Sodium Hydroxide → 5-Phenyl-2-(2-hydroxy-3-phenyl-5-tert-octylphenyl)-2H-benzotriazole

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Reaction Steps

To a solution of sodium hydroxide (6 g, 0.15 mol) in 8 mL of water is added 2-hydroxy-2′nitro-3,4′-diphenyl-5-tert-octylazobenzene (6.56 g), prepared in (D) above. The reaction mixture is heated to reflux and then formadine sulfinic acid (10.8 g, 0.1 mol) is added portionwise over 20 minutes. The reaction mixture is heated at reflux for 1.5 hours. To the cooled reaction mixture is added 200 mL of water and the ethanol is removed under vacuum. The reaction mixture is adjusted to pH 4 with hydrochloric acid. The resultant mixture is extracted twice with methylene chloride and the combined organic phases are extracted with water. The organic phase is dried over anhydrous magnesium sulfate, and the solvent is then removed under vacuum. The residue is recrystallized sequentially from a mixture of water and methanol, and petroleum ether to give the title compound as a white solid melting at 123-125° C.

Provenance & Evidence