23 IDX 18719; IDX 719; Samatasvir




(4S,5R,6R)-5-acetamido-4-carbamimidamido-6-[(1R,2R)-3-hydroxy-2-methoxypropyl]-5,6-dihydro-4H-pyran-2-carboxylic acid
Mol. mass346.33638 g/mol
cas 203120-17-6,
Laninamivir (L174000) prodrug; a novel long-acting neuraminidase inhibitor.
laninamivir octanoate
472.53254, C21H36N4O8,   cas no 203120-46-1, R-125489, CS-8958 
Daiichi Sankyo (Originator)
R-118958 is a potent, long-acting neuraminidase inhibitor (LANI) approved and launched in 2010 in Japan as an inhalable formulation for the treatment of influenza A and influenza B in adults and pediatric patients. In 2013 the product was approved in Japan for the prevention of influenza A and influenza B.
5-(Acetylamino)-4-[(aminoiminomethyl)amino]-2,6-anhydro-3,4,5-trideoxy-7-O-methyl-D-glycero-D-galacto-non-2-enonic Acid 9-Octanoate
(2R,3R,4S)-3-Acetamido-4-guanidino-2-[(1R,2R)-2-hydroxy-1-methoxy-3-(octanoyloxy)propyl]-3,4-dihydro-2H-pyran-6-carboxylic Acid
(4S,5R,6R)-5-Acetamido-4-guanidino-6-[(1R,2R)-2-hydroxy-1-methoxy-3-(octanoyloxy)propyl]-5,6-dihydro-4H-pyran-2-carboxylic Acid
CS 8958
ATLANTA, Dec. 20, 2013 (GLOBE NEWSWIRE) -- Biota Pharmaceuticals, Inc.
(Nasdaq:BOTA) ("Biota" or the "Company") today reported that Daiichi Sankyo Company, Limited ("Daiichi Sankyo") has been granted regulatory approval in Japan to manufacture and market Inavir(R) Dry Powder Inhaler 20mg (generic name laninamivir octanoate) for the prevention of influenza A and B. Inavir(R) was successfully developed and launched by Daiichi Sankyo in Japan for treatment of influenza A and B viruses in October, 2010. Biota is developing laninamivir octanoate outside of Japan for the treatment of influenza, and is currently conducting a large, multi-national Phase 2 trial of laninamivir octanoate in adults infected with influenza. In 2003, the Company and Daiichi Sankyo entered into a collaboration and license agreement to develop long-acting neuraminidase inhibitors, including laninamivir octanoate, and in March 2009, the parties entered into a commercialization agreement, pursuant to which Daiichi Sankyo obtained exclusive marketing rights to laninamivir octanoate in Japan.
Laninamivir (CS-8958) is a neuraminidase inhibitor which is being researched for the treatment and prophylaxis of Influenzavirus A and Influenzavirus B.[1] It is currently in Phase III clinical trials. [2]
Laninamivir was approved for influenza treatment in Japan in 2010 and is currently marketed under the name "Inavir" by Daiichi Sankyo. Biota Pharmaceuticals [3] and Daiichi Sankyo co-own Laninamivir. On 1st April 2011, BARDA awarded up to an estimated U$231m to Biota Pharmaceuticals (Formerly Biota Holdings Ltd) wholly owned subsidiary, Biota Scientific Management Pty Ltd, for the advanced development of Laninamivir in the US. [4]
WO 2013089168
WO 2008126943

