Process for the synthesis of a known tetrazol derivative

Abstract

The invention relates to a 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 from 2-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). According to the process the compound of formula (III) is reacted in an alcohol of formula (VI),—wherein the meaning of R is C1-C4 straight chain alkyl group—with 0.1-1 equivalent of potassium hydroxide. The final product of formula (I) is isolated after crystallizing out by changing the solvent to an aprotic or weakly protic solvent (I).