Synthesis and structure of novel 2,3, 5,6-tetrahydro-1H-imidazo[2,1-b][1,3,5]benzotriazepines with vasocontractile activity in rabbit aortic rings.

A series of novel 2,3,5,6-tetrahydro-1H-imidazo[2,1-b][1,3,5]benzotriazepines (3a-n) and hydrochlorides (4a-b) were prepared and their structure was determined by IR and NMR spectroscopic data as well as by X-ray analysis of the hydrochloride 4a. The newly synthesized benzotriazepine 4b exhibited concentration-dependent vasocontractile activity in isolated rabbit aortic rings. Rimalkalim was found to induce a relaxation in rabbit aortic rings precontracted by 4b (3x10(-5) mol). Present results indicate that K(ATP)-dependant channels may contribute in the contractile activity of benzotriazepine 4b.