Triethylamine → 4-[2-(5-Bromo-4-fluoro-2-methyl-phenyl)-acetylamino]-1-methoxy-piperidine-4-carboxylic acid methyl ester

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Reaction Steps

A suspension of (5-bromo-4-fluoro-2-methyl-phenyl)-acetic acid (preparation example P5.3) (8.0 g) and 1,1′-carbonyldiimidazole (5.8 g) in tetrahydrofuran (150 ml) was heated at reflux for 30 minutes. Upon cooling to room temperature, triethylamine (9.0 ml) and 4-amino-1-methoxy-piperidine-4-carboxylic acid methyl ester hydrochloride salt (preparation example P1, step P1.3) (13.8 g) were added and warming at reflux was continued for 3 hours. The cold reaction mixture was poured on water/ethyl acetate, the layers separated, the organic phase washed with brine, dried over sodium sulfate and concentrated. The residue was solubilised in ethyl acetate/cyclohexane 3:1 and purified by filtration on alumina. Yield: 6.83 g of 4-[2-(5-bromo-4-fluoro-2-methyl-phenyl)-acetylamino]-1-methoxy-piperidine-4-carboxylic acid methyl ester as a solid, mp: 192-193° C.

Provenance & Evidence