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Fosdenopterin hydrobromide



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Fosdenopterin hydrobromide



a cyclic pyranopterin monophosphate (cPMP) substrate replacement therapy, for the treatment of patients with molybdenum cofactor deficiency (MoCD) Type A.

FormulaC10H14N5O8P. 2H2O. HBr
Mol weight480.1631



1,3,2-DIOXAPHOSPHORINO(4′,5′:5,6)PYRANO(3,2-G)PTERIDIN-10(4H)-ONE, 8-AMINO-4A,5A,6,9,11,11A,12,12A-OCTAHYDRO-2,12,12-TRIHYDROXY-, 2-OXIDE, HYDROBROMIDE, HYDRATE (1:1:2), (4AR,5AR,11AR,12AS)-


(4aR,5aR,11aR,12aS)-8-Amino-2,12,12-trihydroxy-4a,5a,6,7,11,11a,12,12aoctahydro-2H-2lambda5-(1,3,2)dioxaphosphinino(4′,5′:5,6)pyrano(3,2-g)pteridine-2,10(4H)-dione, hydrobromide (1:1:2)

1,3,2-Dioxaphosphorino(4′,5′:5,6)pyrano(3,2-g)pteridin-10(4H)-one, 8-amino-4a,5a,6,9,11,11a,12,12a-octahydro-2,12,12-trihydroxy-, 2-oxide, hydrobromide, hydrate (1:1:2), (4aR,5aR,11aR,12aS)-

1,3,2-Dioxaphosphorino(4′,5′:5,6)pyrano(3,2-g)pteridin-10(4H)-one, 8-amino-4a,5a,6,9,11,11a,12,12a-octahydro-2,12,12-trihydroxy-, 2-oxide,hydrobromide, hydrate (1:1:2), (4aR,5aR,11aR,12aS)-

ALXN1101 HBrUNII-X41B5W735TX41B5W735TD11780

Nulibry Approved for Molybdenum Cofactor Deficiency Type A - MPR
ChemSpider 2D Image | Cyclic pyranopterin monophosphate | C10H14N5O8P
Cyclic pyranopterin monophosphate.svg

C10H14N5O8P, Average: 363.223


  • ALXN-1101
  • WHO 11150
  • Synthesis ReferenceClinch K, Watt DK, Dixon RA, Baars SM, Gainsford GJ, Tiwari A, Schwarz G, Saotome Y, Storek M, Belaidi AA, Santamaria-Araujo JA: Synthesis of cyclic pyranopterin monophosphate, a biosynthetic intermediate in the molybdenum cofactor pathway. J Med Chem. 2013 Feb 28;56(4):1730-8. doi: 10.1021/jm301855r. Epub 2013 Feb 19.

Fosdenopterin (or cyclic pyranopterin monophosphatecPMP), sold under the brand name Nulibry, is a medication used to reduce the risk of death due to a rare genetic disease known as molybdenum cofactor deficiency type A (MoCD-A).[1]

Adverse effects

The most common side effects include complications related to the intravenous line, fever, respiratory infections, vomiting, gastroenteritis, and diarrhea.[1]

Mechanism of action

People with MoCD-A cannot produce cyclic pyranopterin monophosphate (cPMP) in their body.[1] Fosdenopterin is an intravenous medication that replaces the missing cPMP.[1][2] cPMP is a precursor to molybdopterin, which is required for the enzyme activity of sulfite oxidasexanthine dehydrogenase/oxidase and aldehyde oxidase.[3]


Fosdenopterin was developed by José Santamaría-Araujo and Guenter Schwarz at the German universities TU Braunschweig and the University of Cologne.[4][5]

The effectiveness of fosdenopterin for the treatment of MoCD-A was demonstrated in thirteen treated participants compared to eighteen matched, untreated participants.[1][6] The participants treated with fosdenopterin had a survival rate of 84% at three years, compared to 55% for the untreated participants.[1]

The U.S. Food and Drug Administration (FDA) granted the application for fosdenopterin priority reviewbreakthrough therapy, and orphan drug designations along with a rare pediatric disease priority review voucher.[1] The FDA granted the approval of Nulibry to Origin Biosciences, Inc., in February 2021.[1] It is the first medication approved for the treatment of MoCD-A.[1]


  1. Jump up to:a b c d e f g h i j “FDA Approves First Treatment for Molybdenum Cofactor Deficiency Type A”U.S. Food and Drug Administration (FDA) (Press release). 26 February 2021. Retrieved 26 February 2021.  This article incorporates text from this source, which is in the public domain.
  2. ^ DrugBank DB16628 . Accessed 2021-03-05.
  3. ^ Santamaria-Araujo JA, Fischer B, Otte T, Nimtz M, Mendel RR, Wray V, Schwarz G (April 2004). “The tetrahydropyranopterin structure of the sulfur-free and metal-free molybdenum cofactor precursor”The Journal of Biological Chemistry279 (16): 15994–9. doi:10.1074/jbc.M311815200PMID 14761975.
  4. ^ Schwarz G, Santamaria-Araujo JA, Wolf S, Lee HJ, Adham IM, Gröne HJ, et al. (June 2004). “Rescue of lethal molybdenum cofactor deficiency by a biosynthetic precursor from Escherichia coli”Human Molecular Genetics13 (12): 1249–55. doi:10.1093/hmg/ddh136PMID 15115759.
  5. ^ Tedmanson S (5 November 2009). “Doctors risk untried drug to stop baby’s brain dissolving”TimesOnline.
  6. ^ Schwahn BC, Van Spronsen FJ, Belaidi AA, Bowhay S, Christodoulou J, Derks TG, et al. (November 2015). “Efficacy and safety of cyclic pyranopterin monophosphate substitution in severe molybdenum cofactor deficiency type A: a prospective cohort study”. Lancet386 (10007): 1955–63. doi:10.1016/S0140-6736(15)00124-5PMID 26343839S2CID 21954888.

