Aryl derivatives diarylamines

The addition of 2,2, 4,4, 6-pentanitro-6 -methyldiphenylamine [64653-47-0] to seawater precipitates potassium (38). Aromatic amines, especially aminotetrahydronaphthalenes and their A[-aryl derivatives, are efficient flotation agents for quartz. The use of DPA for image formation in films has been patented (39,40). Diarylamines are used as intermediates (41) for azo, sulfur, oxidative base, triaryhnethane, oxazine, nitro, and safranine dyes (see Dyes and DYE INTERLffiDIATES). 

Diarylamines can be A/-alkylated with anhydrides and acyl haUdes or A/-alkylated with alkyl haUdes, alkyl sulfates, and tri- / -alkylphosphites. Diphenylamine derivatives of alkyl—aryl gaUium, germanium, phosphoms, and siUcon are known (17), eg, pentaphenylgermanamine [64653-46-9]. 

Menendez et al. reported the synthesis of murrayafoline A (7) by palladium(II)-mediated oxidative double C-H activation of a diarylamine assisted by microwave irradiation (585). The aniline derivative 598 was obtained by O-methylation of 5-methyl-2-nitrophenol (625) followed by catalytic hydrogenation. The required diarylamine 654 was obtained by N-arylation of the aniline derivative 598 with phenyllead triacetate (653) in the presence of copper(II) acetate. Under microwave-assisted conditions, in the presence of more than the stoichiometric amount of palladium(II) acetate and a trace of dimethylformamide, the diarylamine 654 was cyclodehydrogenated to murrayafoline A (7) (585) (Scheme 5.47). 

There has been a review of the effects of high pressure on the substitution reactions of amines with haloaromatic compounds, including polyhalobenzenes.17 Nucleophilic substitutions by amines often proceed readily in dimethyl sulfoxide (DMSO). The pAa values, in DMSO, have been reported for some ammonium ions derived from amines widely used as nucleophiles in, S Ar reactions.18 Correlations have been established19 between the oxidation potentials and the basicities of some arylamine and diarylamine anions and the rate constants for their reactions with aryl halides in DMSO. 

Nishiyama, and co-workers first reported that the catalyst derived from Pd(OAc)2 and (f-Bu)3P effects the C-N bond formation to produce triarylamines in excellent yield [65]. This system also is useful in the coupling of diarylamines and aryl chlorides. Hartwig and co-workers found this protocol optimal for the preparation of triarylamines. The (f-Bu)3P/Pd-catalyst was sufficiently active such that the coupfing of diarylamines and aryl bromides can be performed at room temperature,Eq. (34) [50]. The (f-Bu)3P/Pd-system has been used to produce new triarylamine-based polymers [ 64 a - d]. 

Aryl-3-chloro-l,2-dithiolium ions react with various secondary amines (morpholine, A-alkylanilines, diarylamines) to give 3-amino-5-aryl-l,2-dithiolium ions (41) which may also be considered as iminium derivatives (42). ... 

Dihydroacridines arise from the reaction of ketones with diarylamines at elevated temperatures and pressures, cyclic ketones lead to spirodihydroacridines (23). The 9-aryl spiro derivatives exist in a twisted boat conformation, with the aryl substituent pseudo equatorial, as do the analogous S3rmmetrical 9.9-diaryl dihydroacridines (W, Tritschler et al, Ber., 1984, 117. 2703). 

The efficiency of the arylation is very dependent upon the basicity of the amines. Electron-poor anilines do not react, while electron-rich anilines give high yields of -arylation products. However, in the case of easily oxidised anilines, oxido-reduction of the aryllead reagent can compete with the 7V-arylation when the steric compression becomes too important. For example, in the case of mesitylamine (101), the copper-catalysed reaction with a variety of substituted phenyllead derivatives led to generally high yields of the diarylamines. 

The arylation of ammonia remains one of the most attractive entry points for the synthesis of arylamines. Ammonia is inexpensive and readily available however, it is a gas at room temperature under atmospheric pressure. This significantly increases the operational complexity of its use and requires high-pressure reaction vessels. To address these issues, a range of ammonia alternatives have been used in the synthesis of arylamines. While some were more successful than others, many tended to suffer from an additional complication due to a competing diarylation reaction that led to the formation of diarylamines. A practical solution to the selective synthesis of aniline derivatives was reported by Hartwig... 

Petasis has demonstrated that aryl and heteroaryl boronic adds partidpate in one step three component Mannich reactions with glyoxylic acid and diarylamines to give the corresponding a-aryl/heteroarylglycine derivatives in good yields after deprotection of the diarylamine [79]. Several examples of the reaction with para-substituted aryl boronic acids as well as 2- and 3-thienyl, -fiiryl or -benzo[b]thienyl boronic acids are described (Scheme 3.53) [80]. 

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