A series of new 3-alkylcarbamoyl-1-aryl-3,5-dihydro-7,8-dimethoxy-4H-2,3-benzodiazepin-4-ones was synthesized starting from the corresponding 3-N-unsubstituted derivatives, previously described as noncompetitive AMPA-type glutamate receptor antagonists. The new compounds proved to protect against seizures induced by means of auditory stimulation in DBA/2 mice and some of them showed anticonvulsant properties comparable or better than those of GYKI 52466, the prototype of 2,3-benzodiazepine noncompetitive AMPA receptor antagonists.