Synthesis of polyamides from active N,N′-diacylbis [1,2-benzisothiazol-3(2h)-one]s and 4,4′-oxydianiline under mild conditions

The aminolysis of 3-benzoyloxy-1,2-benzisothiazole and N-benzoyl1,2-benzisothiazol-3(2H)-one] derived from 1,2-benzisothiazol-3-ol was studied in model systems and was found to give good yields of N-substituted benzamides at room temperature. Solution polycondensation of new bisamides, N,N′-isophthaloyldi1,2-benzisothiazol-3(2H)-one], and N,N′-adipoyldi1,2-benzisothiazol-3(2H)-one], proceeded slowly to give polyamides with moderate molecular weights. The chloroform–triethylamine · hydrochloride system was the best polycondensation medium compared with some polar aprotic solvents for the formation of higher-molecular-weight polyamides.