Question

Explain what is meant by the pyranose structure of glucose.

Answer 1

Hint:The pyranose is the chemical structure which contains six membered rings where five carbon atoms are present and one oxygen atom is present. The pyranose structures are seen in saccharides.

Complete step by step answer:The pyranose ring of glucose is formed by reacting the hydroxyl group present in the fifth position of carbon (C-5) of the glucose molecule with the aldehyde group attached to the first position of the carbon (C-1) of the same glucose molecule. This results in the formation of intramolecular hemiacetal molecules.
The name pyranose is taken from the heterocyclic compound containing an oxygen atom with five carbon atoms forming a cyclic structure known as pyran.
The structure of the pyranose ring of glucose is shown below.

In this pyranose ring structure of glucose, five carbon atoms are present and one oxygen atom is present forming a six membered ring structure.
There are a total 38 conformation structures of pyranose ring, 2 chair form, 6 boats form, 6 skew boat form, 12 half-chairs form and 12 envelopes forms.

Note:When the hydroxyl group present on the fourth position of the carbon (C-4) of the glucose molecule reacts with the aldehydic group present in the first position of carbon (C-1) of the same glucose molecule then furanose is formed. In furanose, four carbon atoms and one oxygen atom are present forming a five membered cyclic furanose ring. The pyranose ring is thermally more stable than the furanose ring.