Mannoside methyl 2,3-anhydro-4,6-0-benzylidene

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... 

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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