Aniline, formation Anisol

The mechanism of this activation of the C-H bond is unknown although the reaction may proceed by an oxidative addition. Generally, the pentaammine-osmium(II) system is known to activate phenols, anilines, and anisoles toward electrophilic addition and substitution reactions by binding the aromatic ligand in an T -fashion. Protonation, for example, results in the formation of a heterotriene system [30b] ... 

Hitherto, thio ether formation has clearly been proved only in the case of the ji-donor substituted 4-nitrosophenetol and the electron-rich l-methyl-2-nitrosoimidazole. The low yields of this adduct (about 2% at 1 1- and about 10% at 1 5-stoichiometry for 4-nitrosophenetol reacting with GSH56) may be the reason for its rare discovery. However, other nitrosoarenes should yield this family, too. Semiempirical molecular orbital calculations (MNDO) indicate a similar positive charge at the exposition of the N-(methylthiol-S -yl)-aniline cation and -4-anisole cation as well (Scheme 6). Furthermore, formation of l-(glutathion-S -yl)-2-naphthylamine was reported to occur in mixtures of 2-nitrosonaphthalene and GSH12. 

If a carbonium ion were involved, we should expect the halide to be derived from the more stable, and therefore the more highly branched, alkyl group. It is also pertinent that anisole is not cleaved by dry hydrogen chloride or hydrogen bromide in carbon tetrachloride solution unless a small amount of pyridine, dimethylaniline, or aniline is added.18 Furthermore, the presence of these bases increases the rate of cleavage of ethers in acetic acid solution. All these experiments imply that more than two molecules participate in the formation of the transition complex leading to etherification or cleavage (see p. 83). 

Aminopyradine, MA adduct formation, 238 Ammonia, MA reaction, 81, 85, 511 Ammonium bromide, isomerization catalyst, 13 Ammonium chloride, catalyst, 47 Ammonium persulfate, isomerization catalyst, 13 Ammonium phosphate, MA distillation additive, 22 Ammonium sulfate, MA distillation additive, 22 Anethole see p-Propenyl-anisole Anhydrides, cyclic, hydrolysis, 73, 74 Aniline... 

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