Tamiflu is used for the prevention and treatment of flu. What ...

Question

Tamiflu is used for the prevention and treatment of flu. What is the configuration of each of its asymmetric centers?

Chemical structure of Tamiflu, highlighting its asymmetric centers for chirality analysis.

Accepted Answer

Hello everyone. Let's do this problem. It says traMADol is used as an analgesic drug, determine the configuration of each of its chiral centers in the structure shown below. So we are given the structure of traMADol and two of the carbons are labeled A and B and those are the chiral centers that we need to determine their configuration. So how do we do that? We need to look at the K OL pre log rules. So let's review those. So we know how to assign R or S configuration for these chiral centers. So chiral carbons have four different groups attached to them, right. So we are first going to assign the priorities of these four different groups and we prioritize prioritize them by atomic mass. So the higher the atomic mass of that first atom connected to the chiral center, then the higher the priority of the entire group. So what if there is a tie between the first atom attached to the chiral center? Well, then we simply look at the adjacent atoms using the same criteria. And if we have a double bond or a triple bond, then we'll simply count that atom multiple times two times for a double bond, three times for a triple bond. So we, if, if we have carbon triple bond into nitrogen, that counts as if we have a carbon with three single bonds to three nitrogen atoms. Does that make sense? All right. So once we have our priorities assigned, we're pretty much ready to determine R R S configuration. But we need to look at group number four, our lowest priority group and we need to look at its orientation. Is it wedged or is it dashed? Because this will change the criteria for determining R or S which we do by connecting groups 12 and three in a circle. And that circle will either go counterclockwise or clockwise. So if group number four is wedge and our circle goes counterclockwise between groups 12 and three, then we have our orientation. If the circle goes clockwise, when group four is wedge, then that is S orientation. And the opposite is true for when group number four is dash counterclockwise is S orientation, clockwise circle is our orientation. All right. So let's apply these rules to our two car centers. I'll use different colors to differentiate them. So we have blue Carl center A and pink carl center B. So let's assign the priorities on carbon center A. We have an alcohol group and three carbon groups. So that alcohol is definitely going to get the highest priority because of the oxygen atom, then we have three carbon atoms. So those are all tied. So we have to look at what those are connected to. Well, we have to the left a carbon with two hydrogens and a carbon. So hydrogen, hydrogen carbon, then we have a fetal group. So that carbon is attached to carbon, carbon, carbon, Right, two carbons because of that double bond. And then the carbon below the carb center A is attached to a hydrogen carbon carbon, hydrogen, carbon carbon. So it helps to write out these three atoms that are the first ones connected to those carbons so that we can see which one has the highest priority. So the carbon carbon carbon in that fennel group will get the second highest priority. The carbon carbon hydrogen will get third priority And the carbon hydrogen hydrogen will get 4th priority. All right. So now we connect groups of 1, 2 and three and they are going clockwise, but we need to look at group number four and notice how it's neither wedge or dash but the alcohol group is wedge. So we can basically consider group number four as being dashed. So clockwise will be our orientation. So that is our orientation for Carl center A, let's look at Carl center B, assigning our priorities. We have a hydrogen that is dashed because this carbon group with the tertiary mean is wedge. So the hydrogen is dashed and that is our lowest priority group. And again, we have three carbon groups. So let's write out the atoms they are attached to. So the carbon in the ring has two hydrogens and a carbon attached to it. The carbon with the immune group has two hydrogens and a nitrogen attached to it. And then the carbon in the ring above at Carl center A has an oxygen, a carbon and a carbon. OK. So that one is definitely going to be the highest priority group. No one. Then the next highest priority will be the hydrogen, hydrogen nitrogen leaving the carbon with the hydrogen, hydrogen and carbon attached to it as the third priority connecting groups 12 and three, that is going clockwise. So that is also our orientation. So we have our configuration for both chiral centers A and B which makes a the correct answer for this problem. That's it for this one. I hope this video is helpful and thank you for watching.

Tamiflu is used for the prevention and treatment of flu. What is the configuration of each of its asymmetric centers?

Key Concepts

Chirality and Asymmetric Centers

Cahn-Ingold-Prelog Priority Rules

Stereochemistry

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