Potassium Carbonate → 1-N-Phenoxycarbonyl-4-ethynyl-4-(4-fluoro-2-nitrophenoxy)piperidine

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Reaction Steps

To a stirred suspension of 5.01 g of potassium carbonate, 50 ml of dichloromethane (dried over anhydrous magnesium sulfate) and 10.1 g of 1-N-methyl-4-ethynyl-4-(4-fluoro-2-nitrophenoxy)piperidine was added dropwise a solution of 5.66 g of phenylchloroformate in 50 ml of dichloromethane (dried over anhydrous magnesium sulfate). The mixture was stirred 12 hr at ambient temperature and 6 hr at reflux under nitrogen. The suspension was poured onto ice, extracted with dichloromethane, washed with 15% sodium hydroxide solution, 1N hydrochloric acid and saturated sodium chloride solution. The dichloromethane solution was dried over anhydrous sodium sulfate, filtered and the solvent evaporated to provide an oil. The oil was dissolved in ether, washed with water, 1N hydrochloric acid and saturated sodium chloride solution. The solution was dried over anhydrous sodium sulfate, filtered and the solvent evaporated to provide an oil. The oil was dried overnight at room temperature (1 mm) during which time it crystallized to provide 10.3 g (73.8%) of product. Recrystallization from cyclohexane/ethyl acetate provided the analytical sample, mp 82°-83°.

Provenance & Evidence