BENZOFURAN DERIVATIVE, PROCESS FOR PREPARING THE SAME AND PHARMACEUTICAL COMPOSITION CONTAINING THE SAME

A benzofuran derivative having the general formula (I):whereinR' is hydrogen atom, a benzyl group, unsubstituted or substituted with a halogen atom or an alkyloxy group, or an alkyl group having 1 to 3 carbon atoms, R2 is hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R' is acetyl group, ethy group, carboxyl group or 4-methyl-2,5-dioxoimidazcrndine-4-yl group, R4 is hydrogen atom, hydroxyl group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 9 carbon atoms, carboxymethoxy group, nitro group, acetoamino group, a benzyloxy group unsubstituted or substituted with a halogen atom, nitro group or an alkyloxy group or a group having the formula: -OR6, wherein R6 is an alkenyl group having 2 to 4 carbon atoms or an alkyl group having 2 to 3 carbon atoms having a halogen atom, cyano group or oxo group, R5 is hydrogen atom or methylenedioxy group together with R4 group, n is 1 or 2, and the unsubstituted or substituted N-carboxymethylsulfamoyl group, R4 and R5 are attached at 3-position, 4-position, 5-position, 6-position or 7-position of the benzofuran ring, or a nontoxic salt thereof, process for preparing the same and a parmaceutical composition containing the same.The compounds of the present invention have powerful aldoe reductase inhibiting activity, platelet aggregation inhibiting activity and arachidonic acid metabolism inhibiting activity and are useful for a remedy for treatment of diabetic complication.