Daclatasvir (USAN^[1]) (formerly BMS-790052, trade name Daklinza) is a drug for the treatment of hepatitis C (HCV). It is was developed by Bristol-Myers Squibb and was approved in Europe on 22 August 2014.

Daclatasvir inhibits the HCV nonstructural protein NS5A.^[2][3] Recent research suggests that it targets two steps of the viral replication process, enabling rapid decline of HCV RNA.^[4]

Daclatasvir has been tested in combination regimens with pegylated interferon and ribavirin,^[5] as well as with other direct-acting antiviral agents including asunaprevir^[6][7][8][9] and sofosbuvir.^[10][11]

It is on the World Health Organization’s List of Essential Medicines, a list of the most important medications needed in a basic health system.^[12]

EUROPEAN MEDICINES AGENCY ADVISES ON COMPASSIONATE USE OF DACLATASVIR

• The first compassionate-use opinion for a hepatitis C treatment was adopted by the CHMP in October 2013.
• Sofosbuvir, which is part of this compassionate-use opinion, received a positive opinion from the CHMP recommending granting of a marketing authorisation at its November 2013 meeting.
• Daclatasvir is developed by Bristol-Myers Squibb and sofosbuvir is developed by Gilead.

US20090041716

https://www.google.co.in/patents/US20090041716?pg=PA1&dq=us+2009041716&hl=en&sa=X&ei=3ki4Uo-jEsTirAfzwoHQBQ&ved=0CD4Q6AEwAQ

EXAMPLES

A 1 L, 3-neck round bottom flask, fitted with a nitrogen line, overhead stirrer and thermocouple, was charged with 20 g (83.9 mmol, 1 equiv) 1,1′-(biphenyl-4,4′-diyl)diethanone, 200 mL CH₂Cl₂ and 8.7 mL (27.1 g, 169.3 mmol, 2.02 quiv) bromine. The mixture was allowed to stir under nitrogen for about 20 hours under ambient conditions. The resulting slurry was charged with 200 mL CH₂Cl₂ and concentrated down to about 150 mL via vacuum distillation. The slurry was then solvent exchanged into THF to a target volume of 200 mL via vacuum distillation. The slurry was cooled to 20-25° C. over 1 hour and allowed to stir at 20-25° C. for an additional hour. The off-white crystalline solids were filtered and washed with 150 mL CH₂Cl₂. The product was dried under vacuum at 60° C. to yield 27.4 g (69.2 mmol, 82%) of the desired product  : ¹H NMR (400 MHz, CDCl₃) δ 7.95-7.85 (m, 4H), 7.60-7.50 (m, 4H), 4.26 (s, 4H); ¹³C NMR (100 MHz, CDCl₃) 6 191.0, 145.1, 133.8, 129.9, 127.9, 30.8; IR (KBr, cm−1) 3007, 2950, 1691, 1599, 1199; Anal calcd for C₁₆H₁₂Br₂O₂: C, 48.52; H, 3.05; Br, 40.34. Found: C, 48.53; H, 3.03; Br, 40.53 HRMS calcd for C₁₆H₁₃Br₂O₂ (M+H; DCI⁺): 394.9282. Found: 394.9292. mp 224-226° C.

A 500 mL jacketed flask, fitted with a nitrogen line, thermocouple and overhead stirrer, was charged with 20 g (50.5 mmol, 1 equiv) of Compound 2, 22.8 g (105.9 moles, 2.10 equiv) 1-(tert-butoxycarbonyl)-L-proline and 200 mL acetonitrile. The slurry was cooled to 20° C. followed by the addition of 18.2 mL (13.5 g, 104.4 mmol, 2.07 equiv) DIPEA. The slurry was warmed to 25° C. and allowed to stir for 3 hours. The resulting clear, organic solution was washed with 3×100 mL 13 wt % aqueous NaCl. The rich acetonitrile solution was solvent exchanged into toluene (target volume=215 mL) by vacuum distillation until there was less than 0.5 vol % acetonitrile.

