Triethylamine → 2-(2,4-Difluorobenzyl)-1-(methoxycarbonyl)piperidine-4-carboxylic acid

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Reaction Steps

To a suspension of lithium bromide (18.06 g, 207.99 mmol) in acetonitrile (80 mL) and water (1.6 mL) was added triethylamine (14.42 mL, 104.00 mmol) followed by dimethyl 2-(2,4-difluorobenzyl)piperidine-1,4-dicarboxylate (8.51 g, 26.00 mmol) in acetonitrile (40 mL). The resulting mixture was heated under reflux for 2 h 30 min, then cooled to room temperature and water and MTBE were added. The organic phase was extracted with water twice. The pooled aqueous layers were adjusted to pH 1 with 3.8 M HCl and then extracted with DCM (3×). The combined organic layers were dried over MgSO4 and evaporated to yield 2-(2,4-difluorobenzyl)-1-(methoxycarbonyl)piperidine-4-carboxylic acid (7.48 g, 92%) as an orange solid. MS m/z 314 (M+H)+

Provenance & Evidence