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

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Reaction Steps

A solution of 2.65 g of lithium hydroxide monohydrate in 158 ml of water was added, whilst ice-cooling, to a solution of 30 g of ethyl 4-(1-hydroxy-1-methylethyl)-2-propyl-1-{4-[2-(trityltetrazol-5-yl)phenyl]phenyl}methylimidazole-5-carboxylate [prepared as described in Example 18(a)] in 344 ml of dioxane, and the resulting mixture was stirred at 5°-10° C. for 20 hours. At the end of this time, small pieces of dry ice were added to the mixture, which was then concentrated by evaporation under reduced pressure to a volume of about 100 ml. Ethyl acetate and sodium chloride were added to the concentrate, and the mixture was stirred. The ethyl acetate layer was separated, dried over anhydrous sodium sulfate and concentrated by evaporation under reduced pressure, to give lithium 4-(1-hydroxy-1-methylethyl)-2-propyl-1-{4-[2-(trityltetrazol-5-yl)phenyl]phenyl}methylimidazole-5-carboxylate as a glass. 6.08 g of potassium carbonate were added, whilst ice-cooling, to a solution of whole of this lithium carboxylate in 160 ml of N,N-dimethylacetamide, and then a solution of 11.2 g of 4-chloromethyl -5-methyl -2-oxo-1,3-dioxolene (74% purity) in 26 ml of N,N-dimethylacetamide was added dropwise, whilst ice-cooling, to the mixture. The resulting mixture was stirred at 50° C. for 3 hours. At the end of this time, water and ethyl acetate were added to the reaction mixture, and the ethyl acetate layer was separated, dried over anhydrous magnesium sulfate and concentrated by evaporation under reduced pressure. The residue was crystallized in diisopropyl ether, to give 29.3 g of the title compound as crystals, melting at 98°-100° C. (with decomposition).

Provenance & Evidence