Labelling of steroios by exchange with isotopic water on heterogeneous platinum and palladium: Methods for overcoming competing oxidation
✍ Scribed by J. L. Garnett; J. H. O'Keefe
- Publisher
- John Wiley and Sons
- Year
- 1975
- Tongue
- French
- Weight
- 702 KB
- Volume
- 11
- Category
- Article
- ISSN
- 0022-2135
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
A representative group of steroids have been labelled by exchange with isotopic water in the presence of heterogeneous Group VIII transition metals. Platinum and palladium are the best of the metals studied. Steroids examined included oestrogens, keto and hydroxy derivatives, hydrocarbons and two cardiac glycosides. The presence of an OH group in the steroid leads to oxidation simultaneously with isotope incorporation. Esterification of the OH group prior to exchange eliminates oxidation and yields labelled compounds of high chemical purity. The variables affecting optimum exchange have been determined and include solvent, temperature of reaction and method of catalyst activation. Isotope orientation in the labelled steroids supports a mechanism involving the role of π‐ and σ‐bonded intermediates in the exchange reaction.