2,3,6,7,8,9-hexahydro-8,8-dimethyl-5-phenyl-1-H1,4-benzodiazepin-6-one

Several approaches for the synthesis of the title compound 1 were investigated. Treatment of the ethane-1,2-diamine derivative 2 with phosphoryl chloride afforded 3-chloro-5,5-dimethylcyclohex-2-enone (3) and 1-(5,5-dimethyl-3-oxocyclohex-1-enyl)-4,5-dihydro-2-phenylimidazole (4) , The reaction of 2-benzoyl-dimedone (5) with an equimolar amount of ethane-1,2-diamine led to the 2:1 adduct 6 , whereas with an excess of ethane-1,2-diamine, 4,5-dihydro-2-phenylimidazole (7) and dimedone were obtained. The synthesis of the title compound 1 was achieved by reacting 2-benzoyl-3-chloro-5,5-dimethylcyclohex-2-enone (8) with ethane-1,2-diamine.