Hydrogen Bromide → (+)-Cis-1-methyl-3-ethoxymethyl-4-(3,4-dichlorophenyl)-piperidine hydrobromide

Participants

Reaction Steps

(±)-Cis-1-methyl-3-ethoxymethyl-4-(3,4-dichlorophenyl)-piperidine (9) (1.1 g, 3.7 mmol) and (−)-dibenzoyltartaric acid (0.48 g, 1.3 mmol) were dissolved in 99% ethanol (10 ml) and evaporated to dryness. The evaporation residue was crystallized from toluene (3 ml). Recrystallized from a mixture of toluene (10 ml) and ethanol (10 ml). The precipitate was isolated and dissolved in a mixture of 4 N NaOH (5 ml) and diethyl ether (10 ml). The diethyl ether was separated and dried with magnesium sulfate yielding 0.25 g (45%) of the product as the free base. Hydrobromic acid (0.20 ml, 1.7 mmol) was added and the mixture evaporated to dryness. The residue was recrystallized from ethanol (2 ml) and diethyl ether (10 ml) to yield 0.20 g (28%) of (13), mp 183-185° C., [α]D25=+62.8°, (c=14 mg/ml in 99% ethanol).

Provenance & Evidence