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1.
Carbohydr Polym ; 110: 499-504, 2014 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-24906784

RESUMO

Water-soluble sodium 2,3,6-tricarboxylate cellulose (NaTCC) or sodium mesotartarate/monohydrated glyoxilate alternating co-polyacetal was prepared from regenerated cellulose in a yield of 82% by one-step oxidation with catalytic amounts of 2-azaadamantane N-oxyl (AZADO), NaBr, and excess NaOCl in water at room temperature under alkaline conditions. The AZADO-oxidized product was shown to have an almost homogeneous NaTCC chemical structure by its 1H and 13C NMR spectra. The weight- and number-average molecular masses of the obtained NaTCC were 10,700 and 7000. When AZADO-mediated oxidation was applied to softwood bleached kraft pulp, a water-soluble oxidized product was obtained. However, it had a more heterogeneous chemical structure showing that the complete oxidation of the C2, C3, and C6 hydroxyls to carboxyls is difficult to achieve in native cellulose.


Assuntos
Adamantano/análogos & derivados , Celulose/análogos & derivados , Óxidos N-Cíclicos/química , Ácidos Tricarboxílicos/química , Adamantano/química , Catálise , Celulose/síntese química , Cromatografia em Gel , Oxirredução , Ácidos Tricarboxílicos/síntese química , Água/química
2.
Org Lett ; 14(17): 4303-5, 2012 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-22928597

RESUMO

The total synthesis of (+)-Sch 725680, a member of the hydrogenated azaphilone family, has been accomplished. The synthesis confirmed the absolute configuration and biological activities of the natural product. A key reaction to construct a hydrogenated azaphilone core skeleton is a Ti-mediated aldol reaction.


Assuntos
Benzopiranos/síntese química , Benzopiranos/farmacologia , Inibidores da Síntese de Ácido Nucleico , Aspergillus/química , Benzopiranos/química , Estrutura Molecular , Estereoisomerismo
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