Phenyl benzoate alkaline hydrolysis

Perhaps the most informative studies (Anvia and Bowden, 1990) of leaving groups are of the alkaline hydrolysis of 3-substituted phenyl 2-acetyl- and 2-benzoyl-benzoates [20], The Hammett reaction constants p are ca. 0.50 and 1.48 for the 2-acetyl and 2-benzoyl esters respectively, as. shown in Table 2. These were compared with various limiting models in a similar manner to the effective charge model (Williams, 1984,1992). This comparison indicates that all simple phenyl esters of the latter types hydrolyse by a mechanism... 

The influence of temperature on the ortho effect has been evaluated in the alkaline hydrolysis in aqueous DMSO solutions of ortho-, meta- and para-substituted phenyl benzoates (26). The alcoholysis of phthalic anhydride (27) to monoalkyl phthalates (28) occurs through an A-2 mechanism via rate-determining attack of the alcohol on a carbonyl carbon of the anhydride (Scheme 4). Evidence adduced for this proposal included highly negative A 5 values and a p value of 4-2.1. In the same study, titanium tetra-n-butoxide and tri-n-butyltin ethanoxide were shown to act as effective catalysts of the half-ester formation from (27), the mechanism involving alkoxy ligand exchange at the metal as an initial step. ... 

Complexation with caffeine and theophylline-7-acetate depresses the rate of alkaline hydrolysis of substituted phenyl benzoates and is consistent with the formation of molecular complexes with 1 1 stoichiometry between the hosts and esters stacking of the xanthines is excluded as an explanation in the range of concentrations studied. Inhibition of hydrolysis is attributed to repulsion of the hydroxide ion from the host-ester complex by the extra hydrophobicity engendered by the xanthine host, as well as by the weaker binding of the transition state to the host compared with that in the host-ester complex. ... 

Hydroxyethyl)carbazole can be oxidized with copper(II) oxide-potassium hydroxide at 240°C to the carbazol-9-ylacetic acid the benzoate ester of the alcohol was cleaved to regenerate alcohol using phenyl Grignard reagent. The 9-acetic acid is also produced by alkaline hydrolysis of the corresponding nitrile. ... 

Alkaline Hydrolysis Rates of Acyl- and Aryl-Substituted Phenyl Benzoates... 

Kirsch, J. F., W. Clevell, and A. Simon, Multiple structure-reactivity correlations. The alkaline hydrolysis of acyl- and aryl-substituted phenyl benzoates , J. Org. Chem., 33,127-132 (1968). 

Slightly smaller p values are obtained with more polar solvents, where the medium is able to stabilize the transition state more effectively, and thus the response to the electronic effects of substituents is less critical. For the alkaline hydrolysis of the phenyl esters of substituted benzoates in 33% aqueous acetonitrile Kirsch et al.235 find p = 1.98. The value is not significantly different for more or less reactive leaving groups under the same conditions... 

Exercise 26-40 Explain why p for ionization of benzoic acids is larger than p for phenylethanoic acids. Estimate a value ofp for the ionization of substituted 4-phenyl-butanoic acids. Why should we expect the value of p for alkaline hydrolysis of ethyl benzoates to be larger than for acid ionization and to have the same sign ... 

Generally, the rate of alkaline hydrolysis of a series of substituted phenyl benzoates was decreased in the presence of 0.5 m BiuNBr, the retardation being larger for esters with electron-donating substituents. The data from 22 esters were fitted to a multiparameter equation, the results showing that solvent electrophilicity was the main factor responsible for changes in the ortho, para and meta polar substituent effects with medium.15... 

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 influence of temperature on the ortho effect has been evaluated in the alkaline hydrolysis in aqueous DMSO solutions of ortho-, meta- and para-substituted phenyl benzoates (26). The alcoholysis of phthalic anhydride (27) to monoalkyl phthalates... 

The solid-liquid alkaline hydrolysis of esters such as phenyl benzoate, ethyl p-nitrobenzoate and 2,4-dichlorophenylbenzoate has been studied in the presence of sodium p-toluene sulfonate, sodium xylene sulfonate and the sodium salts of phenol, p-chlorophenol, 2,4-dichlorophenol and 2,4,6-trichlorophenol. The solubilities of the esters in water is very low, but in the presence of the hydrotropes considerably higher reaction rates are obtained due to higher solubilities (30). The same behaviour was observed by using urea in the solid-liquid oximation of cyclododecanone where the reaction rate was increased. From studies of these types of reactions, the following observations were made (31) ... 

Preparation by acyladon of 2,6-dichloro-phenol with p-(trichloromethyl)phenyl p-(trichloromethyl)benzoate in methylene chloride in the presence of aluminium chloride at 0-5° over 1 h, then at r.L for 1 h, followed by alkaline hydrolysis of the resulting keto ester [325] (Jjpanese patmt). 

Khan, M.N. Effects of salts and mixed CHjCN-HjO solvents on alkaline hydrolysis of phenyl benzoate in the presence of ionic micelles. Colloids Surf. A 1998, 139, 63-74. 

Pirinccioglu, N., Williams, A. Studies of reactions within molecular complexes alkaline hydrolysis of substituted phenyl benzoates in the presence of xanthines. J. Chem. Soc. Perkin Trans. 2. 1998, 37 0. 

Khan, M.N., Ismail, E., Yusoff, M.R. Effects of pure non-ionic and mixed nonionic-cationic surfactants on the rates of hydrolysis of phenyl salicylate and phenyl benzoate in alkaline medium. J. Phys. Org. Chem. 2001,14, 669-676. 

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