Solution to Study Question 1:
Remember, you can interchange any two groups on a chiral center, and produce the opposite enantiomer. In the first two examples, simply invert the hydrogen and any other group, so that the hydrogen ends up in the back. Then use the priority rules to assign numbered priorities, and assign either R or S. The molecule as originally drawn has the opposite configuration as the "altered" chiral center.
You can see that ibuprofen as shown in the question exists in the active S-configuration. Also, 4-hydroxyproline has two chiral centers, one of which needs to be artificially inverted before assigning R and S. If you are still confused, try doing this exercise on paper or with a molecular model a few more times!
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