DIARY OF A BIOCHEM MAJOR

I remember this guy! Back in high school, my AP Chem teacher (who used to teach orgo in college, go figure) had us make this in a lab! Now, I didn’t have any idea what I was doing back then (or now for that matter), but all I know is that we got to play with sulfuric acid and that was pretty cool. Well, until I spilled some on my homework which caused to basically turn black and fall apart…

Acetylsalicylic acid, also known as Aspirin, is one of most common pain relievers/fever reducers in the world. Aspirin is made from salicylic acid which is found in willow bark, which was used for centuries to treat pain and fevers. Unfortunately, it also kinda sorta maybe causes somewhat nasty chemical burns. Luckily aspirin has much milder effects, though it can still cause stomach ulcers.

Aspirin works through a variety of pathways. In the biggest mechanism, aspirin inhibits the action of COX-1/COX-2. The COX enzymes are special because they cause certain chemicals called prostaglandins and thromboxanes to be produced. Prostaglandins are the source of inflammation/pain while thromboxanes causes blood to clot up (this is why aspirin is good for preventing heart attacks). Aspirin doesn’t stop the pain, it merely prevents the body from being able to report that you have some damaged tissue. Other smaller mechanisms do play a role, such as the ability of aspirin to cause the creation of NO radicals in the blood, which too can reduce inflammation.

Making aspirin isn’t too difficult either. Typically one starts out with salicylic acid and acetic anhydride. By adding a small amount of acid catalyst (usually sulfuric or phosphoric acid), the acetic anhydride is activated which allows the hydroxyl group on salicylic acid to attack it. The mechanism below shows how the reaction proceeds (courtesy of Wikipedia):