Aryl derivatives arylamines

Heating arylamines with carbon dioxide at 200 C (8500 atm) gives good yields of 3-aryl derivatives of 2,4-dihydroxyquinazoline ° (see 5e). The method is unsatisfactory when riitro, halo, and phenolic anilines and a- or p-naphthylamines are used. 

The arylamine 780c required for the total synthesis of carbazomycin E (264) was prepared in seven steps starting from vanillyl alcohol (803). Vanillyl alcohol (803) was transformed to the tetrasubstituted aryl derivative 804 via generation of the benzyl methyl ether followed by ortho-directed lithiation and subsequent... 

The importance of protonated N-hydroxy arylamines as ultimate carcinogens has been suggested for some time (28,40,139). From studies on their reactivity with nucleic acids at different pH s (2,15,16,63,130,131), the pK for protonation of the N-hydroxy group appears to be between pH 5a and 6 thus, a significant proportion (1-10%) of the N-hydroxy derivative exists as the protonated form even under neutral conditions. This would account for the significant levels of covalent modification of DNA observed in vitro by reaction with N-hydroxy arylamines at neutral pH. Consequently, it has been proposed that in vivo formation of non-acetylated aryl... 

The second method is advantageous over the Gould-Jacobs method with respect to (a) the cyclization step which proceeds smoothly under mild conditions (b) one-pot synthesis of the 1-substituted derivatives and bypassing the alkylation/arylation of the Ni-position of l,4-dihydro-4-oxoquinoline-3-carboxylate, which usually gives rise to mixed N1/O4-substituted products and (c) product versatility due to the ability to utilize a wide range of alkyl-and arylamines in the step before cyclization. 

The required arylamine 973 was prepared starting from the aryl acetate 937. The compound 937 was also used for the palladium(II)-catalyzed total synthesis of carbazoquinocin C (274) (545) (see Scheme 5.124) and carbazomycin G (269) (652). The acetate 937 was transformed to the corresponding 5-nitro derivative 974 by reacting with fuming nitric acid in a mixture of acetic anhydride and glacial acetic... 

The authors also applied this procedure to a 90-member combinatorial library of 5,7-disubstituted-2-aryl-pyrimidotriazines 159 using the same set of l-cyano-3-(pyrimidin-4-ylamino)-2-methylisothiourea intermediates 158 (see Table 10/Scheme 27) with aryldiazonium salts derived from the range of arylamines A-O that is shown in Scheme 27. Isolated yields are shown in Table 10 for indicative amines A-E, and yield ranges are indicated in Scheme 27 for amines F-O <2004TL9319>. 

Alkylamlnes, Alkylarylamines, Aryl amines and Their Explosive Derivatives. Alkylamlnes alkylarylamines and arylamines may form nitrocompds as well as various salts of which the nitrates, perchlorates and pi crates may... 

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. 

Readily accessible aryliminodithiazoles 56 can be converted by LiAlH4 reduction into the rearranged A-aryl-dithiooxamides 112 (Equation 24) <1999S1345>. Although the yields are moderate (35—42%), this reaction provides a convenient two-step synthesis of unsymmetrical rubeanic acid derivatives from arylamines. 

The Sandmeyer procedure for the synthesis of aryl halides from arylamines has been applied, with modification, to the conversion of 5- and 8-aminoquinolines to the iodo and bromo derivative. 8-Aminoquinoline is converted to 8-bromoquinoline in good yield on treatment with /-butyl nitrite in the presence of CuBr in acetonitrile at 60 °C <2003JOC5123> and 5-amino-6-nitroquinoline is converted to the 5-iodo derivative under equally mild conditions using potassium nitrite and copper iodide in DMSO at 60 °C <2005JOC2445>. 

This second mode of preparation of benzothiazoles is also well established and represents a general method for the cyclization of derivatives of arylamines. The main derivatives adapted to the formation of the thiazole ring include A-arylthioamides, arylthioureas, aryl isothiocyanates, esters of arylthiocarbamic acids and esters of aryldithiocarbamic acids. Their cyclization results from the action of an appropriate oxidizing agent. 

Electrophilic aromatic substitution of 5-hydroxy-2,4-dimethoxy-3-methylaniline by reaction with the iron complex salts affords the corresponding aryl-substituted tricarbonyliron-cyclohexadiene complexes. O-Acetylation followed by iron-mediated arylamine cydization with concomitant aromatization provides the substituted carbazole derivatives. Oxidation using cerium(IV) ammonium nitrate (CAN) leads to the carbazole-l,4-quinones. Addition of methyllithium at low temperature occurs preferentially at C-1, representing the more reactive carbonyl group, and thus provides in only five steps carbazomycin G (46 % overall yield) and carbazomycin H (7 % overall yield). 

The BINAP/Pd- and DPPF/Pd-catalyst systems have been used by numerous groups to react aryl bromides with arylamines. Ward and Farina as well as Willoughby and Chapman performed the arylation reaction with arylamines and resin-bound aryl bromides [31,32]. Snieckus reported the use of the Pd-cat-alyzed C-N bond forming reaction to prepare several acridone derivatives, Eq. (81) [92]. Kamikawa et al. prepared phenazine derivatives via an initial C-N bond coupling and subsequent cyclization, Eq. (82) [93]. 

Nickel catalysts have been used in the reaction of aryl halides with A-alkyl aniline derivatives. Nickel catalyst also allow the conversion of aryl halides to A-arylamines via reaction with aliphatic amines. An intramolecular reaction of a... 

---