28. Carbohydrates

Draw the β-anomer predicted through the cyclization of D-mannose

Which OH groups are in the axial position in each of the following?

a. β-D-idopyranose

b. α-D-allopyranose

The aldaric acid of D-glucose forms two five-membered-ring lactones. Draw their structures.

Talose is the C4 epimer of mannose. Draw the chair conformation of D-talopyranose.

In an aqueous solution, D-glucose exists in equilibrium with two six-membered ring compounds. Draw the structures of these compounds.

Draw the α- and β-anomers of d-talopyranose. [The structure of talose is in Figure 27.11.]

Draw the α- and β-anomers of d-mannofuranose. [The structure of mannose is in Figure 27.11.]

Draw each of the following:

a. β-D-talopyranose

b. α-D-idopyranose  

Predict whether D-altrose exists preferentially as a pyranose or a furanose. (Hint: In the most stable arrangement for a five-membered ring, all the adjacent substituents are trans.)

Without referring to the chapter, draw the chair conformations of

(c) β-D-galactopyranose (the C4 epimer of glucose).