Aspirin, synthesis

Phenol, the starting material for the aspirin synthesis, is a petroleum product, like most of the starting materials used In large quantities In Industrial syntheses. A shortage of petroleum reserves thus affects the availability not only of fuels for transportation, but also of raw materials needed for most chemical synthesis. 

A singlet at 8 2.15 is H on carbon next to carbonyl, the only type of proton in the compound. The IR spectrum shows no OH, and shows two carbonyl absorptions at high frequency, characteristic of an anhydride. Mass of the molecular ion at 102 proves that the anhydride must be acetic anhydride, a reagent commonly used in aspirin synthesis. q q... 

In a certain aspirin synthesis, 104.8 g of salicylic acid and 110.9 g of acetic anhydride are combined. Calculate the percent yield of the reaction if 105.6 g of aspirin are produced. 

The key compound m the synthesis of aspirin salicylic acid is prepared from phe nol by a process discovered m the nineteenth century by the German chemist Hermann Kolbe In the Kolbe synthesis also known as the Kolbe—Schmitt reaction, sodium phen oxide IS heated with carbon dioxide under pressure and the reaction mixture is subse quently acidified to yield salicylic acid... 

Section 24 10 The Kolbe-Schmitt synthesis of salicylic acid is a vital step m the preparation of aspirin Phenols as their sodium salts undergo highly regioselective ortho carboxylation on treatment with carbon dioxide at elevated temperature and pressure... 

Currently, almost all acetic acid produced commercially comes from acetaldehyde oxidation, methanol or methyl acetate carbonylation, or light hydrocarbon Hquid-phase oxidation. Comparatively small amounts are generated by butane Hquid-phase oxidation, direct ethanol oxidation, and synthesis gas. Large amounts of acetic acid are recycled industrially in the production of cellulose acetate, poly(vinyl alcohol), and aspirin and in a broad array of other... 

Since nonsteroidal antiinflammatory dmgs, such as aspirin, an inhibitor of the synthesis of prostaglandins, will block the diuretic effects of furosemide, their concomitant use should be avoided (13,117). 

Kolbe-Schmitt reaction (Section 24.10) The high-pressure reaction of the sodium salt of a phenol with carbon dioxide to give an o-hydroxybenzoic acid. The Kolbe-Schmitt reaction is used to prepare salicylic acid in the synthesis of aspirin. 

Take Two Aspirin and. . Inhibit Your Prostaglandin Synthesis... 

In this bromoaspirin-inactivated structure, Ser , which lies along the wall of the tunnel, is bromoacetylated, and a molecule of salicylate is also bound in the tunnel. Deep in the tunnel, at the far end, lies Tyr, a catalytically important residue. Heme-dependent peroxidase activity is implicated in the formation of a proposed Tyr radical, which is required for cyclooxygenase activity. Aspirin and other NSAIDs block the synthesis of prostaglandins by filling and blocking the tunnel, preventing the migration of arachidonic acid to Tyr in the active site at the back of the tunnel. 

Aspirin and other NSAIDs function by blocking the cyclooxygenase (COX) enzymes that carry out the body s synthesis of prostaglandins (Sections 7.11 and 27.4). There are two forms of the enzyme, COX-1, which carries out the normal physiological production of prostaglandins, and COX-2, which mediates the body s response to arthritis and other inflammatory conditions. Unfortunately, both COX-1 and COX-2 enzymes are blocked by aspirin, ibuprofen, and other NSAIDs, thereby shutting down not only tire response to inflammation but also various protective functions, including the control mechanism for production of acid in the stomach. 

Arrhenius, Svante, 86,353 Arsenic, 573-574 Asparagine, 622t Aspartic acid, 622t Aspirin. See Acetylsalicylic acid Astaxanthin, 157 Asymmetric synthesis, 601 Atherosclerosis, 604... 

Vane JR (1971) Inhibition of prostaglandin synthesis as a mechanism of action for aspirin-like drugs. Nat New Biol 231 232-235... 

The starting material is aspirin. The acetyl group in (35) is an activating group, present to allow the synthesis of (35) and removed by 1,3-dicarbonyl cleavage. The strategy is therefore a 1,5-dlcarbonyl disconnection to (37) and a 1,3-dicarbonyl disconnection to (38). 

---