ABSTRACT
The synthesis of five N,N″-substituted thiocarbamides, namely N-(naphthyl)-N″-(pentoxycarbonyl) thiocarbamide (H2L1), N-(2-Chloro-4-nitrophenyl)-N″-(pentoxycarbonyl) thiocarbamide(H2L2), N-(2-methoxy-4-nitrophenyl)-N″-(pentoxycarbonyl) thiocarbamide (H2L3), N-(3-nitrophenyl)-N″-(pentoxycarbonyl) thiocarbamide (H2L4) and N-(naphthyl)-N″-(2, 2, 2-trichloroethoxycarbonyl) thiocarbamide (H2L5) was performed by the reaction of pentoxycarbonyl chloroformate with naphthyl amine, 2-chloro-4-nitroaniline, 2-methoxy-4-nitroaniline, 3-nitroaniline, respectively, for the first four and by the reaction of 2, 2, 2-trichloroethoxycarbonyl chloroformate with naphthyl amine for the last compound. These compounds were fully characterized by using various spectroscopic (FT-IR, 1H and 13C NMR) and single crystal X-ray studies of H2L1 and H2L5. In the crystal structure of both the compounds the (C˭S) and (C˭O) groups are trans to each other across the C−N bond. The crystal packing of H2L1 shows that the molecules form centrosymmetric dimers connected by N2−H····S hydrogen bonds. In H2L5 an offset face-to-face π–π stacking is observed between two naphthalene rings of two molecules. In vitro cytotoxicity of synthesized compounds was evaluated using five human carcinoma cell lines 2008, C13* (cervical carcinoma), A2780, A2780/CP and IGROV-1 (ovarian carcinoma). The IC50 values of compounds H2L2 ─ H2L4 demonstrated them to be very promising anticancer agents.
Acknowledgements
The author, SKP is grateful to Banaras Hindu University, Varanasi, India for the financial assistance. I am thankful to Prof. G. Marverti, Department of Biomedical Sciences, Metabolic and neurosciences, University of Modena, Italy for cytotoxicity studies. I am also very thankful to Prof. R. J. Butcher, Department of Chemistry, Howard University, 525 College Street NW, Washington, DC 20059, USA for the X-ray studies.
Supplementary Information
X-ray crystallographic hydrogen bonding Table S 1 of compounds (H2L1) and (H2L5), Cytotoxicity Table S 2 of compounds (H2L1−H2L5) and Figures (S 1, S 2 and S 3) have been provided in Supporting Information.
CCDC 999080 and 999081 contain the supplementary crystallographic data for compounds (H2L1) and (H2L5). These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif, by e-mailing [email protected] or by contacting the Cambridge Crystallographic Data.