Condensation of Ethyl 2-Oxoindoline-3-glyoxylate with o-Aminophenol and o-Phenylenediamine

A method is presented for the synthesis of 3-(2-oxo-1,2-dihydro-3H-indol-3-ylidene)-1,4-dihydroquinoxalin-2-one and 2-(2-oxo-1,2-dihydro-3H-indol-3-ylidene)-2H-1,4-benzoxazin-3(4H)-one by the reaction of ethyl 2-oxoindoline-2-glyoxylate with o-aminophenol and o-phenylenediamine. Proposed reaction mechanisms are presented.