Synthesis of some substituted benzodiazepines as possible CNS depressant drugs

A new series of 2,3-cyclopentano-3,4-dihydro-4-spirocyclopentano-1,5-benzodi azepine which are substituted in 5-position with beta-N-heterocycloethyl or gamma-N-heterocyclo-n-propyl groups have been synthesized and evaluated for their CNS depressant activity including anticonvulsant, analgesic and pentobarbital induced hypnosis. These compounds were also investigated for their ability to inhibit in vitro succinate dehydrogenase (SDH). In most of the compounds an appreciable CNS depressant activity has been found to be associated with the compounds possessing good SDH inhibitory activity. Low toxicity of these compounds was reflected by their high approximate LD50 values.