Monosaccharides anhydro sugars

Tables V-LVII detail H and F shift and coupling information, and Tables LVIII to LXXI incorporate the C-n.m.r. data. The data within this compilation are arranged according to the following outline hexoses prior to pentoses, followed by anhydro sugars, sugar acids and lactones, amino sugars (and their synthetic, A -containing precursors), mono-, di-, and tri-deoxy sugars, branched derivatives, ketoses, polyfluorinated monosaccharides, and, finally, difluorinated amino sugars. Within this compilation, and even within each table, pyranoid derivatives are listed prior to their furanoid counterparts, hexoses prior to pentoses, functionalized prior to deoxy compounds the arrangement within each sub-table is made alphabetically.

C-6,209,214 anhydro sugars,branched monosaccharides, fluori-nated amino sugars,difluorinated monosaccharides, and fluorinated monosaccharide phosphates,and phosphonates have been described. Further progress has been achieved in the synthesis and n.m.r.-spectral analysis of fluorinated avermectin Bu, tylono-lide, and neuraminic acid derivatives. " ... 

Spirocyclic derivatives 118 of pyranoses were prepared in moderate yields by tethering the succinimide on C-6 of the protected monosaccharide skeleton [24c]. The photochemical behavior of 1,6-anhydro sugars 119 [78e], 121 [78f), and 123 [78e] that bear the succinimide moiety in 2-, 3-, and... 

Among the anhydro sugar family of monosaccharides, 1,6-anhydro-sugars are the most common and are particularly suitable for highly stereoselective protection of the remaining three... 

These derivatives of the monosaccharide structural units are then qualitatively and quantitatively analyzed by gas chromatography on capillary columns. In more difficult cases, a preliminary separation of acidic and neutral polysaccharides on an ion exchanger is recommended. Methanolysis or hydrolysis of polysaccharides containing uronic acids and anhydro sugars are critical due to losses of these labile building blocks. 

It was stated earlier (p. 9) that internal etherification of monosaccharides yields anhydro-sugars. 1,2-, 2,3-(CC), 34-, and 5,6-epoxide rings, 2,4- and 3,5-propylene oxides (2,4-anhydro-D-glucose (CCI), and 3,5-anhydro-D-xylo-P3Tanose), and 1,4-, 2,5-, and 3,6- (CCII) butylene oxide rings are known. 

One trf the most popular methods of synthesizing anhydro derivative of monosaccharide containing a-oxide rings is the alkaline saponification sugar tosylates (5). We have studied the possibility of... 

Some other molecules generated in sugar pyrolysis, while maintaining the initial monosaccharide cycle, do not show any stereoisomers. This is the case for 1,4-dideoxy-D-glycero-hex-1-enopyranos-3-ulose (1-hydroxymethyl-5-hydroxy-2,3-dihydropyranone) and for 1,6-anhydro-3,4-dideoxy-D-glycero-hex-3-enopyranos-2-ulose (levoglucosenone) (showing C-H bonds) ... 

Synthesis. - In a theoretical study on die aBi dation and esterification of monosaccharides, the reactions of 1,6-anhydrO P-D-galactopyranose under diase transfer conditions have been conadered. A MNDO-PM3 study on the sdective activation of 1-0-methoxyacetyl sugars by Zn(II) or Y(in) ions endeavours to explain why 1-0-methoxyacetates are the best donOTs among glycosyl-esters in Lewis add-promoted glycoqiations. ... 

Recent work by Calvin and co-workers and by Horecker et al. have demonstrated the importance of sedoheptulose in the photosynthetic cycle of the carbohydrates as being a transitory intermediate in the regeneration of D-erythropentulose, the monosaccharide involved in the fixation of carbon dioxide . This sugar also plays a part in animal carbohydrate metabolism. Its most characteristic chemical property is its ready conversion into sedoheptulosan.(2,7-anhydro-j8-D-altroheptulopyranose (LVII). 

There are a number of well-known colour tests for monosaccharides, such as condensation of the acid degradation products with phenolic substances. Perhaps the most frequently cited example of this is the Molisch test in which carbohydrates give a purple colour with a-naphthol in the presence of concentrated sulphuric acid. The presence of ketoses and of 3,6-anhydro-hexoses is often detected by the characteristic red colour rapidly developed with acid resorcinol (Seliwanoff test), and the presence of 2-deoxypentoses may be shown by the deep blue colour they yield with diphenylamine after degradation with acid to 5-hydroxy-levulinaldehyde. Before an individual sugar can be identified, however, it must be isolated as a pure substance in crystalline form or converted to a characteristic crystalline derivative. The derivative the author considers the best for the characterisation of the better known monosaccharides is given in Table I (p. 57). 

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