title: Elucidation of the opening of the epoxidic ring of the 3beta-acetoxy-14alpha,15alpha-epoxy-5alpha-cholest-8-en-7-one by methanol, using NMR techniques assisted by a conformational study through theoretical calculations.
abstract: This paper demonstrates that the crystallization of 3beta-acetoxy-14alpha,15alpha-epoxy-5alpha-cholest-8-en-7-one from methanol affords the 3beta-acetoxy-9alpha-methoxy-15alpha-hydroxycholest-8(14)-en-7-one. The structure of this steroid, which shows an apparently anomalous UV absorption maximum, is determined by high field NMR experiments, supporting the coupling constant values assignments and the NOE contacts by a conformational study through theoretical calculations at the B3LYP/6-31G* level. The computational study also justifies the observed UV absorption of the steroid, thus demonstrating the usefulness of computer chemistry in providing support for the identification of unknown compounds.
authors: Dipartimento di Chimica, Biochimica e Biotecnologie per la Medicina, Università di Milano, via Saldini 50, I-20133, Milano, Italy. mario.anastasia@unimi.it
authors: Mario
authors: M
authors: Anastasia
authors: Pietro
authors: P
authors: Allevi
authors: Raffaele
authors: R
authors: Colombo
authors: Elios
authors: E
authors: Giannini
mesh_terms: D002247:Carbon Isotopes; D002783:Cholestenones / Q000737:chemistry*; D004852:Epoxy Compounds / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D000432:Methanol / Q000737:chemistry*; D008956:Models, Chemical; D008968:Molecular Conformation; D011522:Protons; D012399:Rotation; D013056:Spectrophotometry, Ultraviolet; D013261:Sterols / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: C525531:3beta-acetoxy-14alpha,15alpha-epoxy-5alpha-cholest-8-en-7-one; D002247:Carbon Isotopes; D002783:Cholestenones; D004852:Epoxy Compounds; D011522:Protons; D013261:Sterols; D000432:Methanol