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Cebranopadol GRT 6005 セブラノパドール a Potent Analgesic NOP and Opioid Receptor Agonist



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(GRT-6005; GRT 6005; GRT6005)
CAS: 863513-91-1
Spiro[cyclohexane-1,1′(3’H)-pyrano[3,4-b]indol]-4-amine, 6′-fluoro-4′,9′-dihydro-N,N-dimethyl-4-phenyl-
Grünenthal GmbH  innovator
Cebranopadol(GRT-6005) is a novel first in class compounds with potent agonist activity on ORL-1 (opioid receptor like -1) and the well established mu opioid receptor.
 Cebranopadol exhibits highly potent and efficacious antinociceptive and antihypersensitive effects in several experimental model models of acute and chronic pain (tail–flick, rheumatoid arthritis, bone cancer, spinal nerve ligation, diabetic neuropathy) with ED50 values of 0.5–5.6 μg/kg after intravenous and 25.1 μg/kg after oral administration. Unlike morphine, cebranopadol did not disrupt motor coordination and respiration at doses within and exceeding the analgesic dose range. Cebranopadol, by its combination of agonism at NOP and opioid receptors, affords highly potent and efficacious analgesia in various pain models with a favorable side–effect profile.
GRT-6005 is a centrally active analgesic in phase II clinical development for the oral treatment of neuropathic pain in patients with painful diabetic polyneuropathy and for the treatment of pain due to osteoarthritis of the knee. It is being developed by Grüenenthal and Forest. No recent development has been reported for research into the treatment of moderate to severe pain following bunionectomy. In 2010, GRT-6005 was licensed to Forest and Grünenthal in Canada and the U.S. for the treatment of moderate to severe chronic pain.
ChemSpider 2D Image | Cebranopadol | C24H27FN2O
Description: IC50 Value: N/A Cebranopadol and GRT 6006 are novel first-in-class compounds with unique pharmacological and pharmacokinetic profiles that may enhance their effect in certain pain conditions. The unique mode of action of these compounds builds on the ORL-1 receptor and, supported by the established mu opioid receptor, is particularly suitable for the treatment of moderate to severe chronic pain [1]. in vitro: N/A in vivo: N/A Clinical trial: Cebranopadol has successfully completed initial proof-of-concept studies in nociceptive and neuropathic pain with further Phase II studies planned prior to initiation of Phase III studies.

Neuropathic pain

Neuropathic pain is caused when peripheral nerves are damaged by mechanical, metabolic or inflammatory way. The pain occurring images are mainly due to the occurrence of spontaneous pain, hyperalgesia and allodynia (pain is already triggered by non-noxious stimuli) in. As a result, the lesions to increased expression of Na + channels and thus to spontaneous activity in the damaged axons and their Nachbaraxonen (England et al., Neurology, 1996, 47, 272-276).The excitability of the neurons is increased and they react to incoming stimuli with an increased discharge frequency. This results in an increased sensitivity to pain, which contributes to the development of hyperalgesia and spontaneous pain (Baron, Clin J Pain 2000;. 16 (2 Suppl), 12-20). The causes and manifestations, and therefore the treatment needs of neuropathischerm pain are varied. They arise as a result of injury or disease of the brain, spinal cord or peripheral nerves.Causes may be operations, such as phantom pain after amputation, stroke, multiple sclerosis, spinal cord injury, alcohol or drug abuse or other toxins, cancers but also

Metabolic diseases such as diabetes, gout, kidney failure or liver cirrhosis, or infectious diseases such as mononucleosis, ehrlichiosis, typhoid, diphtheria, HIV, syphilis or Lyme disease. The pain experience is very different signs and symptoms that can change over time in number and intensity. Paradoxically, patients with neuropathic pain outline a slowdown or failure of acute pain perception and the simultaneous increase of neuropathic pain. The typical symptoms of neuropathic pain as tingling, burning, shooting or described, or radiating electrifying. Pharmacological basis for treatment of neuropathic pain include tricyclic antidepressants and anticonvulsants, which are used as monotherapy or in combination with opioids. These drugs usually provide only a certain pain relief during a pain-free but is often not achieved. The often-adjusting side effects are dose increases while the drug to achieve adequate pain relief often in the way. In fact, a higher dosage of a μ-opioid is often required as the treatment of acute pain, thereby reducing the side effects get even more important for satisfactory treatment of neuropathic pain. By the occurrence of typical μ-opioid tolerance development and the concomitant need for dose escalation of this problem is exacerbated. In summary it can be stated that neuropathic pain is difficult to treat and today is alleviated by high doses of μ-opioids only partially (Saudi Pharm J. 2002, 10 (3), 73-85). There is therefore an urgent need for medicines for the treatment of chronic pain, the dose should not be increased until the occurrence of intolerable side effects to ensure a satisfactory pain treatment.



