2- Phenylethyl azide

Related to these studies is the work of Boyer and Hamer who treated benzaldehyde with 2-phenylethyl azide in the presence of sulphuric acid and obtained (2-phenylethyl) benzamide (47) in... 

The possibility of ring closure was expected to depend on molecular geometry. Thus, photolysis of n-propyl azide (7) in cyclohexane produced only the imine (8) in 59% yield, isolated as the 2,4-dinitro-phenylhydrazone (9). Irradiation of phenylethyl azide (10) resulted... 

An example with the characteristics of the coupled displacement is the reaction of azide ion with substituted 1-phenylethyl chlorides. Although the reaction exhibits second-order kinetics, it has a substantially negative p value, indicative of an electron deficiency at the transition state. The physical description of this type of activated complex is the exploded S 2 transition state. 

Studies of the solvolysis of 1-phenylethyl chloride and its p-substituted derivatives in aqueous trifluorethanol containing azide anion as a potential nucleophile provide details relative to the mechanism of nucleophilic substitution in this system. 

Phenoxy-1,2-epoxypropane, 3150 Phenyl azide, 2271 2-Phenylethyl isocyanate, 3139 Phenylhydrazine, 2373... 

Figure 2.2. The change with changing aromatic ring substituent X in the azide (az) ion selectivities (feaz/ s)obsd ( ) determined by analysis of the products of the reactions of ring-substituted 1-phenylethyl derivatives (X-l-Y) and ring-substituted cumyl derivatives (X-2-Y) in 50/50 (v/v) water/trifluoroethanol at 25 The selectivities are plotted...

Figure 2.5. Nucleophile selectivities determined from product analysis for the reactions of ring-suhstituted 1-phenylethyl derivatives (X-l-Y) with azide ion, acetate ion and methanol in 50 50 (v/v) water/trifluoroethanol. The selectivities are plotted against the appropriate Hammett substituent constant or a. Leaving group Y ( ) ring-suhstituted benzoates ( ) chloride (T) dimethyl sulfide (A) tosylate.

In analyzing their data, Sneen and Larsen had to correct for salt effects, since they were comparing rate with azide present to rate without.107 Schleyer and co-workers have criticized Sneen s conclusions by pointing out the uncertainties involved in such corrections,108 and Sneen has replied, justifying his earlier conclusions and presenting similar evidence for a-phenylethyl systems,109 and for an allylic system.110 The question is far from settled, and will continue to be a subject of investigation.111... 

Phenyl azide, 2264 Phenyl isocyanate, 2681 2-Phenylethyl isocyanate, 3133 Phenylhydrazine, 2366 Poly(vinyl alcohol), 0827... 

Phenylethylamine has been made by a number of reactions, many of which are unsuitable for preparative purposes. Only the most important methods, from a preparative point of view, are given here. The present method is adapted from that of Adkins,1 which in turn was based upon those of Mignonac,2 von Braun and coworkers,3 and Mailhe.4 Benzyl cyanide has been converted to the amine by catalytic reduction with palladium on charcoal,5 with palladium on barium sulfate,6 and with Adams catalyst 7 by chemical reduction with sodium and alcohol,8 and with zinc dust and mineral acids.9 Hydrocinnamic acid has been converted to the azide and thence by the Curtius rearrangement to /3-phenyl-ethylamine 10 also the Hofmann degradation of hydrocinnamide has been used successfully.11 /3-Nitrostyrene,12 phenylthioaceta-mide,13 and the benzoyl derivative of mandelonitrile 14 all yield /3-phenylethylamine upon reduction. The amine has also been prepared by cleavage of N- (/3-phenylethyl) -phthalimide 15 with hydrazine by the Delepine synthesis from /3-phenylethyl iodide and hexamethylenetetramine 16 by the hydrolysis of the corre-... 

For the recombination of a-phenylethyl cations with strong nucleophiles, Richard and Jencks (1984a,b,c) obtained good Y-T correlations with the same r value of 1.15 as observed for the solvolysis (Fig. 35). The p value of -2.7 for the bimolecular substitution reaction of azide ion with 1-phenylethyl derivatives is significantly more positive than the value of p = -5.7 for the solvolysis reaction. This shows that there is a smaller development of positive charge in the transition state for the reaction of azide ion than for solvolysis. It is consistent with a coupled concerted reaction with a transition state in which positive charge development at the benzylic carbon is neutralized by bonding to azide ion. 

The halogen end group can be transformed into other functionalities by means of standard organic procedures, such as a nucleophilic displacement reaction. Different authors have investigated this process of the nucleophilic displacement reactions with model compounds, to confirm the feasibility and selectivity. Compounds such as 1-phenylethyl halide, methyl 2-bromopropionate, and ethyl 2-bromoisobutane mimic the end groups of PSs, poly(alkyl acrylates), and poly(alkyl methacrylates), respectively. Different compounds have been tested, such as sodium azide, n-butylamine, and n-butylphosphine. 

Figure 2. Estimated rate constants for reactions of nucleophiles with substituted 1-phenylethyl carbocations, plotted against the effective Hammett constant of the ring substituent with r+ = 2.1 (+) trifluoroethanol (A) methanol acetate anion ( ) trifluoroethoxide anion propanethiol (o) azide. (Reproduced from reference 17.

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