The synthesis of selenium- and tellurium-containing nucleosides, derived from uridine is describe... more The synthesis of selenium- and tellurium-containing nucleosides, derived from uridine is described herein. These compounds were prepared in a concise and short synthetic route in good yields, by nucleophilic substitution of a tosylate group by organoselenium nucleophiles.
ABSTRACT The introduction of organoselenium moieties within the structure of carbohydrates has re... more ABSTRACT The introduction of organoselenium moieties within the structure of carbohydrates has received attention recently. Herein, we report on the synthesis of selenium-containing neoglycoconjugates and pseudodisaccharides by the reaction of nucleophilic selenium species, generated from sugar diselenides, with chiral N-Boc aziridines and sugar tosylates. The reaction proceeds with moderate to good yields for various substrates. The introduction of organoselenium moieties within the framework of various sugars, with increased levels of complexity, thus allowing the synthesis of disaccharide and glycoconjugate mimetics.
... Hugo C. Braga a , Hélio A. Stefani a , Márcio W. Paixão b , Francielli W. Santos c and Diogo ... more ... Hugo C. Braga a , Hélio A. Stefani a , Márcio W. Paixão b , Francielli W. Santos c and Diogo S. Lüdtke a , Corresponding Author ... Selenol esters are important intermediates in organic synthesis and also the investigation of new molecular material, in particular, liquid crystals. ...
Cadmium (Cd) toxicity is a concern to the tobacco-smoking sub-population which includes millions ... more Cadmium (Cd) toxicity is a concern to the tobacco-smoking sub-population which includes millions of people worldwide. Although this metal may cause severe damage to embryos and the reproductive organs, the precise mechanisms underlying its toxicity remain unclear. In the present study, the Cd effect on ovary d-aminolevulinate dehydratase (d-ALA-D) activity was investigated in vitro and ex vivo. We observed that low concentrations of Cd inhibited cow ovary d-ALA-D activity in vitro and the IC 50 value obtained was 19.17 mM. Furthermore, the protective effect of a novel organic selenium compound (seleno-furanoside) in restoring enzyme activity was evaluated. Seleno-furanoside (10, 50, 100, 200, 400 and 1000 mM) did not reverse the Cd toxicity in bovine ovarian tissue in vitro. According to the in vitro reults, acute Cd exposure (2.5 and 5 mg kg-1) caused a significant inhibition in ovary d-ALA-D activity in mice (around 27% and 34%, respectively). Therapy with seleno-furanoside (100 mmol kg-1) was able to restore enzyme activity. Thus, we demonstrated for the first time that d-ALA-D activity from ovary is inhibited by Cd both in vitro and ex vivo. Additionally, seleno-furanoside therapy was effective in restoring ovarian enzyme activity inhibited by Cd exposure in mice, but it did not reverse the in vitro metal effect. This study detected a new toxicity marker of Cd toxicity on ovarian tissue as well as the beneficial effect of a new compound to manage the metal effect after acute exposure.
The synthesis of seleno-galactopyranosides in a short and efficient manner is described, starting... more The synthesis of seleno-galactopyranosides in a short and efficient manner is described, starting from the parent carbohydrate d-galactose. The approach described allows the synthesis of small libraries of compounds with a number of structural variations at the group attached to selenium. Compounds with aryl, propargyl, allyl, acyl, and alkyl substituents are described.
The synthesis of selenium- and tellurium-containing nucleosides, derived from uridine is describe... more The synthesis of selenium- and tellurium-containing nucleosides, derived from uridine is described herein. These compounds were prepared in a concise and short synthetic route in good yields, by nucleophilic substitution of a tosylate group by organoselenium nucleophiles.
ABSTRACT The introduction of organoselenium moieties within the structure of carbohydrates has re... more ABSTRACT The introduction of organoselenium moieties within the structure of carbohydrates has received attention recently. Herein, we report on the synthesis of selenium-containing neoglycoconjugates and pseudodisaccharides by the reaction of nucleophilic selenium species, generated from sugar diselenides, with chiral N-Boc aziridines and sugar tosylates. The reaction proceeds with moderate to good yields for various substrates. The introduction of organoselenium moieties within the framework of various sugars, with increased levels of complexity, thus allowing the synthesis of disaccharide and glycoconjugate mimetics.
... Hugo C. Braga a , Hélio A. Stefani a , Márcio W. Paixão b , Francielli W. Santos c and Diogo ... more ... Hugo C. Braga a , Hélio A. Stefani a , Márcio W. Paixão b , Francielli W. Santos c and Diogo S. Lüdtke a , Corresponding Author ... Selenol esters are important intermediates in organic synthesis and also the investigation of new molecular material, in particular, liquid crystals. ...
Cadmium (Cd) toxicity is a concern to the tobacco-smoking sub-population which includes millions ... more Cadmium (Cd) toxicity is a concern to the tobacco-smoking sub-population which includes millions of people worldwide. Although this metal may cause severe damage to embryos and the reproductive organs, the precise mechanisms underlying its toxicity remain unclear. In the present study, the Cd effect on ovary d-aminolevulinate dehydratase (d-ALA-D) activity was investigated in vitro and ex vivo. We observed that low concentrations of Cd inhibited cow ovary d-ALA-D activity in vitro and the IC 50 value obtained was 19.17 mM. Furthermore, the protective effect of a novel organic selenium compound (seleno-furanoside) in restoring enzyme activity was evaluated. Seleno-furanoside (10, 50, 100, 200, 400 and 1000 mM) did not reverse the Cd toxicity in bovine ovarian tissue in vitro. According to the in vitro reults, acute Cd exposure (2.5 and 5 mg kg-1) caused a significant inhibition in ovary d-ALA-D activity in mice (around 27% and 34%, respectively). Therapy with seleno-furanoside (100 mmol kg-1) was able to restore enzyme activity. Thus, we demonstrated for the first time that d-ALA-D activity from ovary is inhibited by Cd both in vitro and ex vivo. Additionally, seleno-furanoside therapy was effective in restoring ovarian enzyme activity inhibited by Cd exposure in mice, but it did not reverse the in vitro metal effect. This study detected a new toxicity marker of Cd toxicity on ovarian tissue as well as the beneficial effect of a new compound to manage the metal effect after acute exposure.
The synthesis of seleno-galactopyranosides in a short and efficient manner is described, starting... more The synthesis of seleno-galactopyranosides in a short and efficient manner is described, starting from the parent carbohydrate d-galactose. The approach described allows the synthesis of small libraries of compounds with a number of structural variations at the group attached to selenium. Compounds with aryl, propargyl, allyl, acyl, and alkyl substituents are described.
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