Pyridine → 6-[3-cyclopentyl-2(R)-(3,4-dichloro-phenyl)-propionylamino]-nicotinic acid methyl ester

Participants

Reaction Conditions

Reaction Steps

A solution of triphenylphosphine (1.23 g, 4.69 mmol) in methylene chloride (15 mL) was cooled to 0° C. and then treated with N-bromosuccinimide (947 mg, 5.32 mmol). The resulting brown-purple solution was stirred at 0° C. for 5 min and then treated with 3-cyclopentyl-2(R)-(3,4-dichloro-phenyl)-propionic acid (prepared as in Example 54A, 900 mg, 3.13 mmol). The reaction mixture was stirred at 0° C. and then allowed to warm to 25° C. over 45 min. The reaction mixture was then treated with 6-aminonicotinic acid methyl ester (620 mg, 4.07 mmol) and pyridine (0.38 mL, 4.7 mmol), and the reaction mixture was allowed to stir at 25° C. for 20 h. The resulting reaction mixture was diluted with water (15 mL) and then extracted with methylene chloride (3×15 mL). The combined organic layers were dried over sodium sulfate, filtered, and concentrated in vacuo. Flash chromatography (Merck Silica gel 60, 230-400 mesh, 9/1 hexanes/ethyl acetate) afforded 6-[3-cyclopentyl-2(R)-(3,4-dichloro-phenyl)-propionylamino]-nicotinic acid methyl ester (1.10 g, 84%) as a white foam: [α]23589=−68.0° (c=0.128, chloroform); FAB-HRMS m/e calcd for C21H22Cl2N2O3 (M+H)+ 421.1086, found 421.1079.

Provenance & Evidence