External links

Molybdenum cofactor deficiency (MoCD) is an exceptionally rare autosomal recessive disorder resulting in a deficiency of three molybdenum-dependent enzymes: sulfite oxidase (SOX), xanthine dehydrogenase, and aldehyde oxidase.1 Signs and symptoms begin shortly after birth and are caused by a build-up of toxic sulfites resulting from a lack of SOX activity.1,5 Patients with MoCD may present with metabolic acidosis, intracranial hemorrhage, feeding difficulties, and significant neurological symptoms such as muscle hyper- and hypotonia, intractable seizures, spastic paraplegia, myoclonus, and opisthotonus. In addition, patients with MoCD are often born with morphologic evidence of the disorder such as microcephaly, cerebral atrophy/hypodensity, dilated ventricles, and ocular abnormalities.1 MoCD is incurable and median survival in untreated patients is approximately 36 months1 – treatment, then, is focused on improving survival and maintaining neurological function.

The most common subtype of MoCD, type A, involves mutations in MOCS1 wherein the first step of molybdenum cofactor synthesis – the conversion of guanosine triphosphate into cyclic pyranopterin monophosphate (cPMP) – is interrupted.1,3 In the past, management strategies for this disorder involved symptomatic and supportive treatment,5 though efforts were made to develop a suitable exogenous replacement for the missing cPMP. In 2009 a recombinant, E. coli-produced cPMP was granted orphan drug designation by the FDA, becoming the first therapeutic option for patients with MoCD type A.1

Fosdenopterin was approved by the FDA on Februrary 26, 2021, for the reduction of mortality in patients with MoCD type A,5 becoming the first and only therapy approved for the treatment of MoCD. By improving the three-year survival rate from 55% to 84%,7 and considering the lack of alternative therapies available, fosdenopterin appears poised to become a standard of therapy in the management of this debilitating disorder.

Fosdenopterin replaces an intermediate substrate in the synthesis of molybdenum cofactor, a compound necessary for the activation of several molybdenum-dependent enzymes including sulfite oxidase (SOX).1 Given that SOX is responsible for detoxifying sulfur-containing acids and sulfites such as S-sulfocysteine (SSC), urinary levels of SSC can be used as a surrogate marker of efficacy for fosdenopterin.7 Long-term therapy with fosdenopterin has been shown to result in a sustained reduction in urinary SSC normalized to creatinine.7

Animal studies have identified a potential risk of phototoxicity in patients receiving fosdenopterin – these patients should avoid or minimize exposure to sunlight and/or artificial UV light.7 If sun exposure is necessary, use protective clothing, hats, and sunglasses,7 in addition to seeking shade whenever practical. Consider the use of a broad-spectrum sunscreen in patients 6 months of age or older.8

Molybdenum cofactor deficiency (MoCD) is a rare autosomal-recessive disorder in which patients are deficient in three molybdenum-dependent enzymes: sulfite oxidase (SOX), xanthine dehydrogenase, and aldehyde dehydrogenase.1 The loss of SOX activity appears to be the main driver of MoCD morbidity and mortality, as the build-up of neurotoxic sulfites typically processed by SOX results in rapid and progressive neurological damage. In MoCD type A, the disorder results from a mutation in the MOCS1 gene leading to deficient production of MOCS1A/B,7 a protein that is responsible for the first step in the synthesis of molybdenum cofactor: the conversion of guanosine triphosphate into cyclic pyranopterin monophosphate (cPMP).1,4

Fosdenopterin is an exogenous form of cPMP, replacing endogenous production and allowing for the synthesis of molybdenum cofactor to proceed.7

  1. Mechler K, Mountford WK, Hoffmann GF, Ries M: Ultra-orphan diseases: a quantitative analysis of the natural history of molybdenum cofactor deficiency. Genet Med. 2015 Dec;17(12):965-70. doi: 10.1038/gim.2015.12. Epub 2015 Mar 12. [PubMed:25764214]
  2. Schwahn BC, Van Spronsen FJ, Belaidi AA, Bowhay S, Christodoulou J, Derks TG, Hennermann JB, Jameson E, Konig K, McGregor TL, Font-Montgomery E, Santamaria-Araujo JA, Santra S, Vaidya M, Vierzig A, Wassmer E, Weis I, Wong FY, Veldman A, Schwarz G: Efficacy and safety of cyclic pyranopterin monophosphate substitution in severe molybdenum cofactor deficiency type A: a prospective cohort study. Lancet. 2015 Nov 14;386(10007):1955-63. doi: 10.1016/S0140-6736(15)00124-5. Epub 2015 Sep 3. [PubMed:26343839]
  3. Iobbi-Nivol C, Leimkuhler S: Molybdenum enzymes, their maturation and molybdenum cofactor biosynthesis in Escherichia coli. Biochim Biophys Acta. 2013 Aug-Sep;1827(8-9):1086-101. doi: 10.1016/j.bbabio.2012.11.007. Epub 2012 Nov 29. [PubMed:23201473]
  4. Mendel RR: The molybdenum cofactor. J Biol Chem. 2013 May 10;288(19):13165-72. doi: 10.1074/jbc.R113.455311. Epub 2013 Mar 28. [PubMed:23539623]
  5. FDA News Release: FDA Approves First Treatment for Molybdenum Cofactor Deficiency Type A [Link]
  7. FDA Approved Drug Products: Nulibry (fosdenopterin) for intravenous injection [Link]
  8. Health Canada: Sun safety tips for parents [Link]


Journal of Biological Chemistry (1995), 270(3), 1082-7.


