7-Chloro-2,3-dihydro-1-methyl-5-phenyl-1H-1,4-benzodiazepine (medazepam)

C~6H~sN2C1, orthorhombic, P212t2 ~ (No. 19), a = 12.857 (3), b = 28.518 (6), e = 7.683 (3) A, Z = 8, D c = 1.28 g cm -3. The structure was solved by direct methods and refined to an R value of 0.053 from diffractometer data. The asymmetric unit consists of two molecules of opposite conformational chirality. The geometries of the two molecules have been compared by half-normal probability plots. The sevenmembered ring is in a twisted-boat conformation and a comparison with the rings of the 1H-1,4-benzodiazepin-2-one derivatives of known molecular structure has been carried out.