Novel Partial Synthetic Approaches to Replace Carbons 2,3,4 of Steroids. A Methodology to Label Testosterone and Progesterone with 13C in the Steroid A Ring. Part 1

A synthetic route to replace A ring carbon atoms 2, 3 and 4 of steroid hormones is described. Readily available testosterone propionate or progesterone, respectively, are degraded to the corresponding 10-formyl-5-oxo-des-A intermediates, in a first stage to the preparation of 2,3,4-(13C3)-labeled steroids.