After a series of KilianiFischer syntheses on (+)@glyceraldehyde, an unknown sugar is

Chapter 23, Problem 23-57

(choose chapter or problem)

After a series of Kiliani-Fischer syntheses on (+)-glyceraldehyde, an unknown sugar is isolated from the reaction mixture. The following experimental information is obtained:

(1) Molecular formula \(\mathrm{C}_6 \mathrm{H}_{12} \mathrm{O}_6\)

(2) Undergoes mutarotation.

(3) Reacts with bromine water to give an aldonic acid.

(4) Reacts with \(\mathrm{HNO}_3\) to give an optically active aldaric acid.

(5) Ruff degradation followed by \(\mathrm{HNO}_3\) oxidation gives an optically inactive aldaric acid.

(6) Two Ruff degradations followed by \(\mathrm{HNO}_3\) oxidation give meso-tartaric acid.

(7) When the original sugar is treated with \(\mathrm{CH}_3 \mathrm{I}\) and \(\mathrm{Ag}_2 \mathrm{O}\), a pentamethyl derivative is formed. Hydrolysis gives a tetramethyl derivative with a free hydroxy group on C5.

(a) Draw a Fischer projection for the open-chain form of this unknown sugar. Use Figure 23-3 to name the sugar.

(b) Draw the most stable conformation of the most stable cyclic hemiacetal form of this sugar, and give the structure a complete systematic name.