Effect of solvents and effect of nucleophiles in nucleophilic substitution on benzyl bromide—A kinetic study

Abstract

The kinetics of the reaction of benzyl bromide with thiourea was studied in different pure (protic and aprotic) solvents and the rate data was correlated using linear multiple regression analysis. From the regression coefficients which describe the susceptibility of rate to different solvent parameters, information regarding the solvent-reagent, and the solvent-intermediate interactions was obtained and solvation models were proposed.Applicability of the Swain-Scott free energy relationship was tested using different sulphur nucleophiles in acetonitrile solvent and the nucleophilicity constant of N-acetylthiourea was computed as 2.74 from the regression line.

Solvent interactions in the allylation of piperidine

“…These coefficients indicate the differential solvation of the reactants and the activated complex and the mode of solvation. The results on such studies have been reported earlier 6–14 using different nucleophiles and substrates. Similar studies of solvent effects on the kinetics of the allylation reactions are limited.…”

N-Chloro and N-bromosaccharins: valuable reagents for halogenation of electron rich aromatics and cohalogenation of alkenes

“…The difference between NCSac (electrophilic and radical attack) and NBSac (electrophilic attack only) are in accordance with the fact that NCSac is more efficient than NBSac for benzylic halogenation, whereas NBSac is more efficient than NCSac for electrophilic reactions. 7,9 The cohalogenation (halogenation in the presence of a nucleophilic solvent 12 ) of representative alkenes was also easily achieved with NCSac and NBSac. The reactions were performed at room temperature with equimolar amounts of alkene and NXSac in aqueous acetone to produce the corresponding halohydrins and the results are summarized in Table 2.…”

“…1 Recently, Dolenc published the reaction of NISac with alkenes and aromatic compounds. 1 On the other hand, NCSac and NBSac are easily prepared from the readily available sodium salt of saccharin 2 and they are used in mild oxidation reactions, [3][4][5][6][7] analytical chemistry, 8 and as halogenating reagents for allylic, 9 benzylic 9,10 and α-carbonylic 10,11 positions. Surprisingly, to the best of our knowledge, there is no description of the reaction of those halosaccharins with alkenes and aromatic compounds and we now present our results on this area.…”

LSER in the allylation of morpholine

“…By studying the reaction in different solvents and correlating the rate with different solvent, parameters we can get an insight into relative solvation of the reactants and the transition state, and the relative contribution of solvent properties in solvating them. The results on such studies have been reported [6][7][8][9][10] earlier using different nucleophiles and substrates. As a part of the broad programme of studying the nucleophilic substitution at allylic carbon using different heterocyclic compounds the authors studied the kinetics of allylation of morpholine with a special focus on the solvent effect on the rate of reaction.…”