28. Carbohydrates

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

a. 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.]

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

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Draw each of the following:

a. beta-d-talopyranose

b. alpha-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) b-D-galactopyranose (the C4 epimer of glucose).