Sodium hydride → tert-butyl 4-oxo-3(R)-phthalimido-2,3,4,5-tetrahydro-1,5-benzothiazepine-5-acetate

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Reaction Steps

To a stirred mixture of 50 ml of N,N-dimethylformamide and 0.5 g of sodium hydride (60% in oil) is added 4 g of 3(R)-phthalimido-2,3-dihydro-1,5(5H)-benzothiazepin-4-one obtained in Reference Example 2 at ice bath temperature. After 5 minutes, 2 g of tert-butyl chloroacetate is added at ice bath temperature. The resulting mixture is stirred in an ice bath for b 15 minutes and diluted with ice water (200 ml). The deposited crystals are collected by filtration, dried and purified by silica gel column chromatography (hexane:ethyl acetate=3:1) to give 4 g of tert-butyl 4-oxo-3(R)-phthalimido-2,3,4,5-tetrahydro-1,5-benzothiazepine-5-acetate as colorless crystals. Recrystallization of a part of the crystals from ethyl ether yields colorless prisms, m.p. 181°-184° C.

Provenance & Evidence