(E)-3-[(Di­methyl­amino)­methyl­idene]-4-phenyl-1-(prop-2-yn­yl)-1H-1,5-benzodiazepin-2(3H)-one

The title compound, C₂₁H₁₉N₃O, exhibits an E configuration with respect to the C=C bond between the benzodiazepine and tri­methyl­amine groups. The seven-membered diazepine ring displays a boat conformation. In the crystal, mol­ecules are linked by a C—H...O hydrogen bond, forming a chain along [110].