Preparation and Examination of Aspirin

Acetyl Salicylic Acid (Aspirin) perhaps most popular medicinal agent ever discovered 30 000 000 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)

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

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

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

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

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

Aspirin: reaction mechanism