Sulfuric Acid → 1-Ethoxy-4-[2-(2,4,6-trimethyl-phenyl)-acetylamino]-piperidine-4-carboxylic acid methyl ester

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Reaction Steps

1.4 ml of concentrated sulfuric acid was slowly added to a solution of 4.3 g of N-(4-cyano-1-ethoxy-piperidin-4-yl)-2-(2,4,6-trimethyl-phenyl)-acetamide in 11 ml of methanol. After stirring 20 hours under reflux, the reaction mixture was allowed to cool down to room temperature and diluted with ice water. Sodium carbonate was added and the aqueous phase was extracted with ethyl acetate. The organic phase was dried over sodium sulfate, filtered and concentrated. Chromatography (dichloromethane+1% of ethanol) gave 3.2 g of 1-ethoxy-4-[2-(2,4,6-trimethyl-phenyl)-acetylamino]-piperidine-4-carboxylic acid methyl ester as a solid, mp: 131-132° C.

Provenance & Evidence