Methyl 3-D-galactopyranoside

Pure methyl / -D-galactopyranoside (m.p. 177-180°C) may be isolated from the combined aqueous filtrates of these several crystallisations by removal of water and recrystallisation of the residue from absolute ethanol. 

The easily prepared 3,4-isopropylidene derivatives of the a and j3 methyl-D-galactopyranosides form the starting points of the synthesis.7,9 Methylation of either substance, followed by hydrolytic removal of first the isopropylidene and then the glycosidic methyl radicals leads to crystalline 2,6-dimethyl-D-galactose. Since the above mentioned syn-... 

This sugar is conveniently obtained by complete methylation of either the a- or /9-form of methyl D-galactopyranoside, followed by acid hydrolysis. Its constitution has followed from the fact that its oxida-... 

Methyl-D-galactopyranoside L -Methoxy-D-hydroxymethyl-diglycohc alclehyde 100% 34,136... 

Stereocontrolled lincomycin was synthesized from methyl - D galactopyranoside, I, of methyl thio -lincosa - minide, II, using the direct synthesis precursor to lincomycin (5). The off - pyranose stereocenters C - 6 and C - 7 were controlled by an intramolecular nitrogen delivery reaction using epoxy alcohol. 

For the current study the next question is how to choose a starting geometry, since an initial set of coordinates is needed for any QM calculation. Operationally, the simplest approach is to draw the structure of interest, in this instance starting with a 2,3,4,6-tetra-O-methyl-D-galactopyranoside, such as the methyl glycoside of either anomer and doing a simple MM optimization, which should find the 4Ci chair minimum. 

Fig. 13.—Separation of Methanolysis Products from Methylated Arabinogalactan of Maple Sap. (Key (1) methyl 2,3,5-tri-0-methyl-a, if-arabinofuranoside (2) methyl 2,5-di-0-methyl-a,)3-L-arabinofuranoside (3,4,5, and 6) not positively identified (7) methyl 2,4,6-tri-0-methyl-/3-D-galactopyranoside (8) methyl 2,4,6-tri-O-methyl-a-n-galaotopyranoside (9) methyl 2,4-di-O-methyl- D-galactopyranoside (10) methyl 2,4-di-O-methyl-a-D-galactopyranoside. Conditions 20% Apiezon M on Celite 545 (60-80 mesh) 150° 170 ml. of argon/min.)...

Similar methodology has been used for the synthesis of Bj (5) and B4 (6) from methyl D-galactopyranoside and methyl D-mannopyranoside, respectively. ... 

Carbohydrates (3-Methyl D-allopyranoside 2.4.6- tribenzoate, (3-Methyl D-glucopyranoside 2.3.6- tribenzoate, (3-Methyl D-galactopyranoside 2.3.6- tribenzoate. Pellosil HC Dichloromethane... 

Methyl -D-galactopyranoside (15) was rapidly acylated by ethyl butanoate in the presence of SP 435 to a mixture of the 6-mono-ester 16 and the 2,6- and 3,6- diesters 17 and 18, respectively (see Scheme 2). In the presence of zeolite CaA the di-esters were the sole products. 

Scheme 12.35. Deuterium exchange at C2, C3, and C4 positions in 1-O-methyl- -D-galactopyranoside.

The site of attachment to E. coli jS-D-galactosidase of the active site-directed inhibitor methyl 4-nitrophenyltriazine j3-D-galactopyranoside has been determined. When the enzyme was completely inactivated, 1 mole of the methyl D-galactopyranoside group was bound per mole of monomer with retention of the tetrameric structure. After reactions with the [ C]methyl version of the reagent, labelled peptides were isolated and analysed. The radioactive label was found to be covalently bound to L-methionine residue 500. 

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