WO 2005073387


WO 2012112922


 Journal of Medicinal Chemistry (2013), 56(4), 1730-1738

Abstract Image

Cyclic pyranopterin monophosphate (1), isolated from bacterial culture, has previously been shown to be effective in restoring normal function of molybdenum enzymes in molybdenum cofactor (MoCo)-deficient mice and human patients. Described here is a synthesis of 1 hydrobromide (1·HBr) employing in the key step a Viscontini reaction between 2,5,6-triamino-3,4-dihydropyrimidin-4-one dihydrochloride and d-galactose phenylhydrazone to give the pyranopterin (5aS,6R,7R,8R,9aR)-2-amino-6,7-dihydroxy-8-(hydroxymethyl)-3H,4H,5H,5aH,6H,7H,8H,9aH,10H-pyrano[3,2-g]pteridin-4-one (10) and establishing all four stereocenters found in 1. Compound 10, characterized spectroscopically and by X-ray crystallography, was transformed through a selectively protected tri-tert-butoxycarbonylamino intermediate into a highly crystalline tetracyclic phosphate ester (15). The latter underwent a Swern oxidation and then deprotection to give 1·HBr. Synthesized 1·HBr had in vitro efficacy comparable to that of 1 of bacterial origin as demonstrated by its enzymatic conversion into mature MoCo and subsequent reconstitution of MoCo-free human sulfite oxidase–molybdenum domain yielding a fully active enzyme. The described synthesis has the potential for scale up.



 European Journal of Organic Chemistry (2014), 2014(11), 2231-2241.


The first synthesis of an oxygen‐stable analogue of the natural product cyclic pyranopterin monophosphate (cPMP) is reported. In this approach, the hydropyranone ring is annelated to pyrazine by a sequence comprising ortho‐lithiation/acylation of a 2‐halopyrazine, followed by nucleophilic aromatic substitution. The tetrose substructure is introduced from the chiral pool, from D‐galactose or D‐arabitol.



Molybdenum cofactor (Moco) deficiency is a lethal hereditary metabolic disease. A recently developed therapy requires continuous intravenous supplementation of the biosynthetic Moco precursor cyclic pyranopterin monophosphate (cPMP). The limited stability of the latter natural product, mostly due to oxidative degradation, is problematic for oral administration. Therefore, the synthesis of more stable cPMP analogues is of great interest. In this context and for the first time, the synthesis of a cPMP analogue, in which the oxidation‐labile reduced pterin unit is replaced by a pyrazine moiety, was achieved starting from the chiral pool materials D‐galactose or D‐arabitol. Our synthesis, 13 steps in total, includes the following key transformations: i) pyrazine lithiation, followed by acylation; ii) closure of the pyrane ring by nucleophilic aromatic substitution; and iii) introduction of phosphate.


Molybdenum cofactor (Moco) deficiency is a pleiotropic genetic disorder. Moco consists of molybdenum covalently bound to one or two dithiolates attached to a unique tricyclic pterin moiety commonly referred to as molybdopterin (MPT). Moco is synthesized by a biosynthetic pathway that can be divided into four steps, according to the biosynthetic intermediates precursor Z (cyclic pyranopterin monophosphate; cPMP), MPT, and adenylated MPT. Mutations in the Moco biosynthetase genes result in the loss of production of the molybdenum dependent enzymes sulfite-oxidase, xanthine oxidoreductase, and aldehyde oxidase. Whereas the activities of all three of these cofactor-containing enzymes are impaired by cofactor deficiency, the devastating consequences of the disease can be traced to the loss of sulfite oxidase activity. Human Moco deficiency is a rare but severe disorder accompanied by serious neurological symptoms including attenuated growth of the brain, untreatable seizures, dislocated ocular lenses, and mental retardation. Until recently, no effective therapy was available and afflicted patients suffering from Moco deficiency died in early infancy.

It has been found that administration of the molybdopterin derivative precursor Z, a relatively stable intermediate in the Moco biosynthetic pathway, is an effective means of therapy for human Moco deficiency and associated diseases related to altered Moco synthesis (see U.S. Pat. No. 7,504,095). As with most replacement therapies for illnesses, however, the treatment is limited by the availability of the therapeutic active agent.

Scheme 3.

Figure US09260462-20160216-C00133

Scheme 4.

Figure US09260462-20160216-C00140


Figure US09260462-20160216-C00141

 Scheme 6.

Figure US09260462-20160216-C00142


Figure US09260462-20160216-C00143

Scheme 8.

Figure US09260462-20160216-C00144


Figure US09260462-20160216-C00145

 Scheme 10.

