Thionyl Chloride → 4-Bromonaphthalene-1-carbonyl chloride

Temperature

40 °C

4-Bromonaphthalene-1-carboxylic acid (9.80 g) was suspended in thionyl chloride (80 mL) and stirred at 40° C. for 16 hours and evaporated under vacuum. Solid was dissolved in DCM (20 mL) and evaporated under vacuum, giving 4-bromonaphthalene-1-carbonyl chloride (13.8 g, crude) as a white solid. 1-(4-Bromonaphthalen-1-yl)-2-diazoethanone: 4-Bromo-naphthalene-1-carbonyl chloride (13.8 g) was dissolved in dichloromethane (130 mL) and cooled to 0° C. TMS diazomethane solution (40 mL, 2 M in DCM) was added, and ice bath was removed. Reaction mixture was stirred for 18 hours and evaporated under vacuum, giving 1-(4-bromonaphthalen-1-yl)-2-diazoethanone (13.8 g, crude) as a brown oil. 2-Bromo-1-(4-bromo-naphthalen-1-yl)-ethanone: 1-(4-Bromonaphthalen-1-yl)-2-diazoethanone (13.8 g) was dissolved in ethyl acetate (200 mL), and hydrobromic acid solution (8.4 mL, 5.7 M in acetic acid) was added at 0° C. Reaction mixture was stirred 15 minutes, NaHCO3 solution (100 mL) was added, and mixture was stirred 10 minutes. Ethyl acetate solution was extracted twice with NaHCO3 solution (50 mL), once with brine (50 mL), and evaporated under vacuum. The oil was dissolved in DCM and purified by chromatography (0-20% ethyl acetate:hexane), giving 2-bromo-1-(4-bromo-naphthalen-1-yl)-ethanone (6.67 g, 51%) as a tan solid. Pyrrolidine-1,2-dicarboxylic acid 2-[2-(4-bromonaphthalen-1-yl)-2-oxo-ethyl]ester 1-tert-butyl ester: Pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester (4.85 g) was dissolved in acetonitrile (65 mL), and triethylamine (3.09 mL) was added. A solution of 2-bromo-1-(4-bromonaphthalen-1-yl)-ethanone (6.60 g) in acetonitrile (35 mL) was added. Reaction mixture was stirred 90 minutes and evaporated under vacuum. Oil was dissolved in DCM (50 mL), extracted once with water (20 mL) and once with NaHCO3 solution (20 mL), and evaporated under vacuum to a concentrated liquid. Solution was purified by chromatography (0-50% ethyl acetate:hexane) and evaporated under vacuum, giving pyrrolidine-1,2-dicarboxylic acid 2-[2-(4-bromonaphthalen-1-yl)-2-oxo-ethyl]ester 1-tert-butyl ester (8.95 g, 95%) as a tan solid. 2-[5-(4-Bromo-naphthalen-1-yl)-1H-imidazol-2-yl]-pyrrolidine-1-carboxylic acid tert-butyl ester: Pyrrolidine-1,2-dicarboxylic acid 2-[2-(4-bromonaphthalen-1-yl)-2-oxo-ethyl]ester 1-tert-butyl ester (8.80 g) and ammonium acetate (7.51 g) were suspended in xylenes. The reaction mixture was stirred at 140° C. for 15 hours and evaporated under vacuum. Solid was dissolved in ethyl acetate (50 mL) and extracted twice with water (20 mL) and once with brine (20 mL). The oil was dissolved in DCM, purified by chromatography (0-50% ethyl acetate:hexanes), and evaporated under vacuum, giving 2-[5-(4-bromo-naphthalen-1-yl)-1H-imidazol-2-yl]-pyrrolidine-1-carboxylic acid tert-butyl ester (4.34 g, 52%) as a tan solid. 