| abstract |
NEW MATERIAL:A compound shown by formula I (R 1 to R 4 are H, lower alkyl, OH, lower alkoxy, etc.; X 1 and X 2 are H, lower alkyl, phenyl, lower alkyloxymethyl, lower alkylthioxymethyl, etc., with the proviso that at least one of R 1 to R 4 , X 1 and X 2 is carbomethoxy, carboxymethoxymethyl or carboxymethylthioxymethyl). n EXAMPLE: Ethyl 7-glycolate of 4-methyl-4,5-diphenylmethylenedioxy-7- hydroxyisocoumarin. n USE: Having inhibitory action on an enzyme capable of converting aldose reductase, useful as a remedy for complication of diabetic, having high safety. n PREPARATION: An isocoumarin derivative shown by formula II (S 1 to S 4 are H, lower alkyl, OH, lower alkoxy, acyloxy, etc.; Y 1 and Y 2 are H, lower alkyl, phenyl, lower alkyloxymethyl, etc., with the proviso that at least one of S 1 to S 4 is OH) is reacted with a halogenoacetic ester and then hydrolyzed or debenzylated. n COPYRIGHT: (C)1991,JPO&Japio |