The toluene solution of Compound 3 was charged with 78 g (1.011 moles, 20 equiv) ammonium acetate and heated to 95-100° C. The mixture was allowed to stir at 95-100° C. for 15 hours. After reaction completion, the mixture was cooled to 70-80° C. and charged with 7 mL acetic acid, 40 mL n-butanol, and 80 mL of 5 vol % aqueous acetic acid. The resulting biphasic solution was split while maintaining a temperature >50° C. The rich organic phase was charged with 80 mL of 5 vol % aqueous acetic acid, 30 mL acetic acid and 20 mL n-butanol while maintaining a temperature >50° C. The resulting biphasic solution was split while maintaining a temperature >50° C. and the rich organic phase was washed with an additional 80 mL of 5 vol % aqueous acetic acid. The rich organic phase was then solvent exchanged into toluene to a target volume of 215 mL by vacuum distillation. While maintaining a temperature >60° C., 64 mL methanol was charged. The resulting slurry was heated to 70-75° C. and aged for 1 hour. The slurry was cooled to 20-25° C. over 1 hour and aged at that temperature for an additional hour. The slurry was filtered and the cake was washed with 200 mL 10:3 toluene:methanol. The product was dried under vacuum at 70° C., resulting in 19.8 g (31.7 mmol, 63%) of the desired product: ¹H NMR (400 MHz, DMSO-d₆) δ 13.00-11.00 (s, 2H), 7.90-7.75 (m, 4H), 7.75-7.60 (m, 4H), 7.60-7.30 (s, 2H), 4.92-4.72 (m, 2H), 3.65-3.49 (m, 2H), 3.49-3.28 (m, 2H), 2.39-2.1 (m, 2H), 2.10-1.87 (m, 6H), 1.60-1.33 (s, 8H), 1.33-1.07 (s, 10H); ¹³C NMR (100 MHz, DMSO-d₆) δ 154.1, 153.8, 137.5, 126.6, 125.0, 78.9, 78.5, 55.6, 55.0, 47.0, 46.7, 33.7, 32.2, 28.5, 28.2, 24.2, 23.5; IR (KBr, cm−1) 2975, 2876, 1663, 1407, 1156, 1125; HRMS calcd for C₃₆H₄₅N₆O₄ (M+H; ESI⁺): 625.3502. Found: 625.3502. mp 190-195° C. (decomposed).

To a 250 mL reactor equipped with a nitrogen line and overhead stirrer, 25.0 g of Compound 4 (40.01 mmol, 1 equiv) was charged followed by 250 mL methanol and 32.85 mL (400.1 mmol, 10 equiv) 6M aqueous HCl. The temperature was increased to 50° C. and agitated at 50° C. for 5 hours. The resulting slurry was cooled to 20-25° C. and held with agitation for about 18 hours. Filtration of the slurry afforded a solid which was washed successively with 100 mL 90% methanol/water (V/V) and 2×100 mL of methanol. The wet cake was dried in a vacuum oven at 50° C. overnight to give 18.12 g (31.8 mmol, 79.4%) of the desired product.

Recrystallization of Compound 5

To a 250 mL reactor equipped with a nitrogen line and an overhead stirrer, 17.8 g of Compound 5 from above was charged followed by 72 mL methanol. The resulting slurry was agitated at 50° C. for 4 hours, cooled to 20-25° C. and held with agitation at 20-25° C. for 1 hour. Filtration of the slurry afforded a crystalline solid which was washed with 60 mL methanol. The resulting wet cake was dried in a vacuum oven at 50° C. for 4 days to yield 14.7 g (25.7 mmol, 82.6%) of the purified product: ¹H NMR (400 MHz, DMSO-d₆) δ 10.5-10.25 (br, 2H), 10.1-9.75 (br, 2H), 8.19 (s, 2H), 7.05 (d, J=8.4, 4H), 7.92 (d, J=8.5, 4H), 5.06 (m, 2H), 3.5-3.35 (m, 4H), 2.6-2.3 (m, 4H), 2.25-2.15 (m, 2H), 2.18-1.96 (m, 2H); ¹³C NMR (100 MHz, DMSO-d₆) δ 156.6, 142.5, 139.3, 128.1, 127.5, 126.1, 116.9, 53.2, 45.8, 29.8, 24.3; IR (KBr, cm⁻¹) 3429, 2627, 1636, 1567, 1493, 1428, 1028. Anal calcd for C₂₆H₃₂N₆Cl₄: C, 54.75; H, 5.65; Cl, 24.86; Adjusted for 1.9% water: C, 53.71; H, 5.76; N, 14.46; Cl, 24.39. Found: C, 53.74; H, 5.72; N, 14.50; Cl, 24.49; KF=1.9. mp 240° C. (decomposed).

