A Comparison of the Flash Vacuum Pyrolysis Products of Some N-Acylbenzotriazoles and N-Acylbenzisoxazolones

Abstract

The flash vacuum pyrolysis (f.v.p.) products of 2-(1H-benzotriazol-1-ylcarbonyl)benzonitrile, methyl 2-(1H-benzotriazol-1-ylcarbonyl)benzoate and 1-(2-chloromethylbenzoyl)-1H-benzotriazole and the cor- responding benzisoxazolones have been characterized. The benzotriazole derivatives gave compounds whose origin suggests the predominance of radical processes. At lower temperatures the benzisoxa- zolones gave benzoxazole products consistent with a singlet carbene intermediate, but which had triplet diradical properties at higher temperatures, leading to the formation of acridine from the chloromethyl compound. The major low-temperature f.v.p. product from the (chloromethylbenzoyl)benzisoxazolone was indolo[1,2-b]benzoxazole.