Heptose synthesis

However, the main biochemical applications of heptose synthesis have been directed toward the study or the inhibition of the bacterial heptose biosynthetic pathways. 

Scheme 5.72 Preparation of modified 1,6-anhydromannosides and their use in the synthesis of heptose-containing oligosaccharide.

Fig. 40 Baylis-Hillman reaction as a key step in the synthesis of heptoses.

The synthesis shown in Fig. 40 provided access to heptoses,55 but according to our definition, this is not a higher sugar synthesis. However, the approach to such derivative was based on the Baylis-Hillman reaction of acyclic sugar-derived aldehydes, a reaction not commonly applied in sugar chemistry and worth to mention in this review. 

Omori T (1996) Substitution Reactions of Technetium Compounds. 176 253-274 Oscarson S (1997) Synthesis of Oligosaccharides of Bacterial Origin Containing Heptoses, Uronic Acids and Fructofuranoses as Synthetic Challengers. 186 171-202 Ostrowicky A, Koepp E, Vogtle F (1991) The Vesium Effect Synthesis of Medio- and Macrocyclic Compounds. 161 37-68 Otsuji Y,see Mizuno K (1994) 169 301-346 Pdlinkd I, see Tasi G (1995) 174 45-72... 

Synthesis of Oligosaccharides of Bacterial Origin Containing Heptoses, Uronic Acids and Fructofuranoses as Synthetic Challenges... 

Scheme 1) whereas the reaction with the D-man/io-hexodialdo-l,5-pyranose derivative 3 produced, in low yield, the cyanohydrin 4 having an L-glycero-D-manno configuration and the stereoisomeric epimer at C-5, rather than at C-6 [14J. With an atm toward the synthesis of d- and L-glycero-D-manno-heptoses, the reaction of 3 with other reagents (2-inethyl-furan, alkyl magnesium chlorides) was also explored, without any substantial improvement of either stereoselectivity or yield. 

M. Dasser, F. Chretien, and Y. Chapleur, A facile and stereospecific synthesis of L-glycero-D-manno-heptose and some derivatives, J. Chem. Soc. Perkin Trans. 7 3091 (1990). 

P. Duchaussoy, P. Di Cesare, and B. Gross, Synthesis of sugars containing the dihalocyclo-propane moiety A new access to the heptose series, Synthesis p. 198 (1979). 

Synthesis of a Heptose Disaccharide Building Unit for Synthetic Bacterial Lipopolysaccharide Antigens [49]... 

In Section III, the synthesis of ethyl 3,4-di-0-benzyI-2-deoxy-6,7-0-isopropylidene-a-L-ga/acro-heptose demonstrates the preparative details of the method. 

C. Berlind and S. Oscarson, Synthesis of a branched heptose- and Kdo-containing common tetrasaccharide core structure of Haemophilus influenzae lipopolysaccharides via a l,6-anhydro-L-g7ycero-/i-D-/Kanno-heptopyranose intermediate, J. Org. Chem., 63 (1998) 7780-7788. 

Omori T (1996) Substitution Reactions of Technetium Compounds. 176 253 - 274 Oscarson S (1997) Synthesis of Oligosaccharides of Bacterial Origin Containing Heptoses, Uronic Acids and Fructofuranoses as Synthetic Challengers. 186 171-202... 

Here the synthesis led to an o-galaheptose (amorphous) and from it a galaoctose (crystalline) was prepared. Many years later the a-gala-heptose was crystallized. The 8-galaheptose crystallized in Fischer s research, and the epimeric character of the two galaheptoses was made highly probable by his interconversion of their aldonic acids on heating with aqueous pyridine. 

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