Crystal Structure and Conformation of a Piperidine-Containing Thiosemicarbazone Derivative

Abstract

Piperidine thiosemicarbazones have the ability to inhibit the enzyme ribonucleoside diphosphate reductase (RDR), which is essential in DNA synthesis. The present compound, t-3-methyl-r-2,c-6-diphenylpiperidin-4-one thiosemicarbazone (MDPTAN), was prepared using the Mannich reaction and crystallized with acetonitrile as solvent. The crystal data are C38H44N8S2 · 2(C2H3N); M · W = 759.06, monoclinic, space group P21/c, a = 16.324(4) A˚, b = 15.179(4) A˚, c = 17.650(5) A˚, β = 104.98(5)°, V = 4225(2) A˚3, Z = 4, Dcal = 1.193 Mgm−3, μ = 0.168 mm−1, and λ (MoKα) = 0.71073 A˚. The structure was solved by direct methods and refined to final R-values of R = 0.089 and wR = 0.1962, respectively. The piperidine rings adopt chair conformations. The planar phenyl rings are oriented equatorially at 2,6-positions of the piperidine ring. The N-H···N and C-H···N types of intra- and intermolecular hydrogen bondings play a major role in stabilizing the molecules in the unit cell. The molecular packing can be viewed as chain of dimers held together by two N-H···S types of intermolecular hydrogen bond networks. C-H···π weak interactions also support the packing of the molecules in addition to van der Waals forces.