Benzeneethanol, 4-hydroxy-3-[2-(2-nitrophenyl)diazenyl]- → Benzeneethanol, 3-(2H-benzotriazol-2-yl)-4-hydroxy-

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Reaction Conditions

Reaction Steps

5.39 g (18 mmols) of crude 4-(2-hydroxyethyl)-2-[(2-nitrophenyl)azo]phenol synthesized in Example 3 was dissolved in 18 ml of aqueous solution of 2N sodium hydroxide. Subsequently, 9 ml of previously prepared aqueous solution of 25% sodium hydroxide and 5.4 g (83 mmols) of zinc powder were simultaneously added over a period of about 3 hours. The reaction mixture was heated to 70° C. and stirred for about 2 hours. The reaction mixture was then cooled to room temperature and filtered to collect inorganic substance. The obtained mother liquor was acidified with concentrated hydrochloric acid. Precipitated crystals were collected by filtration and recrystalized in toluene, giving 3.70 g of 2-(2H-benzotriazole-2-yl)-4-(2-hydroxyethyl)phenol as yellow crystals (yield 70%, purity 87%).

Provenance & Evidence