2-Substituted and 1,2-disubstituted indoles react with m-chloroperbenzoic acid and hydrogen peroxide in the presence of acid or calcium chloride affording 2- and 3-(3-oxoindol-2-yl)indoles; whereas 2,3-disubstituted indoles, reacting with the same oxidants, lead to the formation of products typical of pentaatomic ring opening. The reaction mechanisms are discussed in terms of electron transfer processes based on the redox potentials of the reagents, the Marcus theory and the reaction products distribution. The reactions of 1-hydroxy-2-phenylindole, which yield 2-phenylisatogen (2-phenyl-3-oxo-3H-indole 1-oxide), bisnitrone and 3-(3-oxoindol-2-yl)indole are also explained by an electron transfer mechanism depending on the oxidant and on the conditions of the reaction. The structures of 2- and 3-(3-oxoindol-2-yl)indoles have been elucidated by X-ray analysis.
2-取代和1,2-二取代
吲哚在酸或
氯化钙存在下与间
氯过
苯甲酸和
过氧化氢反应,得到2-和3-(3-氧代
吲哚-2-基)
吲哚;而2,3-二取代
吲哚与相同的氧化剂反应,会形成典型的五原子开环产物。基于试剂的氧化还原电位、Marcus 理论和反应产物分布,从电子转移过程的角度讨论了反应机理。还解释了 1-羟基-
2-苯基吲哚的反应,产生 2-苯基 isatogen (2-苯基-3-氧代-
3H-吲哚 1-氧化物)、双硝酮和 3-(3-氧代
吲哚-2-基)
吲哚通过取决于氧化剂和反应条件的电子转移机制。 2-和3-(3-氧代
吲哚-2-基)
吲哚的结构已通过X射线分析阐明。