Benzocaine → 4-(1H-1,2,3,4-tetrazol-1-yl)benzoic acid

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Reaction Steps

To a solution of ethyl 4-aminobenzoate (1.65 g) in acetic acid (20 mL) is added triethylorthoformate (8 mL) and sodium azide (1.17 g) and the solution is heated at reflux for 4 h. After cooling and removing acetic acid in vacuo, water and dichloromethane are added and the organic layer is separated and dried (MgSO4) and concentrated. The crude ester is dissolved in methanol (30 mL) and 4 M aqueous NaOH solution (3 mL) is added and the solution is stirred at room temperature for 2 h. The mixture is neutralized with 6 M aqueous HCl, concentrated and then acidified with 6 M aqueous HCl. The precipitate is filtered off washing with water and dried by suction to give the title compound.

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