Chapter 24.5, Problem 17ATS

Interpretation Introduction

Interpretation:

Open chain for the given cyclic monosaccharide should be drawn.

Concept introduction:

The Haworth projection: A Haworth projection is a three-dimensional representation of monosaccharides and the structural formula is inscription as a cyclic structures.

In Haworth projection, oxygen atom is placed in back right corner, ${\text{CH}}_{\text{2}}\text{OH}$ is arranged up at the C5 carbon atom because it is D form. Anomeric hydroxyl group is placed down if it is α-anomer which is trans to the ${\text{CH}}_{\text{2}}\text{OH}$ of C5 carbon. The remaining hydroxyl group is placed up if the hydroxyl group left side in Fischer projection. Hydroxyl group is placed down if the hydroxyl group right side in Fischer projection.

Fischer Projection: The orientation of the carbon atoms in a molecule is arranged vertically from top to bottom.

The C1 carbon is at the top of the orientation, the hydrogen and hydroxyl groups are placed in right and left side of the orientation. D and L form are depends on the arrangement of the hydroxyl group. If the hydroxyl group is in the right side of the molecule in the penultimate (next-to-last) carbon is called as D sugar, if the If the hydroxyl group is in the left side of the molecule in the penultimate (next-to-last) carbon is called as L sugar.

Pyranose: A six-member cyclic form of a monosaccharide is called as pyronose.

To find: Open chain form of given cyclic monosaccharide.