The recent flu scares – first H5N1 bird flu and then H1N1 swine flu – transformed Roche’s neuraminidase inhibitor Tamiflu (oseltamivir) into a household name, along with GSK’s Relenza (zanamivir). Both of these require twice-daily dosing, and the orally available oseltamivir is the first choice, but resistance is starting to appear.
A new neuraminidase inhibitor, laninamivir, is being developed by Daiichi Sankyo.5 When administered as the octanoate prodrug form, it appears that a single dose might be sufficient to treat influenza, weekly doses could be preventative, and it is active against extremely pathogenic H5N1 strains.
Laninamivir octanoate
In a double blind, randomised, placebo-controlled Phase I study in 76 healthy male volunteers, subjects were given inhaled single doses of 5, 10, 20, 40, 80 or 120mg of the prodrug, or twice-daily doses of 20 or 40mg for three days.6 No adverse events were observed, and while the prodrug disappeared from the plasma with a half-life of about two hours, the laninamivir itself was much more slowly eliminated, with a half-life of the order of three days, suggesting the potential for giving long-lasting activity against influenza.
In another Phase I trial, a total of 20 healthy subjects with renal function ranging from normal to severely impaired were given single inhaled 20mg doses of the prodrug.7 The degree of renal impairment did not affect the maximum concentration or the time to achieve it, but the half-life increased as renal function reduced. This indicates that the rate-limiting step for elimination is drug release rate to plasma from tissues rather than renal excretion. It was well tolerated, but systemic exposure increased with increasing renal impairment.
It has also been compared with oseltamivir in patients with influenza. A total of 186 children under 10 who had had febrile influenza symptoms for no longer than 36 hours were randomised to receive 20 or 40mg of laninamivir octanoate as a single inhalation or 2mg/kg oseltamivir orally twice a day for five days.8
The new drug gave a significant reduction, of 61 hours for the 40mg group and 66 for the 20mg group, in median time to illness alleviation compared with oseltamivir in those with oseltamivir-resistant H1N1 influenza A. However, there was no significant difference in the time to alleviation of illness with H3N2 influenza A, or influenza B.
The most common side-effects were gastrointestinal problems.
In a Phase III trial, a total of 1,003 adult patients with febrile influenza symptoms for no more than 36 hours were given similar doses to those in the trial in children.9 Median time to alleviation of illness was 73h for 40mg, 86h for 20mg, and 74h for oseltamivir, and the proportion of patients shedding virus at day 3 was significantly lower in the 40mg group than for those given oseltamivir.
  1.  Yamashita M, Tomozawa T, Kakuta M, Tokumitsu A, Nasu H, Kubo S (January 2009)."CS-8958, a prodrug of the new neuraminidase inhibitor R-125489, shows long-acting anti-influenza virus activity"Antimicrobial Agents and Chemotherapy 53 (1): 186–92.doi:10.1128/AAC.00333-08PMC 2612152PMID 18955520.
  2.  Hayden F (January 2009). "Developing new antiviral agents for influenza treatment: what does the future hold?". Clinical Infectious Diseases. 48. Suppl 1 (S1): S3–13.doi:10.1086/591851PMID 19067613.
5. T. Honda et al. Synthesis and in vivo influenza virus-inhibitory effect of ester prodrug of 4-guanidino-7-O-methyl-Neu5Ac2en, Bioorg Med Chem Lett 2009, 19(11): 2938
6. H. Ishizuka et al. J. Clin. Pharmacol. 2010, 50, 1319
7. H. Ishizuka et al. J. Clin. Pharmacol. 2010, epub ahead of print, doi 10.1177/0091270010361914
8. N. Sugaya and Y. Ohashi, Antimicrob. Ag. Chemother. 2010, 54, 2575
9 A. Watanabe et al. Clin. Inf. Dis. 2010, 51, 1167
A new route toward 2-acetamido-4-O-methyl-2-deoxy-D-mannopyranose from a Ferrier derivative of tri-O-acetyl-D-glucal, which contributes to aldolase-catalyzed synthesis of laninamivir (CS-8958)
Tetrahedron 2013, 39(37): 7931
Infection of poultry with H5N1 avian influenza virus has been expanding since 2003 in wide areas including Asia, Europe and Africa. Humans infected with this virus have been found not only in Asia but also in Middle East and Africa. If a new type of H5N1 influenza virus has appeared and its infection has started, it is believed that the infection will rapidly expand to cause a worldwide spread (i.e., influenza pandemic) because most people do not possess immunity against that virus and influenza viruses spread via droplet infection and airborne infection. More than half of human patients infected with H5N1 influenza virus have died so far. Thus, the virus is highly pathogenic. It is known that three influenza pandemics, the Spanish Flu, the Asian Flu and the Hong Kong Flu, occurred in the 20th century. In the Spanish Flu which caused the largest number of patients, it is estimated that about 20-40 million people died in the world and about 0.5 million people in Japan.
According to a report from Japanese Ministry of Health, Labour and Welfare made in November, 2005, if a new type influenza virus has spread, the number of patients who will consult medical doctors in Japan as a result of infection with that virus is estimated about 18-25 million. Further, when the pathogenicity of that new type influenza virus is severe, the number of inpatients is estimated about 0.2 million while the number of dead is estimated about 0.64 million. Therefore, not only health hazard but also significant influences upon social activities are feared.
Thus, a new type influenza can cause a highly severe disease. Early development of effective therapeutics is demanded.
Although it is reported that zanamivir (in particular, zanamivir hydrate) and oseltamivir (in particular, oseltamivir phosphate or oseltamivir carboxylate) which are influenza therapeutics with neuraminidase inhibitory activity show an inhibitory activity against H5N1 influenza virus, compounds with more excellent activity are desired (Non-Patent Document 1 or 2). Further, H5N1 influenza virus strains against which oseltamivir does not show any inhibitory activity (i.e., oseltamivir resistant virus strains) have been reported. Compounds which possess an inhibitory activity against these oseltamivir resistant H5N1 influenza virus strains are desired (Non-Patent Document 1 or 2).
Compounds represented by formula (I) are known to be useful as influenza therapeutics with neuraminidase inhibitory activity (Patent Documents 1 to 3). However, it has not been reported that these compounds have an inhibitory activity against H5N1 influenza virus. Further, the structures of the compounds represented by formula (I) resemble the structure of zanamivir but are completely different from the structure of oseltamivir.
Non-Patent Document 1: Nature, 2005, vol. 437, p. 1108
Non-Patent Document 2: N. Engl. J. Med., 2005, vol. 353, (25):2667-72
Patent Document 1: U.S. Pat. No. 6,340,702 (Japanese Patent No. 3209946)
Patent Document 2: U.S. Pat. No. 6,451,766 (Japanese Patent Publication No. Hei 10-109981)
Patent Document 3: U.S. Pat. No. 6,844,363 (Japanese Patent Publication No. 2002-012590)
Figure US20100204314A1-20100812-C00004
Preparation Example 1 5-Acetamido-4-guanidino-9-O-octanoyl-2,3,4,5-tetradeoxy-7-O-methyl-D-glycero-D-galacto-non-2-enopyranosoic acid
Figure US20100204314A1-20100812-C00005
(1) Diphenylmethyl 5-acetamido-4-(N,N-bis-t-butyloxycarbonyl)guanidino-9-O-octanoyl-2,3,4,5-tetradeoxy-7-O-methyl-D-glycero-D-galacto-non-2-enopyranosoate (3.46 g, 4.1 mmol) disclosed in Example 35 (i) of U.S. Pat. No. 6,340,702 (Japanese Patent No. 3209946) was dissolved in methylene chloride (27 ml) and trifluoroacetic acid (14 ml). The resultant solution was stirred at room temperature overnight. The reaction solution was concentrated to dryness under reduced pressure, followed by three cycles of azeotropic distillation to dryness with toluene (5 ml). The resultant oily material was dissolved in ethyl acetate (10 ml). The solution was poured into a saturated aqueous solution of sodium hydrogencarbonate (50 ml). The pH of the resultant solution was adjusted to 8.5 by addition of 20% aqueous solution of sodium carbonate. Then, the solution was stirred at room temperature for 3 hr and its pH was adjusted to 5.0 with hydrochloric acid (3 ml), followed by stirring at room temperature for another 1 hr. The solution was further stirred for 1 hr while ice-cooling. Subsequently, precipitating crystals were suction filtered and vacuum dried for 10 hr at an external temperature of 50° C. The resultant crystals were left in the air for one day to thereby yield the subject compound as a hydrate crystal (0.97 g; yield 51%).
Infrared Absorption Spectrum (KBr) ν max cm−1: 3412, 2929, 2856, 1676, 1401, 1320, 1285, 1205, 1137, 722.
1H Nuclear Magnetic Resonance Spectrum (400 MHz, CD3OD) δ ppm: 5.88 (1H, d, J=2.5 Hz), 4.45 (3H, m), 4.27 (1H, dd, J=10.0 Hz, 10.0 Hz), 4.15 (1H, m), 3.47 (21-1, m), 3.42 (3H, s), 2.37 (2H, t, J=7.4 Hz), 2.10 (3H, s), 1.31 (2H, m), 1.20-1.40 (8H, m), 0.85-0.95 (3H, m).
13C Nuclear Magnetic Resonance Spectrum (100 MHz, CD3OD) δ ppm: 176.5, 173.7, 164.7, 158.9, 146.7, 108.7, 80.1, 78.0, 69.3, 66.8, 61.4, 52.4, 35.1, 32.8, 30.2, 30.1, 26.0, 23.7, 22.8, 14.4.
(2) The subject compound was also obtained by the method described below.
5-Acetamido-4-guanidino-9-O-octanoyl-2,3,4,5-tetradeoxy-7-O-methyl-D-glycero-D-galacto-non-2-enopyranosoic acid trifluoroacetic acid salt (3.0 g, 5.1 mmol) disclosed in Example 35 (ii) of U.S. Pat. No. 6,340,702 (Japanese Patent No. 3209946) was subjected to reversed phase column chromatography [Cosmosil 75C 18PREP (nacalai tesque), 100 g] and eluted with methanol/water (0/1-1/1-2/1). Fractions containing the compound of interest were vacuum concentrated. The precipitating crystals were suction filtered and vacuum dried. The resultant crystals were left in the air for one day to thereby yield the subject compound as a hydrate crystal (1.2 g; yield 49%). The property data of the resultant compound were consistent with those of the compound obtained in (1) above.
Preparation Example 2 5-Acetamido-4-guanidino-2,3,4,5-tetradeoxy-7-O-methyl-D-glycero-D-galacto-non-2-enopyranosoic acid
Figure US20100204314A1-20100812-C00006
5-Acetamido-4-guanidino-2,3,4,5-tetradeoxy-7-O-methyl-D-glycero-D-galacto-non-2-enopyranosoic acid trifluoroacetic acid salt (3.0 g, 5.1 mmol) disclosed in Example 28 (viii) of U.S. Pat. No. 6,340,702 (Japanese Patent No. 3209946) was purified in an ion-exchange resin column [Dowex-50X; (i) water and (ii) 5% aqueous ammonium solution] and further purified by reversed phase column chromatography [Cosmosil 75C 18PREP (nacalai tesque); water]. Fractions containing the compound of interest were vacuum concentrated. The resultant solid was washed with methanol, filtered and dried to thereby yield the subject compound (1.43 g) as a colorless solid.
1H Nuclear Magnetic Resonance Spectrum (400 MHz, CD3OD) δ ppm: 5.64 (1H, d, J=2.0 Hz), 4.43 (2H, m), 4.22 (1H, dd, J=10.0 Hz, 10.0 Hz), 4.00 (1H, m), 3.85 (1H, dd, J=10.0 Hz, 2.4 Hz), 3.68 (1H, dd, J=10.0 Hz, 5.5 Hz), 3.58 (1H, m), 3.43 (3H, s).
Figure JPOXMLDOC01-appb-C000008
Figure JPOXMLDOC01-appb-C000009
Process W is known as a method for manufacturing a compound represented by the formula (Ia), which is embraced in a compound represented by the formula (I) or a pharmacologically acceptable salt thereof, (hereinafter also referred to as “compound (Ia)”; the same shall be applied with respect to other (Patent Document 1). In Process W, n-Hep represents a 1-heptyl group.
Figure US08455659-20130604-C00004
Figure US08455659-20130604-C00005
Process X is known as a method for manufacturing compound (Ib), which is embraced in compound (I) or a pharmacologically acceptable salt thereof (Patent Document 2). Compound (IVk) is a synthetic intermediate in Process W. In Process X, n-Hep represents a 1-heptyl group.
Figure US08455659-20130604-C00006
Process Y is known as a method for manufacturing compound (IIIa), which is a trifluoroacetic acid salt of compound (III) (Non-patent Document 1). The procedures from compound (IVc) to compound (IVe) and from compound (IVf) to compound (IVh) in Process Y are the same as in Process W.
Figure US08455659-20130604-C00007
Figure US08455659-20130604-C00008
Process Z is known as a method for manufacturing compound (IIIa), which is a trifluoroacetic acid salt of compound (III) (Non-patent Document 2). In Process Z, the procedure from compound (IVf) to compound (IVh) is the same as in Process W, and the procedure from compound (IVh) to compound (IIIa) is the same as in Process Y.
Figure US08455659-20130604-C00009
Figure US08455659-20130604-C00010
From the viewpoint of industrial production, the aforementioned Process W, Process Y, or Process Z could be improved in points such as the following:



