Aryl azides synthesis

Phenyl[3-(trimethylsilyl)naphthyl]iodonium triflate (232) has also been described and utilized with aryl azides for synthesis of two naphthotriazoles 233 (98JOC8579). 

The Siindberg indole synthesis using aromadc azides as precursors of nitrenes has been used in synthesis of various indoles. Somekmds of aryl azides are readily prepared by S Ar reacdon of aromadc nitro compounds v/ilh an azide ion. For example, 2,4,6-trinitrotoliiene (TNT can be converted into 2-aryl-4,6-dinitroindole, as shovmin Eq. 10.60. ... 

The synthesis of 3//-azepines by the photolysis of aryl azides in nucleophilic media is a much more efficient and versatile route than the thermolytic process. Initial studies involved photolysis of the aryl azides in an excess of a secondary aliphatic amine, and moderate yields of A, V-dialkyl-3//-azepin-2-amines 38 were obtained.35-1 72... 

The reaction of arenediazonium ions with hydroxylamine is known, but has been little investigated (Gattermann and Ebert, 1916). The l-aryl-3-hydroxytriazene (6.23) formed initially is in most cases unstable (except if Ar = anthraquinonyl). Under alkaline conditions elimination of N20 yields the amine, whereas the aryl azide is formed in the presence of acid (Scheme 6-15). There are, however, better methods for the synthesis of aryl azides (review Biffin et al., 1971, p. 147). 

The reaction of azide ions with diazonium ions is preferable to the classical synthesis of aryl azides which was found by Griess (1864d, 1866b) in the reaction of benzenediazonium tribromide with ammonia (see discussion in Sec. 6.4). 

The synthesis and mechanism of formation of a triazene from an arenediazonium ion and an amine with one or two aliphatic substituents (see Scheme 13-1, R = alkyl, R = H or alkyl) will be discussed in Section 13.2. Here we will briefly mention Dimroth s method (1903, 1905 a) for synthesis of wholly aliphatic triazenes (Scheme 13-6, R and R = alkyl). Dimroth obtained these by the action of Grignard reagents on alkyl azides followed by isolation via copper(i) salts. The Grignard method can also be applied for the synthesis of triazenes with an aromatic substituent by using an aryl azide. 

Arenesulphinylation 264 Arenesulphinylethanes, synthesis of 267 2-Arenesulphonyl-3-aryloxaziridines, as oxidizing agents 254 Arenesulphonyl azides, reactions of 641 At-Arenesulphonyliminopyridinium betaines, mass spectra of 160-162 Arenesulphonyl radicals 215, 1091 Aryldiazonium salts, reactions of 280, 281 Aryl(methylsulphinyl)(methylthio)alkenes, synthesis of 614... 

Other iron-imido complexes have also been reported. Holland and coworkers reported the synthesis of the imidoiron(III) complex [L FeNAd] [40, 41]. This imidoiron(III) complex has not been isolated and was found to convert to a purple high-spin iron(III) complex. It has an S = 3/2 ground state from EPR measurement. Based on the results of QM/MM computations, [L EeNAd] is a three-coordinated complex with an Fe-N distance of 1.68 A and has a nearly linear Fe=N-C unit with Fe-N-C angle of 174.1°. Chirik and coworkers made use of liable ligands to prepare iron-imido complexes by treatment of C PDI)-Fe(N2)2 ( PDI = (2,6- Pr2CgH3N = CMe)2C5H3N) with a series of aryl azides [47]. 

The general procedure used for the synthesis of [l,2,3]triazolo[l,2-tf][l,2,4]benzotriazin-l-5(6//)-dione derivatives 506 is shown in Scheme 86. Ionic 1,3-dipolar cycloaddition of the appropriate azide 503 to ethyl phenylacetates gives l-(2-nitrophenyl)-4-aryl-5-oxo[l,2,3]triazoles 504. Catalytic reduction of these compounds affords the corresponding amines 505. Cyclocondenzation of these amines to the final tricyclic compounds 506 is performed using triphosgene in anhydrous tetrahydrofuran solution at room temperature (Scheme 86) <2005JME2936>. 

Aryl and heteroaryl nitrene insertion processes have also been employed in the synthesis of heterocycles. The azide 459, for example, is converted on irradiation into the imidazole 460,383 and dihydro-10-thiaisoalloxazines are obtained in good yield on photoelimination of nitrogen from 6-(2-azido-phenylthio)uracils.384... 

Soundararajan, N., Liu, S.H., Soundararajan, S., and Platz, M.S. (1993) Synthesis and binding of new polyfluoninated aryl azides to a-chymotrypsin. New reagents for photoaffinity labeling. Bioconjugate Chem. 4, 256-261. 

Reactions of salts of 1,2,3-triazole with electrophiles provide an easy access to 1,2,3-triazol-jV-yl derivatives although, usually mixtures of N-l and N-2 substituted triazoles are obtained that have to be separated (see Section 5.01.5). Another simple method for synthesis of such derivatives is addition of 1,2,3-triazole to carbon-carbon multiple bonds (Section 5.01.5). N-l Substituted 1,2,3-triazoles can be selectively prepared by 1,3-dipolar cycloaddition of acetylene or (trimethylsilyl)acetylene to alkyl or aryl azides (Section 5.01.9). 

A simple procedure for the synthesis of 4,5-disubstituted 1,2,3-triazoles 1247 involves stirring a mixture of nitroethene 1245 with trimethylsilyl azide and tetrabutylammonium fluoride at 30 °C for 3h. No solvent is needed. Triazoline 1246, which forms in the first step of the reaction, eliminates nitrous acid, and the trimethylsilyl group is cleaved off by the fluoride anion to afford triazole 1247. Various aryl and heteroaryl substituents R are used providing triazoles 1247 in 70-90% yield (Scheme 207) <2005JOC6526>. 

Kamal A, Prasad BR, Ramana AV, Babu AH, Reddy KS (2004) FeCl3-NaI mediated reactions of aryl azides with 3,4-dihydro-2 //-pyran a convenient synthesis of pyrano-quinolines. Tetrahedron Lett 45 3507-3509... 

Kamal A, Prasad BR, Khan MNA (2007) TMSCl-Nal-mediated reaction of aryl azides with cyclic enol ethers an efficient one-pot synthesis of 1,2,3,4-tetrahydroquinolines. J Mol Catal A Che 274 133-136... 

A synthesis of the 11-aryl-1 l-aza[5.3.1 ]propellan-2-one 29 was accomplished by the intermolecular cycloaddition of the cycloheptenone 26 with an aryl azide. The... 

Garanti et al. (30a) reported a synthesis of the l,2,3-triazolo[l,5-a][4.1]benzox-azepine 149 via an intramolecular cycloaddition of an aryl azide with an acetylene (Scheme 9.30). By using a similar strategy, the l,2,3-triazolo[l,5-a][l,4-l ]benzo-diazepine 150, an analogue of Flumazenil, was also reported (30b,c). As an extension of this method, the l,2,3-triazolo[l,5-a][l,4]benzodiazepine-6-one 153 was synthesized using an intramolecular 1,3-dipolar cycloaddition of an azide with a cyano group (30d). 

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