Sodium azide (145.8 mg, 16.2 mmol) was added into a solution of 5-ethylcarbamoyl-4′-methyl-biphenyl-3-carboxylic acid methyl ester (210 mg, 0.7 mmol) and SiCl4 (0.62 mL, 5.4 mmol) in dry acetonitrile (14 mL). After the reaction was stirred at room temperature for 24 hours, the reaction mixture was poured into cold saturated aqueous Na2CO3 solution. This mixture was extracted with ethyl acetate and dried with anhydrous Na2SO4. Solvent was removed under reduced pressure to afford 200 mgs of 5-(1-ethyl-1H-tetrazol-5-yl)-4′-methyl-biphenyl-3-carboxylic acid methyl ester (yield 89%). MS (M+H)=323.
