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

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.