Smyth, R.M and Williams, A. (1993) Anchimeric assistance in the specific acid-catalysed hydration of benzonitriles. Journal of the Chemical Society-Perkin Transactions 2 (11). pp. 2171-2174. ISSN 0300-9580.
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2-(Acylamido)benzonitriles react to give exclusively the corresponding 2-(acylamido)benzamides under relatively mild aqueous acid conditions. The kinetics for hydration at 50-degrees-C in aqueous HCl with ionic strength kept at 1 mol dm-3 with KCl obey the equation rate = k(H) x [H+] [nitrile] at low acid concentrations: at higher concentrations of acid the pseudo first order rate constants show a positive deviation from linearity. The rate constants (k(H)) for the substituted benzamidobenzonitriles fit a Hammett relationship. log k(H) = -0.36 +/- 0.04sigma - 3.49 +/- 0.01 (r = 0.963) The reactivity due to the ortho amido group is more than 25 000 that of the unsubstituted benzonitrile under the same conditions. The mechanism is considered to involve protonation of the nitrile followed by rate limiting intramolecular attack of the amido oxygen to form an intermediate which rapidly breaks down to the acylamidobenzamide.
|Subjects:||Q Science > QD Chemistry|
|Divisions:||Faculties > Science Technology and Medical Studies > School of Biosciences|
|Depositing User:||O.O. Odanye|
|Date Deposited:||21 Jul 2009 19:14|
|Last Modified:||21 Jul 2009 19:14|
|Resource URI:||http://kar.kent.ac.uk/id/eprint/20690 (The current URI for this page, for reference purposes)|
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