K. Radhakrishnan et al., NONLINEAR STRUCTURE-REACTIVITY CORRELATION IN THE ADDITION-REACTION OF N-BUTYLAMINE TO PARASUBSTITUTED ETHYL ALPHA-CYANOCINNAMATES, Indian journal of chemistry. Sect. A: Inorganic, physical, theoretical & analytical, 35(5), 1996, pp. 401-407
The study of kinetics of addition of n-butylamine to a number of para-
substituted ethyl alpha-cyanocinnamates in acetonitrile reveals that t
he reaction is first order in the substrate and the order in nucleophi
le varies with the nature of the para-substituent. The analysis of the
rate data of the various parasubstituted ethyl alpha-cyanocinnamates
in terms of the Hammett equation gives a non-linear concave-down type
of curve. A stepwise mechanism involving the formation of zwitterionic
addition complex in an equilibrium step followed by conversion into t
he reaction product via a proton transfer in two routes, viz., non-cat
alytic and by amine catalysed, has been proposed. The non-linear struc
ture-reactivity correlation has been accounted for by the change in ra
te-controlling step.