Enhanced reactivity in the ammonolysis of phenyl thiolacetates in aqueous medium was written by Rajarathnam, D.;Babu, J.;Nadar, P. Ananthakrishna. And the article was included in International Journal of Chemical Kinetics in 2002.Reference of 35065-86-2 This article mentions the following:
The ammonolysis of several substituted Ph thiolacetates is kinetically studied in aqueous medium, 18°, ionic strength 0.1 M (KCl). By following the leaving groups spectrophotometrically (λmax = 260-410 nm), under excess free ammonia, pseudo-first-order rate coefficients (kobs) are obtained. The plots of (kobs – kH) against free ammonia concentration are linear at constant pH. The macroscopic nucleophilic substitution rate coefficients (kN) are obtained as the slopes of these plots and found to be pH-independent for all the thiolesters. The Bronsted-type plot (log kN against pKa of leaving groups) and the Hammett plot (log kN against σ values of substituents) obtained for the title reactions of thiolesters are linear with slope values of βlg = -0.34 and ρ = 0.74 resp. From the magnitude of these values, exptl. data, the kinetic law, and the anal. of products, it is deduced that the ammonolysis of thiolesters proceeds through a simple bimol. nucleophilic substitution pathway with a zwitterionic tetrahedral addition intermediate whereby its formation is rate-determining (k1 step). Comparison of this reaction of thiolesters with a similar reaction of analog oxyesters shows a mechanistic difference. Further, for thiolesters there is a rate enhancement with larger kN values. The change in mechanism and enhanced reactivity observed by substitution of the oxygen atom by sulfur atom on the Ph moiety are discussed in detail. In the experiment, the researchers used many compounds, for example, 3-Bromophenyl acetate (cas: 35065-86-2Reference of 35065-86-2).
3-Bromophenyl acetate (cas: 35065-86-2) belongs to organobromine compounds. Bromo compounds are employed in a variety of metal-catalyzed coupling reactions. They are also ideal candidates for the synthesis of Grignard reagents that have wide-applicability in organic synthesis. alpha-Bromoesters are employed in the Reformatsky reaction for the synthesis of beta-hydroxyesters. The principal reactions for organobromides include dehydrobromination, Grignard reactions, reductive coupling, and nucleophilic substitution.Reference of 35065-86-2
Referemce:
Bromide – Wikipedia,
bromide – Wiktionary