394739-29-8Relevant articles and documents
Molecular sieves mediated green per-O-acetylation of carbohydrate templates and lipase catalyzed regioselective alcoholysis of 2,3,5-Tri-O-acetyl-D-ribonolactone
Cardozo, Herbert M.,Ribeiro, Thaís F.,Sá, Marcus M.,Sebr?o, Damianni,Nascimento, Maria G.,Silveira, Gustavo P.
, p. 755 - 764 (2015/04/14)
The per-O-acetylation of D-ribono-1,4-lactone and representative carbohydrates through the combination of acetic anhydride and molecular sieves under solvent-free conditions is demonstrated. The use of 13X/KCl molecular sieves as the heterogeneous catalyst was found to be more efficient than the excess of pyridine normally employed in the conventional method, giving high yields of the expected peracetylated product after 3 h at 25 °C or 1 h at 50 °C. The transformation can be carried out in gram scale and in an open flask. Additionally, the catalyst is readily separated from the reaction medium and can be reutilized without significant loss of activity. This green procedure for acetylation was extended to D-ribonolactone derivatives and natural carbohydrates. To demonstrate the synthetic utility of the method, 2,3,5-tri-O-acetyl-D-ribonolactone was selected as the substrate for the regioselective alcoholysis of acetyl group catalyzed by Candida antarctica lipase B in EtOH to selectively produce 2,3-di-O-acetyl-D-ribonolactone in gram scale.
2,3-Anhydrosugars in glycoside bond synthesis: Mechanism of 2-deoxy-2-thioaryl glycoside formation
Hou, Dianjie,Taha, Hashem A.,Lowary, Todd L.
experimental part, p. 12937 - 12948 (2009/12/07)
A series of investigations probing the mechanism of the 2,3-anhydrosugar migration - glycosylation reaction were performed using a thioglycoside with the D-lyxo stereochemistry as the substrate. Among the work reported are the results of quantum mechanical calculations, NMR studies, the measurement of α-deuterium kinetic isotope effects, and the synthesis of a series of substrate analogues. All studies point to a consistent finding: that the reaction proceeds through an oxocarbenium ion intermediate, not an episulfonium ion as previously suggested. It is proposed that the high stereoselectivity of the reaction arises from a preferred "inside attack" of the nucleophile onto the oxocarbenium ion intermediate.
Synthesis of 1′-fluorouracil nucleosides as potential antimetabolites
Kodama, Tetsuya,Matsuda, Akira,Shuto, Satoshi
, p. 10011 - 10017 (2007/10/03)
The first synthesis of 1′-fluoronucleosides, which has long been synthetic targets as the potential antimetabolites, was achieved. Electrophilic fluorination of the 1′-position occurred to form an anomeric mixture of 1′-fluorouridine derivatives, when the
