Rates of reaction of n-butanethiol with some conjugated heteroenoid compounds

Abstract

The reactions of substituted 3-benzal-2,4-pentanediones, ethyl benzalacetoacetates, diethyl benzalmalonates, benzalmalonamides, cinnamalmalononitriles, β-nitrostyrenes, and β-nitropropenylbenzenes with excess n-butanethiol go essentially to completion in 20% aqueous ethanolic solution buffered to pH 7. The second order rate constants derived from the reactions of meta- and para- substituted derivatives correlate well with Hammett a constants. The nature and conformation of the functional group cis to the phenyl group determines the extent to which ortho substituents hinder the reaction.