Glucofuranose 3,5 - 0 - methylene

Schmidt, Distelmaier, and Reinhard later applied the same oxidation technique to the elucidation of the structure of a di-O-methylene-D-glucose. After mono-O-acetylation, the derivative was oxidized at 95° by potassium permanganate, in dilute phosphoric acid, to give 6-0-acetyl-3,5-0-methyl-ene-D-glucofuranose 1,2-carbonate, the structure of which was subsequently proved. 

However, even with primary substrates byproduct formation via elimination and substitution by the solvent (e.g., ethylene glycol or methanol) is a common side reaction. For example, treatment of 1,2 3.5-di-0-methylene-6-0-tosyl-a-D-glucofuranose (5) with anhydrous potassium fluoride in boiling ethylene glycol for three minutes gives a mixture of 6, 7 and... 

The glucose analog, 3-deoxy-3-C-methylene-D-nfco-hexose (102) is a substrate of a D-xylose isomerase. The efficient synthesis from 3-deoxy-3-C-methylene-glucofuranose (101 prepared by the classical method according to [92]) was described recently (O Scheme 44) [93]. 

On the other hand, diacetone D-glucose was transformed to (-)- and (+)-sesbanimide A via the open chain derivative 3-0-benzyl-D-glucose diethyldithioacetal 17, which was prepared by hydrolysis of 3-C -benzyl-l,2 5,6-di-C -isopropylidene-D-glucofuranose (16) and subsequent treatment with ethanethiol in the presence of acid (Scheme 3)4 Acetonation of 17 under kinetic control followed by methylenation with dibromomethane afforded the key intermediate 1,3-dioxane 18. Deprotection of the dithioacetal unit in 18 followed by... 

Methylene acetals of aldoses are distinctly more stable than the other acetals. For the complete hydrolysis of 6-0-methyl-l,2 3,5-di-0-meth-ylene-a-D-glucofuranose, treatment with N sulfuric acid at 110-20° for 5 hours was required. " By contrast, the isopropylidene groups in 1,2 5,6-di-O-isopropylidene-a-D-glucose and in di-O-isopropylidene-L-xylose were removed using 0.1 iV sulfuric acid at room temperature for 2 to 6 hours. ... 

Bromo-6-deoxy-l,2 3,4-di-0-isopropylidene-a-D-galactopyranose, B-72 6-Bromo-6-deoxy-l,2 3,4-di-0-isopropylidene-a-L-galactopyranose, B-72 6-Bromo-6-deoxy-1,2 3,5-di- O -isopropylidene-a-D-glucofuranose, B-76 6-Bromo-6-deoxy-l,2 3,5-di-0-methylene-a-D-glucofiiranose, B-76... 

Deoxy-3-fluoro-l,2 5,6-di-0-isopropylidene-a-D-glucofuranose, D-89 6-Deoxy-6-fluoro-l,2 3,5-di-0-methylene-a-D-glucofuranose, D-92... 

Deoxy-1,2- O-isopropylidene-3,5-di- O -mesy 1-a-D-glucofuranose, D-283 6-Deoxy-l,2-0-isopropylideneglucofuranose d-D-form, D-283 6-Deoxy-2,4-0-methylene-D-glucitol, D-127 6-Deoxy-2,4-0-methylene-L-glucitol, D-127 6-Deoxy-3-0-methyl-D-glucose, D-142... 

Access to 6-deoxy-D-glucose is obtainable through l,2 3,5-di-0-methylene-6-C>-toluene-p-sulphonyl-a-D-glucofuranose which was reduced in high yield to the 6-deoxy compound with lithium triethyl borohydride, and 6-deoxy-o-a//ro-heptose was made as outlined in Scheme 5. The catalytic hydrogenation... 

The 2-, 3-, and 6-0-(2-hydroxyethyl) ethers of o-glucose have been obtained by way of treatment of appropriately protected derivatives (e.g. l,2 3,5-di-0-methylene-a-D-glucofuranose) with sodium and then with 2-bromoethanol. Allyl 3-0-benzyl-4,6-0-benzylidene-o -D-glucopyranoside has been used as the starting material in preparations of 2-0-allyl-3,4,6-tri-0-benzyl-D-gluco-pyranose and 2-0-allyl-3,4-di-0-benzyl-D-glucopyranose, the l-(4-nitrobenzoates) of which are potential intermediates for the synthesis of glycolipids that occur in the cytoplasmic membranes of Streptococci. Allyl ethers can be cleaved on... 

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