Question

Draw a Fischer projection of D-glucose. Draw two stereoisomers of this molecule, including one that is an epimer.

Short answer

Fisher projection of D-glucose:

Two stereoisomers of D-glucose including an epimer:

Step-by-step solution

Diagram of Fischer projection of D-glucose.

A three-dimensional organic molecule is represented in two dimensions by the Fischer projection. The lines that make up the Fischer projection are both horizontal and vertical. Atoms that are projected away from the spectator are represented by the vertical lines and those that are projected towards the viewer by the horizontal lines.

The sugar is referred to as D if the hydroxyl group in the Fischer Projection is pointed to the right. The sugar is referred to as L if the hydroxyl group is pointed to the left in the Fischer projection.

The sketch of Fischer projection of D-glucose is shown below.

Diagram of two stereoisomers of D-glucose.

Molecules known as stereoisomers share the same molecular formula but differ solely in the arrangement of their atoms in three dimensions.

Epimers are carbohydrates with a single difference—where the -OH group is located.For examples are D-glucose and D-galactose. Epimers of D-glucose and D-galactose only vary at the C-4 carbon.

The sketch of two stereoisomers with an epimer.