Substituted phenylene diamines

The classical condensation of substituted phenylene diamines and carboxylic acids19 21 (or aldehydes under oxidising conditions21) to provide benzimidazoles,... 

Formation of a Quinoxaline. Heat together for 5 minutes under reflux 0 2 g. of phenanthraquinone dissolved in i ml. of glacial acetic acid and 0-2 g. of O -phenylene diamine also dissolved in i ml, of glacial acetic acid. The yellow substituted quinoxaline (p. 305) separates rapidly. Cool, filter and recrystallise from benzene m.p. 225 . 

This mechanism is based on the fact that the ozone uptake of elongated rubber containing a substituted p-phenylene diamine type of antiozonant is very fast initially and then decreases rather rapidly with time and eventually stops almost completely. The film has been studied spectroscopically and shown to consist of unreacted antiozonant and its ozonized products, but no ozonized rubber is involved [64], Since these ozonized products are polar, they have poor solubility in the rubber and accumulate on the surface. 

When p-ethylaminobenzoate and N,N-dimethyl-p-phenylene diamine sulfate were similarly treated with the dibromosulfone (I) for 2 h, the yield was only 32% and 15% respectively (Figure 1). A possible explanation is that the nucleophilicity of these monosubstituted anilines is weaker than that of aniline while a Na2C03 1,4-HBr elimination reaction could be competing with the substitution reaction, leading to the lower yield (18). 

A number of substituted chalcones were synthesised by base catalysed condensation of substituted aromatic aldehyde with substituted acetophenone in good yield. These chalcones derivatives were further condensed withortho-phenylene diamine to yield Benzol,5-diazepine derivatives in moderate yield. All the compounds were characterized by 1H-NMR spectral data. These compounds may have good pharmacological activity against bacteria. 

A systanatic investigation of isomeric phenylaie diamines and ring-alkylated MPD s as epoxy curing agents was performed. Initial studies on blends of phenylene diamine isoners shewed that 20% substitution of OPD in MPD increased the Tg of the cured resin but decreased the tensile strength and elongation. When used alone, OPD resulted in resins of inferior properties. 

The resin-bound phenylene diamine intermediates 3 are then generated by nitro group reduction with tin(II) chloride in NMP and cyclization/ aromatization with a wide variety of aldehydes gave the resin-bound benzimidazole intermediates 4. The treatment of this intermediate with 50% TFA/DCM liberates the substituted 3-(benzoimidazol-l-yl)-propionic acid derivative 4a. Analysis of this intermediate by HPLC and LC-MS gave a measure of the purity of the resin-bound product and enabled the optimization of conditions for the incorporation of the Rl-nitroarenes and R2-aldehydes by an iterative process. 

An unexpected product was obtained when the o-phenylene diamine 437 was reacted with an excess of the Mannich base, -substituted 3-dimethylaminopropiophenone hydrochloride. A product, whose relative stereochemistry was determined by NMR, was shown to have structure 438 (Equation 66) <2000EJ01973>. 

Of the commercially-available phenylene diamines tested, the N,N -diphenyl compound is an insoluble, high melting-point, crystalline solid, whereas the unsymmetrically substituted N-phenyl-N -(2-octyl) derivative is a liquid, readily miscible... 

Coupling carbonyl compounds with aromatic amines bearing amino, hydroxy, or thiol groups in o -positions is known to be a general method for the synthesis of 1,3-benzazoles, with the intermediate formation of the respective 2,3-dihydro derivatives. No heterocyclization occurs, however, in the reaction of o-phenylene-diamines or o-aminophenols with /i-quinones. In these cases, the reaction stops at the stage of formation of the deeply colored quinoneimine 105 which is similar to that obtained by the previously studied reaction of a variety of / -substituted anilines with derivatives of p -bcn/oquinonc.6 Compounds 10 do not undergo cyclization under heating or irradiation of its solution (Scheme 4). 

Cauquis and co-workers have generated 92 (R1 = R2 = Ph) and several variously substituted congeners by the anodic oxidation of phenylene diamines.330-332... 

The latter mechanism is met in amine-vinyl monomer systems [41-46] (see Scheme 4). Due to the small n-acceptor ability of normal substituted vinyl monomers, an interaction in the ground-state level does not take place. The exciplexes assumed are detectable in aromatic amine-acrylonitrile (AN) systems by their emission spectra, as is shown in Fig. 1 for typical examples. The emission bands at 350 nm (by JV,JV-dimethyl-p-toluidine (DMT)) and 370 nm (by p-phenylene diamine (TMPD) result from the normal fluorescence of the isolated amine. As can be seen, the intensity of the exciplex emission is much higher in the DMT-AN system. This corresponds to the higher polymerization efficiency of that system (<)>[, by A. = 313 nm and 80 K 0.6 for DMT 0.15 for TMPD [46]). Mainly, the much higher dipole moment of DMT (1.1 D) is responsible for this result. The cation radicals [46] or neutral radicals [42] of the amines formed after PET and proton transfer have been detected by ESR measurements. As expected, the rate of photopolymerization of the systems discussed increases with increasing... 

