It was found that 2-chloroacetyl chloride 7 reacts primarily over the NH-group at position 1 of 1,5-benzodiazepines 6a-e in dry benzene at room temperature in the presence of TEA to render the Nacetylderivatives 8a-e in good yields.Subsequently, cycloaddition reaction of compounds 8a-e with 7 in dry benzene-TEA lead to the formation of the new azeto[l,2-a][l,5]benzodiazepines 9a-e in moderate yields, involving the imino (C=N) moiety at position 4. The structure of compounds 8a-e and 9a-e was assigned by ] H and 13 C NMR spectra and 2D experiments.The importance of ß-lactam derivatives in medicinal chemistry has been clearly demonstrated. 1Owing to their high efficacy and extremely safe toxicological profile; they are the agents of choice in the current therapeutic index for bacterial infections.Tremendous efforts have been made for the synthesis and structural modification of the ß-lactam nucleus to increase antimicrobial activity and pharmacokinetic performance.Apart from their clinical use, recent reports on the use of ß-lactams for purposes other than antibiotic ones are gaining attention.This four-member cyclic amide has been extensively used for the synthesis of several biological active heterocyclic compounds: the anti-tumor drug paclitaxel (Taxol™) can be prepared by coupling of naturally occurring baccatin and an appropriately substituted hydroxy ß-lactam. 2Additionally, it has been established that certain ß-lactams have cholesterol-lowering properties. 3 the other hand, some 1,5-benzodiazepines are compounds showing high bioactivity as neoplasm inhibitors 4 (for example, benzodiazepine 1) and as antiepileptic agents 5 (for example, clobazan 2) (Figure -1).Now we are interested in the synthesis of new acylated and tricyclic benzodiazepine derivatives because it has been found that adding a chain or another ring to the previous system it could improve the biological activity for those compounds. 6