Synthesis of 1,4-diazepin-5-ones under microwave irradiation and their reduction products

A new efficient access to 1,4-diazepane derivatives is described via a microwave assisted synthesis of 7-substituted-1,4-diazepin-5-ones, which proceeds rapidly in good yields. Catalytic reduction gave 1,4-diazepan-5-ones and 1,4-diazepanes whereas a ring opening was observed by hydride reduction when a phenyl group occupies the N-benzylic position.