Hydrochloric Acid → HCID 71147215, compound

Participants

Reaction Steps

To a solution of methyl 3-amino-5-bromothiophene-2-carboxylate (1.14 g) produced in Example 1, step C in tetrahydrofuran (20 mL) was added 1M lithium hexamethyldisilazide-tetrahydrofuran solution (4.84 mL) at 0° C., and the mixture was stirred for 30 min. To the reaction mixture was added a solution of tert-butyl(1S,4R)-3-oxo-1-phenyl-2-oxa-5-azabicyclo[2.2.1]heptane-5-carboxylate (700 mg) in tetrahydrofuran (5 mL), and the mixture was stirred at room temperature for 15 hr. The reaction mixture was neutralized with 1M hydrochloric acid under ice-cooling, and extracted with ethyl acetate (20 mL). The organic layer was washed with brine (5 mL), and dried over anhydrous magnesium sulfate. Insoluble material was filtered off, and the filtrate was concentrated under reduced pressure to give tert-butyl 2-{[5-bromo-2-(methoxycarbonyl)thiophen-3-yl]carbamoyl}-4-hydroxy-4-phenylpyrrolidine-1-carboxylate as a pale-yellow oil. To a solution of tert-butyl 2-{[5-bromo-2-(methoxycarbonyl)thiophen-3-yl]carbamoyl}-4-hydroxy-4-phenylpyrrolidine-1-carboxylate produced above in ethanol (15 mL) was added 2M aqueous sodium hydroxide solution (5.00 mL), and the mixture was stirred at 60° C. for 2 hr. The reaction mixture was neutralized with 6M hydrochloric acid (1.7 mL) under ice-cooling, and concentrated under reduced pressure. To the residue were added ammonium chloride (137 mg), triethylamine (0.520 mL) and N,N-dimethylformamide (5 mL), and the mixture was stirred at room temperature for 5 min. To the reaction system were added 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (399 mg) and 1-hydroxybenzotriazole (278 mg), and the mixture was stirred at room temperature for 15 hr. The reaction system was poured into water (10 mL), and the mixture was extracted with ethyl acetate (10 mL). The organic layer was washed with saturated aqueous sodium hydrogen carbonate, and dried over anhydrous magnesium sulfate. Insoluble material was filtered off, and the filtrate was concentrated under reduced pressure to give tert-butyl 2-[(5-bromo-2-carbamoylthiophen-3-yl)carbamoyl]-4-hydroxy-4-phenylpyrrolidine-1-carboxylate as a pale-yellow oil. To a solution of tert-butyl 2-[(5-bromo-2-carbamoylthiophen-3-yl)carbamoyl]-4-hydroxy-4-phenylpyrrolidine-1-carboxylate produced above in ethanol (5 mL) was added 2M aqueous sodium hydroxide solution (1.71 mL), and the mixture was stirred at 70° C. for 3 hr. The reaction mixture was neutralized with 1M hydrochloric acid (3.4 mL) under ice-cooling, and extracted with ethyl acetate (10 mL). The organic layer was washed with water, and dried over anhydrous magnesium sulfate. Insoluble material was removed by filtration, the filtrate was concentrated under reduced pressure, and the residue was purified by silica gel column chromatography (ethyl acetate/hexane) to give the title compound (62 mg) as a brown solid.

Provenance & Evidence