M.Wt: 529.45
Formula: C22H29FN3O9P
Isopropyl (2S)-2-[[[(2R,3R,4R,5R)-5-(2,4-dioxopyrimidin-1-yl)-4-fluoro-3-hydroxy-4-methyl-tetrahydrofuran-2-yl]methoxy-phenoxy-phosphoryl]amino]propanoate
A prodrug of 2'-deoxy-2'-alpha-F-2'-beta-C-methyluridine 5'-monophosphate.
GS-7977, PSI-7977
  • GS 7977
  • GS-7977
  • PSI 7977
  • PSI-7977
  • Sofosbuvir
  • Sovaldi
CAS Registry Number :1190307 -88-0
Indications: Chronic hepatitis C (HCV GT1, GT2, GT3, GT4)
Mechanism: nucleoside NS5B polymerase inhibitor
approved Time: December 6, 2013
,U.S. Patent Number: 7964580,8415322,8334270,7429572;, patent validity: March 26, 2029 (U.S. Patent No.: 7,964,580 and 8,334,270), April 3, 2025 (U.S. Patent No.: 7,429,572 and 8,415,322)
US patent number 7964580, US patent number 8415322, US patent number 8334270,US patent number 7429572 Patent Expiration Date: March 26, 2029 for US patent number 7964580 and 8334270 (2028 in EU); April 3, 2025 for US patent number 7429572 and 8415322
Sales value (estimated): $ 1.9 billion (2014), 6600000000 USD (2016)
Drug Companies: Gilead Sciences, Inc. (Gilead Sciences)
WASHINGTON, Dec. 6, 2013 (AP) — Federal health officials have approved a highly anticipated hepatitis C drug from Gilead Sciences Inc. that is expected to offer a faster, more palatable cure to millions of people infected with the liver-destroying virus.
The Food and Drug Administration said Friday it approved the pill Sovaldi in combination with older drugs to treat the main forms of hepatitis C that affect U.S. patients.
Current treatments for hepatitis C can take up to a year of therapy and involve weekly injections of a drug that causes flu-like side effects. That approach only cures about three out of four patients. Sovaldi is a daily pill that in clinical trials cured roughly 90 percent of patients in just 12 weeks, when combined with the older drug cocktail.

  • The end of October 2013 saw a nod from the FDA given to Gilead’s New Drug Application for Sofosbuvir, a much needed treatment for hepatitis C.
  • As a nucleotide analogue, Sofosbuvir is designed as a once daily treatment.
  • There are roughly 170 million cases of hepatitis C around the world.
  • A report in the Journal of the American Medical Association on August 28, 2013 revealed that the Sofosbuvir and Ribavirin combination treatment effectively cured many patients with the Hepatitis C Virus.
  • The Sofosbuvir and Ribavirin drug combination was void of interferon-based treatments, which  many patients are resistant too.
  • More than 3 million Americans have chronic Hepatitis C Virus, and 22 percent of these patients are African American.
Sofosbuvir (brand names Sovaldi and Virunon) is a drug used for hepatitis C virus (HCV) infection, with a high cure rate.[1][2] It inhibits the RNA polymerase that the hepatitis C virus uses to replicate its RNA. It was discovered at Pharmasset and developed by Gilead Sciences.[3]
Sofosbuvir is a component of the first all-oral, interferon-free regimen approved for treating chronic Hepatitis C.[4]
In 2013, the FDA approved sofosbuvir in combination with ribavirin (RBV) for oral dual therapy of HCV genotypes 2 and 3, and for triple therapy with injected pegylated interferon (pegIFN) and RBV for treatment-naive patients with HCV genotypes 1 and 4.[4] Sofosbuvir treatment regimens last 12 weeks for genotypes 1, 2 and 4, compared to 24 weeks for treatment of genotype 3. The label furhter states that sofosbuvir in combination with ribavirin may be considered for patients infected with genotype 1 who are interferon-ineligible.[5] Sofosbuvir will cost $84,000 for 12 weeks of treatment and $168,000 for the 24 weeks, which some patient advocates have criticized as unaffordable.
Interferon-free therapy for treatment of hepatitis C eliminates the substantial side-effects associated with use of interferon. Up to half of hepatitis C patients cannot tolerate the use of interferon.[6]

Sofosbuvir is a prodrug that is metabolized to the active antiviral agent 2'-deoxy-2'-α-fluoro-β-C-methyluridine-5'-triphosphate.[7] Sofosbuvir is anucleotide analog inhibitor of the hepatitis C virus (HCV) polymerase.[8] The HCV polymerase or NS5B protein is a RNA-dependent RNA polymerase critical for the viral cycle.

The New Drug Application for Sofosbuvir was submitted on April 8, 2013 and received the FDA's Breakthrough Therapy Designation, which grants priority review status to drug candidates that may offer major treatment advantages over existing options.[9]
On 6th December 2013, the U.S. Food and Drug Administration approved sofosbuvir for the treatment of chronic hepatitis C.[10]

Sofosbuvir is being studied in combination with pegylated interferon and ribavirin, with ribavirin alone, and with other direct-acting antiviral agents.[11][12] It has shown clinical efficacy when used either with pegylated interferon/ribavirin or in interferon-free combinations. In particular, combinations of sofosbuvir with NS5A inhibitors, such as daclatasvir or GS-5885, have shown sustained virological response rates of up to 100% in people infected with HCV.[13]
Data from the ELECTRON trial showed that a dual interferon-free regimen of sofosbuvir plus ribavirin produced a 24-week post-treatment sustained virological response (SVR24) rate of 100% for previously untreated patients with HCV genotypes 2 or 3.[14][15]
Data presented at the 20th Conference on Retroviruses and Opportunistic Infections in March 2013 showed that a triple regimen of sofosbuvir, ledipasvir, and ribavirin produced a 12-week post-treatment sustained virological response (SVR12) rate of 100% for both treatment-naive patients and prior non-responders with HCV genotype 1.[16] Gilead has developed a sofosbuvir + ledipasvir coformulation that is being tested with and without ribavirin.

