4- diphenylamine structure

Deveaux et al. [21] reported that mefenamic acid, being an N-aryl derivative of anthranilic acid, can be characterized by two color reactions. The color reactions, negative with N-aryl derivatives of aminonicotinic acid, are associated with the diphenylamine structure. For the first color reaction, add to a test tube approximately 0.5 g of oxalic acid dihydrate and at least 1 mg of the test material. Place the tube into an oil bath at 180-200°C for 4-5 min. After cooling, dissolve the residue in 10 mL of 95% ethanol to obtain a stable, intense blue solution (absorption maximum at 586-590 nm). To use the reaction for capsule formulations, extract the active ingredient with acetone and filter prior to the assay. For the second color reaction, add mefenamic acid (100-800 pg) in 1 mL of H0Ac-H2S04 (98 2, v/v), 5 mL of HOAc-HCl (50 50, v/v) and 1 mL of 0.10% (w/w) aqueous levulose. Heat the mixture for 25 min at 100°C, and after cooling, measure the absorbance at 597 nm. 

The major peak at 89 ppm in the fulvic acid spectrum may be comprised in part of diphenylamine structures. (The NMR chemical shift of the singly protonated nitrogen in 4-aminodiphenylamine is 87 ppm (Figure 1)). 

Steric effects on the nucleophile, aniline, were clearly evident. Rate constants for bimolecular attack of 2,6-dimethyl- 70a, 2,6-diethyl- 70b, and 3,5-dimethylaniline 70c at 308 K indicate that the ort/zo-substituted anilines react more than an order of magnitude slower at the same temperature (Table 7). Structure 70c must be able approach the reactive nitrogen more closely.42,43 A comparison of the rate constants for reaction of aniline 72c, /V-methyl- 71a and /V-phenylaniline 71b provides further evidence of steric effects although the very small rate constant for the diphenylamine could also be accounted for by reduced nucleophilicity on account of lone pair resonance into the additional phenyl ring. 

In the Colour Index both conventional sulphur dyes and their leuco counterparts are allocated the same Cl constitution number a different number is given to the related solubilised version. Thus, for example, Cl Sulphur Black 1 and Cl Leuco Sulphur Black 1 have the reference Cl 53185 whereas Cl Solubilised Sulphur Black 1 appears under Cl 53186. Because of the complexity of the final products, sulphur dyes are classified according to the chemical structure of the organic starting material that predominates in the manufacturing process. Typical intermediates include aromatic amines, with or without nitro and phenolic groups, and diphenylamine derivatives. 

Methylnitramine decomposes explosively in contact with concentrated sulphuric acid. It is evolved when aniline reacts with tetryl, a diphenylamine derivative (p. 51) is produced simultaneously. Methylnitramine reacts with picryl chloride to form tetryl. The structure of tetryl (p. 40) was first proved by this synthesis. 

Apart from diphenylamine a number of other organic bases were tested for use as stabilizers. Some of them, e.g. aniline, were used only temporarily, chiefly during World War I when diphenylamine was in short supply. The basic properties of aniline are too marked and this is detrimental to stability. On the other hand, relatively good results have been obtained with carbazole which resembles diphenylamine in its structure ... 

The electrochemical oxidation of aromatic aldehydes (1) must be studied in strongly alkaline media. Acidity functions for strongly alkaline aqueous solutions of alkali metal and quaternary ammonium hydroxides, corresponding to dissociation of proton (H ), are well established (2, 3). Substituted anilines and diphenylamines (4,5) and indoles (6) were used as acid-base indicators for establishment of such scales, but whether an acidity scale based on one type of indicator can be rigorously applied to acid-base equilibria involving structurally different acidic groups for reactions in strongly alkaline media remains questionable. For substituted anilines, behavior both parallel (7) and nonparallel (8) to the H scale based on indole derivatives has been reported. The limited solubility of anilines in aqueous solutions of alkali metal hydroxides, the reactions of the aniline derivative with more than one hydroxide ion, irreversible substitution reactions (9), and the possibility of hydroxide ion addition rather than... 

