Anomer

As anomers are in carbohydrates and other glycosides a special kind of isomers - or more precisely diastereomers - denotes that differ only in the configuration at the anomeric center.

The anomeric carbon atom is a chiral center is formed during the formation of the cyclic half or Vollacetals / ketal of a carbohydrate from the prochiral carbonyl carbon of the open-chain form. It is the ring oxygen of sugars adjacent ( in the pyranose or furanose form). The resulting diastereomers are called anomers.

The configuration at the anomeric center described α and β by the stereodescriptors, wherein the α -anomer is the one isomer in which the absolute configuration is in accordance with the CIP rules of the anomeric carbon atom of the configuration of the reference atom, which höchstbezifferten chiral center, opposite. This definition applies to both D-and L- sugars. The hydroxy group of the anomeric center is in the Fischer projection of the D- carbohydrates on the same side as the main chain, the hydroxyl group of the reference atom. Accordingly, in β - anomers of the reference atom is the hydroxy group of the D- carbohydrates on the opposite side of the main chain.