alphaallopyranose

Alphaallopyranose is a stereoisomer of glucose, specifically an epimer at the C-2 position. This means that at the second carbon atom of the pyranose ring, the hydroxyl group is oriented in the opposite direction compared to alpha-glucose. Alphaallopyranose is an aldohexose and exists in a six-membered ring structure, the pyranose form, which is favored due to its stability. Like other pyranose sugars, it exhibits mutarotation in aqueous solution, interconverting between the alpha and beta anomers, and also exists in equilibrium with its open-chain form.

While alpha-glucose is a fundamental component of many natural carbohydrates like starch and cellulose, alphaallopyranose is much less common in biological systems. It is not a primary building block for major polysaccharides. However, it can be found as a component in certain rare or specialized glycoconjugates and can be synthesized in laboratories for research purposes. Its chemical properties are similar to other hexoses, undergoing reactions typical of aldehydes and alcohols. The presence of the inverted hydroxyl group at C-2 influences its reactivity and its ability to form glycosidic bonds, which can differ from those formed by glucose.