Glucosides methylation

The acid-catalyzed methylation of glucose with methanol to give two distinct glucosides, methyl a-D-glucoside and methyl /3-D-glucoside, corresponds to displacement of the hemiacetal hydroxyl by methoxyl to form an acetal (see left side of Figure 20-4). 

Methyl 4,0-O-benzylidene-3-O-methyl-2-O-tosyl-a-D-glucoside Ethyl 2,3,0-tri-O-methyl-6-O-tosyl-a-D-glucoside Methyl 2,3,0-tri-O-methyl-5-O-tosyl-a-D-glucoside Methyl 2,3,0-tri-O-methyl-5-O-tosyl-/3-D-glucoside... 

The synthesis of the partially methylated glucoside, methyl 2,3-di-O-methyl-a-D-glucopyranoside (34) (Expt 5.121) also utilises the 4,6-O-benzylidene derivative (27), which is first converted into the 2,3-di-O-methyl derivative (33) by reaction with dimethyl sulphate in the presence of sodium hydroxide. Selective removal of the acetal grouping is achieved by mild acid hydrolysis the methyl ether groups are stable under both acidic and basic conditions. 

Activity on gentibiose (P-l,6-glucoside), methyl- 3-gluco-side, p-nitrophenyl-P-xyloside, salicin, maltose, sucrose, lactose, xylan (1.0% [w/v]), Avicel (1.0% [w/v]), or carboxy-methylcellulose (1.0% [w/v]) was <1.0% of that on pNPG. 

Glucose-5,6,6 -da, a-D-, nuclear magnetic resonance spectrum of, 45 (8-D-Glucosidase, 212 Glucoside, methyl 4,6-O-benzylidene-a-D-, 0X0 reaction with, 107 —, mediyl 4,6-0-benzylidene-/3-D-, oxo reaction with, 107... 

Synonyms 2-Hydroxymethyl-6-methoxytetrahydropyran-3,4,5-triol a-Methyl-D-glucoside Methyl-a-d-glycopyranoside ClassiTication Nonaromatic alcohol Empirical C,H 06... 

Lactone Methyl ester Methyl glucoside Methyl glucoside-methyl ester Methyl glucoside-lactone Glucaric acid Lactone... 

Hexamethylenetetramine Hydrogen peroxide Isophthalic acid Itaconic acid Meroxapol 105 Meroxapol 171 Meroxapol 172 Meroxapol 174 Meroxapol 252 Meroxapol 254 Meroxapol 258 Meroxapol 311 4,4 -Methylenedianiline a-Methyl glucoside Methyl oleate Methyl stearate a-Methylstyrene monomer Neopentyl glycol Nitroethane Nonanoic acid Oleic acid Pentaerythrityl triallyl ether Phosphorus trichloride Polypropylene glycol Propionaldehyde Pyromellitic acid Pyromellitic dianhydride... 

Disodium tallowiminodipropionate Isostearyl palmitate Lauramidopropyl PEG-dimonium chloride phosphate Laureth-7 Lauroampho PEG-glycinate phosphate Lauryl glucoside Methyl-p-cyclodextrin Methylpropanediol Myristyl myristate Oleth-10... 

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