2,4-Di-O-methyl-a-D-galactopyranose

C8H18O7, 2,4-Di-O-methyl a-D-galactopyranose monohydrate, 40B, 390 C9H1iNOg, 3-(p-D-Ribofuranosyl)-3-pyrroline-2,5-dione, 35B, 260 C9H14IN3O4, 6-A2ido-5,6-dideoxy-5-iodo-1,2-0-isopropylidene-/5-L-ido-furanose, 35B, 262... 

Di-Me 2-Amino-2-deoxy-3,4-di-O-methyl-a-D-galactopyranose CgHivNOs 207.226 [a]o +108 (H2O) (as hydrochloride). 

Other galactoconjugate porphyrins 55-59 have also been prepared from porphyrinic carboxyhc esters [95]. For example, the esters 50-54 achieved transesterification processes when treated with methyl lithivun and 1,2 3,4-di-O-isopropylidene-a-D-galactopyranose (Scheme 8). The deprotected compounds 55a-59a have been obtained, as mixtures of a and p anomers, in excellent yields (92-98%). 

From the 1940 s to the 1960 s, the acryloyl group was induced directly to the hydroxyl group of monosaccharide protected by isopropylidene or benzylidene such as methyl 2,3-di-O-acryloyl 4,6-benzylidene glucoside 1 (//), l,2 3,4-di-0-isopropylidene- 6-O-acryloyl a-D-galactopyranose 2, 6-0-... 

Di-0-cyclohexylidene-a-D-mannopyranosyl chloride, M-42 1,2 5,6-Di-0 -cyclohexylidene-3- O -mesyl-a-D-allofuranose, C-189 l,2 5,6-Di-0-cyclohexylidene-3-C-methyl-a-D-allofuranose, C-189 1,2 3,4-Di-0 -cyclohexylidene-6- O -tosyl-a-D-galactopyranose, G-193 1,2 5,6-Di-0 -cyclohexylidene-3-O -tosyl-a-D-glucofuranose, C-190 l,2 5,6-Di-0-cyclohexylidene-3-C-vinyl-a-D-allofuranose, C-189 l,2 3,5-Di-0-cyclohexylidene-a-D-xylofuranose, C-191 l,2 3,5-Di-(9-cyclohexylidene-a-L-xylofuranose, C-191 Didanosine, D-548 4a,106-Didehydrobergenin, B-29 4, 5 -Didehydro-5 -deoxycytidine, D-333 2, 3 -Didehydro-3 -deoxytliymidine, S-76 4, 5 -Didehydro-5 -deoxyuridine, D-549... 

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. 

Di-O-benzyl-D-galactal was the main product of the dimolar benzylation of d-galactal with benzyl bromide, whereas 3,6-di-O-benzyl derivative was obtained with benzyl chloride from l,2,0-(l-methoxyethylidene)-ot-D-galactopyranose in 56% yield [61]. Reexamination of the results of partial benzylation [62] of methyl 4,6-0-benzylidene-a-D-mannopyranoside revealed [33, 63] that the 2-benzyl ether is in fact the dominant product, with the 2- to 3-ratio of 1.86 1. Approximately equal proportions of monobenzyl derivatives have been obtained from l,2-0-isopropylidene-3,6-di-O-allyl-wjo-inositol [64],... 

RX. n-butyl bromide n-dodecanyl iodide cyclohexyl iodide ethyl bromo acetate methyl 2,3-di-O-acetyl-4-O-benzoyl-6-bromo-6-deoxy-ot-D-glucopyranoside methyl 2,3,4-tri-0-acetyl-6-deoxy-6-iodo-0 -D glucopyranoside l,2 3,4-di-0-isopropylidene-6-deoxy-6-iodo-a-D-galactopyranose methyl 2(R)-[(tert-butoxycarbonyl)amino]-3-iodo-propionate cyclic bis(trifluoromethyl)oxazolidinone bromide. 

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