| abstract |
From the starting 4-bromomethyl-2'-(1-triphenylmethyltetrazol-5-yl)biphenyl, N-[(2'(1-triphenylmethyl-tetrazol-5-yl)biphenyl-4-yl)methyl]-(L)-valine benzyl ester of formula 7 is obtained via a reaction with L-valine benzyl ester, and is converted to valsartan of formula I via a reaction with valeryl chloride and removing of protective groups. The method consists in converting, with hydrochloric acid, N-[(2'-(l-triphenylmethyl-tetrazol-5-yl)biphenyl-4yl)methyl]-(L)-valine benzyl ester of formula 7, obtained in the first stage, to N-[(2'-(1-triphenylmethyl-tetrazol-5-yl)biphenyl-4-yl)methyl]-(L)-valine benzyl ester hydrochloride of formula III, which is optionally re-crystallized. |