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.
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.
Anastasia
Mario
M
Dipartimento di Chimica, Biochimica e Biotecnologie per la Medicina, Università di Milano, via Saldini 50, I-20133, Milano, Italy. mario.anastasia@unimi.it
Allevi
Pietro
P
Colombo
Raffaele
R
Giannini
Elios
E
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
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