Synthesis of optically active 1,4-benzoxazinones and 1,5- benzoxazepinones by regiocontrolled ring transformations of oxirane carboxylic acids and esters with aromatic o-hydroxyarylamines

Article abstract of DOI:10.1016/S0040-4020(99)00488-3

Enantiopure diethyl oxirane dicarboxylate 1 reacts with o-aminophenols 2 either to 1,4-benzoxazin-2-ones 5 or to the 1,5-benzoxazepin-2-one 4 while a condensed 1,4-oxazin-3-one 6 was obtained with 2-amino-3-hydroxypyridine. On the other hand optical activ