Carbon Dioxide → Pivaloyloxymethyl 4-(1-hydroxy-1-methylethyl)-2-methoxymethyl-1-{4-[2-(trityltetrazol-5-yl)phenyl]phenyl}methylimidazole-5-carboxylate

Participants

Reaction Steps

A solution of 41.9 mg of lithium hydroxide monohydrate in 15 ml of water was added, whilst ice-cooling, to a solution of 0.75 g of methyl 4-(1-hydroxy-1-methylethyl)-2-methoxymethyl-1-{4-[2-(trityltetrazol-5-yl)phenyl]phenyl}methylimidazole-5-carboxylate [prepared as described in Example 82(a)] in 15 ml of dioxane, and the mixture was stirred at room temperature overnight. At the end of this time, a small quantity of dry ice was added to the reaction solution, and the dioxane was removed by distillation under reduced pressure. The residue was then dissolved in a small quantity of an aqueous solution of sodium chloride and ethyl acetate. The ethyl acetate layer was separated, washed with an aqueous solution of sodium chloride and dried over anhydrous sodium sulfate. The solvent was removed by distillation under reduced pressure, and the resulting residue was dried in vacuo at 50° C. for 1 hour. 0.25 g of potassium carbonate were then added to a solution of the resulting residue in 10 ml of N,N-dimethylacetamide, and the mixture was cooled with ice-water. A solution of 0.31 ml of pivaloyloxymethyl chloride in 3 ml of N,N-dimethylacetamide was then added dropwise to the mixture, which was then stirred at 70° C. for 1.5 hours. At the end of this time, water and ethyl acetate were added to the reaction solution. The ethyl acetate layer was separated, washed with water and dried over anhydrous sodium sulfate. The solvent was removed by distillation under reduced pressure, and the resulting residue was purified by column chromatography through silica gel, using a 1:1 by volume mixture of hexane and ethyl acetate as the eluent, to give 0.79 g of the title compound as a foam-like solid.

Provenance & Evidence