 

A 1 L jacketed flask equipped with a nitrogen line and an overhead stirrer was sequentially charged with 100 mL acetonitrile, 13.69 g (89.4 mmol, 2.5 equiv) hydroxybenzotriazole hydrate, 15.07 g (86 mmol, 2.4 equiv) N-(methoxycarbonyl)-L-valine, 16.46 g (85.9 mmol, 2.4 equiv) 1-(3-dimethyaminopropyl)-3-ethylcarbodiimide hydrochloride and an additional 100 mL acetonitrile. The resulting solution was agitated at 20° C. for 1 hour and charged with 20.4 g (35.8 mmol, 1 equiv) of purified Compound 5. The slurry was cooled to about 0° C. and 18.47 g (142.9 mmol, 4 equiv) diisopropylethylamine was added over 30 minutes while maintaining a temperature below 10° C. The solution was slowly heated to 15° C. over 3 hours and held at 15° C. for 12 hours. The resulting solution was charged with 120 mL 13 wt % aqueous NaCl and heated to 50° C. for 1 hour. After cooling to 20° C., 100 mL of isopropyl acetate was added. The biphasic solution was filtered through a 0.45 μm filter and the mixture split. The rich organic phase was washed with 2×240 mL of a 0.5 N NaOH solution containing 13 wt % NaCl followed by 120 mL 13 wt % aqueous NaCl. The mixture was then solvent exchanged into isopropyl acetate by vacuum distillation with a target volume of 400 mL. The resulting hazy solution was cooled to 20° C. and filtered through a 0.45 μm filter. The clear solution was then solvent exchanged into ethanol by vacuum distillation with a target volume of 140 mL. While maintaining a temperature of 50° C., 66.4 mL (82.3 mmol, 2.3 equiv) of 1.24M HCl in ethanol was added. The mixture was then charged with 33 mg (0.04 mmol, 0.001 equiv) of seed crystals of Compound (I) (see preparation below) and the resulting slurry was stirred at 50° C. for 3 hours. The mixture was cooled to 20° C. over 1 hour and aged at that temperature for an additional 22 hours. The slurry was filtered and the wet cake was washed with 100 mL of 2:1 acetone:ethanol. The solids were dried in a vacuum oven at 70° C. to give 22.15 g (27.3 mmol, 76.3%) of the desired product.

 

A solution of Compound (I) was prepared by dissolving 3.17 g of Compound (I) from above in 22 mL methanol. The solution was passed through a 47 mm Cuno Zeta Carbon® 53SP filter at ˜5 psig at a flow rate of ˜58 mL/min. The carbon filter was rinsed with 32 mL of methanol. The solution was concentrated down to 16 mL by vacuum distillation. While maintaining a temperature of 40-50° C., 15.9 mL acetone and 5 mg of seed crystals of Compound (I) (see procedure below) were added. The resulting slurry was then charged with 32 mL acetone over 30 minutes. The slurry was held at 50° C. for 2 hours, cooled to 20° C. over about 1 hour and held at 20° C. for about 20 hours. The solids were filtered, washed with 16 mL 2:1 acetone:methanol and dried in a vacuum oven at 60° C. to give 2.14 g (67.5%) of purified Compound (I):

¹H NMR (400 MHz, DMSO-d₆, 80° C.): 8.02 (d, J=8.34 Hz, 4 H), 7.97 (s, 2 H), 7.86 (d, J=8.34 Hz, 4 H), 6.75 (s, 2 H), 5.27 (t, J=6.44 Hz, 2 H), 4.17 (t, J=6.95 Hz, 2 H), 3.97-4.11 (m, 2 H), 3.74-3.90 (m, 2 H), 3.57 (s, 6 H), 2.32-2.46 (m, 2 H), 2.09-2.31 (m, 6 H), 1.91-2.07 (m, 2 H), 0.88 (d, J=6.57 Hz, 6 H), 0.79 (d, J=6.32 Hz, 6 H);

¹³C NMR (75 MHz, DMSO-d₆): δ 170.9, 156.9, 149.3, 139.1, 131.7, 127.1, 126.5, 125.9, 115.0, 57.9, 52.8, 51.5, 47.2, 31.1, 28.9, 24.9, 19.6, 17.7;

IR (neat, cm⁻¹): 3385, 2971, 2873, 2669, 1731, 1650.

