Competition between carbon, nitrogen, and oxygen nucleophilic centres for sulphur(VI) attack in NN′-disubstituted sulphamides

Reactions of five kinds, namely (i) the hydrolysis of substituted sulphamides to sulphamic acids, (ii) the hydrolysis of the substituted sulphamic acids to arylamine sulphates, (iii) the trans-sulphonation reactions of the sulphamic acids, (iv) the trans-sulphamoylation reactions of the substituted sulphamides, and (v) the amine interchange processes of the NN′- disubstituted sulphamides all appear to show certain common critical characteristics. Electron donation to the reaction site, the hexavalent sulphur atom, hinders all these processes, whereas electron withdrawal facilitates them. Because of this consistency we regard the key process around which this present work was constructed (the trans-sulphamoylation reaction) as being best interpreted in terms of direct nucleophilic attack at sulphur (VI) in the protonated sulphamide, most probably by the para-aryl carbon site in the aromatic nucleophilic substrate.