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 is 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 is allowed to cool down to room temperature and diluted with ice water. Sodium carbonate is added and the aqueous phase is extracted with ethyl acetate. The organic phase is 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