Translational energy release and stereochemistry of steroids. VII—the loss of angular methyl groups after the dehydration of molecular ions of cholesterol and related C(5)-unsaturated 3β-hydroxy steroids

✍ Scribed by Z. V. I. Zaretskii; Z. Kustanovich; E. E. Kingston; J. H. Beynon; Carl Djerassi; L. Tökes

• Publisher: John Wiley and Sons
• Year: 1986
• Tongue: English
• Weight: 741 KB
• Volume: 21
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/oms.1210210306

✦ Synopsis

The translational energy, T, released during the loss of the angular 18and 19-methyl groups both from metastable molecular ions and metastable [M -H,O]" and [M -2 H,O]+' ions, in C(5)-unsaturated monoand di-hydroxy steroids, as well as in their 19-nor and deuterated analogues bearing the label in the 19-methyl group, has been measured. It was found that, while the T values for the 19-cH3' loss, following the dehydration of the molecular ions, are increased substantially when compared to those for the same loss from the molecular ions, the T values for the 18-CH3' loss are increased much more moderately. Nevertheless, the amounts of translational energy released in the [M -H,O]+' -18-CH3' and [M -2 H,O]+' -18-CH3' transitions are still higher than those found for the respective 19-methyl loss, in accordance with the general rule established recently.