- Hydroxy group acidities of partially protected glycopyranosides
-
A comprehensive acidity study of carbohydrate hydroxy groups has been carried out. Relative acidities (Ke) were determined spectrophotometrically for partially methylated methyl α-D- glycopyranosides. Apparently, the acidity is strongly affected by intramolecular hydrogen bonding as well as stereochemistry and solvation. By comparison with pKe and pKa values of aliphatic alcohols and polyols the first estimation of the pKa values for partially protected glycopyranosides was obtained. These findings contribute to the understanding of the relative reactivities of carbohydrate hydroxy groups.
- Matwiejuk, Martin,Thiem, Joachim
-
p. 2180 - 2187
(2012/06/30)
-
- SYNTHESES OF METHYL ESTERS OF URONIC ACIDS. IV. SYNTHESIS OF THE 3-O-, 2,3-, 2,4-, AND 3,4-DI-O-, AND 2,3,4-TRI-O-METHYL ETHERS OF METHYL (METHYL α-D-MANNOPYRANOSID)URONATE
-
The synthesis is described of methyl O-benzyl-O-methyl-α-D-mannopyranosides and their oxidation by chromium trioxide, leading, after catalytic hydrogenolysis, to the 3-O, 2,3-, 2,4-, and 3,4-di-O-, and 2,3,4-tri-O-methyl ethers of methyl (methyl α-D-manno
- Grishkovets, V. I.,Zemlyakov, A. E.,Chirva, V. Ya.
-
p. 519 - 521
(2007/10/02)
-
- Preparation of Some Partially Methylated Galactosides from Methyl α-D-Galactopyranoside
-
Methyl 2,3,6-tri-O-methyl-α-D-galactopyranoside (3) and methyl 2,6-di-O-methyl-α-D-galactopyranoside (2) have been synthesized starting from isopropylidene derivatives of methyl α-D-galactopyranoside.
- Roy, Abhijit,Batavyal, Lakshmi,Roy, Nirmolendu
-
p. 498 - 499
(2007/10/02)
-
- SYNTHESIS OF METHYL DERIVATIVES OF URONIC ACIDS. II. SYNTHESIS OF THE 2,3-, 2,4-, AND 2,4-DI- AND 2,3,4-TRI-O-MEETHYL ETHERS OF METHYL (METHYL α-D-GALACTOPYRANOSID)URONATE
-
Unidirectional methods are proposed for the synthesis of the 2,3-, 2,4-, and 3,4-di-, and 2,3,4-tri-O-methyl ethers of methyl (methyl α-D-galactopyranosid)uronate by the oxidation (CrO3-H2SO4-acetone) of the corresponding methyl O-benzyl-O-methyl-α-D-galactopyranosides having unsubstituted 6-OH groups to the corresponding (methyl O-benzyl-O-methyl-α-D-galactosid)uronic acids followed by the esterification with CH2N2 and catalytic hydrogenolysis of the benzyl groups.
- Grishkovets, V. I.,Zemlyakov, A. E.,Chirva, V. Ya.
-
p. 259 - 261
(2007/10/02)
-