Haworth projections are more realistic than the Fisher projections, but you should be able With all its bulky substituents (OH and CH 2OH) in equatorial positions, which probably accounts for its widespread b -D-glucopyranose is the only aldohexose which can be drawn With substituents above or below the ring) or the more plausible bent forms (showing Glc in the chair or boat conformations,įor example). Sugars can be drawn in the straight chain form as either Fisher projections or perspective structuralĬyclic forms can be drawn either as the Haworth projections, which shows the molecule as cyclic and planar However, in polysaccharides, Glc is exclusively pyranose and fructose and ribose are furanoses. Glucose (Glc) is mostly in the pyranose form, fructose is 67% pyranose and 33% furanose, and ribose is 75% furanose and 25% Monosaccharides in solution exist as equilbrium mixtures of the straight and cyclic forms. On nucleophilic attack to form the ring, the carbonyl O becomes an OH which pointsĮither below the ring ( a anomer) or above the ring ( b anomer). The resulting rings are labeled furanose (5 member) or pyranose (6 member) based
Occur if stable 5 or 6 member rings can form. Intramolecular nucleophilic attack of one of the OH's on the carbonyl C of the aldehyde or ketone. It and other 5 and 6C sugars can cyclize through
Glucose, an aldo-hexose, is a central sugar in metabolism. The most common are the aldo- and keto-trioses, tetroses, pentoses, and hexoses. Hence the simplest sugars contain at least Sugars can be defined as polyhydroxy aldehydes or ketones. Carbohydrate Chemistry and Glycobiology: A web tour
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