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https://hdl.handle.net/1822/72921
Título: | 2-naphthalenesulfonyl as a tosyl substitute for protection of amino functions. Cyclic voltammetry studies on model sulfonamides and their preparative cleavage by reduction |
Autor(es): | Nyasse, Barthélémy Grehn, Leif Maia, Hernâni Lopes Silva Monteiro, Luís S. Ragnarsson, Ulf |
Data: | 17-Set-1999 |
Editora: | American Chemical Society |
Revista: | Journal of Organic Chemistry |
Resumo(s): | 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-naphthalenesulfollylindole 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-arenesulfonyl derivatives that give CV peaks above -2.30 V, whereas Al(Hg) requires potentials above about -1.7 V. Selective cleavage of 2-naphthalenesulfonyl in the presence of tosyl by Mg/MeOH is demonstrated. Several examples of reductive cleavage of arenesulfonyl derivatives with Mg/MeOH, Al(Hg), and electrolysis on a preparative scale are given. |
Tipo: | Artigo |
URI: | https://hdl.handle.net/1822/72921 |
DOI: | 10.1021/jo990695q |
ISSN: | 0022-3263 |
Versão da editora: | https://pubs.acs.org/doi/10.1021/jo990695q |
Arbitragem científica: | yes |
Acesso: | Acesso aberto |
Aparece nas coleções: | CDQuim - Artigos (Papers) |
Ficheiros deste registo:
Ficheiro | Descrição | Tamanho | Formato | |
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1999-J. Org. Chem. 7135.pdf | 51,27 kB | Adobe PDF | Ver/Abrir |