Carbon-14 kinetic isotope effects in the debromination of p-nitrodibromocinnamic acid

The kinetic isotope effect (KIE) method was applied to study the mechanism of elimination of bromine from p-nitro-erythro-α,β-dibromocinnamic acid labelled at the α carbon. This compound was obtained starting from [2-14c]malonic acid via [2-14C]cinnamic acid and subsequent addition of bromine. The value of 14C KIE determined for α-position of side chain of p-nitro-erythro-α,β-dibromocinnamic acid proves that elimination of bromine leading to formation of (E)-p-nitrocinnamic acid proceeds via E2 mechanism. (author)