Anal. Calcd for C₄₀H₅₂N₈O₆Cl₂: C, 59.18; H, 6.45; N, 13.80; Cl, 8.73. Found C, 59.98; H, 6.80; N, 13.68; Cl, 8.77. mp 267° C. (decomposed).

Preparation of Seed Crystals of Compound (I)

A 250 mL round-bottom flask was charged with 6.0 g (10.5 mmol, 1 equiv) Compound 5, 3.87 g (22.1 mmol, 2.1 equiv) N-(methoxycarbonyl)-L-valine, 4.45 g (23.2 mmol, 2.2 equiv) 1-(3-dimethyaminopropyl)-3-ethylcarbodiimide hydrochloride, 0.289 g (2.14 mmol, 0.2 equiv) 1-hydroxybenzotriazole, and 30 mL acetonitrile. The resulting slurry was then charged with 7.33 mL (42.03 mmol, 4 equiv) diisopropylethylamine and allowed to stir at 24-30° C. for about 18 hours. The mixture was charged with 6 mL of water and heated to 50° C. for about 5 hours. The mixture was cooled and charged with 32 mL ethyl acetate and 30 mL water. The layers were separated and the rich organic layer was washed with 30 mL of 10 wt % aqueous NaHCO₃, 30 mL water, and 20 mL of 10 wt % aqueous NaCl. The rich organic layer was then dried over MgSO₄, filtered, and concentrated down to a residue. The crude material was then purified via flash chromatography (silica gel, 0-10% methanol in dichloromethane) to provide the free base of Compound (I).

The free-base of Compound (I) (0.03 g) was dissolved in 1 mL isopropanol at 20° C. Anhydrous HCl (70 μL, dissolved in ethanol, approximately 1.25M concentration) was added and the reaction mixture was stirred. To the solution was added methyl tert-butyl ether (1 mL) and the resulting slurry was stirred vigorously at 40° C. to 50° C. for 12 hours. The crystal slurry was cooled to 20° C. and filtered. The wet cake was air-dried at 20° C. A white crystalline solid (Form N-2 of Compound (I)) was obtained.

 

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Daclatasvir synthesis: WO2009020828A1

Procedure:

Step a: A 1 L, 3 -neck round bottom flask, fitted with a nitrogen line, overhead stirrer and thermocouple, was charged with 20 g (83.9 mmol, 1 equiv) 1,1′-(biphenyl-4,4′-diyl)diethanone, 200 mL Dichloromethane and 8.7 mL (27.1g, 169.3 mmol, 2.02 equiv) bromine. The mixture was allowed to stir under nitrogen for about 20 hours under ambient conditions. The resulting slurry was charged with 200 mL Dichloromethane and concentrated down to about 150 mL via vacuum distillation. The slurry was then solvent exchanged into THF to a target volume of 200 mL via vacuum distillation. The slurry was cooled to 20-25 ⁰C over 1 hour and allowed to stir at 20-25 ⁰C for an additional hour. The off-white crystalline solids were filtered and washed with 150 mL Dichloromethane. The product was dried under vacuum at 60 0C to yield 27.4 g (69.2 mmol, 82%) of the desired product: 1H NMR (400 MHz, CDCl3) d 7.95-7.85 (m, 4H), 7.60-7.50 (m, 4H), 4.26 (s, 4H); 13C NMR 100 MHz, CDCl3) d 191.0, 145.1, 133.8, 129.9, 127.9, 30.8; IR (KBr, cm-1) 3007, 2950, 1691, 1599, 1199; Anal calcd for C16H12Br2O2: C, 48.52; H, 3.05; Br, 40.34. Found: C, 48.53; H, 3.03; Br, 40.53. HRMS calcd for C16H12Br2O2 (M + H; DCI+): 394.9282. Found: 394.9292. mp 224-226 0C.