Sofosbuvir will cost $84,000 for 12 weeks of treatment used for genotype 1 and 2, and $168,000 for the 24 weeks used for genotype 3.[17] This represents a substantial pricing increase from previous treatments consisting of interferon and ribavirin, which cost between $15,000 and $20,000.[18] The price is also significantly higher than that of Johnson & Johnson's recently approved drug simeprevir (Olysio), which costs $50,000 and also treats chronic hepatitis C.[18] The high cost of the drug has resulted in a push back from insurance companies and the like, includingExpress Scripts, which has threatened to substitute lower priced competitors, even if those therapies come with a more unfriendly dosing schedule.[18] Other treatments that have recently entered the market have not matched the efficacy of sofosbuvir, however, allowing Gilead to set a higher price until additional competition enters the market.[18] Patient advocates such as Doctors Without Borders have complained about the price, which is particularly difficult for underdeveloped countries to afford.[19]

ChemSpider 2D Image | Sofosbuvir | C22H29FN3O9P

  1.  News: United States to approve potent oral drugs for hepatitis C, Sara Reardon, Nature, 30 October 2013
  2.  Sofia MJ, Bao D, Chang W, Du J, Nagarathnam D, Rachakonda S, Reddy PG, Ross BS, Wang P, Zhang HR, Bansal S, Espiritu C, Keilman M, Lam AM, Steuer HM, Niu C, Otto MJ, Furman PA (October 2010). "Discovery of a β-d-2'-deoxy-2'-α-fluoro-2'-β-C-methyluridine nucleotide prodrug (PSI-7977) for the treatment of hepatitis C virus". J. Med. Chem. 53 (19): 7202–18.doi:10.1021/jm100863xPMID 20845908.
  3.  "PSI-7977". Gilead Sciences.
  4. Tucker M (December 6, 2013). "FDA Approves 'Game Changer' Hepatitis C Drug Sofosbuvir". Medscape.
  5.  "U.S. Food and Drug Administration Approves Gilead’s Sovaldi™ (Sofosbuvir) for the Treatment of Chronic Hepatitis C - See more at:". Gilead. December 6, 2013.
  6.  "Sofosbuvir is safer than interferon for hepatitis C patients, say scientists". News Medical. April 25, 2013.
  7.  Murakami E, Tolstykh T, Bao H, Niu C, Steuer HM, Bao D, Chang W, Espiritu C, Bansal S, Lam AM, Otto MJ, Sofia MJ, Furman PA (November 2010). "Mechanism of activation of PSI-7851 and its diastereoisomer PSI-7977"J. Biol. Chem. 285 (45): 34337–47.doi:10.1074/jbc.M110.161802PMC 2966047PMID 20801890.
  8.  Alejandro Soza (November 11, 2012). "Sofosbuvir". Hepaton.
  9.  "FDA Advisory Committee Supports Approval of Gilead’s Sofosbuvir for Chronic Hepatitis C Infection" October 25, 2013.
  10.  "FDA approves Sovaldi for chronic hepatitis C"FDA New Release. U.S. Food and Drug Administration. 2013-12-06.
  11.  Murphy T (November 21, 2011). "Gilead Sciences to buy Pharmasset for $11 billion".Bloomberg Businessweek.
  12.  Asselah T (January 2014). "Sofosbuvir for the treatment of hepatitis C virus". Expert Opin Pharmacother 15 (1): 121–30. doi:10.1517/14656566.2014.857656PMID 24289735.
  13.  "AASLD 2012: Sofosbuvir and daclatasvir dual regimen cures most people with HCV genotypes 1, 2, or 3"News. European Liver Patients Association. 2012-11-21.
  14.  AASLD: PSI-7977 plus Ribavirin Can Cure Hepatitis C in 12 Weeks without Interferon. Highleyman, L. 8 November 2011.
  15.  Gane EJ, Stedman CA, Hyland RH, Ding X, Svarovskaia E, Symonds WT, Hindes RG, Berrey MM (January 2013). "Nucleotide polymerase inhibitor sofosbuvir plus ribavirin for hepatitis C".N. Engl. J. Med. 368 (1): 34–44. doi:10.1056/NEJMoa1208953PMID 23281974.
  16.  CROI 2013: Sofosbuvir + Ledipasvir + Ribavirin Combo for HCV Produces 100% Sustained Response. Highleyman, L. 4 March 2013.
  17.  Campbell T (December 11, 2013). "Gilead's Sofosbuvir Gets New Name, Price, Headaches". The Motley Fool.
  18.  Cohen, J. (2013). "Advocates Protest the Cost of a Hepatitis C Cure". Science 342 (6164): 1302–1303. doi:10.1126/science.342.6164.1302PMID 24337268edit
The chemical structure 
Chemical Structure of Sovaldi_Sofosbuvir_Hepatatis C-Gilead
GS-7977, (S)-isopropyl 2-(((S)-(((2R,3R,4R,5R)-5-(2,4-dioxo-3,4- dihydropyrimidin^l(2H)-yl)-4-fluoro-3-hydroxy-4-methyltetrahydrofuran-2- yl)methoxy)(phenoxy)phosphoryl)amino)propanoate, available from Gilead Sciences, Inc., is described and claimed in U.S. Patent No. 7,964,580. (See also US 2010/0016251, US 2010/0298257, US 201 1/0251 152 and US 2012/0107278.) GS-7977 has the structure:

Figure imgf000013_0001
GS-7977 can be crystalline or amorphous. Examples of preparing crystalline and amorphous forms of GS-7977 are disclosed in US 2010/0298257 (US 12/783,680) and US 201 1/0251 152 (US 13/076,552),

Chemical Synthesis of Sofosbuvir_Sovaldi_GS-7977_PSI-7977_Hepatitis C_Gilead

Commerically available isopropylidine protected D-glyceraldehyde was reacted with (carbethoxyethylidene)triphenylmethylphosphorane gave the chiral pentenoate ester YP-1. Permanganate dihydroxylation of YP-1 in acetone gave the D-isomer diol YP-2. The cyclic sulfate YP-3 was obtained by first making the cyclic sulfite with thionyl chloride and then oxidizing to cyclic sulfate with sodium hypochlorite. Fluorination of YP-3 with triethylamine-trihydrofluoride(TEA-3HF) in the presence of triethylamine, followed by the hydrolysis of sulfate ester in the presence of concentrated HCl provided diol YP-4 which was benzoylated to give ribonolactone YP-5. Reduction of YP-5 with Red-Al followed by chlorination with sulfuryl chloride in the presence of catalytic amount of tetrabutylammonium bromide yielded YP-6. The conversion of YP-6 to benzoyl protected 2′-deoxyl-2′-alpha-F-2′-Beta-C-methylcytidine (YP-7) was achieved by using O-trimethyl silyl-N4-benzoylcytosine and stannic chloride. Preparation of the uridine nucleoside YP-8 was accomplished by first heating benzoyl cytidine YP-7 in acetic acid then treating with methoanolic ammonia to provide YP-8 in 78% yield.
The phosphoramidating reagent YP-9 was obtained by first reacting phenyldichlorophosphate with L-Alanine isopropyl ester hydrochloride and then with pentafluorophenol. Isolation of single Sp diastereomer YP-9 was achieved via crystallization-induced dynamic resolution in the presence of 20% MTBE/hexane at room temperature.
The uridine nucleoside YP-8 was treated with tert-butylmagnesium chloride in dry THF, followed by pentafluorophenyl Sp diastereomer YP-9 to furnish the Isopropyl (2S)-2-[[[(2R,3R,4R,5R)-5-(2,4-dioxopyrimidin-1-yl)-4-fluoro-3-hydroxy-4-methyl-tetrahydrofuran-2-yl]methoxy-phenoxy-phosphoryl]amino]propanoate (Sovaldi, sofosbuvir, GS-7977, PSI-7977)。
US 7429572
US  8415322
US 7964580
US 8334270B

WO 2006012440
WO 2011123668
In US 20050009737 published Jan. 13, 2005, J. Clark discloses fluoro-nucleoside derivatives that inhibit Hepatitis C Virus (HCV) NS5B polymerase. In particular, 4-amino-1-((2R,3R,4R,5R)-3-fluoro-4-hydroxy-5-hydroxymethyl-3-methyl-tetrahydro-faran-2-yl)-1H-pyrimidin-2-one (18) was a particularly potent inhibitor of HCV polymerase as well as the polymerase of other Flaviviridae.

