1,1-Dichloroethane → 4-(4-Methoxyphenyl)piperidine

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Reaction Steps

A mixture of 1-benzyl-4-(4-methoxy)phenylpiperidine (XVIII, Step 3, 0.4724 g, 1.7 mmol), dichloroethane (4.4 ml) and 1-chloroethylchloroformate (0.66 ml, 6.1 mmol) is refluxed overnight, then concentrated and the residue refluxed in methanol for 2 hours. After cooling, the solvent is removed and the resulting solids are slurried in dichloromethane. Ether is added and the solids are collected and then partitioned between dichloromethane and saturated sodium bicarbonate. The combined organic phases are backwashed with saline, dried over magnesium sulfate, and concentrated to give a residue which is chromatographed on silica gel eluting with methanol/dichloromethane (4/96) containing ammonium hydroxide (0.4%), followed by methanol/dichloromethane (6/94) containing ammonium hydroxide (0.4%). The appropriate fractions are pooled and concentrated to give 4-(4-methoxyphenyl)piperidine (XIX), NMR (CDCl3) 1.66, 1.83, 2.06, 2.58, 2.76, 3.21, 3.79, 6.85 and 7.15 δ.

Provenance & Evidence