| 摘要 |
PURPOSE:To obtain the titled substance useful as an ultraviolet absorber to be added to plastics, paints, oils, etc., in high yield, without causing the pollution of waste water and atmosphere, by reducing an o-nitroazobenzene derivative with a sugar in the presence of a hydrogen-transfer catalyst and a base. CONSTITUTION:The objective compound of formula II can be produced by reducing the compound of formula I (R1 is H, Cl, alkyl, carboxyl, etc.; R2 is H, Cl, alkyl, or alkoxy; R3 is H, Cl, alkyl, phenyl, etc.; R4 is H, Cl, OH, or alkoxy; R5 is H, alkyl or phenylalkyl) with a sugar (preferably glucose) in the presence of a hydrogen-transfer catalyst (e.g. 2,3-dichloro-1,4-naphthoquinone) and a base (e.g. NaOH). The reaction is carried out usually in an aqueous solution or an inert solvent such as alcohol, toluene, DMF, etc., to enable the smooth reaction. If necessary, a surfactant, a phase-transfer catalyst, etc., may be added to the reaction system. |
