To 0.42 ml. of dry pyridine and 6.3 ml. of dry dichloromethane was slowly added 0.264 g. of chromium trioxide and the mixture was stirred for 15 min. at room temperature. To the mixture was added a solution of 175 mg. of the product of Step D in 0.7 ml. of dichloromethane and the resulting mixture was stirred for 20 min. at room temperature. The mixture was diluted with water, extracted with ethyl ether, and washed with 2.5 N sodium hydroxide, water, and brine. The mixture was then dried and evaporated to a clear oil.
