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Base‐catalysed hydrolysis of γ‐lactones: reactivity–structure correlations for 3‐(substituted phenoxy‐ and thiophenoxymethylene)‐( Z )‐1(3 H )‐isobenzofuranones
Author(s) -
Bowden Keith,
Ranson Richard J.,
Perjéssy Alexander,
Lácová Margita,
Hritzová Oĺga,
Fabian Walter M. F.
Publication year - 1998
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/(sici)1099-1395(199807)11:7<467::aid-poc15>3.0.co;2-0
Subject(s) - chemistry , substituent , hydrolysis , reactivity (psychology) , reaction rate constant , alkaline hydrolysis , aqueous solution , base (topology) , medicinal chemistry , computational chemistry , chloroform , kinetics , organic chemistry , mathematical analysis , physics , alternative medicine , mathematics , pathology , quantum mechanics , medicine
Rate coefficients were measured for the base‐catalysed hydrolysis of a series of substituted 3‐(phenoxy‐ or thiophenoxymethylene)‐ (Z) ‐1(3 H )‐isobenzfuranones (3‐phenoxy‐ or thiophenoxymethylenephthalides) in 70% (v/v) aqueous dioxane at 30.0 °C, in addition to the carbonyl stretching frequencies in chloroform and tetrachloromethane following deconvolution and band separation, when required. The Hammett reaction constants for the alkaline hydrolysis of the 3‐/4‐substituted phenoxy and thiophenoxy series are ca 0.75 and 1.10, respectively. These results are related to electrostatic field and resonance effects. Successful correlations between the carbonyl stretching frequencies and substituent constants and the rates of alkaline hydrolysis were found. Computational studies using the semi‐empirical AM1 method correctly model both the details of the mechanistic pathway and the substituent effects. © 1998 John Wiley & Sons, Ltd.