Figure US20080139802A1-20080612-C00002

In WO2006/012440 published Feb. 2, 2006, P. Wang et al disclose processes for the preparation of 18. Introduction of the cytosine is carried out utilizing the Vorbruggen protocol. In US 20060122146 published Jun. 8, 2006, B.-K. Chun et al. disclose and improved procedures for the preparation of the 2-methyl-2-fluoro-lactone 10. In the latter disclosure the nucleobase is glycosylated by reacting with ribofuranosyl acetate which is prepared by reduction of 10 with LiAlH(O-tert-Bu)followed by acetylaton of the intermediate lactol which was treated with an O-trimethylsilyl N4-benzoylcytosine in the presence of SnClto afford the O,O,N-tribenzoylated nucleoside.
The present process as described in SCHEME A and the following examples contain numerous improvements which have resulted in higher yields of the desired nucleoside. The asymmetric hydroxylation of 22 was discovered to be best carried out with sodium permanganate in the presence of ethylene glycol, sodium bicarbonate in acetone which afforded the diol in 60-64% on pilot plant scale. The sodium permanganate procedure avoids introduction of osmium into the process stream. Further more the stereospecific hydroxylation can be accomplished without using an expensive chiral ligand. The requisite olefin is prepared from (1S,2S)-1,2-bis-((R)-2,2-dimethyl-[1,3]dioxolan-4-yl)-ethane-1,2-diol (20) (C. R. Schmid and J. D. Bryant, Org. Syn. 1995 72:6-13) by oxidative cleavage of the diol and treating the resulting aldehyde with 2-(triphenyl-λ5-phosphanylidene)-propionic acid ethyl ester to afford 22.

Figure US20080139802A1-20080612-C00005

(i) NaIO4, NaHCO3, DCM; (ii) MeC(═PPh3)CO2Et; (iii) acetone-NaMnO(aq), ethylene glycol, NaHCO3, −10 to 0° C.; aq. NaHSO(quench); (iv) i-PrOAc, MeCN, TEA, SOCl2; (v) i-PrOAc, MeCN, NaOCl; (vi) TEA-3HF, TEA; (vii) HCl (aq)-BaCl2-aq; (viii) (PhCO)2O, DMAP, MeCN, (ix) RED-AL/TFE (1:1), DCM; (x) SO2Cl2-TBAB, DCM; (xi) 32, SnCl4-PhCl; (xii) MeOH-MeONa
EXAMPLE 3 (2S,3R)-3-[(4R)-2,2-dimethyl-[1,3]dioxolan-4-yl]-2,3-dihydroxy-2-methyl-propionic acid ethyl ester (24)

Figure US20080139802A1-20080612-C00008

A suspension of 22 (10 kg, CAS Reg. No. 81997-76-4), ethylene glycol (11.6 kg), solid NaHCO(11.8 kg) and acetone (150 L) is cooled to ca.-15° C. A solution of 36% aqueous NaMnO(19.5 kg) is charged slowly (over 4 h) to the suspension maintaining reaction temperature at or below −10° C. After stirring for 0.5 h at −10° C., an aliquot of the reaction mixture (ca. 5 mL) is quenched with 25% aqueous sodium bisulfite (ca. 15 mL). A portion of resulting slurry is filtered and submitted for GC analysis to check the progress of the reaction. When the reaction is complete, the reaction mixture is quenched by slow addition (over 40 min) of cooled (ca. 0° C.) 25% aqueous NaHSO(60 L). The temperature of the reaction mixture is allowed to reach 4° C. during the quench. CELITE® (ca. 2.5 kg) is then slurried in acetone (8 kg) and added to the dark brown reaction mixture. The resulting slurry is aged at RT to obtain light tan slurry. The slurry is filtered, and the filter cake is washed with acetone (3×39 kg). The combined filtrate is concentrated by vacuum distillation (vacuum approximately 24 inches of Hg; max pot temperature is 32° C.) to remove the acetone. The aqueous concentrate is extracted with EtOAc (3×27 kg), and the combined organic extracts were washed with water (25 L). The organic phase is then concentrated by atmospheric distillation and EtOAc is replaced with toluene. The volume of the batch is adjusted to ca. 20 L. Heptane (62 kg) is added and the batch cooled to ca. 27° C. to initiate crystallization. The batch is then cooled to −10° C. After aging overnight at −10° C., the product is filtered, washed with 10% toluene in heptane and dried at 50° C. under vacuum to afford 6.91 kg (59.5%) of 24 (CARN 81997-76-4) as a white crystalline solid.
EXAMPLE 4 (3R,4R,5R)-3-Fluoro-4-hydroxy-5-hydroxymethyl-3-methyl-dihydro-furan-2-one (10)

Figure US20080139802A1-20080612-C00009

steps 1 & 2—A dry, clean vessel was charged with 24 (6.0 kg), isopropyl acetate (28.0 kg), MeCN (3.8 kg) and TEA (5.4 kg). The mixture was cooled to 5-10° C., and thionyl chloride (3.2 kg) was added slowly while cooling the solution to maintain the temperature below 20° C. The mixture was stirred until no starting material was left (GC analysis). The reaction was typically complete within 30 min after addition is complete. To the mixture was added water (9 kg) and after stirring, the mixture was allowed to settle. The aqueous phase was discarded and the organic phase was washed with a mixture of water (8 kg) and saturated NaHCO(4 kg) solution. To the remaining organic phase containing 36 was added MeCN (2.5 kg) and solid NaHCO(3.1 kg). The resulting slurry was cooled to ca. 10° C. Bleach (NaOCl solution, 6.89 wt % aqueous solution, 52.4 kg, 2 eq.) was added slowly while cooling to maintain temperature below 25° C. The mixture was aged with stirring over 90-120 min at 20-25° C., until the reaction was complete (GC analysis). After completion of the reaction, the mixture was cooled to ca. 10° C. and then quenched with aqueous Na2SOsolution (15.1% w/w, 21 kg) while cooling to maintain temperature below 20° C. The quenched reaction mixture was filtered through a cartridge filter to remove inorganic solids. The filtrate was allowed to settle, and phases are separated and the aqueous phase is discarded. The organic layer was washed first with a mixture of water (11 kg) and saturated NaHCOsolution (4.7 kg), then with of saturated NaHCOsolution (5.1 kg). DIPEA (220 mL) was added to the organic phase and the resulting solution was filtered through CELITE® (bag filter) into a clean drum. The reactor was rinsed with isopropyl acetate (7 kg) and the rinse is transferred to the drum. The organic phase was then concentrated under vacuum (25-28 inches of Hg) while maintaining reactor jacket temperature at 45-50° C. to afford 26 as an oil (˜10 L). Additional DIPEA (280 mL) was added and the vacuum distillation was continued (jacket temperature 50-55° C.) until no more distillate was collected. (batch volume ca. 7 L).
step 3—To the concentrated oil from step 2 containing 26 was added TEA (2.34 kg) and TEA-trihydrofluoride (1.63 kg). The mixture was heated to 85° C. for 2 h. The batch was sampled to monitor the progress of the reaction by GC. After the reaction was complete conc. HCl (2.35 kg) was added to the mixture and the resulting mixture heated to ca. 90° C. (small amount of distillate collected). The reaction mixture was stirred at ca. 90° C. for 30 min and then saturated aqueous BaCl2solution (18.8 kg) was added. The resulting suspension was stirred at about 90° C. for 4 h. The resulting mixture was then azeotropically dried under a vacuum (9-10 inches of Hg) by adding slowly n-propanol (119 kg) while distilling off the azeotropic mixture (internal batch temperature ca. 85-90° C.). To the residual suspension was added toluene (33 kg) and vacuum distillation was continued to distill off residual n-propanol (and traces of water) to a minimum volume to afford 28.
step 4—To the residue from step 3 containing 28 was added MeCN (35 kg) and ca. 15 L was distilled out under atmospheric pressure. The reaction mixture was cooled to ca. 10° C. and then benzoyl chloride (8.27 kg) and DMAP (0.14 kg) are added. TEA (5.84 kg) was added slowly to the reaction mixture while cooling to maintain temperature below 40° C. The batch was aged at ca. 20° C. and the progress of the benzoylation is monitored by HPLC. After completion of the reaction, EtOAc (30 kg) was added to the mixture and the resulting suspension is stirred for about 30 min. The reaction mixture was filtered through a CELITE® pad (using a nutsche filter) to remove inorganic salts. The solid cake was washed with EtOAc (38 kg). The combined filtrate and washes were washed successively with water (38 kg), saturated NaHCOsolution (40 kg) and saturated brine (44 kg). The organic phase was polish-filtered (through a cartridge filter) and concentrated under modest vacuum to minimum volume. IPA (77 kg) was added to the concentrate and ca. 25 L of distillate was collected under modest vacuum allowing the internal batch temperature to reach ca. 75° C. at the end of the distillation. The remaining solution was then cooled to ca. 5° C. over 5 h and optionally aged overnight. The precipitate was filtered and washed with of cold (ca. 5° C.) IPA (24 kg). The product was dried under vacuum at 60-70° C. to afford 6.63 kg (70.7% theory of 10 which was 98.2% pure by HPLC.
EXAMPLE 1 Benzoic acid 3-benzoyloxy-5-(4-benzoylamino-2-oxo-2H-pyrimidin-1-yl)-4-fluoro-4-methyl-tetrahydro-furan-2-ylmethyl ester (14)

