Lab AB-Two step synthesis of aspirin(1) - Laboratory AB:...

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Laboratory AB: The Synthesis of Aspirin from Methyl Salicylate Laboratory Techniques: WEEK A: Laboratory Safety Keeping a notebook Vacuum Filtration and Water Aspirators WEEK B: Melting Points Interpreting a handbook Recrystallization Organic Chemistry Background Chemistry: Acid-Base Equilibrium Saponification New pharmaceuticals can be discovered either by isolating a natural product and identifying its medicinal properties, or by chemically synthesizing a new drug. Often, small changes in a molecule, such as changing a single functional group, can lead to improvements in a molecule’s properties and mode of action. Methyl salicylate is a natural product that is also known as oil of wintergreen. It is a liquid compound with a minty smell that is used to flavor candy and perfumes. Methyl salicylate is also one of the active ingredients (along with menthol) in the Bengay pain relieving ointment. A simple change in a functional group from a methyl ester to a carboxylic acid turns methyl salicylate into salicylic acid. Salicylic acid is a crystalline solid that is found in the extracts of willow bark. Willow bark extracts have been used as pain relievers since before Hippocrates. However, while these extracts served both as a pain reliever and an anti-inflammatory, they were also extremely irritating to the lining of the stomach. In the late 19 th century, Felix Hofmann, who worked at the Bayer Company, began to investigate the properties of salicylic acid derivatives. Hoffman found that by converting the phenol group into an acetyl group, he was able to obtain a drug that had many of the same pain relieving properties as salicylic acid but that did not produce as severe gastrointestinal side effects. This acetyl salicylic acid (ASA) is known by the trade name of aspirin, because salicylic acid can also be isolated from spiraea ulmaria . methyl salicylate salicylic Acid Acetyl Salicylic Acid (Aspirin) O OH OH OH O O O O O OH
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Aspirin still remains one of the most widely used painkillers today, with over 30 million pounds consumed in the US alone. Salicylic acid and its derivatives methyl salicylate and acetyl salicylate are still of considerable interest. The widespread use of aspirin revealed its effects on heart attack risk and its anti-clotting activity. 1 Furthermore, some evidence suggests that it can prevent additional ischemic strokes in patients who have experienced one. 2 However, salicylic acid is not only synthesized by plants; recent radiolabeling studies have suggested that humans synthesize salicylic acid in vivo from benzoic acid, and that there may be endogenous regulation of the synthesis of this anti-inflammatory molecule. 3
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This note was uploaded on 11/02/2010 for the course ORGANIC CH Organic Ch taught by Professor Grecko during the Spring '10 term at School of Public Health at Johns Hopkins.

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Lab AB-Two step synthesis of aspirin(1) - Laboratory AB:...

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