49. Shown below, as a Fischer projection, is the open chain confi guration of D-

Question

49. Shown below, as a Fischer projection, is the open chain confi guration of D-gulose. What is the structure of the B-D-pyranose form of this sugar that results from the intramolecular reacti on of the hydroxy group on the penultimate carbon with the carbonyl group? D Gulose l, ???? b. ???? d. ?? ???? 50. D-Fructose, shown below, gives a positive result for reducing sugars when mixed with Toll en's reagent, even though it is a ketose. This is best explained how? CH2OH HOH CH2OH D-Fructose a. Under the basic conditions, a C1-C2 enolate is formed which rearanges to an aldehyde. b. The hydroxy group on C1 is oxidized The hydroxy group on C6 is oxidized The hydroxy group on the penulti mate carbon is oxidized d.

Explanation / Answer

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49) D. - Answer

50) a. under the basic conditions, a C1-C2 enolate is formed which rearranges to an aldehyde.

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