Abstract
In order to explain the rate difference of Zimmermann reaction with the 16-oxosteroids in terms of the conformational concepts, two pairs of the epimeric 17-bromo-16-ketones in estratriene and androst-5-ene series have been synthesized (Chart 1 and 2). The conformation of ring D with a ketone at C-16 was examined on the basis of their spectral data litsed in Table I. Contrary to the expectations, however, no definite evidence for the long-range effect on the conformation of ring D due to the structure alteration in distant part of the molecule has been obtained.