The influence of the rigid structure on the basicity of quinuclidine derivatives30 is demonstrated by comparison of the pKa values of benzo- and dibenzoquinuclidines with the structurally allied diethyl-aniline and diphenylamine (see Table II). 

The only representative of this macrocyclic group of molecules is a hexaaza derivative believed to possess the heavily annulated structure shown in 133 and formed quantitatively on reaction of 2,2 -diaminobi-phenyl with diphenylamine-2,2 -dicarboxyaldehyde.88 From the limited... 

Sulfonic acid derivatives of diphenylamine and diphenylbenzidine are suitable indicators in many redox titrations. The structures of these indicators are shown below ... 

As in the case of the metal-free direct dyes, a large diversity of structures is encountered here, too, there are direct dyes with pyrazolones, substituted 4,4 -diphenylamines, or the 1,3,5-triazine ring, urea and stilbene derivatives, and condensation dyes. 

CpCo(CO)2 under UV irradiation and from the polymerizations of metallolyl (57 and 58) and silyldiynes (66-70) catalyzed by tantalum halides [86-91]. The homopolycyclotrimerizations of other aromatic diynes (38-56) all proceeded very rapidly, giving polymeric products that were only partially or totally insoluble in common organic solvents due to the involved cross-linking reactions. The large free volumes and irregular molecular structures generated by the nonlinear carbazolyl, diphenylamine, metallolyl and silyl groups may have helped endow the homopolymers (hb-P57 to hb-P70) with the excellent solubility. 

A closer inspection of the chemical structures of these compounds shows that they contain a modification of the diphenylmethane moiety, a diphenylamine. 

Fig. 3.6 Privileged structures are scaffolds or substituents that often produce biologically active compounds for example, phenethyl-amines, diphenylmethyl and diphenylamine compounds (X = Cor N, respectively), tricyclic...

In diphenylamine and finally triphenylamine the basicity is still lower, so that this last amine only forms salts with the strongest acids of all, such as HC104. A condition for maximum resonance is a completely plane structure, which can, however, not be satisfied in the last-mentioned substance. This is also the case with dimethyl 0-toluidine, which is a weaker base than dimethylaniline, while 0-toluidine has practically the same strength as aniline. 

The one-electron oxidation of a secondary amine results in the formation of a secondary aminium ion which on deprotonation gives an aminyl radical (Scheme 1). The nature of the final products derived from these intermediates dqiends very much on the structure of the substrate and the reaction conditions. If the amine has a hydrogen atom on the a-carbon atom the major products usually result from deprotonation at this a-position. With aromatic secondary amines, products can result from coupling of the delocalized radicals at a ring carbon atom. The formal dimerization of aminyl radicals shown in Scheme 21 is therefore not often a useful method of preparation of hydrazines. Nickel peroxide has been used to oxidize diphenylamine to tetraphenylhydrazine in moderate yield, and other secondary arylamines also give... 

There are many cleavage reactions of the phenothiazine heterocycle which may be interpreted as substitutions at the carbon atom adjacent to sulfur. These reactions depend to a great extent upon the oxidation state of sulfur they occur with phenothiazines and phenothiazine-5-oxides, but not with the 5,5-dioxides. In structure proofs such cleavage reactions are of particular importance, because they often lead to diphenylamines with known structimes. 

Raney nickel was recommended as a convenient reagent for desulfurization of phenothiazine, and it has been used in many structural investigations. More recently, the method has been applied to various phenothiazines, - in its classical form, that is Raney nickel and hydrogen, as well as in some modified variants. Thus, working with a special Raney nickel, without hydrogen, 1,3,7,9-tetrachlorophenothiazine was desulfurized without dehalogenation the usual procedure leads, for example, to diphenylamine, when applied to 3,7-dichlorophenothiazine. ... 

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