A solution of crude 1-benzyl-1H-tetrazole-5-carbonyl chloride (prepared from 2.4 g of potassium 1-benzyl-1H-tetrazole-5-carboxylate in the manner hereinbefore described in Reference Example 3) in dry methylene chloride (50 ml) was added to a stirred solution of 3-amino-2-hydroxyacetophenone (1.5 g) and pyridine (0.9 g) in dry methylene chloride (40 ml) at 10° C. After standing at room temperature overnight, the solution was evaporated in vacuo and the resulting solid residue was recrystallised from a large volume of ethanol to give 3'-acetyl-1-benzyl-2'-hydroxy-1H-tetrazole-5-carboxanilide (1.5 g), in the form of pale yellow needles, m.p. 155°-157° C.
