“…On treatment of (183) with a very mild base, the primary product is the 5~,7~-cyclo-compound (1 87), which is converted, with strong base, into (184) and (186). 223 Reduction of 6-nitrocholesteryl acetate with lithium dimethylcopper gives the E-oxime of 3a,5a-cyclocholestan-6-one, from which the ketone is obtained by treatment with sodium bisulphite. *'j Mild reagents for the conversion of a 6-oxo-3~-tosyloxy-5c-steroid into the 3a75a-cyclo-6-one are tetramethylguanidine at 60 "C for 5 minutes or benzyltrimethylammonium hydroxide in pyridine at 60 "C for 10 minutes.…”