question_answer

Direction (1 - 5): Glucose \[\left( {{C}_{6}}{{H}_{12}}{{O}_{6}} \right)\] contains six carbon atoms and an aldehyde group and is therefore referred to as an aldohexose. The glucose molecule can exist in an open- chain (acyclic) and ring (cyclic) form (in equilibrium), the latter being the result of an intramolecular reaction between the aldehyde C atom and the C-5 hydroxyl group to form an intramolecular hemiacetal. As the ring contain five carbon atoms and one oxygen atom, which resembles the structure of pyran, the cyclic form of glucose is also referred to as glucopyranose. In the ring, each carbon is linked to a hydroxyl side group with the exception of the fifth atom, which links to a sixth carbon atom outside the ring, forming a \[C{{H}_{2}}OH\] group.

(Source : Shendurse A.M. and Khedkar C.D. (2016)

Glucose: Properties and Analysis. In: Caballero, B., Finglas, P., and Toldra, F. (eds.) The Encyclopedia of Food and Health vol. 3, pp. 239-247. Oxford: Academic Press.)

Glucopyranose structure was proposed by

A) Fischer                          

B) Haworth

C) Tollen                           

D) Fehling.