Step b: A 500 mL jacketed flask, fitted with a nitrogen line, thermocouple and overhead stirrer, was charged with 20 g (50.5 mmol, 1 equiv) of Compound 2, 22.8 g (105.9 moles, 2.10 equiv) 1-(tert-butoxycarbonyl)-L-proline and 200 mL acetonitrile. The slurry was cooled to 20 ⁰C followed by the addition of 18.2 mL (13.5 g, 104.4 mmol, 2.07 equiv) DIPEA. The slurry was warmed to 25 ⁰C and allowed to stir for 3 hours. The resulting clear, organic solution was washed with 3 x 100 mL 13 wt% aqueous NaCl. The rich acetonitrile solution was solvent exchanged into toluene (target volume = 215 mL) by vacuum distillation until there was less than 0.5 vol% acetonitrile.

Step c: The toluene solution of Compound 3 was charged with 78 g (1.011 moles, 20 equiv) ammonium acetate and heated to 95-100 ⁰C. The mixture was allowed to stir at 95-100 ⁰C for 15 hours. After reaction completion, the mixture was cooled to 70- 80 ⁰C and charged with 7 mL acetic acid, 40 mL n-butanol, and 80 mL of 5 vol% aqueous acetic acid. The resulting biphasic solution was split while maintaining a temperature > 50 ⁰C. The rich organic phase was charged with 80 mL of 5 vol% aqueous acetic acid, 30 mL acetic acid and 20 mL n-butanol while maintaining a temperature > 50 ⁰C. The resulting biphasic solution was split while maintaining a temperature > 50 ⁰C and the rich organic phase was washed with an additional 80 mL of 5 vol% aqueous acetic acid. The rich organic phase was then solvent exchanged into toluene to a target volume of 215 mL by vacuum distillation. While maintaining a temperature > 60 ⁰C, 64 mL methanol was charged. The resulting slurry was heated to 70-75 0C and aged for 1 hour. The slurry was cooled to 20-25 ⁰C over 1 hour and aged at that temperature for an additional hour. The slurry was filtered and the cake was washed with 200 mL 10:3 toluene:methanol. The product was dried under vacuum at 70 ⁰C, resulting in 19.8 g (31.7 mmol, 63%) of the desired product: 1H NMR (400 MHz, DMSO-^) d 13.00-11.00 (s, 2H), 7.90-7.75 (m, 4H), 7.75-7.60 (m, 4H), 7.60-7.30 (s, 2H), 4.92-4.72 (m, 2H), 3.65-3.49 (m, 2H), 3.49-3.28 (m, 2H), 2.39-2.1 (m, 2H), 2.10-1.87 (m, 6H), 1.60-1.33 (s, 8H), 1.33-1.07 (s, 10H); 13C NMR (100 MHz, DMSO-?fe) d 154.1, 153.8, 137.5, 126.6, 125.0, 78.9, 78.5, 55.6, 55.0, 47.0, 46.7, 33.7, 32.2, 28.5, 28.2, 24.2, 23.5; IR (KBr, cm-1) 2975, 2876, 1663, 1407, 1156, 1125; HRMS calcd for C36H45N6O4 (M + H; ESI+): 625.3502. Found: 625.3502. mp 190-195 0C (decomposed).

Step d: To a 250 mL reactor equipped with a nitrogen line and overhead stirrer, 25.0 g of Compound 4 (40.01 mmol, 1 equiv) was charged followed by 250 mL methanol and 32.85 mL (400.1 mmol, 10 equiv) 6M aqueous HCl. The temperature was increased to 50 ⁰C and agitated at 50 ⁰C for 5 hours. The resulting slurry was cooled to 20-25 ⁰C and held with agitation for about 18 hours. Filtration of the slurry afforded a solid which was washed successively with 100 mL 90% methanoI/water (WV) and 2 x 100 mL of methanol. The wet cake was dried in a vacuum oven at 50 ⁰C overnight to give 18.12 g (31.8 mmol, 79.4%) of the desired product.

