c. Draw d-idose, the C3 epimer of D-talose. Now compare your a...

Question

c. Draw d-idose, the C3 epimer of D-talose. Now compare your answers with Figure 23-3.

d. Draw the C4 “epimer” of D-xylose. Notice that this “epimer” is actually an L-series sugar, and we have seen its enantiomer. Give the correct name for this L-series sugar.

Accepted Answer

All right. Hello everyone. So this question has two parts to it. Part one says that D Manos is the C four epimer of D Talos draw the structure of D manos. Part two says to draw the structure of the C four epimer of D rivals. The change in C four makes this epimer an L series sugar. What is the name of this LC sugar? All right. So in this particular case, we're going to go ahead and use fissure projections to represent these sugar molecules. Now recall that epimer are two sugars that differ in the configuration of only one chiral center. So let's talk a little bit about the D and L series recall that the D or L configuration represents the positioning of the hydroxy group on the last asymmetric center. So when considering the last asymmetric center, if the oh group is on the right, then thats ad sugar. And if the O group is on the left, then that's an L circuit. So first lets start with part one. Now, before we go ahead and draw the structure of D menos, let's recall the structure of D Talos. Recall that D Talos is specifically ad although heos this means that there are six carbons in total, there's an aldehyde functional group on the first carbon. And the hydroxy group of the final symmetric center or asymmetric center, excuse me is going to be on the right, the hydroxy group is going to be on the right. So first, let's go ahead and draw the fissure projection of a molecule containing six carbons. The first of which is going to contain the aldehyde functional group abbreviated as co. So that's carbon one. And from here, I would draw out the remaining carbons in the chain, specifically 234 and five. And then carbon number six, which is not an asymmetric center. So that's C H2O H. So because this is ad sugar, the hydroxy group on carbon number five should be on the right side, which means that hydrogen should be on the left side. So from here, the structure of D Talos is relatively easy to remember because the three hydroxy groups on the remaining asymmetric centers are going to be on the left side. So on carbons 23 and four, their hydroxy groups are going to be on the left. So with this in mind, we can go ahead and figure out the structure of D manos D manos is the C four epimer of D Talos. So because we have the structure of Taos on the screen here, all we would need to do is swap the configurations of the hydroxy group and hydrogen to create the structure of D manos. So now on carbon floor, the hydroxy group should be on the right side. So from here, let's go ahead and focus on part two. Now, for part two were going to find the C four epimer of D rivals. So recall, the D ribose is an example of ad Aldo pantos. So now we have five carbons in total, but we still have an aldehyde functional group. And the last asymmetric center has the hydroxy group on the right side. So carbon number one is the aldehyde followed by carbons two three four N five, which is not an asymmetric center, thats ch two 08. Now it's ad sugar. So the very last asymmetric center is located on carbon four. So its hydroxy group should be on the right and hydrogen should be on the left. Now, as for the rest of the structure, our remaining chiral centers are carbons two and three. Recall that in the case of D ribose, the hydroxy groups on carbons two and three are going to be on the right side as well. So hydrogen is on the left. So in this case, our other compound is the C four epimer of D rivals, which means that on carbon number four, we're going to switch the positions of both the hydroxy group and the hydrogen. Meaning the hydroxy group is on the left, hydrogen is on the right. Now, this does result in an L ce sugar because C four was the last asymmetric center. And now the hydroxy group is on the left. But now to name this epimer, we have to first recall the structure of the enantiomer. So I am going to imagine a dashed line in the center. And I'm going to go ahead and swap the configurations of each of my asymmetric centers that would give me my non superimposable mirror image, otherwise known as the anatomy. So after swapping our hydroxy groups and hydrogens for each of our asymmetric centers, we get the D series sugar, which is the enantiomer of the LSE sugar. Now, the inane tumor happens to be de Lixo, which means that the LC sugar must have been L Laos and there you have. So here we've completed both parts to the question. Here is part one and here is part two. So with that being said, thank you so very much for watching and I hope you found this helpful.

c. Draw d-idose, the C3 epimer of D-talose. Now compare your answers with Figure 23-3.
d. Draw the C4 “epimer” of D-xylose. Notice that this “epimer” is actually an L-series sugar, and we have seen its enantiomer. Give the correct name for this L-series sugar.

Key Concepts

Epimers

C3 and C4 Epimers

L-series Sugars

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