Kinetic studies on the reactions of 3‐isothiazolones with 2‐methyl‐2‐propanethiol |
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| Authors: | John O Morley A Jayne Oliver Kapur Michael H Charlton |
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| Institution: | 1. Chemistry Department, University of Wales Swansea, Singleton Park, Swansea, SA2 8PP, UKChemistry Department, University of Wales Swansea, Singleton Park, Swansea, SA2 8PP, UK;2. Chemistry Department, University of Wales Swansea, Singleton Park, Swansea, SA2 8PP, UK;3. Evotec OAI, 111 Milton Park, Abingdon, Oxfordshire, OX14 4SD, UK |
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| Abstract: | The kinetics of the ring‐opening reactions of the 3‐isothiazolones ( 1a–d ) with aqueous 2‐methyl‐2‐propanethiol has been explored at pH 4. The results strongly suggest that the reaction is second order in thiol and third order overall. Extrapolation of the kinetic data gives third‐order rate constants that lie in the order ( 1a ) > ( 1b ) > ( 1c ) > ( 1d ) in line with the known biological activity of these derivatives. The mechanism of the reaction is thought to involve attack by one thiol at the sulfur atom of the isothiazolone with the concomitant hydrogen bonding of a second thiol to the amide nitrogen. Calculations of the structure and electronic properties of the isothiazolones at the RHF 6‐31G** level are supportive. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 254–260, 2005 |
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