Figure US09260462-20160216-C00146

EXAMPLESExample 1Preparation of Precursor Z (cPMP)

Figure US09260462-20160216-C00214
Figure US09260462-20160216-C00215


Air sensitive reactions were performed under argon. Organic solutions were dried over anhydrous MgSOand the solvents were evaporated under reduced pressure. Anhydrous and chromatography solvents were obtained commercially (anhydrous grade solvent from Sigma-Aldrich Fine Chemicals) and used without any further purification. Thin layer chromatography (t.l.c.) was performed on glass or aluminum sheets coated with 60 F254 silica gel. Organic compounds were visualized under UV light or with use of a dip of ammonium molybdate (5 wt %) and cerium(IV) sulfate 4H2O (0.2 wt %) in aq. H2SO(2M), one of I(0.2%) and KI (7%) in H2SO(1M), or 0.1% ninhydrin in EtOH. Chromatography (flash column) was performed on silica gel (40-63 μm) or on an automated system with continuous gradient facility. Optical rotations were recorded at a path length of 1 dm and are in units of 10−1 deg cmg−1; concentrations are in g/100 mL. 1H NMR spectra were measured in CDCl3, CD3OD (internal Me4Si, δ 0 ppm) or D2O(HOD, δ 4.79 ppm), and 13C NMR spectra in CDCl(center line, δ 77.0 ppm), CD3OD (center line, δ 49.0 ppm) or DMSO d(center line δ 39.7 ppm), D2O (no internal reference or internal CH3CN, δ 1.47 ppm where stated). Assignments of 1H and 13C resonances were based on 2D (1H—1H DQF-COSY, 1H—13C HSQC, HMBC) and DEPT experiments. 31P NMR were run at 202.3 MHz and are reported without reference. High resolution electrospray mass spectra (ESI-HRMS) were recorded on a Q-TOF Tandem Mass

Spectrometer. Microanalyses were performed by the Campbell Microanalytical Department, University of Otago, Dunedin, New Zealand.

A. Preparation of (5aS,6R,7R,8R,9aR)-2-amino-6,7-dihydroxy-8-(hydroxymethyl)-3H,4H,5H,5aH,6H,7H,8H,9aH,10H-pyrano[3,2-g]pteridin-4-one mono hydrate (1)

2,5,6-Triamino-3,4-dihydropyrimidin-4-one dihydrochloride (Pfleiderer, W.; Chem. Ber. 1957, 90, 2272; Org. Synth. 1952, 32, 45; Org. Synth. 1963, Coll. Vol. 4, 245, 10.0 g, 46.7 mmol), D-galactose phenylhydrazone (Goswami, S.; Adak, A. K. Tetrahedron Lett. 2005, 46, 221-224, 15.78 g, 58.4 mmol) and 2-mercaptoethanol (1 mL) were stirred and heated to reflux (bath temp 110° C.) in a 1:1 mixture of MeOH—H2O (400 mL) for 2 h. After cooling to ambient temperature, diethyl ether (500 mL) was added, the flask was shaken and the diethyl ether layer decanted off and discarded. The process was repeated with two further portions of diethyl ether (500 mL) and then the remaining volatiles were evaporated. Methanol (40 mL), H2O (40 mL) and triethylamine (39.4 mL, 280 mmol) were successively added and the mixture seeded with a few milligrams of 1. After 5 min a yellow solid was filtered off, washed with a little MeOH and dried to give 1 as a monohydrate (5.05 g, 36%) of suitable purity for further use. An analytical portion was recrystallized from DMSO-EtOH or boiling H2O. MPt 226 dec. [α]D 20 +135.6 (c1.13, DMSO). 1H NMR (DMSO d6): δ 10.19 (bs, exchanged D2O, 1H), 7.29 (d, J=5.0 Hz, slowly exchanged D2O, 1H), 5.90 (s, exchanged D2O, 2H), 5.33 (d, J=5.4 Hz, exchanged D2O, 1H), 4.66 (ddd, J˜5.0, ˜1.3, ˜1.3 Hz, 1H), 4.59 (t, J=5.6 Hz, exchanged D2O, 1H), 4.39 (d, J=10.3 Hz, exchanged D2O, 1H), 3.80 (bt, J˜1.8 Hz, exchanged D2O, 1H), 3.70 (m, 1H), 3.58 (dd, J=10.3, 3.0 Hz, 1H), 3.53 (dt, J=10.7, 6.4 Hz, 1H), 3.43 (ddd, J=11.2, 5.9, 5.9 Hz, 1H), 3.35 (t, J=6.4 Hz, 1H), 3.04 (br m, 1H). 13C NMR (DMSO dcenter line 6 39.7): δ 156.3 (C), 150.4 (C), 148.4 (C), 99.0 (C), 79.4 (CH), 76.5 (CH), 68.9 (CH), 68.6 (CH), 60.6 (CH2), 53.9 (CH). Anal. calcd. for C10H15N5O5H2O 39.60; C, 5.65; H, 23.09; N. found 39.64; C, 5.71; H, 22.83; N.

