Diphenylamine, reaction with

In the synthesis of commercial sulfur-heterocycles two interesting reactions are used (i) diphenylamines may be connected by a sulfur bridge in the orfho-positions (ii) the amino grouping of sulfonamides undergoes condensation reactions with neighboring imino- and amide groups. 

Addition of acetone, ammonia, aniline or diphenylamine to the oxidant causes rapid exothermic reactions, with or without flame, and large amounts under confinement would explode. The trichloro analogue is similar, but less vigorous. 

Different reactivity of a-oxyalkyl and boryloxyalkyl fragments was revealed in reactions with amines of weak basicity. For example, in the reaction with diphenylamine or o-aminobenzoic acid with a reagent ratio of 1 1, substitution of the oxymethyl group by the aminomethyl one takes place [Eq. (117)]. The P,B-containing heterocycle is retained (89IZV1340). 

Although diselenonium-, ditelluronium- and mixed sulfonium-selenonium dications can exhibit either oxidative or electrophilic properties in reactions with nucleophiles, substitution at the onium chalcogen atom is more typical.96 Owing to the increased stability of heavier dichalcogenium-dications, they react only with highly activated substrates such as aniline and tV,A-dimethylaniline, while no reaction is observed with phenol and diphenylamine.113 Reactions of ditelluronium dications with activated aromatics are also not known (Scheme 44).114... 

Anilinediphenylamine phosphate 1 ml aniline + 1 g diphenylamine in 100 ml acetone. Add 10 ml 85% orthophosphoric acid Dip Reaction with aromatic amine in hot acid... 

Due to the high interest in metalation reactions with lithium amide or alkyllithiums, an indicator scale of lithium ion pairs in THF has been developed119. Aggregation studies have indicated that organolithium species exist predominantly, if not exclusively, as monomers in the 10-3-10-4 M concentration range. Particular attention has been devoted to the lithium and caesium ion-pair acidities of diphenylamine in THF120 that, at 25 °C, have been found to be 19.05 and 24.20, respectively. 

Another point worth mentioning is the selectivity of the electrogenerated electrophilic sulfur species toward aromatic substrates in the reaction with diphenylether and diphenylamine. In the first case, an internal ortho-cyclization yields in phenoxathiin, in the second, a para-substitution occurs [252] giving a linear product (8cheme 59). 

Arylbenzotriazoles (797) are prepared via 2-nitro- and 2-amino-diphenylamines (Scheme 161). The 2-nitrodiphenylamines (796) are prepared from the appropriate aniline by reaction with 2-fluoronitrobenzene in the presence of KF <808215,85JCS(Pl)2725>. Azo-coupling of 2-amino-1-cyano-azulene (798) with p-tolyldiazonium chloride gives (799) (Scheme 162). Catalytic reduction of (799) quantitatively yields the diamino derivative (800), which on diazotization affords 9-cyano-azuleno[l,2-J]triazole (801) in 77% yield <85TL335>. 

Stability. In order to have maximum effectiveness over long periods of time, an antioxidant should be stable upon exposure to heat, light, oxygen, water, etc. Many antioxidants, especially in the presence of an impurity when exposed to light and oxygen, are subject to oxidation reactions with the development of colored species. Alkylated diphenylamines are least susceptible and the />-phenylenediamine derivatives the most susceptible to direct oxidation. 

The rate constant of this reaction was measured by flash photolysis with tetraphenyl-hydrazine as a source of diphenylaminyl radicals [64]. Peroxyl radicals were generated through the photodecay of bis(l,l-dimethylethyl) peroxide followed by the rapid reaction of formed alkoxyl radicals with cyclohexane used as a solvent the reaction conditions were chosen in such a way that [R02 ]o > [Ph2N ]0. Under these conditions, aminyl radicals were destroyed only in the reaction with peroxyl radicals and, hence, the concentration of peroxyl radicals during the measurement of the kinetics of Ph2N consumption varied insignificantly. The rate constant of the recombination of peroxyl and diphenylamine radicals was found to be equal to 6 x 108 L mol 1 s 1 (cyclohexane, 283-303 K). 

Katritzky et al. [76CC48 77JCS(P1)1162] synthesized the quina-zolin[l,2-a]-quinazoline (536) by the reaction of 2,2 -bis(chloroformyl) diphenylamine (535) with N,N-diphenylbenzamidine. 

The higher the nitrosaccharose percentage in the mixture, the lower its stability. According to Naoum [25] wood meal admixed with dynamite may act as a stabilizer, because it absorbs the impurities or the decomposition products and can enter into reaction with these compounds, thus removing them. With the aim of improving storage life, 0.1-0.2% of diphenylamine is also added to act as a stabilizer. A mixture prepared in this way can be kept for 75 days at 55°C or for 8 years at 20°C with no sign of decomposition. 

Regarding the increased sensitiveness of the nitric-acid reaction with diphenylamine in water analyses, see R. Cimmino, Ztschr. anal. Chem., 38, 429 (1899) J. Chem. Soe., 70, II, 805 (1899). 

Detection oj nitrocellulose. A little of the residue obtained on evaporation of the solvent (see above) is treated in a thoroughly dry disli with concentrated sulphuric acid containing in solution a little diphenylamine in presence of nitrocellulose the intense blue coloration due to nitric acid and nitro-derivatives is observed. Sometimes, however, the nitrocelluloses are partially denitrated, so that the reaction with diphenylamine is feeble in such cases test 4, b should be carried out. 

The perchlorates of various secondary amines, such as diphenylamine and indole derivatives, are colorless.64 The similarity of colors produced in the presence of hydrochloric acid also attests to the non-auxochromic character of the perchlorate ion in the production of the colored derivative. Consequently, the only role attributable to the perchloric acid in this test is that with nucleic acids it leads to more effective hydrolysis and releases more 2-desoxyribose for reaction with tryptophan. This reaction leads to the production of a substance of the type represented by XV and XVI (R " = H), and the increase in the number of conjugated double bonds results in the product being colored. With ribose, which has a free hydroxyl group at carbon atom 2, a ketone of the type shown in XVII can be formed, and in this case the net result is no increase in the number of double bonds conjugated with the indole nucleus and no comparable increase in color. Hence the test will distinguish between ribose and 2-desoxyribose. 

Nucleophiles with high tendency to migrate preferentially undergo the tandem MCR reaction, providing a useful route for the synthesis of substituted 1-alkynes. Examples of the MCR reaction with little or no tendency to compete with the MCI pathway are summarized in Eq. (113) Nu = thiocyanate [200,201], thiotosylate [202], thiolate [203], phosphorodithioate [204], tosylate [205], car-boxylate [206], phosphate [206], lithium diphenylamine [207], and halide [171]. It appears likely that, because of the electron-deficient nature of the carbenic... 

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