5155-50-0Relevant articles and documents
Regioselective methylation of methyl glycopyranosides with diazomethane in the presence of transition-metal chlorides and of boric acid
Evtushenko, Evgeny V.
, p. 187 - 200 (2007/10/03)
Partial methylation of the methyl pyranosides of a number of pentoses, hexoses, 6-deoxyhexoses, methyl uronates and their methyl ethers with diazomethane in the presence of transition-metal chlorides and boric acid was studied. It was found for methyl glycosides of pentoses and 6-deoxyhexoses that tin(II), antimony(III), and titanium(IV) chlorides as well as boric acid promoted substitution mainly of OH-3, but with cerium(III) and zinc(II) salts mainly substitution of OH-2 was observed. Methylation of methyl β-l-rhamnopyranoside demonstrated higher reactivity of OH-2 in all cases. The methylation of methyl glycosides of hexoses in the presence of tin(II), antimony(III) and cerium(III) chlorides gave mainly 3-methyl ethers. The 3-methyl ethers, which are not involved in further complexation, accumulated up to 50-80% of the reaction mixture (95-100% of monomethyl ether fraction). Convenient preparative syntheses of methyl ethers for a number of sugars are suggested. Copyright (C) 1999 Elsevier Science Ltd.
A Study of the Rapid Anomerization of Poly-O-benzyl-β-D-glucopyranosides with Titanium Tetrachloride
Koto, Shinkiti,Morishima, Naohiko,Kawahara, Reiko,Ishikawa, Katsuhiko,Zen, Shonosuke
, p. 1092 - 1096 (2007/10/02)
Titanium tetrachloride rapidly anomerizes methyl 2,3,4,6-tetra-O-benzyl-β-D-glucopyranoside in dichloromethane at 25 deg C.Evidence for the proposal that the benzyloxymethyl group on C-5 and the ring oxygen of the glucoside cooperate to prompt the reaction is described.The reagent anomerizes the interglycosidic linkage of several disaccharide derivatives.