B. Preparation of Compounds 2 (a or b) and 3 (a, b or c)

Di-tert-butyl dicarbonate (10.33 g, 47.3 mmol) and DMAP (0.321 g, 2.63 mmol) were added to a stirred suspension of 1 (1.5 g, 5.26 mmol) in anhydrous THF (90 mL) at 50° C. under Ar. After 20 h a clear solution resulted. The solvent was evaporated and the residue chromatographed on silica gel (gradient of 0 to 40% EtOAc in hexanes) to give two product fractions. The first product to elute was a yellow foam (1.46 g). The product was observed to be a mixture of two compounds by 1H NMR containing mainly a product with seven Boc groups (2a or 2b). A sample was crystallized from EtOAc-hexanes to give 2a or 2b as a fine crystalline solid. MPt 189-191° C. [α]D 20 −43.6 (c 0.99, MeOH). 1H NMR (500 MHz, CDCl3): δ 5.71 (t, J=1.7 Hz, 1H), 5.15 (dt, J=3.5, ˜1.0, 1H), 4.97 (t, J=3.8, 1H), 4.35 (br t, J=˜1.7, 1H), 4.09-3.97 (m, 3H), 3.91 (m, 1H), 1.55, 1.52, 1.51, 1.50, 1.45 (5s, 45H), 1.40 (s, 18H). 13C NMR (125.7 MHz, CDCl3): δ 152.84 (C), 152.78 (C), 151.5 (C), 150.9 (C), 150.7 (2×C), 150.3 (C), 149.1 (C), 144.8 (C), 144.7 (C), 118.0 (C), 84.6 (C), 83.6 (C), 83.5 (C), 82.7 (3×C), 82.6 (C), 76.3 (CH), 73.0 (CH), 71.4 (CH), 67.2 (CH), 64.0 (CH2), 51.4 (CH), 28.1 (CH3), 27.8 (2×CH3), 27.7 (CH3), 27.6 (3×CH3). MS-ESI+ for C45H72N5O19 +, (M+H)+, Calcd. 986.4817. found 986.4818. Anal. calcd. for C45H71N5O19H2O 54.39; C, 7.39; H, 6.34; N. found 54.66; C, 7.17; H, 7.05; N. A second fraction was obtained as a yellow foam (2.68 g) which by 1H NMR was a product with six Boc groups present (3a, 3b or 3c). A small amount was crystallized from EtOAc-hexanes to give colorless crystals. [α]D 2O −47.6 (c, 1.17, CHCl3). 1H NMR (500 MHz, CDCl3): δ 11.10 (br s, exchanged D2O, 1H), 5.58 (t, J=1.8 Hz, 1H), 5.17 (d, J=3.4 Hz, 1H), 4.97 (t, J=3.9 Hz, 1H), 4.62 (s, exchanged D2O, 1H), 4.16 (dd, J=11.3, 5.9 Hz, 1H), 4.12 (dd, J=11.3, 6.4 Hz, 1H), 3.95 (dt, J=6.1, 1.1 Hz, 1H), 3.76 (m, 1H), 1.51, 1.50, 1.49, 1.48, 1.46 (5s, 54H). 13C NMR (125.7 MHz, CDCl3): δ 156.6 (C), 153.0 (C), 152.9 (C), 151.9 (C), 150.6 (C), 149.4 (2×C), 136.2 (C), 131.8 (C), 116.9 (C), 85.0 (2×C), 83.3 (C), 82.8 (C), 82.49 (C), 82.46 (C), 73.3 (CH), 71.5 (CH), 67.2 (CH), 64.5 (CH2), 51.3 (CH), 28.0, 27.72, 27.68, 27.6 (4×CH3). MS-ESI+ for C40H64N5O17 +, (M+H)+calcd. 886.4287. found 886.4289.

C. Preparation of Compound 4a, 4b or 4c

Step 1—The first fraction from B above containing mainly compounds 2a or 2b (1.46 g, 1.481 mmol) was dissolved in MeOH (29 mL) and sodium methoxide in MeOH (1M, 8.14 mL, 8.14 mmol) added. After leaving at ambient temperature for 20 h the solution was neutralized with Dowex 50WX8 (H+) resin then the solids filtered off and the solvent evaporated.

Step 2—The second fraction from B above containing mainly 3a, 3b or 3c (2.68 g, 3.02 mmol) was dissolved in MeOH (54 mL) and sodium methoxide in MeOH (1M, 12.10 mL, 12.10 mmol) added. After leaving at ambient temperature for 20 h the solution was neutralized with Dowex 50WX8 (H+) resin then the solids filtered off and the solvent evaporated.

The products from step 1 and step 2 above were combined and chromatographed on silica gel (gradient of 0 to 15% MeOH in CHCl3) to give 4a, 4b or 4c as a cream colored solid (1.97 g). 1H NMR (500 MHz, DMSO d6): δ 12.67 (br s, exchanged D2O, 1H), 5.48 (d, J=5.2 Hz, exchanged D2O, 1H), 5.43 (t, J=˜1.9 Hz, after D2O exchange became a d, J=1.9 Hz, 1H), 5.00 (br s, exchanged D2O, 1H), 4.62 (d, J=5.7 Hz, exchanged D2O, 1H), 4.27 (d, J=6.0 Hz, exchanged D2O, 1H), 3.89 (dt, J=5.2, 3.8 Hz, after D2O became a t, J=3.9 Hz, 1H), 3.62 (dd, J=6.0, 3.7 Hz, after D2O exchange became a d, J=3.7 Hz, 1H), 3.52-3.39 (m, 4H), 1.42 (s, 9H), 1.41 (s, 18H). 13C NMR (125.7 MHz, DMSO d6): δ 157.9 (C), 151.1, (C), 149.8 (2×C), 134.6 (C), 131.4 (C), 118.8 (C), 83.5 (2×C), 81.3 (C), 78.2 (CH), 76.5 (CH), 68.1 (CH), 66.8 (CH), 60.6 (CH2), 54.4 (CH), 27.9 (CH3), 27.6 (2×CH3). MS-ESI+ for C25H40N5O11 +, (M+H)+ calcd. 586.2719. found 586.2717.

