Synthesis of C-19 deuterium labelled steroids

Preparation of the synthetically useful steroid intermediate 19-d3-androst-4-ene-3,17-dione (Ia) together with its 19-d2-(Ib) and 19-d1-(Ic) analogues is described. The conditions and work-up of the synthesis have been designed to eliminate tedious chromatographic separation and purification steps thus enabling decigrams of material to be conveniently prepared using standard laboratory apparatus. The deuterium label in the C-19 angular methyl group is inert to normal chemical exchange processes, thus offering the opportunity for synthesis of more complex, biologically active, stable labelled steroids, whose metabolism can be studied mass spectrometrically.