CRYSTAL-STRUCTURES OF CIS AND TRANS-7-PHENYLCARBAMOYL-7,9-DIAZABICYCLO [4.3.0] NONAN-8-THIONES

C14H17N3OS, M(r) = 275.37, CAD4F diffractometer, Cu Kalpha, T = 293K. cis: orthorhombic, Fdd2, a = 22.166(2), b = 48.948(3), and c = 5.165(1 )angstrom; final R = 0.045 for 2519 observed reflections. trans: tricl inic, P1BAR, a = 11.375(2), b = 11.388(2), c = 11.823(1)angstrom, alph a = 110.72(1), beta = 89.97(1) and gamma = 93.86(2)degrees; final R = 0.043 for 3993 observed reflections. Structures were solved with direc t methods and refined by full-matrix least-squares with anisotropic th ermal parameters for non-H-atoms. The molecules of the studied isomers have very similar conformations, except for the obvious difference in the bicyclic system junction. Similar orientations of a flexible phen ylcarbamoyl substituent results from an intramolecular hydrogen bond S ... H-N(carbamoyl). Generally, molecules of the trans form are flat a nd those of cis are not. The observation may be of pharmacological imp ortance as the trans isomer is a far more potent tuberculostatic agent than the cis.