D. Preparation of Compound 5a, 5b or 5c

Compound 4a, 4b or 4c (992 mg, 1.69 mmol) was dissolved in anhydrous pyridine and concentrated. The residue was dissolved in anhydrous CH2Cl(10 mL) and pyridine (5 mL) under a nitrogen atmosphere and the solution was cooled to −42° C. in an acetonitrile/dry ice bath. Methyl dichlorophosphate (187 μL, 1.86 mmol) was added dropwise and the mixture was stirred for 2 h 20 min. Water (10 mL) was added to the cold solution which was then removed from the cold bath and diluted with ethyl acetate (50 mL) and saturated NaCl solution (30 mL). The organic portion was separated and washed with saturated NaCl solution. The combined aqueous portions were extracted twice further with ethyl acetate and the combined organic portions were dried over MgSOand concentrated. Purification by silica gel flash column chromatography (eluting with 2-20% methanol in ethyl acetate) gave the cyclic methyl phosphate 5a, 5b or 5c (731 mg, 65%). 1H NMR (500 MHz, CDCl3,): δ 11.72 (bs, exchanged D2O, 1H), 5.63 (t, J=1.8 Hz, 1H), 5.41 (s, exchanged D2O, 1H), 4.95 (d, J=3.2 Hz, 1H), 4.70 (dt, J=12.4, 1.8 Hz, 1H), 4.42 (dd, J=22.1, 12.1 Hz, 1H). 4.15 (q, J=3.7 Hz, 1H), 3.82 (s, 1H), 3.75 (s, 1H), 3.58 (d, J=11.7 Hz, 3H), 2.10 (bs, exchanged D20, 1H+H2O), 1.50 (s, 9H), 1.46 (s, 18H). 13C NMR (125.7 MHz, CDCl3, centre line δ 77.0): δ 157.5 (C), 151.2 (C), 149.6 (2×C), 134.5 (C), 132.3 (C), 117.6 (C), 84.7 (2×C), 82.8 (C), 77.3 (CH), 74.8 (d, J=4.1 Hz, CH), 69.7 (CH2), 68.8 (d, J=4.1 Hz, CH), 68.6 (d, J=5.9 Hz, CH), 56.0 (d, J=7.4 Hz, CH3), 51.8 (CH), 28.1 (CH3), 27.8 (CH3). MS-ESI+ for C26H40N5NaO13P+ (M+Na)+, calcd. 684.2252. found 684.2251.

E. Preparation of Compound 6a, 6b or 6c

Compound 5a, 5b or 5c (223 mg, 0.34 mmol) was dissolved in anhydrous CH2Cl(7 mL) under a nitrogen atmosphere. Anhydrous DMSO (104 μL, 1.46 mmol) was added and the solution was cooled to −78° C. Trifluoroacetic anhydride (104 μL, 0.74 mmol) was added dropwise and the mixture was stirred for 40 min. N,N-diisopropylethylamine (513 μL, 2.94 mmol) was added and the stirring was continued for 50 min at −78° C. Saturated NaCl solution (20 mL) was added and the mixture removed from the cold bath and diluted with CH2Cl(30 mL). Glacial acetic acid (170 μL, 8.75 mmol) was added and the mixture was stirred for 10 min. The layers were separated and the aqueous phase was washed with CH2Cl(10 mL). The combined organic phases were washed with 5% aqueous HCl, 3:1 saturated NaCl solution:10% NaHCOsolution and saturated NaCl solution successively, dried over MgSO4, and concentrated to give compound 6a, 6b or 6c (228 mg, quant.) of suitable purity for further use. 1H NMR (500 MHz, CDCl3): δ 5.86 (m, 1 H), 5.07 (m, 1 H), 4.70-4.64 (m, 2 H), 4.49-4.40 (m, 1 H), 4.27 (m, 1 H), 3.56, m, 4 H), 1.49 (s, 9 H), 1.46 (s, 18 H) ppm. 13C NMR (500 MHz, CDCl3): δ 157.5 (C), 151.1 (C), 150.6 (2 C), 134.6 (C), 132.7 (C), 116.6 (C), 92.0 (C), 84.6 (2 C), 83.6 (C), 78.0 (CH), 76.0 (CH), 70.4 (CH2), 67.9 (CH), 56.2 (CH3) δ6.0 (CH), 28.2 (3CH3), 26.8 (6 CH3) ppm. 31P NMR (500 MHz, CDCl3): δ−6.3 ppm.

