Carbon monosaccharide derivatives

Disacchandes are carbohydrates that yield two monosaccharide molecules on hydroly SIS Structurally disaccharides are glycosides m which the alkoxy group attached to the anomeric carbon is derived from a second sugar molecule... 

This section relates to the introduction of a double or triple bond between two contiguous carbon atoms of the backbone chain of a monosaccharide derivative. A double bond between a carbon atom of the backbone chain and an atom outside that chain, or a double or triple bond between two carbon atoms outside the backbone chain, will be treated according to the normal rules of organic nomenclature [13,14],... 

Note 1. The term glycal is a non-preferred, trivial name for cyclic enol ether derivatives of sugars having a double bond between carbon atoms 1 and 2 of the ring. It should not be used or modified as a class name for monosaccharide derivatives having a double bond in any other position. 

Vicinal proton-carbon coupling constants in a series of conformationally rigid monosaccharide derivatives showed a satisfactory dependence of upon the torsion angles (2). The... 

Another way of getting substantially the same result is based upon a homonuclear experiment to saturate selectively the chosen resonance under proton decoupled conditions. (202) The spectrum is again acquired under fully coupled conditions and thus is a complete coupled spectrum except that the multiplet from the saturated site is absent. This spectrum is subtracted from a normal fully coupled one to yield a trace that contains only the multiplet from the desired carbon. Full fine structure is displayed. Figure 27 shows the application of this method to the spectrum of the monosaccharide derivative... 

Jarosz, S, Salanski, P, Mach, M, Application of stabilized sugar-derived phosphoranes in the synthesis of higher carbon monosaccharides. First synthesis of a C-21-dialdose, Tetrahedron, 54, 2583-2594, 1998. 

Condensation of syn- or anti-27 with hydrazine afforded new pyrazole derivatives 28 with a stereodefined and protected amino diol side chain [64]. The preparation of push-pull substituted unsaturated monosaccharide derivatives and their use in the synthesis of nucleoside analogs have been reviewed [65]. Thus, the 2-formyl pentose glycals were transformed to the corresponding acyclo-C-nucleosides 29 [66]. Similarly, the benzy-lated 2-formylglycals reacted with hydrazine derivatives to afford the substituted l,2,4-tri-0-benzyl-lC-(lH-pyrazol-4-yl)-D-tetritols the deprotection of which was achieved with Pd/H2 to yield the lC-( 1-methyl-lH-pyrazol-4-yl)-D-tetritols [67]. 3-0-Benzyl-6-deoxy-l,2-0-isopropylidene-o -D-xylo-hept-5-ulofuranurono-nitrile was reacted with f, N-dimethylformamide dimethyl-acetal in THF to furnish the (E)-3-0-benzyl-6-deoxy-6-dimethyl-aminometh-ylene-l,2-0-isopropylidene-Q -D-xylo-hept-5-ulofuranurono-nitrile as a major product, and on treatment with carbon disulfide and methyl iodide under basic conditions afforded 3-0-benzyl-6-deoxy-l,2-0-isopropylidene-6-[bis(methylsulfanyl)methylene]-a-D-xylo-hept-5-ulofuranurono-nitrile. Further reaction with hydrazines yielded the reversed pyrazole-C-nucleoside analogs [68]. 

Sinay s group have used silicon tethering to facilitate radical addition reactions for construction of C-disaccharides. Thus, 166, prepared by reacting the constituent monosaccharide derivatives with BuLi and dichlorodimethylsilane, undergoes radical reaction (AIBN) followed by cleavage of the silyl tether (TBAF) to provide C-disaccharide 167 (see also Chapter 3) which is related to the carbon skeleton of the herbicidins." ... 

New drugs to treat influenza were developed based on an understanding of the oligosaccharide structure on the surface of the virus. The key player is A -acetylneuraminic acid which is the A -acetyl derivative of a nine-carbon monosaccharide. A -Acetylneuraminic acid is part of the cell-surface glycoprotein that is recognized by an invading influenza virus (Figure 23.14). 

Fig. 8 0 C vs F C ratio for a range of carbohydrate-derived chcanicals and derivatives thereof. Feedstocks highlighted in green box. Cx resp. x-carbon monosaccharide...

---