Following the same rationale, the Cl sequence can also be applied to the synthesis of seven-membered heteroazepines. Thus, upon CIR of electron-deficient (hetero) aryl halides 11 and (hetero)aryl propargyl alcohols 12, and subsequent addition of orf/io-phenylene diamines 50 or ortho-zmmo thiophenols 52, 2,4-di(hetero)aryl substituted 2,3-dihydro benzo[b][l,4]diazepines 90 or di(hetero)aryl substituted 2,3-dihydro benzo[h][l,4]thiazepines 91 can be obtained in a consecutive three-component reaction in moderate to good yields (Scheme 49) [242, 243]. 

Condensation of aromatic nitroso compounds with primary amines is a satisfactory procedure for obtaining azo compounds. An example is the combination of nitrosobenzene and aniline in acetic acid, which results in a quantitative yield of azobenzene. Similarly, a series of methyl-substituted azobenzenes have been prepared, although the yields are poor in the case of the oriAo-substituted compounds. As an illustration of the versatility of the reaction, nitrosobenzene can be condensed with o-methoxyaniline (o-anisidine)," p-aminobenzoic acid, o-phenylene-diamine monobenzoate, and m-nitroaniline to form the corresponding substituted azobenzenes. 

Certain nuclear substituents ortho to a newly formed diazonium group may interact to form a cyclic structure with or without retention of the nitrogen atoms. Such is the case in the diazotization of o-phenylene-diamine in aqueous solution, the product being 1,2,3-benzotriazole (81%). If the ortho substituent is an activated methyl group, an indazole is formed. Hydroxyl groups ortho or para to the diazonium group may interact to form internal condensation products called diazo oxides. These compounds may also form in the reaction of halo- and nitro-substituted aminophenols. 

Ammonium salts with two different alkyl chains were prepared directly via subsequent alkylations of dimethylamine with primary bromides and crystallization. Commercial hexadecyl-methylamine can be conveniently applied in the same way in order to convey functionality to cationic synkinons. A recent example describes subsequent alkylations with a small functional and a long-chain primary bromide (Scheme 2.4). A-acylated / -phenylenediamine was also alkylated at the second nitrogen atom which had two different alkyl chains, with or without extra functionality . After deacylation, this head group can be diazotized or coupled oxidatively with various heterocycles in water (Scheme 2.4). Photoactive and coloured membrane surfaces are thus obtained. Phenylene-diamine, pyridine and in particular A-methyl-4,4-bipyridinium chloride are relatively weak nucleophiles. Substitution of bromides is slow and the more reactive iodides can rarely be obtained commercially, but the selection of nitromethanes as solvent for bromide substitution is of great help as well as the addition of sodium iodide to enforce a Finkelstein reaction or a combination of both. 

Aramides have a 40°C higher melting point with durene diamine than with p-phenylene diamine(5). Furthermore, durene diamine may be able to be produced at a price equivalent to or lower than that of p-phenylene diamine. This arises because the linear substitution is not generally simple in nitration reactions for durene, however, there is no other option. 

Diaminoquinoxalines are obtained from the reaction of o-phenylenediamines with cyanogen in methanol containing a little aqueous sodium hydroxide solution." A variant on this procedure is first to prepare the oxaldiimido ester 7 from cyanogen and methanolic sodium methoxide and then to react the isolated ester with an o-phenylene-diamine (Scheme 5). " The latter method has been used with a wide range of nuclear-substituted diamines. 

To reinforce the point that a similar electron directing effect operates, results published by Emanuel [32] for the autoxidation of a mixture of hydrocarbons in the presence of substituted 7V,7V -dialkyl-p-phenylene-diamines show that substituents raising the electron density at the inhibitor reaction centre increase the efficiency of the antioxidant, while substituents that decrease electron density decrease inhibitory powers. No attempt was made to quantify these observations in terms of a or a factors. 

The synthesis of substituted benzimidazolone analogues (Xi H) was started from appropriate 2-chloronitrobenzenes (VII) as outlined in Scheme 3. The reaction of VII with aminoalkanols in an inert solvent afforded N-hydroxy-alkyl-2-nitroanilines (VIII). Catalytic hydrogenation of the nitro group resulted in o-phenylene-diamines (IX) which reacted with urea to give the N-hydroxyalkyl-benzimidazol-2-ones (X). After treatment of Xwith thionylchlo-ride, the desired chloroalkylbenzimidazol-2-ones (I) could be isolated. 

Conventional aliphatic polyamides, like PA-66, melt at 250 °C. By inserting aromatic rings between the amide groups, near-infusible polymers are formed. Aromatic polyamides (aramides) are known mainly in the form of fibres. Two grades of DuPont are widely used. Nomex is made from m-phenylene diamine and isophthalic acid (anhydride). In Kevlar, phenylene groups are para-substituted by amide groups,... 

Dihydrobenzodiazepine derivatives, which are generated from phenylene-diamine and substituted acetophenone, are racemized by the intramolecular retro-Mannich/Mannich process. Combination of this racemization with chiral phosphoric acid-catalysed transfer hydrogenation by Hantzsch ester gave cyclic 1,3-diamine having a quaternary stereogenic centre (Scheme 5.41) [114]. 

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