Synthesis of 6,9-Diaryl-5H-imidazo[2,1-d][1,2,5]triazepines and Their Dihydro Derivatives

2-(2-Benzoyl-1H-imidazol-1-yl)-1-arylethanones were obtained by alkylation of 2-benzoylimidazole with phenacyl bromides; their cyclization with hydrazine hydrate leads to the formation of previously undescribed 6-aryl-9-phenyl-5H-imidazo[2,1-d][1,2,5]triazepines. The reduction of the latter with sodium borohydride in a dioxane medium leads to the production of 6-aryl-9-phenyl-6,7-dihydro-5H-imidazo[2,1-d][1,2,5]triazepines.