6-(4-Substituted-phenyl)-2,4-diphenylverdazylium salts 2 (8 examples, 55-93%) were prepared by the reaction of 3-(4-substituted-phenyl)-1,5-diphenylformazans 1 with formaldehyde and different organic and inorganic acids in a two-phase chloroform/water medium by brief and gentle heating. Self-phase-transfer catalysis is apparently involved. Subsequent reductions of the salts 2 with excess ascorbic acid in the two-phase system give the corresponding verdazyl radicals, while in methanol the reduction proceeds to form leuco-verdazyls.
6-(4-取代苯基)-2,4-二苯基verdazylium盐2(8个例子,产率55-93%)是通过将3-(4-取代苯基)-1,5-二苯基福尔马赞1与
甲醛及不同有机和
无机酸在双相
氯仿/
水介质中进行短暂温和加热反应制备的。显然涉及自相转移催化。随后在双相系统中用过量
抗坏血酸还
原盐2,生成相应的verdazyl自由基,而在
甲醇中还原则形成亚甲基verdazyl。