反应详情

A solution of this half-acid half-ester in toluene is added to a refluxing solution of 2-n-butyl-1-(4-carboethoxy-2-chlorobenzyl)imidazole-5-aldehyde and piperidine in toluene. Twice at 1 hour intervals an additional amounts of the half-acid, half-ester is added, and the solution is then refluxed for 17 hours. Evaporation of the toluene and chromatography of the residue over silica gel using 2:3 ethyl acetate-hexane for elution gives the diester of the title product. This diester is hydrolyzed in 2:1 ethanol-water with 5 equivalents of potassium hydroxide for 18 hours and worked up in the usual manner to give the final product.

1. temperaturethe solution is then refluxed for 17 hours
2. customEvaporation of the toluene and chromatography of the residue over silica gel using 2:3 ethyl acetate-hexane
3. washfor elution