Abstract The selective reduction of 3, 4-dicarbomethoxyquinoline by lithium aluminium hydride at low temperature affords only the unexpected 3-formyl 4-carbomethoxy quinoline. The difficulty of reduction of the usually more reactive 4-ester group can be explained by a steric hindrance by the H 5, peri proton on one side and by the 3-ester group on the other side.
