Octose

Octose

Octose is a term used to describe a monosaccharide with eight carbon atoms. It is a type of sugar that falls under the category of aldoses or ketoses, depending on the position of the carbonyl group. Octoses are less common than other monosaccharides such as hexoses and pentoses.

Structure

Octoses have the chemical formula C₈H₁₆O₈. They can exist in both linear and cyclic forms, similar to other monosaccharides. The linear form of an octose can be represented as a straight chain of eight carbon atoms, with hydroxyl groups (-OH) attached to each carbon except for the one that forms the carbonyl group.

Aldo-octoses

Aldo-octoses have an aldehyde group at the first carbon atom. The general structure of an aldo-octose can be represented as:

 H-(CHOH)₇-CHO

Keto-octoses

Keto-octoses have a ketone group, typically at the second carbon atom. The general structure of a keto-octose can be represented as:

 H-(CHOH)₆-CO-CH₂OH

Stereochemistry

Octoses, like other sugars, exhibit stereochemistry due to the presence of multiple chiral centers. Each carbon atom that is bonded to four different groups is a chiral center, leading to a variety of stereoisomers. The number of possible stereoisomers for an octose is 2⁶, or 64, due to the presence of six chiral centers.

Biological Significance

While octoses are not as prevalent in nature as other sugars, they can be found in certain biological systems. They may play roles in specific metabolic pathways or be components of complex carbohydrates.

Synthesis

Octoses can be synthesized through chemical methods, such as the Kiliani-Fischer synthesis, which involves chain elongation of smaller sugars. This process can be used to study the properties and potential applications of octoses in various fields, including biochemistry and pharmacology.

Applications

Research into octoses is ongoing, with potential applications in the development of new pharmaceuticals and as building blocks for complex carbohydrates. Their unique structure and properties make them of interest in the study of carbohydrate chemistry.

Also see

• Monosaccharide
• Carbohydrate
• Hexose
• Pentose
• Aldose
• Ketose