Aminolysis of phenyl salicylate

Aminoguanidine sulfate, 26, 12 2-Aminoheptane, 23, 70 df-/3-AMINOHYDROCINNAMIC ACID, 22, 26 ck-Aminoisovaleric ACID, 20, 106 Aminolysis, of phenyl salicylate, 26, 92 2-Amino-6-methylbenzothiazole, 22, 16... 

Reaction of n-butylamine with methyl salicylate in dioxane is second-order in amine (Snell et al., 1967), but reaction with methyl p-hydroxybenzoate could not be detected. The aminolysis of phenyl... 

The reactions of salicylate esters in aprotic solvents are also intra-molecularly catalysed. Thus the reactions of phenyl salicylate and phenyl o-methoxybenzoate with n-butylamine in acetonitrile are both second-order in amine but phenyl salicylate reacts 132 times faster [31]. These reactions are also catalysed by triethylenediamine and the rate constant for the reaction which is first-order in n-butylamine and first-order in triethylenediamine is over one hundred times greater for phenyl salicylate than for phenyl o-methoxybenzoate. The reaction of phenyl o-methoxybenzoate, but not that of phenyl salicylate, is catalysed by n-butylamine hydrochloride, which suggests that the phenolic hydroxyl group of the latter acts as an internal acid catalysis. Since the rate-limiting step in the aminolysis of esters in acetonitrile solutions is the breakdown of tetrahedral intermediate [32], a reasonable mechanism for the reaction of phenyl salicylate is one in which breakdown of the tetrahedral intermediate is catalysed intermolecularly by a second molecule of amine and intramolecularly by the phenolic hydroxyl group as shown in 25. The reaction of... 

Khan, M.N., Dahiru, M., Naaliya, J. Effects of anionic micelles on intramolecular general base-catalyzed aminolysis of phenyl and methyl salicylates. J. Chem. Soc., Perkin Trans. 2. 1989, 623-628. 

The kinetics of the alkaline hydrolysis of 2-methylpentyl salicylate (24) have been studied in various aqueous propanol and r-butanol mixtures and in mixtures of water and ethane-l,2-diol. ° Further smdies of the aminolysis of ionized phenyl salicylate (25) have been reported, in which it was observed that, in mixed acetonitrile-water solvents, glycine, 1,2-diaminoethane and 3-aminopropanol all reacted as did simple amines, via an intramolecular general-base-catalysed process. ... 

The aminolysis and methanolysis of ionized phenyl salicylate (189) have been examined under micellar conditions. The effect of CTABr on the rates of aminolysis of (189) by -butylamine, piperidine, and pyrrolidine is to bring about a rate decrease (up to 17-fold with pyrrolidine). The results are interpreted in terms of binding constants for the amines with CTABr and the pseudo-phase model.The effects of mixed surfactants SDS and CTABr on the methanolysis of (189) and the alkaline hydrolysis of phenyl benzoate suggest that micellar aggregates are involved in the processes.The effects of NaOH and KBr on the intramolecular general base-catalysed methanolysis of (189) in the presence of CTABr has been investigated. Pseudo-first-order rate constants were not affected by either additive but other changes were noted. The effect of mixed MeCN-water solvents on the same reaction has also been probed. 

The effects of [KBr] and [NaBr] on the rates of CTABr micellar-mediated methanolysis"° and aminolysis " of ionized phenyl salicylate (PS ) showed that the CTABr micellar binding constants (Kg) of PS" followed the following empirical relationship ... 

The rates of hydrolysis of phenyl and methyl salicylates became independent of [HO ] within the [HOi range of 0.002 to 0.070 M in the absence of micelles. The values of ionization constants, K, for phenyl salicylate and methyl salicylate in water solvent are 5.67 x 10 ° M and 2.48 x 10 ° M, respectively. Thus, within the [HO ] range of - 0.002 to 0.070 M, both phenyl and methyl salicylates exist in fully ionized forms. The pH-independent rate of hydrolysis of salicylate esters involve ionized salicylate ester and H2O as the reactants. Intramolecular general base catalysis has been shown to occur in the aminolysis of ionized phenyl salicylate in both aqueous pseudophase and micellar pseudophase of SDS. - The brief reaction scheme for hydrolysis or alkanolysis of salicylate ester or any substrate containing an easily ionizable proton in the presence of micelles, D , may be given in terms of PP model of micelle as depicted in 8cheme 4.2... 

Khan, M.N., Arifin, Z., Lasidek, M.N., Hanifiah, M.A.M., Alex, G. Effects of cationic micelles on rate of intramolecular general base-catalyzed aminolysis of ionized phenyl salicylate. Langmuir 1997, 73(15), 3959-3964. 

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