Collect. Czech. Chem. Commun. 1982, 47, 315-337

Epoxidation of 4,4-dimethyl-A-homo-4a-cholestene derivatives and a study of electron impact mass spectra of the epoxidation products

Helena Velgová and Antonín Trka

Institute of Organic Chemistry and Biochemistry, Czechoslovak Academy of Sciences, 166 10 Prague 6


The effect of the substituent in the position 3 on the epoxidation of some 4,4-dimethyl-A-homo-4a-cholestene derivatives was investigated. The stereochemistry of the epoxidation is affected mainly by sterical and conformational effects. The mass spectrometric behaviour of epoxides IV-XI, XV-XX, XXIII and XXIV and of 4a,5-unsaturated 3-ketones XXI and XXVI was also studied. The double-transannular cleavage represents a common and characteristic decomposition pathway of molecular ions of these compounds.