PROCESS FOR THE SYNTHESIS OF TETRAZOL DERIVATIVES

摘要

1. Process for the synthesis of losartan potassium of formula (I), chemical name: 2-n-butyl-4-chloro-1-[(2'-(tetrazol-5-yl)-1,1'-biphenyl-4-yl)-methyl]-imidazol-5-methanol potassium, starting from2-n-butyl-4-chloro-1-[(2'-(2-triphenylmetyl-2H-tetrazol-5-yl)-1,1'-biphenyl-4-yl)-methyl]-1H-imidazol-4-methanol of formula (III), characterized by reacting the compound of formula (III) in an alcohol of formula (VI),-wherein R is C1-4 straight chain alkyl group-with 0.1-1 equivalent of potassium hydroxide and isolating the final product of formula(I) after crystallizing out by changing the solvent to an aprotic or weakly protic solvent. 2. The process according to claim 1, characterized by using methanol as alcohol. 3. The process according to claim 1 and 2 characterized by, carrying out the reaction at 50-80 degree C. 4. The process according to any one of claims 1,2 and 3 characterized by using acetonitrile as dipolar aprotic solvent for the crystallization of the final product. 5. The process according to any one of claims 1,2 and 3 characterized by using straight or branched chain or cyclic aliphatic hydrocarbons as aprotic solvent for the crystallization of the final product. 6. The process according to any one of claims 1,2 and 3 characterized by using sec-butanol as protic solvent for the crystallization of the final product.