Medium effect on the direction of the reaction of 3-chloro-1,3-diphenyl-1,2-propanedione with ortho-phenylenediamine

The reaction of 3-chloro-1,3-diphenyl-1,2-propanedione (I) with ortho-phenylenediamine in acetic acid gave 2-phenyl-3-(α-chlorobenzyl)quinoxaline (II). This reaction in methanol with MeONa gave 2-(α-hydroxybenzylidene)-3-phenyl-1,4-dihydroquinoxaline (VI).