1-Acetyl-4-phenyl-5a,6,7,8,9,9a-hexahydro-5H-1,5-benzodiazepin-2(1H)-one

The seven-membered ring of the title compound, C(17)H(20)N(2)O(2), adopts an approximate boat conformation while the cyclohexyl ring adopts a chair conformation. In the crystal, adjacent molecules are linked by N-H center dot center dot center dot O hydrogen bonds into a zigzag chain running along the c axis of the monoclinic unit cell.