Chromium trioxide oxidation of ring-A-substituted 19-norcholesta-1, 3, 5 (10)-trienes gives results similar to those obtained for analogous oestra-1, 3, 5 (10)-trienes. 3-Methoxy-19- norcholesta-1, 3, 5 (10)-triene yields the 9β-hydroxy-11-oxo-derivative as the major product but introduction of a methyl group in the C-1 position blocks oxidation in the C-11 position. Oxidation of compounds with substituents in positions other than C-3 yields the 6-oxo- ...