F. Preparation of compound 7: (4aR,5aR,11aR,12aS)-1,3,2-Dioxaphosphorino[4′,5′:5,6]pyrano[3,2-g]pteridin-10(4H)-one,8-amino-4-a,5a,6,9,11,11a,12,12a-octahydro-2,12,12-trihydroxy-2-oxide

Compound 6a, 6b or 6c (10 mg, 14.8 μmol was dissolved in dry acetonitrile (0.2 mL) and cooled to 0° C. Bromotrimethylsilane (19.2 μL, 148 μmol) was added dropwise and the mixture was allowed to warm to ambient temperature and stirred for 5 h during which time a precipitate formed. HCl(aq) (10 μl, 37%) was added and the mixture was stirred for a further 15 min. The mixture was centrifuged for 15 min (3000 g) and the resulting precipitate collected. Acetonitrile (0.5 mL) was added and the mixture was centrifuged for a further 15 min. The acetonitrile wash and centrifugation was repeated a further two times and the resulting solid was dried under high vacuum to give compound 7 (4 mg, 75%). 1H NMR (500 MHz, D2O): δ 5.22 (d, J=1.6 Hz, 1H), 4.34 (dt, J=13, 1.6 Hz, 1H), 4.29-4.27 (m, 1H), 4.24-4.18 (m, 1H), 3.94 (br m, 1H), 3.44 (t, J=1.4 Hz, 1H). 31P NMR (500 MHz, D2O): δ −4.8 MS-ESI+ for C10H15N5O8P+, (M+H)+calcd. 364.0653. found 364.0652.

Example 2Comparison of Precursor Z (cPMP) Prepared Synthetically to that Prepared from E. Coli in the In vitro Synthesis of Moco

In vitro synthesis of Moco was compared using samples of synthetic precursor Z (cPMP) and cPMP purified from E. coli. Moco synthesis also involved the use of the purified components E. coli MPT synthase, gephyrin, molybdate, ATP, and apo-sulfite oxidase. See U.S. Pat. No. 7,504,095 and “Biosynthesis and molecular biology of the molybdenum cofactor (Moco)” in Metal Ions in Biological Systems, Mendel, Ralf R. and Schwarz, Gunter, Informa Plc, 2002, Vol. 39, pages 317-68. The assay is based on the conversion of cPMP into MPT, the subsequent molybdate insertion using recombinant gephyrin and ATP, and finally the reconstitution of human apo-sulfite oxidase.

As shown in FIG. 1, Moco synthesis from synthetic cPMP was confirmed, and no differences in Moco conversion were found in comparison to E. coli purified cPMP.

Example 3Comparison of Precursor Z (cPMP) Prepared Synthetically to that Prepared from E. coli in the In vitro Synthesis of MPT

In vitro synthesis of MPT was compared using samples of synthetic precursor Z (cPMP) and cPMP purified from E. coli. MPT synthesis also involved the use of in vitro assembled MPT synthase from E. coli. See U.S. Pat. No. 7,504,095 and “Biosynthesis and molecular biology of the molybdenum cofactor (Moco)” in Metal Ions in Biological Systems, Mendel, Ralf R. and Schwarz, Gunter, Informa Plc, 2002, Vol. 39, pages 317-68. Three repetitions of each experiment were performed and are shown in FIGS. 2 and 3.

As shown in FIGS. 2 and 3, MPT synthesis from synthetic cPMP confirmed, and no apparent differences in MPT conversion were found when compared to E. coli purified cPMP. A linear conversion of cPMP into MPT is seen in all samples confirming the identity of synthetic cPMP (see FIG. 2). Slight differences between the repetitions are believed to be due to an inaccurate concentration determination of synthetic cPMP given the presence of interfering chromophores.

Example 4Preparation of Precursor Z (cPMP)

A. Preparation of Starting Materials

Figure US09260462-20160216-C00216

B. Introduction of the protected Phosphate

Figure US09260462-20160216-C00217

The formation of the cyclic phosphate using intermediate [10] (630 mg) gave the desired product [11] as a 1:1 mixture of diastereoisomers (494 mg, 69%).

Figure US09260462-20160216-C00218

C. Oxidation and Overall Deprotection of the Molecule

Oxidation of the secondary alcohol to the gem-diol did prove successful on intermediate [12], but the oxidized product [13] did show significant instability and could not be purified. For this reason, deprotection of the phosphate was attempted before the oxidation. However, the reaction of intermediate [11] with TMSBr led to complete deprotection of the molecule giving intermediate [14]. An attempt to oxidize the alcohol to the gem-diol using Dess-Martin periodinane gave the aromatized pteridine [15].

Oxidation of intermediate [11] with Dess-Martin periodinane gave a mixture of starting material, oxidized product and several by-products. Finally, intermediate [11] was oxidized using the method described Example 1. Upon treatment, only partial oxidation was observed, leaving a 2:1 mixture of [11]/[16]. The crude mixture was submitted to the final deprotection. An off white solid was obtained and analyzed by 1H-NMR and HPLC-MS. These analyses suggest that cPMP has been produced along with the deprotected precursor [11].

Because the analytical HPLC conditions gave a good separation of cPMP from the major impurities, this method will be repeated on a prep-HPLC in order to isolate the final material.