Example 24 1,1-(3-Dimethylamino-3-phenylpentamethylene)-6-fluoro-1,3,4,9-tetrahydropyrano[3,4-b]indole hemicitrate, More Non-polar diastereoisomer

4-Dimethylamino-4-phenylcyclohexanone (651 mg, 3 mmoles) and 2-(5-fluoro-1H-indol-3-yl)-ethanol (“5-fluorotryptophol”, 537 mg, 3 mmoles) were initially introduced into abs. MC (20 ml) under argon. Trifluoromethanesulfonic acid trimethylsilyl ester (0.6 ml, 3.1 mmoles) was then added very rapidly. The mixture was stirred at RT for 20 h. For working up, 1 M NaOH (30 ml) was added to the reaction mixture and the mixture was stirred for 30 min. The organic phase was separated, and the aqueous phase which remained was extracted with MC (3×60 ml). The combined organic phases were washed with water (2×30 ml) and dried over sodium sulfate. Methanol (30 ml) was added to the solid residue obtained after the solvent had been distilled off, and the mixture was heated, and stirred for 15 hours. The solid contained in the suspension was filtered off with suction and dried. 955 mg of the more non-polar diastereoisomer of 1,1-(3-dimethylamino-3-phenylpentamethylene)-6-fluoro-1,3,4,9-tetrahydropyrano[3,4-b]indole were obtained (m.p. 284-292° C.). 850 mg of this were dissolved in hot ethanol (900 ml), and a similarly hot solution of citric acid (1 g, 5.2 mmoles) in ethanol (20 ml) was added. After approx. 15 minutes, crystals precipitated out at the boiling point. After cooling to approx. 5° C., the mixture was left to stand for 2 h. The solid formed was filtered off with suction. 640 mg of the hemicitrate were obtained as a white solid (m.p. 258-282° C.).

Example 25 1,1-(3-Dimethylamino-3-phenylpentamethylene)-6-fluoro-1,3,4,9-tetrahydropyrano[3,4-b]indole hemicitrate, More Polar diastereoisomer

4-Dimethylamino-4-phenylcyclohexanone (217 mg, 1 mmole) and 2-(5-fluoro-1H-indol-3-yl)-ethanol (“5-fluorotryptophol”, 179 mg, 1 mmole) were dissolved in conc. acetic acid (4 ml). Phosphoric acid (1 ml, 85 wt. %) was slowly added dropwise to this mixture. The mixture was stirred at RT for 16 h. For working up, the mixture was diluted with water (20 ml), brought to pH 11 with 5 M NaOH and extracted with MC (3×20 ml). The combined organic phases were dried with sodium sulfate and evaporated. The residue (364 mg of white solid) was suspended in hot ethanol (20 ml), and a similarly hot solution of citric acid (185 mg, 0.96 mmole) in ethanol (5 ml) was added. The residue thereby dissolved completely and no longer precipitated out even on cooling to approx. 5° C. Ethanol was removed on a rotary evaporator and the hemicitrate of the more polar diastereoisomer of 1,1-(3-dimethylamino-3-phenylpentamethylene)-6-fluoro-1,3,4,9-tetrahydropyrano[3,4-b]indole was obtained in this way in a yield of 548 mg as a white solid (m.p. 148-155° C.).


Figure US07547707-20090616-C00031
hemicitrate more non-polar diastereomer
Figure US07547707-20090616-C00032
hemicitrate more polar diastereomer



WO 2013113690

(1 r,4r)-6′-fluoro-N,N- dimethyl-4-phenyl-4′,9′-dihydro-3’H-spiro[cyclohexane-1 ,1 ‘-pyrano[3,4-b]indol]-4-amine (free base), has the following structural formula (I):

Figure imgf000007_0001
Figure imgf000033_0001
see A4

One particular drug that is of great interest for use in treating cancer pain (and other acute, visceral, neuropathic and chronic pain pain disorders) is (1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclohexane-1,1′-pyrano[3,4b]indol]-4-amine. This drug is depicted below as the compound of formula (I).


Figure US20130231381A1-20130905-C00001


The solid forms of (1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclohexane-1,1′-pyrano[3,4b]indol]-4-amine that are known so far are not satisfactory in every respect and there is a demand for advantageous solid forms

A) Synthesis of Crystalline Form A100 mg (1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclohexane-1,1′-pyrano[3,4,b]indol]-4-amine [crystalline form D according to D)] was suspended in 0.5 mL TBME. The suspension was stirred at RT for six days. The resulting solid was filtered out and dried in air. A crystalline solid of crystalline form A was obtained and characterized by FT Raman, TG-FTIR and PXRD.
Abstract Image

In a previous communication, our efforts leading from 1 to the identification of spiro[cyclohexane-dihydropyrano[3,4-b]indole]-amine 2a as analgesic NOP and opioid receptor agonist were disclosed and their favorable in vitro and in vivo pharmacological properties revealed. We herein report our efforts to further optimize lead 2a, toward trans-6′-fluoro-4′,9′-dihydro-N,N-dimethyl-4-phenyl-spiro[cyclohexane-1,1′(3′H)-pyrano[3,4-b]indol]-4-amine (cebranopadol, 3a), which is currently in clinical development for the treatment of severe chronic nociceptive and neuropathic pain.

