Nizatidine, N-[2-[[[2-[(dimethylamino)methyl]-4-thiazolyl]methyl] thio]ethyl]-N'-methyl-2-nitro-1,1-ethenediamine

C12H21N5S2O2, M(r) = 331.46, triclinic, <P(1)over bar>, a = 7.3645(5), b = 8.8785(9), c = 25.678(4) Angstrom, alpha = 89.35(1)degrees, beta = 82.49(1)degrees, gamma = 87.46(1)degrees, V = 1662.9(5) Angstrom(3), Z = 4, D-x = 1.324 g cm(-3), lambda(Cu K alpha) = 1.54184 Angstrom, mu = 29.57 cm(-1), F(000) = 704.0, T = 293 K, final R = 0.057 for 4830 observed reflections. Nizatidine, Axid(R), is a selective H-2-receptor antagonist used in the treatment of duodenal ulcers. The pharmaceutical nizatidine crystallizes with two independent molecules in the asymmetric unit. The two molecules have similar conformations, with the exception of the dimethylamino group. The bisalkylamino-2-nitroethene moiety differs from the structurally related hydrogen oxalate salt form of ranitidine in that the nitro group of nizatidine is the cis geometrical isomer with respect to the ethylamino group.