Download Group G

Group G
Brandon Moebes
Wenjin Wang
Julian Dickerson
Marketta Ladson
Article Link: http://www.onlineathens.com/stories/101601/hea_1016010009.shtml
This article discusses how many people take the use of over the counter (OTC)
drugs too lightly. These drugs in high doses or with frequent use can carry certain
harmful effects on the body. One example cited is the use of the chemical
phenylpropanolamine (PPA) in many OTC drugs. Recently a study at Yale has linked
this chemical to strokes in people under 50. The FDA believes that PPA may have been
the cause for tens of thousands of strokes and has since banned its use in any OTC drugs.
Other drugs, such as ibuprofen, are known to cause irritation to the digestive system,
even ulcers, yet the drug is still being commonly used throughout the world. Even
Tylenol, one of the most common pain relievers on the market, can cause liver damage
with frequent use. The point is that even though a drug may be FDA approved doesn’t
mean it has no risks. Under certain situations, almost every drug can become harmful,
and it is the job of the consumer to protect themselves by becoming familiar with the
drugs they are taking.
Question 1: Draw the structure of PPA (IUPAC name: 2-amine 1-phenyl 1-propanol).
Answer: Here is a drawing of the molecule:
Drawing structure based on recognizing the names of functional groups and can be found
in chapters 11 (aromatic rings), 15 (alcohols), and 22 (amines).
Question 2: PPA is commonly prepared from propenylbenzene (IUPAC name: 1phenyl 1-propene). Discuss what reactions would be used to complete this preparation.
Answer: The first step is to add the hydroxyl group over the double bond. This is done
with NBS and water. The second step is to replace the bromide with an amine group by
reacting with ammonia. These steps are represented in the following diagram:
These reactions are detailed in chapters 6 (alkenes) and 22 (amines).
Question 3: In the first step of the reaction sequence above, why does the bromine add
to the second carbon and the hydroxyl add to the first rather than just the opposite?
In the conversion of alkenes to vicinal hydrohalins (Chapter 6: Alkenes), bromine bonds
with both the 1 and 2-carbons to form a bromonium ion. The water then attacks the 1carbon because it is adjacent to the phenyl group (making it the benzyl carbon).
Question 4: Are there any chiral centers in the PPA molecule? If so how many and
which carbons are chiral.
Answer: PPA has two chiral centers (Chapter 7: Stereochemistry). The 1-carbon is a
chiral center because it id bonded to four different substituents (phenyl group, hydroxyl
group, hydrogen, and ethyl amine). The 2-carbon is a chiral center because it also has
four different substituents (amine group, methyl group, hydrogen, and benzenol).