Preparation of Compound (I)

A 1 L jacketed flask equipped with a nitrogen line and an overhead stirrer was sequentially charged with 100 mL acetonitrile, 13.69 g (89.4 mmol, 2.5 equiv) hydroxybenzotriazole hydrate, 15.07 g (86 mmol, 2.4 equiv) N-(methoxycarbonyl)- L-valine, 16.46 g (85.9 mmol, 2.4 equiv) l-(3-dimethyaminopropyl)-3- ethylcarbodiimide hydrochloride and an additional 100 mL acetonitrile. The resulting solution was agitated at 20 ⁰C for 1 hour and charged with 20.4 g (35.8 mmol, 1 equiv) of purified Compound 7. The slurry was cooled to about 0 ⁰C and 18.47 g (142.9 mmol, 4 equiv) diisopropylethylamine was added over 30 minutes while maintaining a temperature below 10 ⁰C. The solution was slowly heated to 15 ⁰C over 3 hours and held at 15 ⁰C for 12 hours. The resulting solution was charged with 120 mL 13 wt% aqueous NaCl and heated to 50 ⁰C for 1 hour. After cooling to 20 ⁰C, 100 mL of isopropyl acetate was added. The biphasic solution was filtered through a 0.45 μm filter and the mixture split. The rich organic phase was washed with 2 x 240 mL of a 0.5 Ν NaOH solution containing 13 wt% NaCl followed by 120 mL 13 wt% aqueous NaCl. The mixture was then solvent exchanged into isopropyl acetate by vacuum distillation with a target volume of 400 mL. The resulting hazy solution was cooled to 20 ⁰C and filtered through a 0.45 μm filter. The clear solution was then solvent exchanged into ethanol by vacuum distillation with a target volume of 140 mL. While maintaining a temperature of 50 ⁰C, 66.4 mL (82.3 mmol, 2.3 equiv) of 1.24M HCl in ethanol was added. The mixture was then charged with 33 mg (0.04 mmol, 0.001 equiv) of seed crystals of Compound (I) (see preparation below) and the resulting slurry was stirred at 50 ⁰C for 3 hours. The mixture was cooled to 20 ⁰C over 1 hour and aged at that temperature for an additional 22 hours. The slurry was filtered and the wet cake was washed with 100 mL of 2: 1 acetone:ethanol. The solids were dried in a vacuum oven at 70 ⁰C to give 22.15 g (27.3 mmol, 76.3%) of the desired product.

Alternative Preparation of Compound (I)

A jacketed reactor equipped with a mechanical agitator, a thermocouple and a nitrogen inlet was sequentially charged with 10 L acetonitrile, 0.671 kg (4.38 moles, 2.50 equiv) 1-hydroxybenzotriazole, 0.737 kg (4.21 moles, 2.40 equiv) N- (methoxycarbonyl)-L-valine and 0.790 kg (4.12 moles, 2.35 equiv) l-(3- dimethyaminopropyl)-3-ethylcarbodiimide hydrochloride. The mixture was agitated at 20⁰C for 1 hour, cooled to 5 ⁰C and charged with 1 kg (1.75 moles, 1.00 equiv) Compound 7. While maintaining a temperature < 10 ⁰C, 0.906 kg (7.01 moles, 4 equiv) diisopropylethylamine was added. The mixture was heated to 15-20 ⁰C over 2 hours and agitated for an additional 15 hours. After the reaction was complete, the mixture was washed once with 6.0 L 13 wt% aqueous NaCl, twice with 6.1 L (6.12 moles, 3.5 equiv) 1.0 M aqueous NaOH containing 13 wt% NaCl and once with 6.0 L 13 wt% aqueous NaCl. Water was then removed from the rich organic solution via azeotropic distillation. The mixture was cooled to 20 ⁰C, agitated for 1 hour and filtered. The rich organic solution was then solvent exchanged into EtOH via vacuum distillation to a target volume of 5 L. While maintaining a temperature of 50 ⁰C, 3.2 L (4.0 moles, 2.3 equiv) 1.25M HCl in EtOH was charged. The mixture was seeded with 1.6 g Compound (I) (see preparation below) and agitated at 50 ⁰C for 3 hours. The resulting slurry was cooled to 20 ⁰C and agitated for at least 3 hours. The product was collected by filtration and washed with 5 L 2: 1 acetone:

