Phenylacetylene azide

The additions of phenyl azide and phenylnitrile oxide to pentafluorophenyl-acetylene are also regiospecific [75, 7S] (equation 12). Interestingly, in the latter reaction, phenylacetylene gives regiochemistry that is opposite to that observed for pentafluorophenylacetylene [75]... 

Toluene-p-sulfonyl azide adds to electron-deficient acetylenes and to phenylacetylene at 80°-100° over a period of several days. The azide adds much more readily to ynamines, - refiecting the electronic compatibility of these components. The triazoles so formed are labile and exist in equilibrium with open-chain diazo tautomers (Section IV, G) the adduct with ethoxyacetylene exists entirely in the diazo form. Other sulfonyl azides have been reacted with arylacetylenes, but yields of triazoles are generally poor. ... 

In general, acyl azides are too unstable to survive at the temperatures required for addition to acetylenes, although benzoyl azide adds readily to ynamines in toluene. Ethoxycarbonyl azide also gives triazoles in good yield with ynamines. The azide adds to propargylic alcohols in boiling ethanol, and to acetylene at 100° under pressure. Addition to phenylacetylene and to electron-deficient acetylenes has been carried out at 130°. Oxazoles are also formed at this temperature by competing thermal decomposition of the azide, and addition of ethoxycarbonylnitrene to the acetylenes. The triazole obtained from phenylacetylene is 2-ethoxycarbonyl-4-phenyltriazole the two 1-ethoxycarbonyltriazoles can be isolated if the addition is carried out at 50° over several weeks. Since the IH- to -triazole isomerization takes place readily in these systems, a IH-structure cannot be assumed for a triazole formed by addition of these azides. 

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-... 

Triazoles of this type are glycosylamines and, consequently, they lack the stability of triazoles of other types. However, acid-stable triazoles of this type are obtained when primary or secondary azides of sugars are treated with phenylacetylene.193... 

With monosubstituted acetylenes, such as phenylacetylene (94) and propiolaldehyde diethyl acetal (95), the orientation of phenyl azide is determined both by electronic and steric effects.307 08... 

The photolysis of acyl azides has also been studied, and in some respects these appear to behave analogously. Pivaloyl azide, for example, adds to cyclohexene to give a 26% yield of an aziridine [Eq. (85)],321 and the assumption is that this addition again occurs via a nitrene. The photodecomposition of acetyl azide (295) in benzo-nitrile and phenylacetylene, on the other hand, affords322 2-methyl-5-phenyl-l,3,4-oxadiazole (296) and 2-methyl-5-phenyloxazole (297),... 

It has been shown that allylic azides can be trapped, using either phenylacetylene cycloaddition to the azide, or alkene epoxidation, and that [3,3]-sigmatropic equilibration of the possible allylic azides is generally faster than the trapping reactions 42 Nucleoside-derived azide (46) has been shown to undergo reversible [3,3]-sigmatropic... 

FIGURE 18 Top Molecular structure of Rebek s capsule (59) for the acceleration of a 1,3-dipolar cycloaddition between phenylacetylene and phenyl azide. Bottom CAChe-minimized structure of the ternary complex. Symmetrically loaded capsules are also found in solution. (See Color Insert in the back of this book.)... 

In the addition to unsymmetrical acetylenes the orientation is controlled by electronic effects. Thus, while in the reaction of phenyl azide with phenylacetylene the two isomeric diphenyltriazoles 252 and 253 were obtained in almost equal amounts , methyl propiolate yielded mainly l-phenyl-4-carbomethoxy-1,2,3-triazole (254) and only minor amounts of the isomeric 255 °. Dimethylaminoacety-lene yielded l-phenyl-5-dimethylamino-1,2,3-triazole (256) as the sole product... 

Phase-transfer catalysts, 220, 221,305-306 Phenanthrenes, 319, 320 9-Phenanthrol, 431 Phenol annelation, 272 Phenoxysulfonyl azide, 377-378 Phenylacetaldehyde, 217 Phenylacetylene, 7 2 (S)-3-Phenyl-1-butene, 36 Phenyl chlorothionocarbonate, 306-307 Phenyl cyanate, 307-308 Phenyldiazomethane, 308 o-Phenylene phosphorochloridate, 91-92 o-Phenylglydne methyl ester, 308 Phenyl isocyanate, 309 Phenyl isocyanide, 309-310 Phenyl iso thiocyanate, 122 Phenyllithium, 5... 

Fig. 4-64 Frontier orbitals for phenyl azide, styrene and phenylacetylene...

Wooley et al.234 reported the first dendrimer— fullerene hybrid, 165 (Scheme 21), via the alkylation of a prederivatized fullerene diphenol, 166, with the dendritic bromide 6. Because of purification problems related to impure fullerene starting material, Hawker et al. later investigated the direct cycloaddition235 of a fourth generation azide-functionalized Frechet-type dendron, 167, with Ceo- This dendritic fullerene, 168, could be easily isolated by flash chromatography and showed a significant increase in solubility over the parent fullerene. Avent et al. reported a similar cycloaddition of poly(phenylacetylene) dendrons bearing a focal tosylhydrazone functionality.236... 

The following chemicals were obtained from the Aldrich Chemical Company, Inc., and were used without further purification p-acetamidoben2enesulfonyl chloride, 97% acetone, 99.9+%, HPLC grade sodium azide, 99% ethyl acetoacetate, 99% triethylamine, 99% rhodium(ll) acetate dimer phenylacetylene, 98%. The following solvents were obtained from Fisher Scientific and were used without further purification toluene, certified A. C. S. ethyl ether (Solvent grade. Concentrated) petroleum ether, certified A. C. S. Dichloromethane was distilled from calcium hydride. 

The photodecomposition of acetyl azide in phenylacetylene similarly affords 2-methyl-5-phenyloxazole.167... 

A step-wise procedure for the preparation of Al-sulfonylamidines via A-sulfonylimidates has also been reported [34]. Similar multi-component reaction using alcohols gives N-sulfonylimidates, which are converted to Al-sulfonylamidines by treatment with primary and secondary amines in the presence of catalytic amount of sodium cyanide (NaCN) [24a] (Scheme 3.19). This indirect process sometimes shows abetter yield than the above direct method for example, the one-pot reaction of phenylacetylene (R = Ph), p-toluenesulfonyl azide (R = Ts) and morpholine (2R = CH2CH2OCH2CH2) provides amidines in 19% yield, whereas product is obtained in 72% yield in the step-wise procedure via imidate (R = Me). 

M. T. Garcia-Lopez, G. Garcia-Munoz, J. Iglesias, and R. Madronero, Heterocyclic JV-glyco-sides. III. Synthesis of A-glycosyl-v-triazoles from glycosyl azides and phenylacetylene, J. Heterocycl. Chem., 6 (1969) 639-642. 

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