1. Preparation and Examination of Aspirin

2. Acetyl Salicylic Acid (Aspirin)
perhaps most popular medicinal agent ever discovered
lb/year sold in the US
Antipyretic (reduces fever)
Anti-inflammatory (reduces swelling suppresses prostaglandin hormone)
Analgesic (relieves mild pain suppresses prostaglandin hormone)
Aspirin also has an antiplatelet effect (stop blood clotting by inhibiting thromboxane)
Acetyl Salicylic Acid
prostaglandin is a hormone that communicates pain and creates inflammation
thromboxane is needed to start blood clotting of platelets
salicylic acid
(willow bark extract)
Acetyl Salicylic Acid (Aspirin)

3. Aspirin
Salicylic Acid – was found to be the active ingredient of willow bark – a well known home remedy in the 1800s
less stomach upset
salicylic acid
Aspirin
Ester of salicylic acid

4. Aspirin: how it works
Aspirin is hydrolyzed to salicylic acid in the stomach
Production of prostaglandins in the cell communicates pain in the nerves
Salicylic acid inhibits prostaglandins by deactivating COX-2 which makes them
prostaglandins cause tiny particles in your blood (known as platelets) to stick together to form a blood clot – so aspirin helps prevent blood clotting

5. Aspirin: how it works
Salicylic acid inhibits prostaglandins by deactivating COX-2 by blocking the tunnel to the active site of the enzyme

6. Aspirin: synthesis H3PO4
Place 1.5g of salicylic acid in a 125 mL Erlenmeyer flask
In the fume hood, add 4 mL of acetic anhydride and 4 drops of 85% H3PO4
Stir and place in a boiling water bath for 5 mins
Remove the flask, and immediately stir in 3 mL of water stir for 2 mins then add another 30 mL
Aspirin should start to precipitate
Place flask in ice bath to complete precipitation

7. Aspirin: synthesis
Isolate your aspirin by pouring the solution into a Büchner funnel
Wash the crystals with 10 mL of water
Leave the crystals in the funnel for 10 mins
Further dry the crystals by pressing them between two pieces of folded paper towel
Weigh aspirin and determine the yield

8. Aspirin: reaction mechanism