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.