Citric Acid → 3-(5-fluoro-1H-indol-3-yl)piperidine-1-carboxylic acid-(4-dimethylamino-4-phenylcyclohexylmethyl)-amide citrate

Participants

Reaction Steps

The polar diastereoisomer of 3-(5-fluoro-1H-indol-3-yl)piperidine-1-carboxylic acid-(4-dimethylamino-4-phenylcyclohexylmethyl)-amide (115 mg, 0.241 mmole) was dissolved in abs. ethanol (1.5 ml). Citric acid (46.8 mg, 0.244 mmole) was added in one portion at ca. 40° C. while stirring. No precipitate formed at RT. Diethyl ether (50 ml) was slowly added to the reaction solution. The resulting suspension was stirred for 1 hour at RT. The precipitate was filtered off, washed with diethyl ether (3×2 ml) and dried in vacuo. The polar diastereoisomer of 3-(5-fluoro-1H-indol-3-yl)piperidine-1-carboxylic acid-(4-dimethylamino-4-phenylcyclohexylmethyl)-amide citrate (133 mg, m.p. 128°-130° C., 83%, Example 50) was a colourless solid.

Provenance & Evidence