| 摘要 |
NEW MATERIAL:The compound of formula I [R<1> is alkyl, cycloalkyl or (substituted) phenyl; R<2> is (substituted) alkyl] or its acid addition salt. EXAMPLE:Ethyl 3, 6-dimethyl-4-(3-nitrophenyl)-4, 7-dihydroisothiazo[5,4-b] p-yridine-5-carboxylate. USE:A calcium antagonist. Useful for the remedy of circulatory diseases such as stenocardia, hypertension, cerebral blood flow disorder, etc. PREPARATION:A 5-aminoisothiazole derivative of formula II (e.g. 5-amino-3- methylisothiazole) is made to react with an alpha,beta-unsaturated ketone derivative of formula III (e.g. ethyl-3-nitrobenzylidene acetoacetate) preferably in the presence of an alcohol solvent at 50-90 deg.C in an inert atmosphere.
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