Studies in the Acid Catalysed Glycosylation of α-Tocopherol

Abstract

Condensation of α-tocopherol and 2,2,5,7,8-pentamethyl-6-hydroxychroman (the model compound) with peracetylated glucose, mannose and galactose was carried out. The influence of various acidic catalysts on the chemical yield and the stereochemical outcome of the glycosylation was investigated.

Combination of ionic liquid [bmim]PF6 with boron trifluoride etherate as an efficient catalytic system for the glycosylation of α-tocopherol and naphthotocopherol

“…UV (EtОН), λ max /nm (ε): 288 (1786). IR and 1 Н and 13 С NMR spectra are in agreement with those described 6. (R,S) Naphthotocopheryl 2,3,4,6 tetra О acetyl ββ β β β D glu copyranoside (8), [α] D 20 +2.8 (с 1.00, CH 2 Cl 2 ).…”

“…There fore, the yields of β glycosides were low or they partially isomerized to α anomers. 6 When acetylated sugars were used as the glycosyl donors, boron trifluoride etherate turned out to be the most efficient catalyst out of those studied, 5,6 however, acetates of α anomers of D gluco and D galactopyranoses did not enter the reaction.…”

“…21 An increase in polarity of the solvent and ionic strength of the solution results in accel eration of the reaction, 21-23 which, obviously, is favored by the ionic liquid. In addition, ionic liquid [bmim]PF 6 considerably increases the catalytic activity of BF 3 •OEt 2 , 12 and its anion (hexаfluorophosphate) stabi lizes ions B and С.…”

Phenyl galactopyranosides – 13 C CPMAS NMR and conformational analysis using genetic algorithm

“…Phenyl O-galactosides 1-4 were prepared accordingly to the commonly known procedure [28][29][30] starting from a mixture a/b peracetylated galactose in a yield 65-70%. The fraction of pure aand b-anomers 1 and 3 were obtained by column chromatography (hexane-ethyl acetate 15:1, v/v) performed on Merck silica gel (70-230 mesh).…”

Partition of tocopheryl glucopyranoside into liposome membranes studied by fluorescence methods

“…Enhanced physiological activity is expected from synthesized tocopherol derivatives, whose physiological activity of vitamin E is enabled by the enzymatic hydrolysis of the glycoside bond. The reported attempts to obtain readily hydrolysable derivatives include the synthesis of various tocopherol glycosides [5][6][7][8][9][10] by introducing a sugar group at C-6 position of the chromanol ring. Contrary to the expectations, some tocopheryl glycosides prove resistant to hydrolysis; however, some other types of physiological activity were observed in these compounds [5,11].…”