STRUCTURE OF 4'-(9-ACRIDINYLAMINO)-2'-METHOXYMETHANESULFONANILIDE (O-AMSA) METHANOL SOLVATE, AN INACTIVE ISOMER OF THE ANTICANCER DRUG AMSACRINE (M-AMSA)

C21H19N3O3S.CH4O, M(r) = 425.51, triclinic, P1BAR, a = 9.545 (2), b = 14.338 (1), c = 8.3748 (7) angstrom, alpha = 106.032 (6), beta = 103.230 (9), gamma = 70.96 (1)-degrees, V = 1029.0 (3) angstrom 3, Z = 2, D(x) = 1.373 g cm-3, Mo K-alpha, lambda = 0.71069 angstrom, mu = 1.94 cm-1, F(000) = 448, T = 293 (1) K, R = 0.039 for 2169 observed reflections (I > 2.5-sigma). The crystal packing is enhanced by intermolecular hydrogen bonds, by hydrogen bonds with the methanol solvate molecule, and by stacking interactions between the acridine rings. There are no obvious structural features which explain the lack of anti-tumour activity.