New synthesis of benzotriazole photostabilizers

Abstract

1-(2-Nitrophenyl)-5-aryltetrazoles and 1-aryl-5(2nitropheny1)tetrazoles are converted into 2-arylbenzotriazoles by the action of heat, the former reacting much faster than the latter. By appropriate use of methoxyl groups, useful benzotriazole ultraviolet absorbers may be synthesized conveniently by this method.