Question

Define the term anomeric carbon. In glucose, which carbon is the anomeric carbon?

Short answer

Answer: The anomeric carbon in glucose is the first carbon atom (C1). It is formed when the carbonyl carbon in the straight-chain form of glucose becomes a chiral center during the formation of a cyclic hemiacetal structure. This results in two possible configurations: α-D-glucopyranose and β-D-glucopyranose.

Step-by-step solution

Understanding anomeric carbon

Anomeric carbon is the carbonyl carbon atom (C=O) that becomes a chiral center (an asymmetric carbon atom) when the carbonyl group is converted to a hydroxyl group (-OH) during cyclic hemiacetal or hemiketal formation in carbohydrates. In simple words, it is the stereocenter formed when a cyclic carbohydrate is formed.

Identifying the anomeric carbon in glucose

Glucose is a common monosaccharide with the molecular formula C6H12O6. In its straight-chain form, the carbonyl group is an aldehyde, and this makes glucose an aldose. When glucose forms a cyclic structure, the carbonyl carbon (C1) in the aldehyde group becomes a chiral center with two possible configurations (α-D-glucopyranose and β-D-glucopyranose). Therefore, the anomeric carbon in glucose is the first carbon atom (C1).