5-(4-Bromo-naphthalen-1-yl)-2-pyrrolidin-2-yl-1H-imidazole: 2-[5-(4-Bromo-naphthalen-1-yl)-1H-imidazol-2-yl]-pyrrolidine-1-carboxylic acid tert-butyl ester (1.00 g) was dissolved in DCM (12 mL), and trifluoroacetic acid (4 mL) was added. The reaction mixture was stirred at ambient temperature for 3 hours and evaporated under vacuum. Solid was dissolved in DCM (10 mL) and extracted with saturated NaHCO3 solution (30 mL). A solid was collected by vacuum filtration, washed with DCM, and dried under vacuum, giving 5-(4-bromo-naphthalen-1-yl)-2-pyrrolidin-2-yl-1H-imidazole (0.940 g, crude) as an off-white solid. (1-{2-[5-(4-Bromo-naphthalen-1-yl)-1H-imidazol-2-yl]-pyrrolidine-1-carbonyl}-2-methyl-propyl)-carbamic acid methyl ester: 5-(4-bromo-naphthalen-1-yl)-2-pyrrolidin-2-yl-1H-imidazole (0.925 g), 2-methoxycarbonylamino-3-methyl-butyric acid (0.441 g), and HATU (1.00 g) were dissolved in anhydrous DMF (15 mL), and N-methylmorpholine (0.497 mL) was added. The reaction mixture was stirred at ambient temperature for 30 minutes and evaporated under vacuum. The oil was dissolved in DCM, purified by chromatography (0-100% ethyl acetate:hexanes), and evaporated under vacuum, giving (1-{2-[5-(4-bromo-naphthalen-1-yl)-1H-imidazol-2-yl]-pyrrolidine-1-carbonyl}-2-methyl-propyl)-carbamic acid methyl ester (0.814 g, 72%) as an off-white solid. [1-(2-{5-[4-(4-{2-[1-(2-Methoxycarbonylamino-3-methyl-butyryl)-pyrrolidin-2-yl]-3H-imidazol-4-yl}-phenyl)-naphthalen-1-yl]-1H-imidazol-2-yl}-pyrrolidine-1-carbonyl)-2-methyl-propyl]carbamic acid methyl ester: (1-{2-[5-(4-Bromo-naphthalen-1-yl)-1H-imidazol-2-yl]-pyrrolidine-1-carbonyl}-2-methyl-propyl)-carbamic acid methyl ester (0.115 g), [2-Methyl-1-(2-{5-[4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-phenyl]-1H-imidazol-2-yl}-pyrrolidine-1-carbonyl)-propyThcarbamic acid methyl ester (0.111 g), and NaHCO3 (0.0623 g) were dissolved in a mixture of 1,2-dimethoxyethane (3 mL) and water (1 mL). The solution was degassed with nitrogen, and Pd(PPh3)4 (0.0114 g) was added. The reaction mixture was stirred at 85° C. for 16 hours and evaporated under vacuum. Solid was dissolved in ethyl acetate (10 mL) and extracted twice with water (10 mL) and once with brine (10 mL). Solution was evaporated, dissolved in DMF, purified by reverse phase HPLC (5-70% acetonitrile:water), and lyophilized, giving [1-(2-{5-[4-(4-{2-[1-(2-Methoxycarbonylamino-3-methyl-butyryl)-pyrrolidin-2-yl]-3H-imidazol-4-yl}-phenyl)-naphthalen-1-yl]-1H-imidazol-2-yl]-pyrrolidine-1-carbonyl)-2-methyl-propyl]-carbamic acid methyl ester (0.037 g, 21%) as a white solid: 1H-NMR: 300 MHz, (CHCl3-d1) δ: 8.9 (m, 1H), 7.6 (m, 2H), 7.4 (m, 5H), 7.0 (m, 2H), 6.8 (m, 2H), 5.8 (m, 2H), 5.3 (m, 2H), 4.3 (m, 2H), 4.0 (m, 4H), 3.6 (s, 6H), 2.4 (m, 6H), 2.0 (m, 6H), 0.8 (m, 12H); MS (ESI) m/z 789 [M+H]+.

1. customevaporated under vacuum
2. dissolutionSolid was dissolved in DCM (20 mL)
3. customevaporated under vacuum

ORD record

ord-1ba7f12b7c034823881a73a7c3daaaec

Source dataset

uspto-grants-2012_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08273341B2