Recent applications of N.M.R. to the investigation of steroid structures.

A detailed and clear understanding of the solution state structure and conformation of steroids is now possible. This is achieved using high field super conducting magnets and sophisticated computer control systems in nuclear magnetic resonance (n.m.r.) spectroscopy. The combination of greater signal dispersion and sensitivity obtained at high magnetic fields (cf. greater than 9.4 T--1H resonant frequency 400 MHz) has increased the utility of traditional assignment techniques such as nuclear Overhauser enhancement (nOe) and spin decoupling measurements. It has also permitted the application of various two dimensional (2D) n.m.r. experiments and resulted in complete unambiguous analysis of the proton spectra of various steroids [1-3]. The power of the various methods is illustrated by their application to the solution conformation of 17 alpha-acetoxy-6 alpha-methylpregn-4-en-3,20-dione (Medroxyprogesterone acetate, MPA).