BridgeBio Pharma And Affiliate Origin Biosciences Announces FDA Acceptance Of Its New Drug Application For Fosdenopterin For The Treatment Of MoCD Type A

Application accepted under Priority Review designation with Breakthrough Therapy Designation and Rare Pediatric Disease Designation previously grantedThere are currently no approved therapies for the treatment of MoCD Type A, which results in severe and irreversible neurological injury for infants and children.This is BridgeBio’s first NDA acceptanceSAN FRANCISCO, September 29, 2020 – BridgeBio Pharma, Inc. (Nasdaq: BBIO) and affiliate Origin Biosciences today announced the US Food and Drug Administration (FDA) has accepted its New Drug Application (NDA) for fosdenopterin (previously BBP-870/ORGN001), a cyclic pyranopterin monophosphate (cPMP) substrate replacement therapy, for the treatment of patients with molybdenum cofactor deficiency (MoCD) Type A.The NDA has been granted Priority Review designation. Fosdenopterin has previously been granted Breakthrough Therapy Designation and Rare Pediatric Disease Designation in the US and may be eligible for a priority review voucher if approved. It received Orphan Drug Designation in the US and Europe. This is BridgeBio’s first NDA acceptance.“We want to thank the patients, families, scientists, physicians and all others involved who helped us reach this critical milestone,” said BridgeBio CEO and founder Neil Kumar, Ph.D. “MoCD Type A is a devastating disease with a median survival of less than four years and we are eager for our investigational therapy to be available to patients, who currently have no approved treatment options. BridgeBio exists to help as many patients as possible afflicted with genetic diseases, no matter how rare. We are grateful that the FDA has accepted our first NDA for priority review and we look forward to submitting our second NDA later this year for infigratinib for second line treatment of cholangiocarcinoma.”About Fosdenopterin
Fosdenopterin is being developed for the treatment of patients with MoCD Type A. Currently, there are no approved therapies for the treatment of MoCD Type A, which results in severe and irreversible neurological injury with a median survival between 3 to 4 years. Fosdenopterin is a first-in-class cPMP hydrobromide dihydrate and is designed to treat MoCD Type A by replacing cPMP and permitting the two remaining MoCo synthesis steps to proceed, with activation of MoCo-dependent enzymes and elimination of sulfites.About Molybdenum Cofactor Deficiency (MoCD) Type A
MoCD Type A is an ultra-rare, autosomal recessive, inborn error of metabolism caused by disruption in molybdenum cofactor (MoCo) synthesis which is vital to prevent buildup of s-sulfocysteine, a neurotoxic metabolite of sulfite. Patients are often infants with severe encephalopathy and intractable seizures. Disease progression is rapid with a high infant mortality rate.Those who survive beyond the first few month’s experience profuse developmental delays and suffer the effects of irreversible neurological damage, including brain atrophy with white matter necrosis, dysmorphic facial features, and spastic paraplegia. Clinical presentation that can be similar to hypoxic-ischemic encephalopathy (HIE) or other neonatal seizure disorders may lead to misdiagnosis and underdiagnosis. Immediate testing for elevated sulfite levels and S-sulfocysteine in the urine and very low serum uric acid may help with suspicion of MoCD.About Origin Biosciences
Origin Biosciences, an affiliate of BridgeBio Pharma, is a biotechnology company focused on developing and commercializing a treatment for Molybdenum Cofactor Deficiency (MoCD) Type A. Origin is led by a team of veteran biotechnology executives. Together with patients and physicians, the company aims to bring a safe, effective treatment for MoCD Type A to market as quickly as possible. For more information on Origin Biosciences, please visit the company’s website at

About BridgeBio Pharma
BridgeBio is a team of experienced drug discoverers, developers and innovators working to create life-altering medicines that target well-characterized genetic diseases at their source. BridgeBio was founded in 2015 to identify and advance transformative medicines to treat patients who suffer from Mendelian diseases, which are diseases that arise from defects in a single gene, and cancers with clear genetic drivers. BridgeBio’s pipeline of over 20 development programs includes product candidates ranging from early discovery to late-stage development. For more information visit

Clinical data
Trade namesNulibry
Other namesPrecursor Z, ALXN1101
License dataUS DailyMedFosdenopterin
ATC codeNone
Legal status
Legal statusUS: ℞-only [1]
showIUPAC name
CAS Number150829-29-1
PubChem CID135894389
CompTox Dashboard (EPA)DTXSID90934067 
Chemical and physical data
Molar mass363.223 g·mol−1
3D model (JSmol)Interactive image

//////////Fosdenopterin hydrobromide, ホスデノプテリン臭化水素酸塩水和物 , ALXN1101 HBrUNII-X41B5W735TX41B5W735TD11780, BBP-870/ORGN001, Priority Review designation, Breakthrough Therapy Designation, Rare Pediatric Disease Designation, Orphan Drug Designation, molybdenum cofactor deficiency, ALXN-1101, WHO 11150, FDA 2021, APPROVALS 2021

#Fosdenopterin hydrobromide, #ホスデノプテリン臭化水素酸塩水和物 , #ALXN1101 HBr, #UNII-X41B5W735TX41B5W735T, #D11780, #BBP-870/ORGN001, #Priority Review designation, #Breakthrough Therapy Designation, #Rare Pediatric Disease Designation, #Orphan Drug Designation, #molybdenum cofactor deficiency, #ALXN-1101, #WHO 11150, #FDA 2021, #APPROVALS 2021


1 Comment

  1. #Fosdenopterin hydrobromide, #ホスデノプテリン臭化水素酸塩水和物 , #ALXN1101 HBr, #UNII-X41B5W735T, X41B5W735T, #D11780, #BBP-870/ORGN001, #Priority Review designation, #Breakthrough Therapy Designation, #Rare Pediatric Disease Designation, #Orphan Drug Designation, #molybdenum cofactor deficiency, #ALXN-1101, #WHO 11150, #FDA 2021, #APPROVALS 2021

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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, 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...... , 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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