Salicylates preparations

Ethyl salicylate (prepared by the same method) has an odour similar to that of methyl salicylate but less intense it is therefore usually impracticable to attempt to distinguish methanol and ethanol by this test alone. 

Choline salicylate ((2-hydroxyethyl)trimethylammonium salicylate) is contained in a list of safe and effective compounds (30). Choline salicylate [2016-36-6] (5) is the only liquid salicylate preparation available and is often useful for arthritic patients who have difficulty swallowing tablets. 

Gastrointestinal decontamination with multiple dose activated charcoal is recommended for recent acute ingestion [86] and may be most effective (along with cathartics) for enteric coated salicylate preparations. Induction of emesis with ipecac is no longer recommended [86]. Alkalinization of the urine is recommended for patients with preserved renal function who are unsuitable or do not meet criteria for dialysis [87] and may be of benefit during preparation for hemodialysis. 

Magnesium Salicylate, USP. Magnesium. salicylate (Mobidin. Magan) is a. stHlium-free salicylate preparation for use when sodium intake is restricted. It is claimed to produce le.ss gastrointestinal upset. The dosage and indications are the same us those for sodium. salicylate. 

C7H6O2 Oily liquid of aromatic odour b.p. 196°C. (t is prepared by the action of chloroform and caustic potash on phenol (the Reimer-Tiemann reaction) or by the oxidation of the glucoside salicin. It is easily reduced to salicyl alcohol or oxidized to salicylic acid. 

C7H9N402- M.p. 337 C, an alkaloid obtained from cacao seeds or prepared synthetically. Constitutionally it is similar to caffeine, and is also a weak base. It is usually administered as the sodium compound combined with either sodium ethanoate or sodium salicylate, and is employed almost entirely as a diuretic. Physiologically theobromine resembles caffeine, but its effect on the central nervous system is less, while its action on the kidneys, is more pronounced. 

It should be emphasised that salicylic acid can be readily acetylated by Method 1, and that the above preparation of acetylsalicyclic acid is given solely as an illustration of Method 2. To employ Method 1, add 10 g. of salicylic acid to 20 ml. of a mixture of equal volumes of acetic anhydride and acetic acid, and boil gently under reflux for 30 minutes. Then pour into about 200 ml. of cold water in order to precipitate the acetylsalicylic acid (11 g.) and finally recrystallise as above. Method 2, however, gives the purer product. 

The methyl ester formed by substituting methanol for ethanol in the above reaction has an even stronger odour and should be prepared if salicylic acid is suspected. 

Salicylic acid. The preparation of salicylic acid by passing carbon dioxide into dry sodium phenoxide at 170-190° is the classical example of the Kolbe-Schmltt reaction. The latter is a method for introducing a carboxyl group directly into a phenol nucleus. 

It is of interest to record that />-hydroxybenzoic acid may be prepared by the thermal rearrangement of potassium salicylate at 230° ... 

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... 

Kolbe-Schmitt reaction (Section 24 10) The high pressure re action of the sodium salt of a phenol with carbon dioxide to give an o hydroxybenzoic acid The Kolbe-Schmitt reac tion IS used to prepare salicylic acid in the synthesis of as pinn... 

The preparation of an ion-selective electrode for salicylate is described. The electrode incorporates an ion-pair of crystal violet and salicylate in a PVC matrix as the ion-selective membrane. Its use for the determination of acetylsalicylic acid in aspirin tablets is described. A similar experiment is described by Creager, S. E. Lawrence, K. D. Tibbets, C. R. in An Easily Constructed Salicylate-Ion-Selective Electrode for Use in the Instructional Laboratory, /. Chem. Educ. 1995, 72, 274-276. 

Students determine the concentrations of caffeine, acetaminophen, acetylsalicylic acid, and salicylic acid in several analgesic preparations using both CZE (70 mM borate buffer solution, UV detection at 210 nm) and HPLC (C18 column with 3% v/v acetic acid mixed with methanol as a mobile phase, UV detection at 254 nm). 

Manufacture. Several methods have been described for the preparation of -hydroxyben2oic acid. The commercial technique is similar to that of salicylic acid, ie, Kolbe-Schmitt carboxylation of phenol. The modification includes the use of potassium hydroxide in place of caustic (51). The dried potassium phenate is heated under pressure, 270 kPa (2.7 atm) or more, with dry carbon dioxide at 180—250°C. The potassium salt [16782-08-4] of Nhydroxyben2oic acid forms almost quantitatively and can be converted to free acid by using a mineral acid. 

As of 1991 in the United States, OTC antiacne preparations may contain only a few active dmgs, for example, sulfur [7704-34-9] resorcinol acetate [102-29-4], resorcinol [108-46-3], salicylic acid [69-72-7], and some combinations (52). OTC anti-acne constituents maybe included in a variety of conventional cosmetic preparations, which then become OTC dmgs. These include lotions, creams, solutions, facial makeups, facial cleansers (including abrasive cleansers), and astringents. Products must contain the specified dmgs at the designated concentrations. Compositions of antiacne products have beenpubhshed (53). 

Salicyl-u-toluide has been prepared only by the action of phosphorus oxychloride upon a mixture of salicylic acid and o-toluidine. The useful methods of preparation of salicylanilide are by the interaction of salicylic acid and aniline in the presence of phosphorus trichloride, by heating phenyl salicylate and aniline, and from o-hydroxybenzamide and bromobenzene in the presence of small amounts of sodium acetate and metallic copper. A number of these and other anilides have been described. ... 

Salicylic acid, the starting material for the preparation of aspirin. 

The best known aryl ester is O-acetylsalicylic acid, better known as aspirin. It is prepared by acetylation of the phenolic hydroxyl group of salicylic acid ... 

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