The mass spectral fragmentation of 9α-hydroxy steroids and related compounds

Abstract

The fragmentation processes occurring in various 9alpha-hydroxy steroids upon electron ionization have been studied. The mechanisms proposed for the formation of the prominent ions in these spectra have been confirmed with the aid of deuterium labelling, measurements on metastable ion decompositions, low eV spectra and high resolution mass measurements. The fragmentation of the corresponding 9-oxo-9,10-seco steroids, which shows analogy to that of the 9alpha-hydroxy compounds in many respects, has also been discussed.

Mass spectrometry in structural and stereochemical problems. 254. Elucidation of the course of the electron impact induced fragmentation of .alpha.,.beta.-unsaturated 3-keto steroids

“…1.4-Cholestadien-3-one-#)S-d\. A mixture of 48 mg of 4-cholesten-3-one-S(3-ifi (13) (prepared by the method of Tókés et al17) and 26 mg of selenium dioxide in 5 mL of rm-butyl alcohol containing one drop of acetic acid was heated under nitrogen at 70 °C for 24 h.16…”

Oxazole chemistry. A review of recent advances

“…This result was rationalized on the basis of frontier and perturbation MO Ethyl diazoacetate (163) undergoes a 1,3-dipolar addition to acrylonitrile or methacrylonitrile at 25 °C without added catalysts to afford the 2-pyrazoline 165 via the initially formed cycloadduct 164. In contrast, the reaction of 163 with these nitriles in the presence of catalytic amounts of palladium acetate gives the 2-vinyl-5-ethoxyoxazoles 166 R = H, Me {65). The latter reaction probably proceeds Ethyl diazopyruvate 167 provides the ethyl oxazole-5carboxylates 168, R = Me, Ph, when allowed to undergo copper(II) catalyzed decomposition in acetonitrile or benzonitrile {66). 13C spectral data are reported for the oxazoles 168.…”

“…The mechanism for loss of OHwas investigated by deuterium labeling and is given in eq 144. (144) Mass spectral data and fragmentation patterns for the oxazole prostaglandin analogues 387 have been reported (167).…”