Hydrochloric Acid → 1-Phenoxycarbonyl-4-ethynyl-4-(2-nitrophenoxy)piperidine

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Reaction Steps

To a solution of 1-methyl-4-ethynyl-4-(2-nitrophenoxy)piperidine (liberated from 10.0 g of the hydrochloride) in 45 ml of methylene chloride was added dropwise a solution of 5.8 g of phenylchloroformate in 45 ml of methylene chloride. The mixture was stirred at room temperature for 1 hr and at reflux, under nitrogen, for 16 hrs. The solution was allowed to cool to room temperature, poured into water, extracted with methylene chloride, washed with saturated sodium chloride solution and dried over anhydrous potassium carbonate. Filtration followed by evaporation of solvent provided an oil (13.9 g). A 2.2 g sample of the oil was chromatographed on 150 g of alumina. The column was eluted with three 150 ml volume of ether. Evaporation of the solvent from the second fraction provided 1.36 g (65%) of product. Recrystallization from isopropyl alcohol provided the analytical sample, mp 76°-80°.

Provenance & Evidence