Antibacterial activity and chemical reactivity of sulphanylamides. Rate constants of alkaline hydrolysis of N4-acetylsulphanylamides.

The alkaline deacylation rate constants of a collection of N4-acetylderivatives of acidic and non-acidic sulphonamides (SA) clearly show a definite trend due to the intramolecular effects induced by the different substitutions on the N1 nitrogen. The rate constant is interpreted as a reactivity index of the corresponding non-acetylated compound, and is found to be strictly correlated with the electron-availability of the p-amino group; thus providing an interesting correlation with the antibacterial activity of these drugs. Moreover, the reported experiments corroborate early predictions that the greatest reactivity of the p-amino group pertains to p-aminobenzoate (PAB) in the series of chemically related compounds, and that SA anions show the highest chemical and electronic resemblance to the essential metabolite (PAB); thus the high antibacterial activity of SA anions correctly corresponds to its close resemblance to the metabolite.