Methanol → 1-Dimethylamino-4-{methyl-[2-(2,4,6-trimethyl-phenyl)-acetyl]-amino}-piperidine-4-carboxylic acid methyl ester

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Reaction Steps

1.30 g N-(4-Cyano-1-dimethylamino-piperidin-4-yl)-N-methyl-2-(2,4,6-trimethyl-phenyl)-acetamide (from Step 2) is dissolved in 2.6 ml methanol, and 1 ml concentrated sulfuric acid is added. The mixture is stirred at room temperature for 3 hours, then at 65° C. for 3 hours, then poured on ice. The mixture is extracted three times with ethyl acetate, washed with brine, dried over sodium sulfate, and the solvent evaporated. Thus, 750 mg 1-Dimethylamino-4-{methyl-[2-(2,4,6-trimethyl-phenyl)-acetyl]-amino}-piperidine-4-carboxylic acid methyl ester is obtained. 1H-NMR (CDCl3): 6.80 ppm (s, 2H), 3.60 ppm (s, 5H), 3.15 ppm (s, 3H), 3.15 ppm (s, 3H), 2.85 ppm (m, broad, 4H), 2.45 ppm (s, 6H), 2.30 ppm (m, broad, 2H), 2.20 (s, 3H), 2.15 (s, 6H), 2.10 ppm (m, broad, 2H).

Provenance & Evidence