New psychotropic agents. I. Synthesis and pharmacologic activity of derivatives of 5H-imidazo-[2,1-c][1,4]benzodiazepine

The synthesis of 5H-imidazo [2,1-c] [1,4] benzodiazepine derivatives is described. Hydroxymethylation of 1-(2-nitrobenzyl)imidazoles by reaction with formaldehyde in a sealed tube and subsequent oxidation of hydroxymethylimidazoles with activated manganese dioxide afforded 1-(2-nitrobenzyl)imidazole-2-carboxaldehydes. The latter compounds were treated with iron(II) sulphate to yield directly the expected tricyclic imidazobenzodiazepines by intramolecular cyclization of the intermediates aminoaldehydes. The tricyclic derivatives were subjected to pharmacological screening to evaluate the effects on the behavior of the animals and the interaction with some biogenic amines. Some of the tested compounds were comparable to chlordiazepoxide in sedative and muscle-relaxant activities. None of them showed antiserotonin, anticholinergic or adrenolytic activities.