Mannoside methyl 2,3-anhydro

Structure and Reactivity of Anhydro-sugars. Part I. Branched-chain Sugars. Part I. Action of Di-ethylmagnesium on Methyl 2 3-Anhydro-4 6-0-benzylidene-a-D-mannoside, A. B. Foster, W. G. Overend, M. Stacey, and G. Vaughan,/. Chem. Soc., (1953) 3308-3313. 

Shortly after the above work appeared, Bolliger and Prins90 reported a similar synthesis leading to a 3- rather than a 2-desoxy derivative. Methyl 2,3-anhydro-4,6-benzylidene-a-D-mannoside (LXIV), upon treatment with sodium thiomethoxide, was converted into methyl 3-methyl-thio-4,6-benzylidene-a-D-altroside (LXV) which, after desulfurization and rebenzylidenation, gave methyl 3-desoxy-4,6-benzylidene-a-D-man-noside (LXVI). Methylation of LXV with methyl iodide and silver oxide followed by desulfurization gave methyl 2-methyl-3-desoxy-4,6-benzylidene-a-D-mannoside in poor yield. 

In the field of sugar chemistry Foster and co-workers5 0 have found that diethylmngneeiiim adds to Cia) of methyl 4,6-0-ben2ylidene-2,3-anhydro-a-o-mannoside (Eq. 797), and Richards145 has observed C attack with methyl 4,6-0-benzylidene-2r3-anhydro- -l>-aUo6jde and diphenylmagncsi um (Eq. 798). 

With methyl 2,3-anhydro-4,6-benzylidene-a-D-mannoside (LI), cleavage of the anhydro ring by this method results in the formation of methyl 4,6-benzylidene-3-methylthio-3-desoxy-a-D-altroside (LII) in practically quantitative yield. Reductive desulfurization gave methyl 4,6-benzyli-dene-3-desoxy-a-D-altroside (LIII)170 171 since under the conditions used only slight debenzylidenation occurred. 

Myers and Robertson, and Robertson, Myers and Tetlow, have reported a synthesis of methyl epiglucosamine starting with methyl 2,3-anhydro-4,6-benzylidene-a-D-mannoside (XLIII). By opening the ethylene oxide ring with ammonia they obtained a crystalline product, of m. p. 188° and - -88.9° in chloroform, which was a mixture of... 

According to Irvine and Hynd, the deamination of methyl 2-deoxy-2-(dimethylamino)-D-glucopyranoside with a hot solution of barium hydroxide provides methyl n-glucoside. The effect of conformation on the nitrous acid deamination of amino hexoses is further illustrated by the reaction of methyl 3-amino-4,6-0-benzylidene-3-deoxy-a-D-altropyrano-side (LXVII) which, on deamination with nitrous acid, provides a quantitative yield of methyl 2,3-anhydro-4,6-0-benzylidene-a-D-mannoside (LXVIII). The deamination of methyl 3-amino-3-deoxy-)8-D-altropy-ranoside, methyl epiglucosamine, gives a sirupy mixture. Similar treatment of methyl 2-amino-4,6-0-benzylidene-2-deoxy-a-D-altroside... 

The first preparation of a 4,6-dimethyl ether of 2-amino-2-deoxy-D-glucose was reported by Haworth, Lake, and Peat. Action of ammonia on methyl 2,3-anhydro-4,6-di-0-methyl-j3-D-mannoside, followed by N-acetylation of the product, led to the formation of methyl 3-acetamido-3-deoxy-4,6-di-0-methyl- S-D-altroside (in high yield) and of methyl 2-acetamido-2-deoxy-4,6-di-0-methyl- S-D-glucoside (in a 9.4% yield). Methylation of the latter compound yielded a 3,4,6-trimethyl ether identical with the one prepared from natural n-glucosamine. ... 

By contrast, phenyl a-D-mannopyranoside under the same conditions gives only methyl a-D-mannopyranoside. It was suggested that neighboring group participation from the 2-oxygen atom produces 1,2-anhydro-D-mannopyranose, which then reacts with methoxide ion to give the methyl mannoside.219... 

Selective benzoylation (and allylation) of methyl (and benzyl 4-O-benzyl-a-L-rhamnopyranoside (4) has been studied by phase-transfer catalysis and by activation via the tributyl stannate. The former reaction gave the 2,4-dibenzyl ether (5) in high yield, whereas the latter process gave mainly the 3,4-diether (6). An alternative means of obtaining the 2,4-diether (5) involved selective tritylation to give (7) followed by benzylation and removal of the trityl group. These dibenzyl ethers have been employed in the synthesis of the tetrasaccharide repeating unit of the immunodeterminant of Klebsiella serotype K36 polysaccharide. Similar results have been recorded for the selective benzylation of other 4,6-blocked a-mannosides. The syntheses of 3-O-benzyl-D-ribose, 2-0-benzyl-D-ribose, and l,6-anhydro-2,3,2, 4-tetra-0-benzyl-jS-lactose have been recorded. The latter was employed in the synthesis of lacto-A -tetraose. ... 

Methyl mannoside Mannosaminitol JV-Acetylmannosamine -Acetylmannosaminitol Anhydro Mannitol Deoxy... 

C2fiH2iBr07, Tri-0-benzoyl-/3-D-xylopyranosyl bromide, 40B, 402 C26H21CIO7, 2,3,4-Tri-0-benzoyl-j3-D-xylopyranosyl chloride, 42B, 336 C26H21FO7, 2,3,4-Tri-O-benzoyl- -D-xylopyranosyl fluoride, 45B, 478 C26H22O7 r 1f5-Anhydro-2,3,4-tri-0-benzoylribitol, 45B, 480 C26H22O7 r 1,5-Anhydro-2,3,4-tri-0-benzoylxylitol, 45B, 480 C26H2sNaOft, Methyl 4,6-0 benzylidene-2,3-dideoxy-2,3-diphenylazo-a-D-mannoside, 44B, 413... 

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