D-Galactopyranose derivatives

Similarly, various a-D-glucopyranose derivatives having a mesyloxy group at C-4 and an acetoxyl group at C-l are also converted into 1,4-anhydro-/3-D-galactopyranose derivatives on treatment with sodium azide in such aprotic solvents as N,N-dimethylformamide.51 The use of sodium azide in N,N-dimethylformam ide under forcing conditions originated in attempts at nucleophilic displacements to form azido,... 

In contrast to that of glucose, the hydroxyl group at position 3 of D-galactopyranose derivatives is more reactive than that at position 2. Thus, tosylation160 of methyl 4,6-0-benzylidene-a(or -/8)-D-galactoside gives a preponderance of the 3-O-tosyl derivative admixed161-163 with a little of the 2-O-tosyl and 2,3-di-O-tosyl derivatives. 

T. Ziegler and G. Herold, Preparation of diastereomeric 3,4-O-pyruvate acetal-containing D-galactopyranose derivatives, structural assignment and use for oligosaccharide synthesis, Liebigs Ann. Chem., (1994) 859-866. 

Marra, A, Gauffeny, F, Sinay, P, A novel class of glycosyl donors anomeric S-xanthates of 2-azido-2-deoxy-D-galactopyranose derivatives. Tetrahedron, 47, 5149-5160, 1991. 

Mubarak, A, Fraser-Reid, B, Synthetic routes to 3-C-cyano-3-deoxy-D-galactopyranose derivatives,... 

A. M. Heras-Lopez, M. S. Pino-Gonzalez, F. Sarabia-Garcia, and F. J. Lopez-Herrera, Reaction of O-benzyl- and 4,6-benzylidene-D-gluco- and D-galactopyranose derivatives with amide-stabilized sulfur ylides, J. Org. Chem., 63 (1998) 9630-9634. 

Reductive cleavage (LiAlH -AlCl, NaCNBH -HCl, or AlCl -Me N) of 2-substituted l 6-anhydro-3 -0-endo-(M-methoxybenzylidene)-B-D-galactopyranose derivatives gave predominantly the axial 3-0 -(4-methoxybenzyl) ethers with a free -hydroxy group. -Methoxy... 

Reductive cleavage with lithium aluminium hydride-aluminium chloride, or with sodium cycloborohydride-hydrochloric acid, or with aluminium chloride-trimethylamine, of endo-3t4-0-(4-methoxybenzylidene) acetal rings of 1,6-anhydro- -D-galactopyranose derivatives gives predominantly the axial 3-0-(4-0-methoxybenzyl)ether derivatives. Oxidative cleavage with DDQ affords the axial 3-0-(4-inethoxybenzoyl)... 

The 2,4-di-C-methyl-D-galactopyranose derivative (16) has been rearranged to the furanose isomer (17) and hence to the derivative (18)(Scheme 4) required for the synthesis of an erythronolide ring fragment. 

Inch, T. D., and H. G. Fletcher, Jr. Synthesis with partially benzylated sugars. VI. Some solvolytic reactions of 2-acetamido-l-0-acyl-2-deoxy-D-glucopyranose and D-galactopyranose derivatives. J. Org. Chem. 31, 1810 (1965). 

Specifically C-6 deuterated D-galactopyranose derivatives have been shown by n.m.r. to have the 2. preferred rotamer state about... 

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