title: Experimental and theoretical assessment of the mechanism involved in the reaction of steroidal ketone semicarbazone with hydrogen peroxide.
abstract: 3β-Acetoxy-5α-cholestan-6-one semicarbazone 1 on reaction with hydrogen peroxide affords selectively 3β-acetoxy-5α-cholestan-6-spiro-1',2',4'-triazolidine-3'-one 2. The structural assignment of the product was confirmed by spectral data and elemental analysis. A free radical mechanism of the present reaction was described successfully by calculating theoretical models of 1, A, B and 2, using DFT with B3LYP/6-31G* basis set. It was found that the reaction undergoes through the formation of two radical intermediates and the only one isomer of the product in which -NH-CO- group is cis with respect C5α-H, was selectively obtained. Frontier molecular orbital, spin electronic density, electrostatic potential and atomic charges were discussed.
authors.affiliation: Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, PO Wits, 2050, South Africa.
authors.forename: Kamlesh
authors.initials: K
authors.lastname: Sharma
authors.forename: Shivani B
authors.initials: SB
authors.lastname: Mishra
authors.forename: Ajay K
authors.initials: AK
authors.lastname: Mishra
mesh_terms: D002776:Cholestanes / Q000737:chemistry* / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000737:chemistry* / Q000378:metabolism; D007659:Ketones / Q000737:chemistry* / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008962:Models, Theoretical; D015394:Molecular Structure; D012664:Semicarbazones / Q000737:chemistry* / Q000378:metabolism; D013237:Stereoisomerism
chemical_list: D002776:Cholestanes; D007659:Ketones; D012664:Semicarbazones; D006861:Hydrogen Peroxide