Triethylamine → 4-Cyclopentyl-9-methoxy-1,4-benzothiazepine-2,5 (3H)-dione

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Reaction Steps

N-(2-mercapto-3-methoxybenzoyl)-N-cyclopentylglycine (14.5 g, 0.0469 m) and triethylamine (4.7 g, 0.0469 m) in methylene chloride (500 ml) were cooled to 0° C., and ethyl chloroformate (5.1 g, 0.0469 m) was added over one minute. The mixture was stirred 2 hours at 0°-10° C., washed (water, then brine), dried (Na2SO4) and concentrated. HPLC purification using hexane/ethyl acetate (1/1) as eluent gave the desired product. Recrystallization from ethyl acetate provided 5.4 g analytically pure material (yield: 35%).

Provenance & Evidence