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Ch.4 Introduction to Organic Compounds

Chapter 1, Problem 4.36b

ALLIED Health Mark the chiral centers in the following molecules, if any, with an asterisk (*):


(b) <IMAGE>                                                                                                                                                                   

 Pantothenic Acid, a B vitamin

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Welcome back, everyone determine whether any chiral centers are present in the compound below label the chiral centers with an asterisk if applicable. Now, in the given problem, we are looking for the carbon atoms with four different subscriptions. And specifically, this problem is really simplified for us because we see those wedges. Let's recall that wedges and dashes, they are used to represent chirality. So essentially what we want to do is identify the carbon atoms that have those wedges and dashes. And of course, we can verify if those carbons are chiral by counting the number of different subscriptions. So first of all, let's label the potential candidates that have wedges, we have labeled one of them. And now let's see if that specific carbon has four different subscriptions. Now, first of all, it has carbonel, it has an implicit hygiene atom that is not shown because carbon has four bonds and it is on a dash bond because we can see a wedge. So that's substituent number two, then it has nitrogen from the A mi that's substituent number three. And then it has another carbon, but that carbon is different from carbo carbon because it's ch two, right? And basically ch two is different from CEO. So we indeed have four different substituents and that carbon is indeed ciral. So we are correct in our analysis and a simple one to add an asterisk indicating the chirality of that specific carbon. Now, for the other carbon that has a wedge, we can see that there is an amino group NH two substitute number one, an implicit hegen substi number two. Then we have C two on the right in carbonel on the left. Those are different, which makes that specific carbon chiral. We have simply verified that it is chiral. So we can add an asterisk. Now, what about the other carbons? First of all, we can exclude all of the carbon atoms that are sp two hybridized, they have double bonds. So we can exclude all of the carbons. We can exclude all of the carbon atoms within the benzene ring because they are double bonded. And now for the remaining carbons, we can see that we have a muscle group which is CH three. So it has three, exactly same hydrogens. And what else? We have CH two and another CH two because once again, carbon must have four bonds. So the remaining two bonds are hydrogens and the presence of two exactly same hydrants means that those carbons are not chiral. And that's it. We have determined that there are only two carol centers in this structure, let's label them. And as we can see indeed, it was just sufficient for us to identify those carbons with wedges, right? It indicates chirality. Thank you for watching.
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