yield a solution of step c title product the solution from step c was diluted with 35 ml acetic acid and 16 2 grams 0 0695 mole of n carbobenzoxy 4 piperidone was added the reaction mixture was heated to reflux for 30 minutes cooled to ambient temperature acidified with 60 ml conc hcl and refluxed an additional 1 5 hours after adding 100 ml of water the solution was refluxed for 5 minutes and filtered hot the solids were washed with water at 45 u00b0 c followed by 50 ml of cold methanol and then dissolved in 400 ml ch 2 cl 2 the resulting solution was dried mgso 4 treated with activated charcoal and filtered by repeated addition of methanol and distillation to a final pot temperature of 65 u00b0 c and a final volume of 200 ml ch 2 cl 2 was displaced with methanol the resulting slurry of step d title product was recovered by filtration 17 8 g m p 157 u00b0 160 u00b0 c anal calcd for c 25 h 20 n 2 o 2 f 2 c 71 76 h 4 82 n 6 70 m e 418 found c 71 76 h.