Discovery of a Potent Analgesic NOP and Opioid Receptor Agonist: Cebranopadol

ACS Med. Chem. Lett., Article ASAP
DOI: 10.1021/ml500117c
b]indol]-4-amine, trans-, 2-hydroxy-1,2,3-propanetricarboxylate (2:1)
hemicitrate were obtained as a white solid (mp 258-282 °C).1H-NMR (300 MHz; DMSO-d6): 1.75-1.87 (m, 4 H); 2.14 (s, 6 H); 2.27 (t, 2 H); 2.61-
2.76 (m,6 H); 3.88 (t, 2 H); 6.86 (dt, 1 H); 7.10 (dd, 1 H); 7.30-7.43 (m, 6 H); 10.91 (br
s, 1 H).
13C-NMR (75.47 MHz; DMSO-d6): 22.1; 27.6; 30.2 (2 C); 38.0 (2 C); 43.1; 58.8 (2 C,
overlap); 71.5; 72.2; 102.3 (2JC,F = 23 Hz); 105.6 (3JC,F = 4 Hz); 108.3 (2JC,F = 26 Hz);
112.0 (3JC,F = 10 Hz); 126.5; 126.6; 126.7 (2 C); 127.4 (2 C); 132.4; 138.7; 141.5;
156,7 (1JC,F = 231 Hz); 171.3 (2 C), 175.3.HPLC-MS: m/z 378.9 [M + H]+
US20120034297 * Aug 4, 2011 Feb 9, 2012 Gruenenthal Gmbh Pharmaceutical dosage forms comprising 6′-fluoro-(N-methyl- or N,N-dimethyl-)-4-phenyl-4′,9′-dihydro-3’H-spiro[cyclohexane-1,1′-pyrano[3,4,b]indol]-4-amine
US20130012563 * Jul 6, 2012 Jan 10, 2013 Gruenenthal Gmbh Crystalline (1r,4r)-6′-fluoro-n,n-dimethyl-4-phenyl-4′,9′-dihydro-3’h-spiro[cyclohexane-1,1′-pyrano[3,4,b]indol]-4-amine
WO2004043967A1 Nov 5, 2003 May 27, 2004 Otto Aulenbacher Spirocyclic cyclohexane derivatives
WO2008040481A1 Sep 26, 2007 Apr 10, 2008 Gruenenthal Gmbh MIXED ORL 1/μ AGONISTS FOR TREATING PAIN
WO2004043967A1 * Nov 5, 2003 May 27, 2004 Otto Aulenbacher Spirocyclic cyclohexane derivatives
WO2005066183A1 * Dec 21, 2004 Jul 21, 2005 Gruenenthal Gmbh Spirocyclic cyclohexane derivatives with affinity for the orl1-receptor
US20050153998 * Aug 19, 2004 Jul 14, 2005 Fumitaka Ito Tetrahydroisoquinoline or isochroman compounds



Citing Patent Filing date Publication date Applicant Title
US7799931 * Feb 17, 2009 Sep 21, 2010 Gruenenthal Gmbh Spirocyclic cyclohexane compounds
US7951948 * Apr 19, 2010 May 31, 2011 Gruenenthal Gmbh Spirocyclic cyclohexane compounds
US7960404 Aug 21, 2009 Jun 14, 2011 Gruenenthal Gmbh Spirocyclic cyclohexane compounds
US8034936 Nov 4, 2010 Oct 11, 2011 Gruenenthal Gmbh Spirocyclic cyclohexane compounds useful to treat substance dependency
US8053576 Feb 17, 2009 Nov 8, 2011 Gruenenthal Gmbh Treating conditions associated with the nociceptin/ORL1 receptor system, e.g. pain, drug withdrawal, anxiety, muscle relaxants, anxiolytic agents; e.g. 1,1-[3-dimethylamino-3-(pyridin-2-yl)pentamethylene]-3,4-dihydro-1H-2,9-diazafluorene
US8288406 Sep 22, 2010 Oct 16, 2012 Gruenenthal Gmbh Hydroxymethylcyclohexylamines
US8288430 Mar 25, 2009 Oct 16, 2012 Grunenthal Gmbh Spiro(5.5)undecane derivatives
US8293758 * Mar 25, 2009 Oct 23, 2012 Grunenthal Gmbh Substituted spirocyclic cyclohexane derivatives
US8357705 Mar 25, 2009 Jan 22, 2013 Gruenenthal Gmbh Substituted cyclohexyldiamines
US8404740 Aug 21, 2009 Mar 26, 2013 Gruenenthal Gmbh Spirocyclic cyclohexane compounds
US8614245 * Jan 8, 2013 Dec 24, 2013 Gruenenthal Gmbh Crystalline (1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclohexane-1,1′-pyrano[3,4,b]indol]-4-amine
US8618156 * Jul 6, 2012 Dec 31, 2013 Gruenenthal Gmbh Crystalline (1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3’H-spiro[cyclohexane-1,1′-pyrano[3,4,b]indol]-4-amine
US20130012563 * Jul 6, 2012 Jan 10, 2013 Gruenenthal Gmbh Crystalline (1r,4r)-6′-fluoro-n,n-dimethyl-4-phenyl-4′,9′-dihydro-3’h-spiro[cyclohexane-1,1′-pyrano[3,4,b]indol]-4-amine




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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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