Triethylamine → ethyl 4-[[1-(2-phenylethyl)-1H-imidazol-2-yl]carbonyl]-1-piperidinecarboxylate

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Reaction Steps

To a cooled mixture of 54.2 g of 1-(2-phenylethyl)-1H-imidazole, 34.7 g of N,N-diethylethanamine and 50 ml of pyridine there were added dropwise 69.2 g of ethyl 4-chlorocarbonyl-1-piperidinecarboxylate(temp.≤0.20° C.) and then 30 ml of acetonitrile. The whole was stirred for 2 hours at room temperature and for 4 hours at reflux temperature. After cooling, there were added 30 ml NaOH 50% and refluxing was continued for 1/2 hour. The cooled reaction mixture was evaporated and the residue was taken up in water. The product was extracted with dichloromethane and the extract was dried, filtered and evaporated. The residue was purified by column chromatography (silica gel; CH2Cl2 /CH3OH 97:3). The eluent of the desired fraction was evaporated and the residue was dried, yielding 38 g (33.9%) of ethyl 4-[[1-(2-phenylethyl)-1H-imidazol-2-yl]carbonyl]-1-piperidinecarboxylate (interm. 1).

Provenance & Evidence