NIZATIDINE, 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, m u = 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 pharmaceutic al nizatidine crystallizes with two independent molecules in the asymm etric unit. The two molecules have similar conformations, with the exc eption of the dimethylamino group. The bisalkylamino-2-nitroethene moi ety differs from the structurally related hydrogen oxalate salt form o f ranitidine in that the nitro group of nizatidine is the cis geometri cal isomer with respect to the ethylamino group.