Diarylamines preparation

Diarylamines do not react with carbon disulfide, whereas dialkylamines readily form dithiocarbamates. However, N,Ar-diaryldithiocarbamates can be prepared from metal salts of diarylamines and carbon disulfide (15). They are more stable than diaLkyldithiocarbarnic acids, eg, N,N -diphenyldithiocarbamic acid [7283-79-6] mp 142°C. Similarly, various metal salts of DPA react with carbon dioxide and an epoxide to give the P-hydroxyalkyldiphenylcarbamates (16). 

It has also proved possible to close larger rings in this manner 8 and even 12-membered. Triarylamines have been prepared in a similar manner from Arl and Ar NLi, even with unactivated Arl. In the Goldberg reaction, an aryl bromide reacts with an acetanilide in the presence of K2CO3 and Cul to give an N-acetyl-diarylamine, which can be hydrolyzed to a diarylamine ArBr-I- Ar NHAc—> ArAr NAc. ... 

In a preparatively useful process diarylamines can be cyclized photolyti-cally. Substrates having alkyl groups,fluorine, methoxyl, ethylamino, and N-alkyF - " and N-aryl groups have been used. Not all triarylamines could be cyclized, especially... 

The preparation of a diarylamine required for the synthesis of a phenothiazine via the sulfuration reaction requires the use of an activated chlorobenzene. 

Wester et al (Ref 24) patented an industrial method of preparation of diarylamine, and more particularly of DPhA. Essentially the process comprises heating aniline in an autoclave at pressures betw 100 and 200psi, in the presence of ferric chloride catalyst in an amount betw 0.3% to 8.0% by wc of the aniline used. Yields as high as 58.8% were reported after heating for only 8 hrs at l60psi... 

Sapountzis, I. Knochel, P. A new general preparation of polyfunctional diarylamines by the addition of functionalized arylmagnesium compounds to nitroarenes. J. Am. Chem. Soc. 2002, 124, 9390-9391. 

The palladium-catalyzed formation of diarylamines has been used in several contexts to form molecules with biological relevance. The ability to prepare haloarenes selectively by an ortho-metallation halogenation sequence allows for the selective delivery of an amino group to a substituted aromatic structure. Snieckus has used directed metallation to form aryl halides that were subsequently reacted with anilines to prepare diarylamines (Eq. 34)) [156]. Frost and Mendon a have reported an iterative strategy to prepare (by palladium-catalyzed chemistry) amides and sulfonamides that may act as peptidomimetics. Diarylamine units are constructed using the DPPF-ligated palladium catalysts, and the products are then acylated or sulfo-nated with 4-bromo benzoyl or arylsulfonyl chlorides [157]. 

Several recent papers have reported the palladium-catalyzed formation of diarylamines to prepare nucleosides of damaged DNA. Sigurdsson, Hopkins et al. reported the formation of... 

Nitrosoarenes give unstable diaryl hydroxylamines with aryl Grignard reagents, which can be reduced directly to diarylamines.312 Since arylmagnesium halides reduce nitroarenes to nitroso compounds, readily available nitroarenes and nitrohetarenes can be involved in this reaction allowing a simple preparation of polyfunctionalized diaryl- and heteroarylamines (Scheme 108).313... 

Hartwig first reported the arylation of diarylamines using both (o-to jP/Pd-and DPPF/Pd-catalysts, Eq. (33) [29,64]. The Yale group utilized the (o-tol jP/Pd-and DPPF/Pd-based protocols for the preparation of triarylamine-containing dendrimers and cyclophanes, respectively. 

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]. 

Hartwig has reported a DPPF/Pd-catalyzed C-N coupling reaction between a diarylamine and an aryl nonaflate, Eq. (63) [64bj. The coupling below proceeded in 95 -100% yield (NMR) and was used in a strategy to prepare oligo(m-aniline) compounds. 

Louie and Hartwig described an application of the DPPF/Pd-catalyst toward the synthesis of oligo(m-anilines). The diarylamine monomer was prepared using this protocol in quantitative yield, Eq. (86) [64b]. Goodson and Hartwig have extended the method to synthesize other monomers for the preparation of poly(N-arylanilines) [54 c]. 

Harris and Buchwald took advantage of the differential reactivity between aryl chlorides and aryl bromides in the Pd-catalyzed C-N bond coupling to design a simple one-pot procedure for the preparation of unsymmetrical tri-arylamines, Eq. (95) [101]. Reaction of the aniline with an aryl bromide and an aryl chloride in the presence of the 6/Pd-catalyst resulted in clean production of the desired triarylamine. After complete consumption of the aryl bromide to furnish the corresponding diarylamine, the aryl chloride then reacted to yield the desired unsymmetrical product. 

Copper complexes (152) of o-hydroxy-o -(p-aminoethylamino)diarylazo compounds have been prepared ° by the reaction of the corresponding o-chloro-o -hydroxydiarylazo compounds and ethylenediamine in the presence of copper(II) ions (c/. Section 58.2.3. l(iii)(c)). Dyestuffs of this type have been evaluated on nylon but are reported to have very poor fastness properties. Copper complexes such as (153) have been preparedby similar methods. Other, related tetradentate diarylazo compounds, e.g. (154), (155) and (156), are obtained by the reaction of a suitable diazonium salt with the appropriate diarylamine. Chromium(III) and cobalt(III) complexes of dyes of this type, in which the coordination sphere of the metal is completed by a colourless bidentate ligand such as ethylenediamine, salicylic acid or 8-hydroxyquinoline, are reported to have dyeing properties on wool similar to those of the comparably charged 2 1 complexes derived from tri-... 

A series of diarylamines and diaryl ethers based on combretastatin A-4 was prepared, via coupling of a benzyl protected phenol or aniline, and evaluated for anticancer activity [39]. The target ether 66 was prepared via the new copper-catalyzed Ullmann-type coupling recently described by Buchwald and co-workers (Scheme 17). 

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