2- Methylindole, oxidation

Unlike the intermolecular reaction, the intramolecular aminopalladation proceeds more easily[13,14,166], Methylindole (164) is obtained by the intramolecular exo amination of 2-allylaniline (163). If there is another olefinic bond in the same molecule, the aminopalladation product 165 undergoes intramolecular alkene insertion to give the tricyclic compound 166[178]. 2,2-Dimethyl-l,2-dihydroquinoline (168) is obtained by endo cyclization of 2-(3,3-dimethyiallyl)aniline (167). The oxidative amination proceeds smoothly... 

Methylpyrrole and dimethyl acetylenedicarboxylate interact at 0°C to give a 1 2 adduct which is now known " to have structure (48). It is formed by addition of the ester across the 2,5-positions of the pyrrole yielding (47), which was not isolated but combined with a second molecule of the ester across the 2,7-positions accompanied by scission of the 4,7-bond as indicated. This adduct (48) was oxidized by bromine in methanol to trimethyl l-methylindole-2,3,4-tricarboxyl-ate and reacted further with hot dimethyl acetylenedicarboxylate. 

The oxidation of indole magnesium bromide and its 2- and 3-methyl derivatives at room temperature with p-nitroperbenzoic acid, in the absence of light and air, results in the formation of 3-bromoindole (370), 3-bromo-2-methylindole (371), and 2-bromo-3-methylindole (372), respectively. ... 

Ingraffia studied the oxidation of the Grignard reagents derived from indole, skatole, and 2-methylindole with hydrogen peroxide and... 

The 4-hydroxy-2-methylindole (MP 112°C to 115°C from benzene/ethyl acetate), used as starting material, may be obtained by hydrogenation of 4-banzyloxy-2-dimethylamino-methylindole (MP 117°C to 120°C from benzene) in the presence of a palladium catalyst (5% on aluminum oxide). 

Treatment of l-ethylideneamino-3-methylindole 95 with p-toluene sulfonic acid in boiling benzene gave l,2-dihydro[l,2,4]triazino[l,6-a]indole 96 (75CPB2891). The reaction was said to be due to an initial formation of a Diels-Alder-type adduct followed by the liberation of 3-methylindole. Compound % was oxidized either on exposure to air or by the action of chloranil to give 97 (Scheme 24). 

The results presented above indicate that the previously unknown head-to-tail polymerization is the major reaction product of the iminium methide species. To investigate the generality of this reaction, we next studied a neutral ene-imine species shown in Scheme 7.9.48 As illustrated in this scheme, the generation of this reactive species requires quinone reduction followed by elimination of acetic acid. The ene-imine is structurally related to the methyleneindolenine reactive species that is a metabolic oxidation product of 3-methylindole (Scheme 7.9).57 59... 

Ruangyuttikam, W. Skiles, G. L. Yost, G. S. Identification of a cysteinyl adduct of oxidized 3-methylindole from goat lung and human liver microsomal proteins. Chem. Res. Toxicol. 1992, 5, 713-719. 

Jensen, G. M., D. B. Goodlin, and S. W. Bunte. 1996. Density Functional and MP2 Calculations of Spin Densities of Oxidized 3-Methylindole Models for Tryptophan Radicals. J. Phys. Chem. 100, 954. 

A number of other indole derivatives have also been observed to yield CL subsequent to oxidation. Among these is skatole (3-methylindole), which emits light after oxidation by 02 under strongly alkaline conditions [9],... 

In a series of papers, Itahara established the utility of Pd(OAc)2 in the oxidative cyclization of C- and A-benzoylindoles, and two examples are shown [61-63], Itahara also found that the cyclization of 3-benzoyl-1,2-dimethylindole proceeds to the C-4 position (31% yield) [61]. Under similar conditions, both 1-acetylindole and l-acetyl-3-methylindole are surprisingly intermolecularly arylated at the C-2 position by benzene and xylene (22-48% yield) [64,65],... 

Abdrakhmanov and co-workers observed the cycloaddition of N-( 1 -methyl-2-butenyl)aniline or 2-(l-methyl-2-butenyl)aniline with PdCyDMSO to give a 69% yield of a mixture of 2-ethyl-3-methylindole and 2,4-dimethylquinoline [87]. The authors propose that a Claisen rearrangement is initially involved. A similar oxidative cyclization of a 5-amino-indoleacrylate was the starting point for syntheses of CC-1065 and related compounds [88],... 

Electrochemical oxidation of indole [202] and N-methylindole [203] in acetonitrile gives rise to dimers and trimers. These are oxidised further to polymers. Oxidation of N-acetylindoles in acetic acid results in acetoxylation of the heterocyclic... 

The non-oxidative formation of melanin from adrenochrome in acid solution, reported by Harley-Mason,6 has recently been shown by Bu Lock to be controlled by a second-order reaction between adrenochrome and acid.107 It was suggested that the initial product (not isolated) was probably l-methylindole-5,6-quinone, which polymerized rapidly to melanin via dimers and oligomers.107 (The intermediate monomer quinone also gave a melanin-like copolymer with indole.107)... 

---