Phenyl azide substituted

Benzenediazonium fluoroborate, 2-carboxy-xanthone synthesis from, 3, 838 Benzenediazonium ions phenyl azide formation from, 5, 839 Benzenediazonium salts, o-(imidazol-l-yl)-intramolecular diazo coupling, 5, 404 Benzene-1,2-disulfonimides N-substituted reactions, 6, 930 Benzene episulfide formation, 7, 577 Benzeneimine... 

Photolyses of 3-substituted phenyl azides 53 in hot diethylamine containing pyrene, a singlet sensitizer, furnish mixtures of the 4- and 6-substituted 3ff-azepines 54 and 55. The isomers, however, were not separated and the yields were based on quantitative GC analysis of the reaction mixtures.176 Of mechanistic significance is that the ratios of the isomeric azepines obtained compare favorably with those observed in the deoxygenation of 3-nitroarenes with trivalent phosphorus compounds. 

An in-depth study of the photolysis of a series of fluoro-substituted phenyl azides, e.g. 58, shows clearly that, in general, 3-substituted phenyl azides yield mixtures of the 4,5- and 5,6-disubstitutcd 3//-azepines, e.g. 59 and 60.188 Tri- and tetrafluoro-substituted azidoben-zoates yield NH-insertion products rather than 3//-azepines. 

The pyridines which are formed as minor products (1-8%) during the photolysis of 2-substituted phenyl azides in diethylamine are thought to be products of the aerial oxidation of nonisolable l//-azepine intermediates.11... 

Several comparative studies are available in the literature, which clearly shows that, according to the latest results, tetrafluoro-pheny/ azides (AZ), trifluoro-methyl-phenyl diazirines (DZR), and particularly benzophenone (BP) are the best choice (Scheme 3.). Diazocarbonyl compounds, which played a historically role in the evolution of PAL, can also be considered together with aryl-diazonium salts [6] (not shown). For aryl azides the more common unsubstituted photophore is presented. It should be noted that tetrafluoro-phenyl azides have an increased reactivity towards CH-groups and they do not rearrange. Other substituted phenyl azides can readily alter the excitation wavelength allowing the application of milder or differential photoactivation. 

Electron-rich aromatic compounds, such as phenol, anisole and A,./V-dimethylaniline, add to bis(2-trichloroethyl) azodicarboxylate under the influence of lithium perchlorate, boron trifluoride etherate or zinc chloride to yield para-substituted products 74, which are transformed into the anilines 75 by means of zinc and acetic acid86. Triflic acid (trifluoromethanesulphonic acid) catalyses the reactions of phenyl azide with benzene, toluene, chlorobenzene and naphthalene, to give TV-arylanilines (equation 34)87. 

This property is relatively rare in the very large number of reactions for which substituent effects were evaluated quantitatively106. It seems to be common, however, for all dediazoniations of arenediazonium ions and of related compounds, e.g. of substituted phenyl azides forming nitrenes, as well as for additions of carbenes to alkenes. 

Cycloaddition of p-methoxyphenyl azide to alkynic dipolarophiles at room temperature gives triazoles (697) and (698) (Equation (54)). A regiospecific addition is only observed in the case of Z = CH(OMe)2 <89H(29)967>. Phenyl azide and substituted benzyl azides undergo 1,3-dipolar cycloadditions with DM AD, phenylacetylene, and ethyl propiolate to afford 1-phenyl- and 1-benzyl-... 

Substituted phenyl azides react with acrolein and morpholine to give A -l,2,3-triazolines (743) (Scheme 149). Hoffmann elimination of A -methylmorpholine from the quaternized intermediates (744) by treatment with Ag20 affords 4-methylene triazoles (745) <86JCR(S)132>. 

A mixture of alkyl azides, substituted phenyl isothiocyanate and aryl or alkyl isocyanate are reported to yield 5-arylamino-l,2,4-thiadiazolin-3-ones (283) via a proposed 1,2,3,4-thiatriazoline (282) (Scheme 64) <84CHEC-I(6)463>. 

The similarity of the results obtained with phenyl azide and N-phenyl-hydroxylamine in benzene/TFA indicates that both reactions proceed by similar mechanisms, but N-phenylhydroxylamine in benzene/TFSA produces a higher yield of the C-substitution products 27 and 28 As previously suggested (Scheme 5), N-phenylhydroxylamine can be doubly protonated to yield the dication 11 in strong acids, but the more weakly basic phenyl azide is less likely to be doubly protonated. The differences observed between the behavior of N-phenylhydroxylamine and phenyl azide in TFSA may be due to the inability of phenyl azide to directly generate 11. 

