Abstract
Potassium salts (22) of various carboxylic acids readily react with 2, 2'-oxalyldi(2, 3-dihydro-3-oxobenzisosulfonazole) (17) to form the corresponding 2-acyl-2, 3-dihydro-3-oxobenzisosulfonazoles (24) as intermediates, which undergo aminolysis, alcoholysis, and thioalcoholysis to afforded amides (5), esters (6), and thioesters (7), respectively. These findings show that 17 can be conveniently used as a condensing agent for the synthesis of carboxylic acid derivatives (5, 6 or 7).