Ammonia → 1-(4-Ethynyl-4-hydroxypiperidin-1-yl)ethan-1-one

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Reaction Steps

To 350 ml of liquid ammonia was added 0.06 g of ferric nitrate. When the ferric nitrate dissolved, 1.0 g of sodium was added. The mixture was stirred until a black precipitate formed. To the mixture was then added 3.25 g of sodium. The solution was stirred until the mixture turned gray after which acetylene was bubbled through the reaction for 2 hrs. To the mixture was then added 25 g (0.177 mol) of N-acetyl-4-piperidone in 100 ml of dry THF. The mixture was subsequently stirred for 3 hrs. during which time acetylene was bubbled through. The reaction was then quenched by addition of 10 g (0.187 mol) of ammonium chloride. The ammonia was allowed to evaporate overnight. To the mixture was then added 75 ml of saturated ammonium nitrate and 40 ml of 25% ammonium hydroxide. The mixture was then extracted twice with chloroform, dried over potassium carbonate, filtered and the solvent evaporated to provide a white solid. The solid was washed with anhydrous ether and dried. The crude yield of 1-acetyl-4-ethynyl-4-piperidinol was 17.9 g (0.107 mol, 60.6%). Recrystallization from ethyl acetate provided analytically pure material, m.p. 132°-134° C. The material appeared pure by TLC (silica; 2% methanol/chloroform), Rf =0.2; (silica; 10% methanol/dichloromethane), Rf =0.4, IR (chloroform), 1H-NMR (CDCl3) and MS (MH+ =168) are consistent with the assigned structure.

Provenance & Evidence