Aspirin See Acetylsalicylic acid

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

Aspirin see Acetylsalicylic acid Astbury, William T, 210 Aston, Francis W., 131, 208,... 

Arylpropionic acids, stereoisomers 32.229 Aspirin, see Acetylsalicylic acid Asthma medications, exacerbation of asthma, 20.165... 

Acetylsalicylic Acid (Aspirin). Acetylsalicylic add. (o-acetyoxybenzoic add) was first synthesized in 1853 by reaction of acetyl chloride with sodium salicylate. As a drug, acetylsalicylic acid was introduced in Germany in 1899 and into the United States in 1900. Aspirin is a registered trademark of Bavcr in many nations, but in the United States and the United Kingdom, aspirin is accepted as the generic name for acetylsalicylic add. See Acetylsalicylic Acid. 

Aspirin and Derivatives. See Acetylsalicylic Acid and Derivatives Asplund Process of Pulping. See under Pulp and Pulping... 

Acetylium tetrailuoroborate, 4 144t N-Acetyl-p-aminophenol (acetaminophen), acetic anhydride used in production of, 1 158. See also Acetaminophen Acetyl perchlorate, 1 157 Acetylsalicylic acid (aspirin), 22 17-21 acetic anhydride used in production of, 1 158... 

Asphalt chemicals, ethyleneamines application, 8 500t, 506 Asphalt emulsifier amine oxides, 2 473 fatty acid amides, 2 458 Asphalt emulsions, 10 131 Asphaltenes, in petroleum vacuum residua, 18 589-590 Asphyxiants, 21 836 Aspirating aerators, 26 165-169 compressed, 26 168-169 propeller driven, 26 168 submersible, 26 169, 170t subsurface, 26 168 Aspiratory, 11 236-237 Aspirin, 4 103-104, 104t, 701 22 17-21. See also Acetylsalicylic acid as trade name, 22 19 for cancer prevention, 2 826 Aspirin resistance, 4 104 ASP oil recovery process, 23 532-533 Assay format, competitive, 14 142 Assay limits, in Investigational New Drug Applications, 18 692 Assays, for silver, 22 650. See also... 

The case of aspirin in Table 8.3 is of special interest. Indeed, its acetyl ester group is particularly labile to enzymatic and nonenzymatic hydrolysis (see Sect. 7.4), and the reaction is even faster when the carboxy group is neutralized by esterification. A true ester prodrug of acetylsalicylic acid must fulfill the condition that its hydrolysis liberates aspirin rather than a prodrug of salicylic acid. An investigation of several aspirin prodrugs confirmed the interest of carbamoylmethyl esters and showed the (ATV-diethylcarbamoyl)methyl ester (Table 8.3) to liberate the highest proportion (ca. 60%) of aspirin [37], In... 

Salicin is an (9-glycoside of a phenol, namely salicyl alcohol. Salicin is a natural antipyretic and analgesic found in willow bark, and is the template from which aspirin (acetylsalicylic acid, see Box 7.13) was developed. Prunasin from cherry laurel is an example of a cyanogenic glycoside, hydrolysis of which leads to release of toxic HCN (see Box 7.7). It is the (9-glucoside of the alcohol mandelonitrile, the trivial name for the cyanohydrin of benzaldehyde. It is the further hydrolysis of mandelonitrile that liberates HCN. 

Two different pathways lead from arachidonate to prostaglandins, prostacyclins, and thromboxanes, on the one hand, or leuko-trienes on the other. The key enzyme for the first pathway is prostaglandin synthase [2]. Using up O2, it catalyzes in a two-step reaction the cyclization of arachidonate to prostaglandin H2, the parent substance for the prostaglandins, prostacyclins, and thromboxanes. Acetylsalicylic acid (aspirin) irreversibly ace-tylates a serine residue near the active center of prostaglandin synthase, so that access for substrates is blocked (see below). 

Salicylic acid is a simple organic acid with a pKa of 3.0. Aspirin (acetylsalicylic acid ASA) has a pKa of 3.5 (see Table 1-3). The salicylates are rapidly absorbed from the stomach and upper small intestine yielding a peak plasma salicylate level within 1-2 hours. Aspirin is absorbed as such and is rapidly hydrolyzed (serum half-life 15 minutes) to acetic acid and salicylate by esterases in tissue and blood (Figure 36-3). Salicylate is nonlinearly bound to albumin. Alkalinization of the urine increases the rate of excretion of free salicylate and its water-soluble conjugates. 

It was found that salicylic acid in its pure form had a number of defidencies, and for a number of years chemists sought a salicylic acid-based compound that would be effective yet less harsh and that could counteract pain with smaller dosages. This process ended in 1898 with the introduction by Bayer of acetylsalicylic acid, which has the formula C6H4(COOH)C02CHs and since then has been commonly referred to as aspirin, See also Acetylsalicylic Acid and Salicylic Acid and Related Compounds. 

Nonsteroidal Antiinflammatory Drugs. Nonsteroidal antiinflammatory drugs (NSAIDs) include, among the numerous agents of this class, aspirin (acetylsalicylic acid), the arylacetic acids indomethacin and sulindac, and the arylpropionic acids, tS)-<8) and (/ )-(9) ibuprofen, (S)-(10) and (/ )-(11), flurbiprofen naproxen, and fenoprofen. See also Analgesics, Antipyretics, and Antiinflammatory Agents and Salicylic Acid and Related Compounds. 

However, this method is applied only when esterification cannot be effected by the usual acid—alcohol reaction because of the higher cost of the anhydrides. The production of cellulose acetate (see Fibers, CELLULOSE esters), phenyl acetate (used in acetaminophen production), and aspirin (acetylsalicylic acid) (see Salicylic acid) are examples of the large-scale use of acetic anhydride. The speed of acylation is gready increased by the use of catalysts (68) such as sulfuric acid, perchloric acid, trifluoroacetic acid, phosphorus pentoxide, zinc chloride, ferric chloride, sodium acetate, and tertiary amines, eg, 4- dimethylaminopyridine. 

The best representative of an NSAID is aspirin (acetylsalicylic acid Fig. 15-1). Newer NSAIDs are usually compared to aspirin in terms of efficacy and safety. Acetaminophen is another agent that is similar to aspirin and other NSAIDs in its ability to decrease pain and fever. Acetaminophen, however, is not considered an NSAID because it lacks anti-inflammatory and anticoagulant properties. For a discussion of the comparative effects of aspirin, newer NSAIDs, and acetaminophen, see Comparison of Aspirin with Other NSAIDs. ... 

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