In a nitrogen atmosphere, a solution of 0.1 mole 4-benzyloxyphenol in 50 cc dimethylformamide is added dropwise at about 15° C. to 0.1 mole 57% sodium hydride in 25 cc dimethylformamide. When evolution of hydrogen ceases, 0.1 mole 3,7-dichloro-1,2,4-benzotriazine-1-oxide is added and the reaction mixture is heated at 125° C. for about 2 hours. After standing overnight at room temperature, the reaction mixture is poured into ice-water (~500 cc). The solid product is filtered and crystallized from methanol or acetonitrile.
