A method of preparing 2-phenylbenzotriazoles expressed by Formula I: ##STR1## (wherein R.sub.1 denotes a hydrogen or chlorine atom, a lower alkyl group having 1 to 4 carbon atoms, a lower alkoxyl group having 1 to 4 carbon atoms, a carboxyl group or a sulfonic acid group; R.sub.2 denotes a hydrogen or chlorine atom, a lower alkyl group having 1 to 4 carbon atoms or a lower alkoxyl group having 1 to 4 carbon atoms; R.sub.3 denotes a hydrogen or chlorine atom, an alkyl group having 1 to 12 carbon atoms, a lower alkoxy group having 1 to 4 carbon atoms, a phenyl group, a phenyl group substituted by an alkyl group having 1 to 8 carbon atoms, a phenoxy group or a phenylalkyl group with an alkyl part having 1 to 4 carbon atoms; R.sub.4 denotes a hydrogen or chlorine atom, a hydroxyl group or an alkoxyl group having 1 to 4 carbon atoms; and R.sub.5 denotes a hydrogen atom, an alkyl group having 1 to 12 carbon atoms or a phenylalkyl group with an alkyl part having 1 to 4 carbon atoms) comprises reducing with hydrogen 2-phenylbenzotriazole-N-oxides expressed by Formula II: ##STR2## (wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 each denotes the same as in Formula I).
一种制备式I所示的2-苯基苯并
三氮唑的方法:##STR1##(其中R.sub.1表示氢或
氯原子,具有1至4个碳原子的低烷基,具有1至4个碳原子的低烷氧基,羧基或
磺酸基;R.sub.2表示氢或
氯原子,具有1至4个碳原子的低烷基或具有1至4个碳原子的低烷氧基;R.sub.3表示氢或
氯原子,具有1至12个碳原子的烷基,具有1至4个碳原子的低烷氧基,苯基,被具有1至8个碳原子的烷基取代的苯基,苯氧基或具有1至4个碳原子的烷基部分的苯基烷基;R.sub.4表示氢或
氯原子,羟基或具有1至4个碳原子的烷氧基;R.sub.5表示氢原子,具有1至12个碳原子的烷基或具有1至4个碳原子的烷基部分的苯基烷基)包括将式II所示的2-苯基苯并
三氮唑-N-氧化物还原为:##STR2##(其中R.sub.1,R.sub.2,R.sub.3,R.sub.4和R.sub.5与式I中的相同)。