Method for synthesizing 2-normal-butyl-4-chloro-5-formylimidazole

Abstract

The invention discloses a method for synthesizing 2-normal-butyl-4- chloro-5-formylimidazole shown by a formula (I). Imidazolone shown in the formula (II) reacts with bis (trichloromethyl) carbonate shown by a formula (III) and formamide shown by a formula (IV) in an organic solvent for 1-10 hours at the temperature of 20 DEG C below zero to 200 DEG C, and reaction solution is hydrolyzed to obtain 2-normal-butyl-4-chloro-5-formylimidazole. The invention has mild reaction conditions, good selectivity, no generation of phosphorus wastewater and low cost of proposal of waste water, waste gases and waste residues, and is suitable for industrial production.

Description

technical field The invention relates to a synthesis method of a losartan intermediate 2-n-butyl-4-chloro-5-formyl imidazole. Background technique 2-n-butyl-4-chloro-5-formyl imidazole is a key intermediate of losartan, a non-peptide angiotensin II receptor blocker. U.S. Patent No. 5,442,076 reports that 2-n-butyl-3,5-dihydroimidazol-4-ketone is treated with phosphorus oxide and N,N-dimethylformamide to obtain 2-n-butyl-4-chloro-5 - formyl imidazole. U.S. Patent No. 5,486,617 reported that 2-n-butyl-3,5-dihydroimidazol-4-ketone was treated with phosphorus oxychloride and N,N-dimethylformamide dimethyl acetal to obtain 2-n-butyl -4-Chloro-5-formyl imidazole. U.S. Patent No. 5,606,072 reported that 2-n-butyl-3,5-dihydroimidazol-4-ketone was first treated with chlorination reagents such as phosphorus trichloride or thionyl chloride to obtain 2-n-butyl-5-chloroimidazole, Then, in the presence of phosphorus oxychloride, react with N,N-dimethylformamide to obtain 2-n-butyl-...

AI Technical Summary

Problems solved by technology

The above-mentioned methods all use a large amount of highly toxic phosphorus oxychloride, and a large amount of phosphorus-containing wastewater is produced in the industrial production process, resulting in high cost for the treatment of the three wastes, and there are disadvantages such as unsafe operation, difficult separation and purification of products, and harsh reaction conditions.

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