Basicity of nitrogen–sulphur(VI) compounds. Part 5. Ionization of trisubstituted sulphamides
Abstract
The ionization equilibria in base of 27 trisubstituted sulphamides, mainly represented by the following series: X-C6H4NHSO2NR2R1, where NR2R1= piperidyl, morpholinyl, and NPrn2, and RHNSO2NR2R1, where R, R1, and R2 are cyclo-C6H11, Ac, and X-C6H4 and X-C6H4, Ac, and X-C6H4, have been studied in 60% v/v ethanol–water using the potentiometric method. In a few cases pKa values have been determined by the u.v. method. The effect of substituents has been correlated in Hammett plots and values are generally ca. 2.6 (as for an aryl linked introgen in sulphonanilide ionizations). The acid-strengthening effect of the acetyl group and the acid-weakening effect of the methyl group are seen in some series.