25.4The confguration at C-5 is opposite to that ofD-(1)-glyceraldehyde. This particular carbohydratetherefore belongs to theLseries. Comparing it with the Fischer projection formulas of the eightD-aldohexoses reveals it to be in the mirror image ofD-(1)-talose; it isL-(2)-talose25.5(b)The Fischer projection formula of D-arabinose may be found in text Figure 25.2. The Fischerprojection and the eclipsed conformation corresponding to it areCyclic hemiacetal formation between the carbonyl group and the C-4 hydroxyl yields the a- and b-furanose forms of D-arabinose.(c)The mirror image of D-arabinose [from part (b)] is L-arabinose.The C-4 atom of the eclipsed conformation ofL-arabinose must be rotated 120°in a clock-wise sense so as to bring its hydroxyl group into the proper orientation for furanose ring
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