Into a 500-ml flask equipped with a reflux condenser, thermometer and stirrer were placed 43.5 g (0.10 mole) of ethyl ester of 1-(2'-cyanobiphenyl-4-yl)methyl-4-(1-hydroxy-1-methylethyl)-2-propylimidazole-5-carboxylic acid, 19.5 g (0.30 mole) of sodium azide, 41.3 g (0.30 mole) of triethylamine hydrochloride and 206 ml of toluene. The mixture was heated with stirring to a temperature of 95° to 100° C. to undergo a reaction for 24 hours. After completion of the reaction, the reaction mixture was cooled to room temperature. Then, 35.0 g (0.42 mole) of a 48 wt % aqueous solution of NaOH and 335 ml of water were added. The mixture was fractionated after 2 hours' stirring at room temperature. The aqueous layer was washed and fractionated with the addition of 103 ml of toluene. The aqueous layer was adjusted to a pH of 2 to 3.5 with 36 wt % hydrochloric acid to separate out crystals, which were collected by filtration and dried. The crystals were heated, washed with methanol with stirring, cooled, filtered for collection and dried, giving 32.6 g (0.07 mole) of 4-(1-hydroxy-1-methylethyl)-2-propyl-1-{4-[2-(tetrazole-5-yl)phenyl]phenyl}methylimidazole-5-carboxylic acid (yield 72.4% based on ethyl ester of 1-(2'-cyanobiphenyl-4-yl)methyl-4-(1-hydroxy-1-methylethyl)-2-propylimidazole-5-carboxylic acid). The reaction is illustrated below with chemical formulas. ##STR29##
