Eight derivatives of 3-methyl-6-azaquinoxalin-2(1H)-one and of 3-methyl-8-azaquinoxalin-2(1H)-one were prepared. They bear on position 1 an aminoalkyl chain (dimethylaminoethyl, morpholinylethyl, dimethylaminopropyl and N-methylpiperazinylpropyl). Three of these compounds exhibit a high degree of deconditioning activity on rats; compound (I) is particularly active on the acquisition of a conditioned avoidance response, while compound (II) is more active than chloropromazine on the modification of a C.A.R. Compound (II) is characterized also by low toxicity.