Takeuchi and co-workers showed that the ratio of N- to C-substitution on the apparent intermediate 75a by a series of aromatics in arene/TFA mixtures was sensitive to the structure of the precursor to 75a (phenyl azide, N-phenylhydroxylamine or O-trifluoroacetyl-N-phenylhydroxylamine) even though the decomposition rates of these precursors were unaffected by the identity of the arene. This result is consistent with the characterization of 75a from N3 and Br trapping studies as a short-lived intermediate that will usually react through ion pair or preassociation processes that may be leaving-group dependent. ... 

Photogenerated nitrenes can undergo cycloaddition with alkenes intermolecular reaction leads to aziridine products (5.38), and intramolecular reaction in vinyl azides gives azirines (5.39). The bicyclic azirine from phenyl azide has not been isolated, but it is the intermediate that best accounts for the formation of a substituted azepine when this azide is irradiated in the presence of a secondary amine (5.401. 

This reaction may involve stepwise addition of the two equivalents of PhNCS via a 3-membered ring intermediate, RN—S—C=NPh.66 A thia-ziridine was also suggested by Borsche67 to explain the formation of 4-phenyl-5-phenylimino-l,2,4-dithiazolidine-3-thione from the aluminum chloride-catalyzed decomposition of phenyl azide in carbon disulfide. If a 4-substituted thiatriazoline is formed from phenyl isothiocyanate and the alkyl azide, the reaction may then be formulated as indicated in Eq. (21). This scheme is supported by the recent findings of Neidlein and... 

Kinetic studies of the addition of substituted phenyl azide to norbornene show a small substituent effect with a Hammett p value of +0.84, a large... 

Progress in the areas of photoscrambling and valence bond isomerization reactions in aromatic156 and heteroaromatic compounds157 has led to the study of new cyclic systems with strained olefinic double bonds.158 Dewar benzene, Dewar thiophene, benzvalene, and their heteroaromatic counterparts substituted with fluoro and/or perfluoroalkyl substituents have been synthesized and their reactions with phenyl azide have been investigated. 

The results have been corroborated by further studies of o-(allyloxy)phenyl azide and 14 derivatives substituted on the allyl group. The allyloxy azide in Scheme 39 underwent complete conversion to triazoline at 35°C in 3 weeks as indicated by NMR.197 Thermolysis of o-allylphenyl azides, on the other hand, required high temperatures of the order of 155-200°C, apparently suggesting nitrene insertion reactions.197 The higher rate of decomposition of ortho-substituted phenyl azides as compared to the corresponding meta or para isomers, noted primarily in those systems where the ortho substituents have... 

The reaction of 1-azidoadamantane with ethyl acrylate affords exclusively a 4-substituted triazoline.155 The assigned regiochemistry is supported by 1H-and 13C-NMR spectra. The H-NMR spectral characteristics of the triazoline ring protons are similar to those reported for the corresponding adduct from phenyl azide.32, 3C-NMR spectra reveal a characteristic triplet at 8 61.9 assignable to C-5. 55 Different NMR techniques have been used in structure assignments of isoindolo[2,l-c]-A2-triazolines,324 spiroanthrone-triazolines,193,194 5-heteroaryl-substituted A2-1,2,3-triazolines,329 and some l-fluoro-(5-trifluoromethyl)-A2-l,2,3-triazolines.356... 

There are several cases of polycyclic triazolines, obtained by azide addition to the strained olefinic bond in bi- and tricyclic systems, that are susceptible to retro Diels-Alder reaction to yield 1-substituted triazoles. A well-established example is the monoadduct from norbornadiene and phenyl azide, which decomposes at 90-100°C to give 1-phenyltriazole and a cyclopentadiene (Scheme 138).2s 97—" 1 47 430 Similarly, the cycloadduct from the reaction of 7-oxabenzonorbornadiene and 1-azidoadamantane, when heated at 110°C, affords good yields of l-(l-adamantyl)-l,2,3-triazole in a retro Diels-Alder reaction.155... 

Schroedel and Schmidpeter reported the preparation of triphenylphosphonio-substituted 1,2,3,4-triazaphospholes 95 by cycloaddition reactions of phosphonium salts 94 (generated in situ from dichlorophosphane 93) with phenyl azide (Scheme 6). A novel phosphoniotriazaphospholide 96 was prepared by the reaction of dichlorophosphane 93 with trimethylsilyl azide and isolated in 28% yield as a relatively stable colorless powder with decomposition point above 105 °C <1997CB89>. 

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