Figure US20080139802A1-20080612-C00006

Trifluoroethanol (4.08 kg) is added slowly to a cold solution (−15° C.) of RED-AL® solution (12.53 kg) and toluene (21.3 kg) while maintaining the reaction temperature at or below −10° C. After warming up to RT (ca. 20° C.), the modified RED-AL reagent mixture (30.1 kg out of the 37.6 kg prepared) is added slowly to a pre-cooled solution (−15° C.) of fluorolactone dibenzoate 10 (10 kg) in DCM (94.7 kg) while maintaining reaction temperature at or below −10° C. After reduction of the lactone (monitored by in-process HPLC), a catalytic amount of tetrabutylammonium bromide (90 g) is added to the reaction mixture. Sulfiiryl chloride (11.86 kg) is then added while maintaining reaction temperature at or below 0° C. The reaction mixture is then heated to 40° C. until formation of the chloride is complete (ca. 4 h) or warmed to RT (20-25° C.) and stirred over night (ca. 16 h). The reaction mixture is cooled to about 0° C., and water (100 L) is added cautiously while maintaining reaction temperature at or below 15° C. The reaction mixture is then stirred at RT for ca. 1 h to ensure hydrolytic decomposition of excess sulfuryl chloride and the phases are separated. The organic layer is washed with a dilute solution of citric acid (prepared by dissolving 15.5 kg of citric acid in 85 L of water) and then with dilute KOH solution (prepared by dissolving 15 kg of 50% KOH in 100 L of water). The organic phase is then concentrated and solvents are replaced with chlorobenzene (2×150 kg) via atmospheric replacement distillation. The resulting solution containing 30 is dried azeotropically.
A suspension of N-benzoyl cytosine (8.85 kg), ammonium sulfate (0.07 kg) and hexamethyldisilazane (6.6 kg) in chlorobenzene (52.4 kg) is heated to reflux (ca. 135° C.) and stirred (ca. 1 h) until the mixture becomes a clear solution. The reaction mixture is then concentrated in vacuo to obtain 32 as a syrupy liquid. The anhydrous solution of 30 in chlorobenzene (as prepared) and stannic chloride (28.2 kg) is added to this concentrate. The reaction mixture is maintained at about 70° C. until the desired coupling reaction is complete (ca. 10 h) as determined by in-process HPLC. Upon completion, the reaction mixture is cooled to RT and diluted with DCM (121 kg). This solution is added to a suspension of solid NaHCO(47 kg) and CELITE® (9.4 kg) in DCM (100.6 kg). The resulting slurry is cooled to 10-15° C., and water (8.4 kg) is added slowly to quench the reaction mixture. The resulting suspension is very slowly (caution: gas evolution) heated to reflux (ca. 45° C.) and maintained for about 30 min. The slurry is then cooled to ca. 15° C. and filtered. The filter cake is repeatedly reslurried in DCM (4×100 L) and filtered. The combined filtrate is concentrated under atmospheric pressure (the distillate collected in the process is used for reslurrying the filter cake) until the batch temperature rises to about 90° C. and then allowed to cool slowly to about −5° C. The resulting slurry is aged for at least 2 h at −5° C. The precipitated product is filtered and washed with IPA (30 kg+20 kg), and oven-dried in vacuo at about 70° C. to afford 8.8 kg (57.3%) of 1-(2-deoxy-2-fluoro-2-methyl-3-5-O-dibenzoyl-β-D-ribofuranosyl)-N-4-benzoylcytosine (14, CAS Reg No. 817204-32-3) which was 99.3% pure.
EXAMPLE 2 4-Amino-1-(3-fluoro-4-hydroxy-5-hydroxymethyl-3-methyl-tetrahydro-furan-2-yl)-1H-pyrimidin-2-one (18)

Figure US20080139802A1-20080612-C00007

A slurry of 14 (14.7 kg) in MeOH (92.6 kg) is treated with catalytic amounts of methanolic sodium methoxide (0.275 kg). The reaction mixture is heated to ca. 50° C. and aged (ca. 1 h) until the hydrolysis is complete. The reaction mixture is quenched by addition of isobutyric acid (0.115 kg). The resulting solution is concentrated under moderate vacuum and then residual solvents are replaced with IPA (80 kg). The batch is distilled to a volume of ca. 50 L. The resulting slurry is heated to ca. 80° C. and then cooled slowly to ca. 5° C. and aged (ca. 2 h). The precipitated product is isolated by filtration, washed with IPA (16.8 kg) and dried in an oven at 70° C. in vacuo to afford 6.26 kg (88.9%) of 18 which assayed at 99.43% pure.

EXAMPLE 4 Preparation of 2′-deoxy-2′-fluoro-2′-C-methyluridine

2′-Deoxy-2′-fluoro-2′-C-methylcytidine (1.0 g, 1 eq) (Clark, J., et al., J. Med. Chem., 2005, 48, 5504-5508) was dissolved in 10 ml of anhydrous pyridine and concentrated to dryness in vacuo. The resulting syrup was dissolved in 20 ml of anhydrous pyridine under nitrogen and cooled to 0° C. with stirring. The brown solution was treated with benzoyl chloride (1.63 g, 3 eq) dropwise over 10 min. The ice bath was removed and stirring continued for 1.5 h whereby thin-layer chromatography (TLC) showed no remaining starting material. The mixture was quenched by addition of water (0.5 ml) and concentrated to dryness. The residue was dissolved in 50 mL of dichloromethane (DCM) and washed with saturated NaHCOaqueous solution and H2O. The organic phase was dried over NaSOand filtered, concentrated to dryness to give N4,3′,5′-tribenzoyl-2′-Deoxy-2′-fluoro-2′-C-methylcytidine (2.0 g, Yield: 91%).
N4,3′,5′-tribenzoyl-2′-Deoxy-2′-fluoro-2′-C-methylcytidine (2.0 g, 1 eq) was refluxed in 80% aqueous AcOH overnight. After cooling and standing at room temperature (15° C.), most of the product precipitated and then was filtered through a sintered funnel. White precipitate was washed with water and co-evaporated with toluene to give a white solid. The filtrate was concentrated and co-evaporated with toluene to give additional product which was washed with water to give a white solid. Combining the two batches of white solid gave 1.50 g of 3′,5′-dibenzoyl-2′-Deoxy-2′-fluoro-2′-C-methyluridine (Yield: 91%).
To a solution of 3′,5′-dibenzoyl-2′-Deoxy-2′-fluoro-2′-C-methyluridine (1.5 g, 1 eq) in MeOH (10 mL) was added a solution of saturated ammonia in MeOH (20 mL). The reaction mixture was stirred at 0° C. for 30 min, and then warmed to room temperature slowly. After the reaction mixture was stirred for another 18 hours, the reaction mixture was evaporated under reduced pressure to give the residue, which was purified by column chromatography to afford pure compound 2′-deoxy-2′-fluoro-2′-C-methyluridine (500 mg, Yield: 60%).

