| 摘要 |
PURPOSE:To obtain the titled compound useful as an ultraviolet absorber economically, by reducing a 2-nitro-2'-hydroxyazobenzene compound with thiourea dioxide in the presence of an alkali metal hydroxide in a mixed solvent of water and an alcohol. CONSTITUTION:The titled compound, especially the compound of formula II is produced easily and rapidly, in high yield and purity, using a safe and easily handleable reducing agent, by reducing a 2-nitro-2'-hydroxyazobenzene compound, especially the compound of formula I (R<1> is H or Cl; R<2> and R<3> are H, Cl, lower alkyl or lower alkoxy, or R<2> may be COOH or SO3H and R<3> may be phenyl, phenoxy, etc.; R<4> is H, Cl, OH or lower alkoxy; R<5> is H, alkyl or phenyl-lower alkyl) with thiourea dioxide in the presence of an alkali metal hydroxide in a mixed solvent composed of water and an alcohol, especially secondary propanol or secondary butanol.
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