Synthesis of polyamides from active 2‐benzothiazolyl diesters and diamines under mild conditions

Abstract 2‐Benzothiazolyl benzoate as a model compound was successfully synthesized from the benzoylation of 2‐benzothiazolone under kinetically controlled conditions. The aminolysis of 2‐benzothiazolyl benzoate afforded excellent yields of N‐substituted benzamides at room temperature in a short reaction time. Solution polycondensations of new active diesters, di‐2‐benzothiazolyl isophthalate and di‐2‐benzothiazolyl terephthalate, with aliphatic and aromatic diamines, took place rapidly even at room temperature and yielded polyamides with high molecular weight. The high reactivity of 2‐benzothiazolyl benzoate was discussed in relation to intramolecular general base catalysis and the tautomeric effect of the benzothiazolone moiety.