Example numbers 13-54 and 56-66 are prepared using similar procedures described for examples 5-8. The example number, compound identification, and NMR/MS details are shown below:

entry 25
Figure US08334270-20121218-C00063
entry 251H NMR (DMSO-d6) δ 1.13-1.28 (m, 12H), 3.74-3.81 (m, 2H), 3.95-4.08 (m, 1H), 4.20-4.45 (m, 2H), 4.83-4.87 (m, 1H), 5.52-5.58 (m, 1H),5.84-6.15 (m, 3H), 7.17-7.23 (m, 3H), 7.35-7.39 (m, 2H), 7.54-7.57(m, 1H), 11.50 (s. 1H); MS, m/e 530.2 (M + 1)+


Synthesis of diastereomerically pure nucleotide phosphoramidates.
Ross BS, Reddy PG, Zhang HR, Rachakonda S, Sofia MJ.
J Org Chem. 2011 Oct 21;76(20):8311-9. doi: 10.1021/jo201492m. Epub 2011 Sep 26.

The HCV NS5B nucleoside and non-nucleoside inhibitors.
Membreno FE, Lawitz EJ.
Clin Liver Dis. 2011 Aug;15(3):611-26. doi: 10.1016/j.cld.2011.05.003. Review.

Discovery of a β-d-2'-deoxy-2'-α-fluoro-2'-β-C-methyluridine nucleotide prodrug (PSI-7977) for the treatment of hepatitis C virus.
Sofia MJ, Bao D, Chang W, Du J, Nagarathnam D, Rachakonda S, Reddy PG, Ross BS, Wang P, Zhang HR, Bansal S, Espiritu C, Keilman M, Lam AM, Steuer HM, Niu C, Otto MJ, Furman PA.
J Med Chem. 2010 Oct 14;53(19):7202-18. doi: 10.1021/jm100863x.

Mechanism of activation of PSI-7851 and its diastereoisomer PSI-7977.
Murakami E, Tolstykh T, Bao H, Niu C, Steuer HM, Bao D, Chang W, Espiritu C, Bansal S, Lam AM, Otto MJ, Sofia MJ, Furman PA.
J Biol Chem. 2010 Nov 5;285(45):34337-47. doi: 10.1074/jbc.M110.161802. Epub 2010 Aug 26.

Michael J. Sofia,Donghui Bao, Wonsuk Chang, Jinfa Du, Dhanapalan Nagarathnam, Suguna Rachakonda, P. Ganapati Reddy, Bruce S. Ross, Peiyuan Wang, Hai-Ren Zhang, Shalini Bansal, Christine Espiritu, Meg Keilman, Angela M. Lam, Holly M. Micolochick Steuer, Congrong Niu, Michael J. Otto, and Phillip A. Furman; Discovery of a β-D-2-Deoxy-2-a-fluoro-2-β-C-methyluridine Nucleotide Prodrug (PSI-7977) for the Treatment of Hepatitis C Virus; J. Med. Chem. 2010, 53, 7202–7218; Pharmasset, Inc.

Bruce S. Ross, P. Ganapati Reddy , Hai-Ren Zhang , Suguna Rachakonda , and Michael J. Sofia; Synthesis of Diastereomerically Pure Nucleotide Phosphoramidates; J. Org. Chem., 2011, 76 (20), pp 8311–8319; Pharmasset, Inc.

Peiyuan Wang, Byoung-Kwon Chun, Suguna Rachakonda, Jinfa Du, Noshena Khan, Junxing Shi, Wojciech Stec, Darryl Cleary, Bruce S. Ross and Michael J. Sofia; An Efficient and Diastereoselective Synthesis of PSI-6130: A Clinically Efficacious Inhibitor of HCV NS5B Polymerase; J. Org. Chem., 2009, 74 (17), pp 6819–6824;Pharmasset, Inc.

Jeremy L. Clark, Laurent Hollecker, J. Christian Mason, Lieven J. Stuyver, Phillip M. Tharnish, Stefania Lostia, Tamara R. McBrayer, Raymond F. Schinazi, Kyoichi A. Watanabe, Michael J. Otto, Phillip A. Furman, Wojciech J. Stec, Steven E. Patterson, and Krzysztof W. Pankiewicz; Design, Synthesis, and Antiviral Activity of 2‘-Deoxy-2‘-fluoro-2‘-C-methylcytidine, a Potent Inhibitor of Hepatitis C Virus Replication; J. Med. Chem., 2005, 48 (17), pp 5504–5508; Pharmasset, Inc

SOVALDI is the brand name for sofosbuvir, a nucleotide analog inhibitor of HCV NS5B polymerase.
The IUPAC name for sofosbuvir is (S)-Isopropyl 2-((S)-(((2R,3R,4R,5R)-5-(2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)-4-fluoro-3-hydroxy-4-methyltetrahydrofuran-2-yl)methoxy)-(phenoxy)phosphorylamino)propanoate. It has a molecular formula of C22H29FN3O9P and a molecular weight of 529.45. It has the following structural formula:

SOVALDI™ (sofosbuvir) Structural Formula Illustration

Sofosbuvir is a white to off-white crystalline solid with a solubility of ≥ 2 mg/mL across the pH range of 2-7.7 at 37 oC and is slightly soluble in water.
SOVALDI tablets are for oral administration. Each tablet contains 400 mg of sofosbuvir. The tablets include the following inactive ingredients: colloidal silicon dioxide, croscarmellose sodium, magnesium stearate, mannitol, and microcrystalline cellulose. The tablets are film-coated with a coating material containing the following inactive ingredients: polyethylene glycol, polyvinyl alcohol, talc, titanium dioxide, and yellow iron oxide.


Elbasvir, MK 8742
1370468-36-2  cas
 methyl N-[(2S)-1-[(2S)-2-[4-[(6S)-3-[2-[(2S)-1-[(2S)-2-(methoxycarbonylamino)-3-methylbutanoyl]pyrrolidin-2-yl]-4H-imidazol-4-yl]-6-phenyl-6H-indolo[1,2-c][1,3]benzoxazin-10-yl]-2H-imidazol-2-yl]pyrrolidin-1-yl]-3-methyl-1-oxobutan-2-yl]carbamate
Methyl [(2S)-1-[(2S)-2-[4-[(6S)-3-[2-[(2S)-1-[(2S)-2-[(methoxycarbonyl)amino]-3-methylbutanoyl]pyrrolidin-2-yl]-1H-imidazol-4-yl]-6-phenylindolo[1,2-c][1,3]benzoxazin-10-yl]-1H-imidazol-2-yl]pyrrolidin-1-yl]-3-methyl-1-oxobutan-2-yl]carbamate
Carbamic acid, N,​N‘-​[[(6S)​-​6-​phenyl-​6H-​indolo[1,​2-​c]​[1,​3]​benzoxazine-​3,​10-​diyl]​bis[1H-​imidazole-​5,​2-​diyl-​(2S)​-​2,​1-​pyrrolidinediyl[(1S)​-​1-​(1-​methylethyl)​-​2-​oxo-​2,​1-​ethanediyl]​]​]​bis-​, C,​C‘-​dimethyl ester
MW 882.0171, C49 H55 N9 O7, 


HCV NS5A Inhibitors 
MK-8742 is in phase II clinical development at Merck & Co. for the oral treatment of chronic hepatitis C infection in combination with MK-5172 and ribavirin. Phase I clinical trials are uongoing for the treatment of hepatitis C infected males. In 2013, breakthrough therapy designation was assigned to the compound.
MK-8742 is an inhibitor of Hepatitis C Virus (HCV) non-structural protein 5A (NS5A) that is being developed for the treatment of HCV infection. MK-8742 has broad, potent HCV genotypic activity in vitro against viral variants that are resistant to other NS5A inhibitors. MK-8742 exhibits potent antiviral activity during 5 days of monotherapy in patients with GT1 and GT3 chronic HCV infection. MK-8742 is currently in Phase IIB development.

MK-8742 is an inhibitor of Hepatitis C Virus (HCV) non-structural protein 5A (NS5A) that is being developed for the treatment of HCV infection. MK-8742 has broad, potent HCV genotypic activity in vitro against viral variants that are resistant to other NS5A inhibitors. MK-8742 exhibits potent antiviral activity during 5 days of monotherapy in patients with GT1 and GT3 chronic HCV infection. MK-8742 is currently in Phase IIB development.

