95309-04-9Relevant academic research and scientific papers
Basicity of Nitrogen-Sulphur(VI) Compounds. Part 6. Ionization of NN'-Di- and N-Mono-substituted Sulphamides and Dihydro-2,1,3-benzothiadiazoline and Benzothiadiazine 2,2-Dioxides (Cyclic Sulphamides)
Burke, Padraig O.,McDermott, Sean D.,Hannigan, Thomas J.,Spillane, William J.
, p. 1851 - 1854 (2007/10/02)
36 Di- and mono- and two tri-substituted sulphamides have been synthesised and their ionization equilibria in base (Schemes 1-3) have been studied.Many of the sulphamides are new materials.The pKa values obtained for each series have been correlated in Hammett and Taft plots.The Hammett ? values obtained for the ionization of the proximate hydrogen are ca. 2.3.The Taft ?* value obtained for ionization of the 'remoter' hydrogen is 1.68.The six-membered cyclic sulphamides are more acidic than their acyclic analogues by ca. 2.5 pKa units and the five-membered cyclic sulphamides are ca. 4 pKa units more acidic than model open-chain counterparts.Sulphur d-orbital involvement and ring-strain are suggested as possible sources of this 'acid-strengthening' effect.
