PURPOSE: To obtain the titled compound useful as a coronary vasodilator under a mild condition in high purity in high yield, by alkylating hydrogen bonded to the 5-position of a 1,5-benzothiazepine derivative corresponding to the aimed compound with a dialkylamino-alcohol.
CONSTITUTION: A compound shown by the formula I (A is aryl which may contain lower alkoxy; R1 is lower alkyl) is subjected to ring closure in the presence of dimethylformamido-thionyl chloride, N, N'-di-substituted carbodiimide and/or N,N-di-substituted carbonyldiimidazole, then the prepared compound shown by the formula II is reacted with a compound shown by the formula III (X is lower alkylene; R2 and R3 are lower alkyl) in the presence of a neutral dehydrating agent such as a combination of a tris-substituted phosphine and a di lower alkylazodicarboxylate, and the reaction is easily advanced under a neutral mild condition to give a compound shown by the formula IV or its salt in high purity in high yield industrially advantageously.
MASAGAKI TAKESHI
KAKITA TAKAO
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