Preparation of Compound A
Figure imgf000117_0001
A mixture of Compound Int-19b (1.1 g, 3 mmol), (dibromomethyl)benzene (2.25 g, 9 mmol) and K2C03 (1.2 g, 9 mmol) in 15 mL of DMF was heated to 100 °C and allowed to stir at this temperature for 3 hours. The reaction mixture was cooled to room temperature, concentrated in vacuo and the residue obtained was dissolved with
dichloromethane and water. The aqueous phase was extracted with dichloromethane. The combined organic extracts were washed with brine, dried over Na2S04, filtered and concentrated in vacuo. The resulting residue was purified using flash column
chromatography on silica gel to provide Compound Int-23a (380 mg, 28 %) as a white solid. 1H MR (CDCI3): δ 7.72 (bs, 1 H), 7.44 – 7.46 (d, J= 8.4 Hz, 1 H), 7.21 – 7.28 (m, 3 H), 7.09 – 7.12 (m, 3 H), 7.04 (s, 1 H), 6.99 – 7.01 (bs, J= 6.8 Hz, 2 H), 6.78 (s, 1 H), 6.63 – 6.65 (d, J = 8.4 Hz, 1 H). MS (ESI)
m/e (M+H+): 456. Step B – Pre aration of Compound Int-23b
Figure imgf000118_0001
lnt-23a lnt-23b
To a solution of Int-23a (456 mg, 1.0 mmol) in 1,4-dioxane was added bis pinacol borate (2.2 mmol) , Pd(dppf)Cl2 (0.04 mmol) and KOAc (4 mmol). The reaction mixture was put under N¾ heated to 110°C and allowed to stir at this temperature for 3 hours. The reaction mixture was cooled to room temperature, concentrated in vacuo, and the residue obtained was purified using column chromatography on silica gel to provide Compound Int- 23b (590 mg, 87 % yield). 1H MR (CDC13): δ 8.13 (s, 1 H), 7.60 (d, J= 7.6 Hz, 1 H), 7.52 (d, J= 8.0 Hz, 1H), 7.36 – 7.39 (m, 1 H), 7.14 -7.19 (m, 4 H), 6.93 – 6.95 (m, 3 H), 6.90 (s, 1 H), 1.26 – 1.29 (s, 24 H). MS (ESI) m / e (M+H+): 550.
- Pre aration of Compound Int-23c
Figure imgf000118_0002
lnt-23b lnt-23c
A suspension of Int-23b (550 mg, 1.0 mmol), tert-butyl 2-(2-bromo-lH- imidazol-5-yl) pyrrolidine- 1-carboxylate (2.4 mmol), Pd(dppf) Cl2 (200 mg), Na2C03 (3 mmol) and in THF/H20 (10: 1, 33 mL) was allowed to stir at reflux for about 15 hours under N2. The reaction mixture was cooled to room temperature and filtered, and the filtrate was washed with water (50 mL) and extracted with EtOAc (100 mL). The organic extract was washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The resulting residue was purified using column chromatography on silica gel to provide Compound Int-23c (160 mg). MS (ESI) m / e (M+H+): 768.
Preparation of Compound Int-23d
Figure imgf000119_0001
Int-23c (0.10 g, 0.13 mmol) was added to HCl/CH3OH (5 mL, 3M) and the resulting reaction was allowed to stir at room temperature for about 3 hours. The reaction mixture was then concentrated in vacuo to provide Compound Int-23d, which was used without further purification. MS (ESI) m / e (M+H+): 568.
- Preparation of Compound A
Figure imgf000119_0002
To a solution of Int-23d (56.8 mg, 0.10 mmol), (S)-2- (methoxycarbonylamino)-3-methylbutanoic acid (35.0 mg, 0.20 mmol) and DIPEA (0.8 mmol) in CH3CN (1 mL) was added BOP (98 mg, 0.22 mmol). The resulting reaction was allowed to stir at room temperature and monitored using LCMS. After LCMS showed the starting material to be consumed, the reactionmixture was filtered, and the filtrate was purified using HPLC to provide Compound A as a white solid. 1H MR (MeOD): δ 7.94 (s,
1 H), 7.85 (d, J= 8.0 Hz, 1 H), 7.74 (s, 1 H), 7.63 (s, 1 H), 7.48 (s, 1 H), 7.35 – 7.37 (m, 2 H), 7.31 (s, 1 H), 7.17 – 7.18 (m, 4 H), 7.11 (s, 1 H), 6.96 – 6.98 (d, J = 7.6 Hz, 2 H), 5.09 – 5.17
(m, 2 H), 4.13 (t, J= 8.0 Hz, 2 H), 3.99 (bs, 2 H), 3.78 (bs, 2 H), 3.56 (s, 6 H), 2.44 – 2.47 (m,
2 H), 1.92 – 2.19 (m, 8 H), 0.77 – 0.85 (m, 12 H). MS (ESI) m / e (M+H+): 882.
The diastereomers were separated on a chiral SFC column: Isomer A: 1H NMR (MeOD): δ 8.08 (s, 1H), 7.91 – 7.93 (m, 1 H), 7.72 (s, 1 H), 7.56 (s, 1 H), 7.24 – 7.43 (m, 7 H), 7.19 (s, 1 H), 7.03 – 7.05 (m, 2 H), 5.16 – 5.24 (m, 2 H), 3.81 – 4.21 (m, 6 H), 3.62 (s, 6 H), 2.52 – 2.54 (m, 2 H), 2.00 – 2.25 (m, 8 H), 0.84 – 0.91 (m, 12 H). MS (ESI) m/z (M+H)+: 882.
Isomer B: 1H NMR (MeOD): δ 7.90 (s, 1 H), 7.81 – 7.83 (m, 1 H), 7.72 (s, 1 H), 7.62 (s, 1 H), 7.45 (s, 1 H), 7.14 – 7.33 (m, 6 H), 7.09 (s, 1 H), 6.93 – 6.95 (m, 2 H), 5.06 – 5.14 (m, 2 H), 3.71 – 4.11 (m, 6 H), 3.52 (s, 6 H), 2.41 – 2.44 (m, 2 H), 1.90 – 2.15 (m, 8 H), 0.74 – 0.86 (m, 12 H). MS (ESI) m/z (M+H)+: 882.
 Discovery of MK-8742: An HCV NS5A inhibitor with broad genotype activity
ChemMedChem 2013, 8(12): 1930
The NS5A protein plays a critical role in the replication of HCV and has been the focus of numerous research efforts over the past few years. NS5A inhibitors have shown impressive in vitro potency profiles in HCV replicon assays, making them attractive components for inclusion in all oral combination regimens. Early work in the NS5A arena led to the discovery of our first clinical candidate, MK-4882 [2-((S)-pyrrolidin-2-yl)-5-(2-(4-(5-((S)-pyrrolidin-2-yl)-1H-imidazol-2-yl)phenyl)benzofuran-5-yl)-1H-imidazole]. While preclinical proof-of-concept studies in HCV-infected chimpanzees harboring chronic genotype 1 infections resulted in significant decreases in viral load after both single- and multiple-dose treatments, viral breakthrough proved to be a concern, thus necessitating the development of compounds with increased potency against a number of genotypes and NS5A resistance mutations. Modification of the MK-4882 core scaffold by introduction of a cyclic constraint afforded a series of tetracyclic inhibitors, which showed improved virologic profiles. Herein we describe the research efforts that led to the discovery of MK-8742, a tetracyclic indole-based NS5A inhibitor, which is currently in phase 2b clinical trials as part of an all-oral, interferon-free regimen for the treatment of HCV infection.

Journal of Medicinal Chemistry (2014), 57(5), 1643-1672.
WO2010111483A1 *Mar 25, 2010Sep 30, 2010Merck Sharp & Dohme Corp.Inhibitors of hepatitis c virus replication
US20070049593 *Feb 23, 2005Mar 1, 2007Japan Tobacco Inc.Tetracyclic fused heterocyclic compound and use thereof as HCV polymerase inhibitor

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