Leticia Lafuente, María Florencia Rochetti, Rodolfo D. Bravo, Leandro D. Sasiambarrena, Cintia C. Santiago, Agustı́n Ponzinibbio,
Cu-Fe spinels promoted the Ferrier rearrangement of 2-nitroglycals with several O-nucleophiles. 2,3-Unsaturated carbohydrate derivatives were prepared by the reaction of 3,4,6-tri-Oacetyl- 2-nitroglucal and alcohols in the presence of 5 % of CuFe2O4. After separation of the catalyst with an external magnet, the reaction products were obtained in good yields and high stereo and regioselectivity. Also, S- and heterocyclic C-3 substituted 2-nitro-endo-glycals could be prepared by this method.
Tópico(s): Chemical Synthesis and Reactions
2018 - Bentham Science Publishers | Letters in Organic Chemistry
Cintia C. Santiago, Leticia Lafuente, Rodolfo D. Bravo, Gisela Díaz, Agustı́n Ponzinibbio,
Ionic liquids promoted the direct epoxidation of glycals acting as PTC. 1,2-anhydrosugars were prepared by the oxidation of glycals under biphasic conditions with dimethydioxirane generated in situ from oxone/acetone and amphiphilic IL’s as catalysts. β-O-glycosides were synthesized in good yields by the nucleophilic ring opening of epoxy carbohydrate derivatives. Also, 3,4,6-benzyl protected carbohydrates and β-N-glycosides could be prepare by this method.
Tópico(s): Organic and Inorganic Chemical Reactions
2017 - Elsevier BV | Tetrahedron Letters
Cintia C. Santiago, Leticia Lafuente, Agustı́n Ponzinibbio,
Abstract Several β‐ N ‐glycosides were obtained upon a simple and efficient two‐step methodology. First, α‐1,2‐anhydrosugars were prepared diastereoselectively by the oxidation of 3,4,6‐tri‐O‐benzyl‐D‐glucal under biphasic conditions (CH 2 Cl 2 /water) using dimetyldioxirane (DMDO) generated in situ from oxone/acetone mixture and amphiphilic imidazolium ionic liquid (DodMImBF 4 ) as phase transfer catalyst. Immediately, β‐ N ‐glycosides were synthesized in good yields by aminolysis of these α‐1,2‐anhydrosugars ...
Tópico(s): Chemical Synthesis and Reactions
2020 - Wiley | ChemistrySelect
Guido G. Fraga, Diego D. Colasurdo, Cintia C. Santiago, Agustı́n Ponzinibbio, Leandro D. Sasiambarrena,
We studied the E/Z rotamers of new N-substituted 2‑chloro-N-(2-nitrobenzyl)acetamides by applying 1H-NMR and 13C-NMR techniques. The restricted rotation around the amide bond generates a mixture of E/Z diastereomers visualized as a set of appreciably separated signals in the NMR spectra. In order to assign each signal to its corresponding rotamer, the criterion of the anisotropic solvent-induced shift (ASIS) effect, observed in the 1H-NMR spectra, was used. The effects of solvent and substituent ...
Tópico(s): Synthesis of heterocyclic compounds
2022 - Elsevier BV | Journal of Molecular Structure
Leticia Lafuente, Cintia C. Santiago, Agustín H. Rojas, Oscar E. Piro, Gustavo A. Echeverría, Agustı́n Ponzinibbio,
Abstract We present the selective synthesis of novel aminooxy glycosyl derivatives bearing hydroxy phenyl moieties. A strict control over the anomeric and E / Z configurations has been achieved. The products obtained are α‐glycosides and the aromatic moiety substitute the Schiff's base trans to the O‐glycosidic bond. Single crystal X‐ray diffraction and NMR spectral data are reported and analysed.
Tópico(s): Ferrocene Chemistry and Applications
2020 - Wiley | ChemistrySelect
Natividad Bejarano Rengel, Juliana Esteche, Gustavo A. Echeverría, Oscar E. Piro, Cintia C. Santiago, Agustı́n Ponzinibbio,
We present here the efficient preparation of 6‐N‐haloaryl‐galactosides through a reductive amination process. A complete set of 6‐deoxy‐1,2;3,4‐di‐O‐isopropylidene‐6‐N‐phenylamino‐α‐D‐galactopyranosides were obtained with a straightforward method. The products were structurally analyzed by X‐ray diffraction techniques and NMR spectroscopic data. A complete investigation of the galactosyl derivatives is described, including an unexpected N,N´‐diphenylamino by‐product. Moreover, relevant conformational ...
Tópico(s): Glycosylation and Glycoproteins Research
2024 - Wiley | European Journal of Organic Chemistry
Produção Nacional
Revisado por pares
Cintia C. Santiago, Natividad Bejarano, Pablo S. Fernández, Agustı́n Ponzinibbio,
Abstract: The last decades have witnessed significant advances in the synthesis of bioactive carbohydrates. As in all fields of organic synthesis, the search for more environmentally friendly alternative synthetic methods is a current and expanding concern. Consequently, electrochemical organic synthesis has emerged as an efficient and sustainable methodology. Herein, we present recent developments in the synthesis of glycosides and other carbohydrate derivatives using electrochemical methods. Diverse ...
Tópico(s): Catalysis for Biomass Conversion
2024 - Bentham Science Publishers | Mini-Reviews in Organic Chemistry
Cintia C. Santiago, Leticia Lafuente, Rodolfo D. Bravo, Gisela Díaz, Agustı́n Ponzinibbio,
Tópico(s): Microwave-Assisted Synthesis and Applications
2017 - Elsevier BV | Tetrahedron Letters