Hydrochloric Acid → 4-Dimethylamino-4-phenylcyclohexanecarbaldehyde

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Reaction Steps

Under argon, methoxymethyltriphenylphosphonium chloride (6.3 g, 18.4 mmol) was dissolved in DMF (25 ml), and sodium hydride (60 wt. % in mineral oil, 737 mg, 18.4 mmol) was added. A solution of 4-dimethylamino-4-phenylcyclohexanone (2.0 g, 9.2 mmol) in 25 ml of DMF was added dropwise over 30 min and the suspension was stirred for 3 d at RT. For the work-up, the suspension was poured slowly into 2 M HCl (50 ml) cooled with ice-water, stirred at RT for 2 h and then extracted with diethyl ether (5×25 ml) and EE (6×20 ml). The aqueous phase was then brought to pH 10-11 with 1 M NaOH and extracted with EE (5×20 ml). The combined extracts were dried with sodium sulfate, filtered and concentrated. The residue was 4-dimethylamino-4-phenylcyclohexanecarbaldehyde (2.0 g of brown oil) in a diastereoisomer ratio of 55:45 (1H NMR).

Provenance & Evidence