Synthesis of polyamides from active 2-benzothiazolyl dithiolesters and diamines under mild conditions

Novel examples were presented of the use in polyamide synthesis of active 2-benzothiazolyl dithiolesters for which aminolysis is assisted by a neighboring group. Solution polycondensation of new dithiolesters, 2,2′-(adipoyldithio)bisbenzothiazole and 2,2′-(isophtahloyldithio)bisbenzothiazole, with both aliphatic and aromatic diamines in polar aprotic solvents (N-methyl-2-pyrrolidone and hexamethylphosphoramide) took place rapidly at room temperature yielding polyamides with high molecular weight. The interfacial polycondensation in a chloroform–water system was also successful for polyamide formation. S,S′-Di-p-nitrophenyl dithioisophthalate reacted much more slowly toward diamines than the 2-benzothiazolyl dithiolesters. Prior to polymer synthesis, the aminolysis of active monothiolesters was carried out as a model compound study.