Salicylic acids sources

Synonyms 2-Hydroxybenzoic acid Salicylic acid Source Reverchon, E. Donsi, G. Gorgoglione, D. J. Supercrit. Fluids (1993), 6(4), 241-248. 

Synonyms 2-Hydroxybenzoic acid Salicylic acid Source Stahl, E. Schilz, W. Talanta (1979), 26, 675-679. 

Methyl salicylate is produced synthetically for commercial purposes by the esterification of salicylic acid with methanol or by extraction by steam distillation of wintergreen leaves or sweet birch bark. The source, natural or synthetic, is declared on the label. The methyl salicylate NF must assay not less than 98.0% and not more than 100.5% and be processed by Good Manufacturing Practice described in USP (20). 

Alpha hydroxy acids (AHAs) are water-soluble substances and thereby penetrate the outermost epidermal skin layers. In contrast, beta hydroxy acids (BHAs) are lipid (fat) soluble and are capable of penetrating to the underlying layers of skin (the dermis) located 1-5 mm below the surface of the skinJ2 Most AHAs are derived from plant materials and marine sources. Commonly used AHAs include malic acid (found in apples), ascorbic acid (a common ingredient in numerous fruits), glycolic acid (a constituent of sugar cane), lactic acid (a component of milk), citric acid (naturally abundant in citrus fruits), and tartatic acid (found in red wine). A common BHA is salicylic acid (an ingredient in aspirin). 

Figure 5. Dependence of rate of dissolution of 5pM Y-FeOOH in pH 4.0, 0.01M NaCl on concentration of a) tartaric acid, and b) salicylic acid. Fitted parameters obtained for rectangular hyperbolic model are given. Light source mercury arc lamp with 365nm band-pass filtering.

Several studies identify WWTPs effluents as the main conveyors of APIs and their metabolites into receiving water sources that are used for drinking-water supply [6, 30, 32, 52, 56, 59, 62-71]. For instance, the presence of ibuprofen, paracetamol and salicylic acid which are readily bio(degradable) is an indicator of non- or poorly treated wastewater [72]... 

Many medicines that we now use and often take for granted were based on the healing properties of plants and other natural sources known to traditional healers. Aspirin, or acetylsalicylic acid, is a chemically modified form of salicylic acid, a chemical extracted in the early 19 century from willow tree bark, which had been known for centuries to reduce fevers. Today, aspirin is chemically... 

A large number of salts of salicylic acid have been prepared and evaluated for therapeutic or other commercial use. Table 7 lists those most frequently referenced. Sodium salicylate has analgesic, antiinflammatory, and antipyretic activities and was used extensively in the sixteenth and seventeenth centuries as a remedy, prepared from natural sources, for arthritis and rheumatism. In the 1990s the salt can be obtained directly from Kolbe-Schmitt carboxylation or by the reaction of salicylic acid with either aqueous sodium bicarbonate or sodium carbonate. The resulting mixture is heated until effervescence stops the salt is then isolated by filtration and evaporation to dryness at low temperatures. Generally, the solution must be kept slightly acidic so that a white product is obtained if the mixture is basic, a colored product results. The USP product contains 99.5—100.5% NaC H503 (anhydrous). The May 1996 price was 8.15/kg (18). 

Figure 8 Mean serum levels of salicylic acid, gentisic acid, and salicyluric acid of 10 volunteers. Total salicylate represents the sum of the three individual compounds. Error bars indicate 95% confidence interval of the mean. Source From Ref. 99.

Salicylic acid derivatives serve a similar purpose to 2-hydroxyacetophenones in a number of chromone syntheses, acting as a precursor of the 1,3-diketone fragment. For instance, a Claisen reaction between methyl 2-methoxybenzoate and acetone takes place in the presence of sodium to give the diketone. Demethylation occurs on reaction with hydriodic acid with concomitant ring closure to the chromone (00CB1998). The corresponding naphthol derivatives are a source of benzochromones (52JOC1419). 

A number of 2,3-fused chromones have been prepared from ethyl chloroformate and acetylsalicylic acid, a source of the mixed anhydride of formic and salicylic acids, and piperidinocycloalkenes (69JCS(C)935). A plausible mechanism is outlined in Scheme 165. It has not proved possible to isolate the chromanone (460) but the formation of 3-acetyl-2-methylchromone from 2-pyrrolidinopropene lends support to the intermediacy of the chromanone. The migration of the acyl group from oxygen to carbon is supported by the synthesis of 3-benzoyl-2-methylchromone rather than 3-acetylflavone from benzoylsalicylic acid and the pyrrolidinopropene. 

Salicylate. Sodium salicylate. LCAS 54-21-7J, NaC7H503, white solid, soluble, formed by reaction of sodium phenate and CO2 under pressure. Used as a source of salicylate and for salicylic acid. 

The effect of Salix alba L. (white willow) is largely owed to a glycoside, salicin. Salicin is antipyretic and analgesic and has been used in the treatment of rheumatic fever (salicilin tablets British Pharmaceutical Codex, 1949). In 1893, Felix Hofmann, a chemist working for the Bayer chemical company in Germany, first synthesized acetyl-salicylic acid, the acetylated form of salicin. Aspirin is one of the most commonly used pharmaceuticals containing salicin. Today, the main commercial sources of salicin are Salix fragilis and Salix purpurea (Salicaceae), which are native to Eurasia. 

This is a subcosmopolitan family with concentration in the northern hemisphere. The family of the weeping willow, it has been known since biblical limes and was the source of salicylic acid for the Greek physicians, which led, eventually, to the synthesis of aspirin for the relief of minor pain. Pliable, thin branches are used in basket weaving, and some timber is produced. 

Acetylsalicylic acid (ASA) was first produced commercially under the brand name Aspirin by Frederick Bayer and Company in 1897. The word "aspirin" comes from "a," for acetyl, and "spir," for spirea. Spirea is a genus of plants that is another natural source of salicylic acid. 

Salicin.—It derives its name from the glucoside salicin which is present in the bark of willow trees, the generic name of which is Salix, When the glucoside is hydrolyzed it yields glucose and a compound known as saligenin, which is salicylic alcohol or ortho-hydroxy benzyl alcohol, and which on oxidation yields salicylic acid. This is one of the natural sources of the acid. 

Oil of Wintergreen. Methyl Salicylate.— The most interesting natural source of the acid, however, is oil of wintergreen obtained from the wintergreen plant, Gatdtheria procumbens. The chief constituent of this oil is the methyl ester of salicylic acid, methyl salicylate,... 

Acetylsalicylic acid (aspirin) Although acetyl-salicylic acid is a drug frequently used in effervescent form, it cannot be used as the acid source because of its low water solubility. Additional acid is necessary to decrease the reaction time. 

The mass spectra (10) of salicylic acid was obtained by electron impact ionization (Fig. 7) and was recored on Finigen MAT 90 mass spectrometer. The spectrum was scanned from 50-250 a.m.a. Electron energy was 70 ev. Emission current 1 mA and ion source pressure 10 6 torr. The base peak is with a relative intensity 100%. Table 5 shows the most prominent fragments and their relative intensities. 

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