B. Nyassé, L. Grehn, H. Maia
Aug 31, 1999
Citations
0
Influential Citations
34
Citations
Journal
Journal of Organic Chemistry
Abstract
With the aim to develop a practically useful, reductively more labile alternative to tosyl for protection of amino functions, initially a number of N-arenesulfonyl-protected heterocycles (pyrroles, imidazoles, indole, and carbazole) have been prepared and studied by cyclic voltammetry (CV). The recorded activation potentials vary from −1.32 to −1.99 V (vs SCE). In N-sulfonylazolides such as tosylindole the cathodic potentials are shifted by over 0.5 V compared to simple sulfonamides. An additional effect of the sulfonic acid component is also indicated. Among the compounds studied, 1- and 2-naphthalenesulfonylindole give CV peaks at about 0.4 and 0.2 V, respectively, less negative potential than tosylindole. To further investigate naphthalenesulfonyl for this purpose, we have also prepared a variety of simple 1- and 2-naphthalenesulfonyl derivatives and studied them similarly. They have activation potentials above −2.14 V and are all smoothly cleaved by Mg/MeOH. The latter reagent is capable of cleaving N...