EtOH to give 1.29 kg (ca. 90 wt% product) of wet crude product. A reactor equipped with an overhead agitator, nitrogen inlet and thermocouple was charged with 1.11 kg of the above crude product and 7 L methanol. The resulting solution was treated with Cuno Zeta Carbon (TM) 55SP. The carbon was washed with 15 L MeOH and the combined filtrate and wash was concentrated down to 4 L via vacuum distillation. The concentrated solution was charged with 5 L acetone and seeded with 1.6 g Compound (I) (see preparation below) while maintaining a temperature of 50 ⁰C. An additional 10 L acetone was charged and the resulting slurry was stirred at 50 ⁰C for 3 hours. The slurry was cooled to 20 ⁰C and allowed to agitate at 20⁰C for 3 hours. The product was collected by filtration, washed with 5 L 2: 1 acetone: EtOH and dried under vacuum at 50-60 ⁰C to give 0.900 kg (1.11 moles, 74% adjusted) of Compound (I)-

Carbon Treatment and Recrystallization of Compound (I) A solution of Compound (I) was prepared by dissolving 3.17 g of Compound (I) from above in 22 mL methanol. The solution was passed through a 47mm Cuno Zeta Carbon 53SP filter at ~5 psig at a flow rate of~58mL/min. The carbon filter was rinsed with 32 mL of methanol. The solution was concentrated down to 16 mL by vacuum distillation. While maintaining a temperature of 40-50 ⁰C, 15.9 mL acetone and 5 mg of seed crystals of Compound (I) (see procedure below) were added. The resulting slurry was then charged with 32 mL acetone over 30 minutes. The slurry was held at 50 ⁰C for 2 hours, cooled to 20 ⁰C over about 1 hour and held at 20 ⁰C for about 20 hours. The solids were filtered, washed with 16 mL 2: 1 acetone:methanol and dried in a vacuum oven at 60 ⁰C to give 2.14 g (67.5%) of purified Compound (I):

¹H NMR (400 MHz, DMSO-έfc, 80 ⁰C): 8.02 (d, J=8.34 Hz, 4 H), 7.97 (s, 2 H), 7.86 (d, J=8.34 Hz, 4 H), 6.75 (s, 2 H), 5.27 (t, J=6.44 Hz, 2 H), 4.17 (t, J=6.95 Hz, 2 H), 3.97 – 4.11 (m, 2 H), 3.74 – 3.90 (m, 2 H), 3.57 (s, 6 H), 2.32 – 2.46 (m, 2 H), 2.09 – 2.31 (m, 6 H), 1.91 – 2.07 (m, 2 H), 0.88 (d, J=6.57 Hz, 6 H), 0.79 (d, J=6.32 Hz, 6 H);

¹³C NMR (75 MHz, DMSO-έfc): δ 170.9, 156.9, 149.3, 139.1, 131.7, 127.1, 126.5, 125.9, 115.0, 57.9, 52.8, 51.5, 47.2, 31.1, 28.9, 24.9, 19.6, 17.7;

IR (neat, cm^“1): 3385, 2971, 2873, 2669, 1731, 1650.

Anal. Calcd for C₄₀H₅₂N₈O₆Cl₂: C, 59.18; H, 6.45; N, 13.80; Cl, 8.73. Found C, 59.98; H, 6.80; N, 13.68; Cl, 8.77. mp 267 ⁰C (decomposed).

Characteristic diffraction peak positions (degrees 2Θ + 0.1) @ RT, based on a high quality pattern collected with a diffractometer (CuKa) with a spinning capillary with 2Θ calibrated with a NIST other suitable standard are as follows: 10.3, 12.4, 12.8, 13.3, 13.6, 15.5, 20.3, 21.2, 22.4, 22.7, 23.7

Daclatasvir faces problems in USA

The US-FDA in 2014 issued a complete response letter for NS5A inhibitor daclatasvir saying it was unable to approve the drug because the marketing application was for its use in tandem with asunaprevir, an NS3/NS4A protease inhibitor discontinued in the US by BMS for commercial reasons. Daclatasvir is already on the market in Europe-where it is sold as Daklinza-and also in Japan where it was approved alongside asunaprevir in July as the country’s first all-oral HCV therapy. However, a delay in the large US market is clearly a major setback for BMS’ ambitions in hepatitis therapy.

To make the matter worse, US FDA has rescinded breakthrough therapy designation status from Bristol-Myers Squibb for Daclatasvir for the treatment of hepatitis C virus infection in Feb 2015.