Kinetic and 3H NMR studies on tritiated steroids.

The present work deals with steroid labelling with tritium using different preparative methods - simple exchange processes and reduction of double bonds by H[2]/T[2] gas mixture - to produce tritiated steroids at high molar specific activity. With respect to tritium labelling, it is necessary to study the following: (a) the positions of tritium atoms in the tritiated compound, and (b) the reactivity (stability) of tritium atoms located at the a-carbon atoms to the ketone function. [3]Hnmr Spectroscopy is an excellent technique for establishing the positions of the tritium atoms and their stereochemistry in the tritiated steroids. In the case of the point (b), the detritiation process under aqueous basic media is an invaluable technique for quantitive determination of the stability of these tritium atoms. Moreover, the detritiation technique can be applied to study the steric hinderance on the labelled sites (stereoselectivity of the reaction) in the tritiated keto-steroid using different alcohol-alkoxide solutions. The present work can therefore be described into the following three chapters: - 1 - Preparation of tritiated steroids. - 2 - [3]Hnmr Spectroscopy of tritiated steroids, and - 3 - Kinetics of detritiation of certain steroids