16751-37-4Relevant academic research and scientific papers
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.
Preparation of acetylated 2,6-anhydrohept(hex)-2-enononitriles (1-cyano-2-hydroxyglycals)
Somsak,Papp,Batta,Farkas
, p. 173 - 178 (2007/10/02)
The reactions of acetylated 1-bromo-D-glycosyl cyanides with acetate3 and thiolates have been described, and reactions with cyanides are now reported. The mechanism of the formation of the lactones is unclear. Oxidative decyanation of nitriles to give ketones and other carbonyl compounds in the presence of a strong base is well documented. Compounds of the type ArRC(I)CN were converted into ArRC = O with silver oxide in tetrahydrofuran, whereas the corresponding bromides were inert. In these reactions, air is the source of the oxygen. Since the transformations reported here give the lactones in an atmosphere of nitrogen, methyl sulfoxide may be the oxidising agent.
Metal-Catalyzed Organic Photoreactions. Iron (III)-Catalyzed Photoreactions of Aldo- and Ketohexoses
Ichikawa, Shuji,Tomita, Isao,Hosaka, Akira,Sato, Tadashi
, p. 513 - 520 (2007/10/02)
Under UV irradiation in the presence of iron(III) chloride or iron (III) triflate in pyridine, D-glucose, D-mannose, and D-galactose underwent a selective bond cleavage at the C1-C2 position, producing 4-O-formyl-D-arabinopyranose and 4-O-formyl-D-lyxopyranose.D-Fructose, under the same conditions, gave arabino-γ-lactone.The reaction was interpreted in terms of the photoinduced electron transfer within a chelate of iron ion with the carbohydrate molecule.
Preparation of 3-Deoxy-aldonolactones by Hydrogenolysis of Acetylated Aldonolactones
Bock, Klaus,Lundt, Inge,Pedersen, Christian
, p. 155 - 162 (2007/10/02)
Acetylated aldono-1,4-lactones, when treated with hydrogen in the presence of triethylamine and palladium on carbon, form acetylated 3-deoxy-aldono-1,4-lactones in high yield through elimination of the 3-acetoxy group and subsequent stereospecific hydrogenation of the unsaturated intermediate.Thus, acetylated D-galactono-1,4-lactone (1) yields tri-O-acetyl-3-deoxy-D-xylo-hexono-1,4-lactone (3a).Acetylated D-mannono- or D-glucono-1,4-lactone both give 3-deoxy-D-arabino-hexono-1,4-lactone (10a), whereas the four acetylated D-pentono-1,4-lactones (14-17) all afford di-O-acetyl-D-threo-pentono-1,4-lactone (18a).D-Gluconolactone can be converted into (R)-γ-caprolactone (27) on treatment with hydrogen bromide followed by a series of reductions.Similarly, D-lyxonolactone produces 2,3-dideoxy-D-glycero-pentono-1,4-lactone (29).
