Novel 2H-1,3-benzoxazine ring formation by intramolecular heterocyclization of N-(α-aryloxyalkyl)imidoyl chlorides

A convenient synthetic approach to derivatives of 2-trichloromethyl and 2-dichlorometylene-2 -1,3-benzoxazines, based on intramolecular heterocyclization of readily accessible -(α-aryloxytrichloroethyl)imidoyl chlorides, was developed. Base induced dehydrochlorination of 4-phenyl- or 4-trifluoromethyl-2-trichloromethylbenzoxazines allows preparation of 2-dichloromethylene-1,3-benzoxazines, whereas dehydrochlorination of 4-fluoromethyl analogs under similar conditions is accompanied by formal 1,5- -shift to afford respective 2-dichloromethyl-4-fluoromethylene-1,3-benzoxazines.