Regioselective synthesis of a vitamin K3 based dihydrobenzophenazine derivative: its novel crystal structure and DFT studies

A novel acid catalyzed regioselective Michael addition of o-phenylenediamine to vitamin K3 has been carried out to synthesize a dihydrobenzophenazine derivative viz. 6a-methyl-6a,7-dihydrobenzo[α]phenazin-5(6H)-one (1). The compound has been characterized using the single crystal X-ray diffraction and density functional theory.