid was discharged from the filter to afford 2.09 kg of methyl 4-(2-fluoro-3-(3-(6-methylpyridin-3-yl)ureido)benzyl)piperazine-l- carboxylate as an off-white crystalline solid in 89% yield at 99.88 wt% by HPLC, 100.0% AUC. Total losses to liquors was 0.10 kg (4.7%).

[0103] DSC: Tonset = 61.7 °C, Tmax = 95.0 °C; TGA = 2.2%, degradation onset = 222 °C; 1H HMR (D20, 500 MHz) δ 8.87 (s, 1H), 8.18 (d, J = 8.9 Hz, 1H), 7.83 (t, J = 1.5 Hz, 1H), 7.71 (d, J = 8.8 Hz, 1H), 7.35-7.29 (m, 2H), 4.48 (s, 2H), 4.24 (br s, 2H), 3.73 (s, 3H), 3.31 (br s, 6H), 2.68 (s, 3H); 13C HMR (D20, 150 MHz) δ 156.8, 154.2, 153.9 (J = 249 Hz), 147.8, 136.3, 136.1, 130.1, 129.4, 128.0, 127.2, 125.5 (J = 11.8 Hz), 125.1 (J = 4.2 Hz), 116.1 (J = 13.5 Hz), 53.54, 53.52, 53.49, 50.9, 40.5, 18.2.

Figure imgf000029_0001

[0104] A reaction vessel was charged methyl 4-(3-amino-2-fluorobenzyl)piperazine-l- carboxylate (2.5 g, 1.0 equiv), acetonitrile (25.0 mL, 10.0 mL/g) and l-methyl-2- pyrrolidinone (12.5 mL, 5.0 mL/g). The batch was cooled to 0 °C whereupon phenyl chloroformate (1.20 mL, 1.02 equiv) was added over approximately 5 min. After 45 minutes the resulting slurry resulted was allowed to warm to 20 °C. The solids were collected by filtration and rinsed twice with acetonitrile (10.0 mL, 4.0 mL/g). The solids were dried under a stream of dry nitrogen to afford methyl 4-(2-fluoro-3-

((phenoxycarbonyl)amino)benzyl)piperazine- l -carboxylate hydrochloride 2.8 g (71 % yield) as a white solid.

[0105] 4-(2-fluoro-3-((phenoxycarbonyl)amino)benzyl)piperazine-l-carboxylate hydrochloride: 1H NMR (400 MHz, DMSO-J6) δ ppm 3.08 (br. s., 2 H), 3.24 – 3.52 (m, 4 H), 3.62 (s, 3 H), 4.03 (d, J=11.25 Hz, 2 H), 4.38 (br. s., 2 H), 7.11 – 7.35 (m, 4 H), 7.35 – 7.49 (m, 2 H), 7.49 – 7.66 (m, 1 H), 7.80 (s, 1 H), 10.12 (br. s, 1 H), 11.79 (br. s, 1 H); HRMS = 388.1676 found, 388.1667 calculated. [0106] A reaction vessel was charged methyl 4-(2-fluoro-3-

((phenoxycarbonyl)amino)benzyl)piperazine-l-carboxylate hydrochloride (0.50 g, 1.0 equiv), 6-methylpyridin-3-amine (0.15 g, 1.2 equiv), tetrahydrofuran (2.0 mL, 4.0 mL/g) and

N,N-diisopropylethylamine (0.23 mL, 1.1 equiv). The batch was heated to 65 °C for 22 h, whereupon quantitative HPLC analysis indicated 0.438 g (92% assay yield) of omecamtiv mecarbil.

Alternative Omecamtiv Mecarbil Dihydrochloride Hydrate procedure

[0107] Omecamtiv Mecarbil, free base (3.0 kg, 1.0 equiv) was charged to a nitrogen purged jacketed vessel followed by water (4.6 L, 1.5 mL/g) and 2-propanol (6.1 L, 2.60 mL/g). The slurry was agitated and heated to approximately 40 °C, whereupon 6N HC1 (2.6 L, 2.10 equiv) was charged to the slurry resulting in a colorless homogenous solution. The solution was heated to between 60-65 °C and transferred through an inline filter to a 60L reactor pre -heated to 60 °C. The batch was cooled to 45 °C whereupon Omecamtiv Mecarbil dihydrochloride hydrate (150 g, 5.0 wt%) was charged to the vessel as a slurry in 95:5 (v/v) 2-Propanol/Water (600 mL, 0.20 mL/g). The resulting slurry was maintained at 45 °C for 0.5 h followed by cooling to approximately 20 °C then held for 3-16 h. 2-Propanol (33.0 L, 11.0 mL/g) was added over >2h followed by a >1 h isothermal hold at approximately 20 °C.

(Supernatant pH <7).

[0108] The batch was recirculated through a wet mill for 5-10 batch turnovers until sufficient particle reduction was achieve as compared to offline calibrated visual microscopy reference. The slurry was filtered by vacuum and the resulting solids were washed with two washes of 95:5 (v/v) 2-Propanol/Water (3.0 L, 1.0 mL/g) and a final cake wash with 2- Propanol (6.0 L, 2.0 mL/g). The cake was dried on the filter by pushing humidified nitrogen through the cake until <5,000 ppm 2-propanol and 2.5-5% water were measured by GC and KF analysis, respectively. Omecamtiv Mecarbil dihydrochloride hydrate was isolated as a colorless crystalline solid (3.40 kg, 93% yield). pH dependent release profiles

CLIP

J Am Chem Soc. 2012 July 11; 134(27): 11132–11135. doi:10.1021/ja305212v.

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Omecamtiv mecarbil
Omecamtiv mecarbil.svg
Clinical data
Synonyms CK-1827452
Routes of
administration
Intravenous infusion
ATC code
  • None
Legal status
Legal status
  • Investigational
Identifiers
CAS Number
PubChem CID
ChemSpider
KEGG
Chemical and physical data
Formula C20H24FN5O3
Molar mass 401.43 g/mol
3D model (JSmol)

/////////////Omecamtiv mecarbil, オメカムティブメカビル  , AMG 423, AMG-423, CK1827452, CK-1827452, K1827452, Cladribine, PHASE 3

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