Catalytic hydrogenations of 5-acylamido-2, 3-disubstituted quinoxalines (IIa-e) with palladized carbon in carboxylic acid afforded 4, 5-disubstituted 5, 6-dihydro-4Himidazo [1, 5, 4-d, e] quinoxalines (IIIa-e). Conformations of the substituents at 4- and 5-position of the products were also investigated.
