Names | |||
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Preferred IUPAC name 2-Hydroxybenzoic acid [1] | |||
Identifiers | |||
3D model (JSmol) | |||
ChEBI | |||
ChEMBL | |||
ChemSpider | |||
DrugBank | |||
ECHA InfoCard | 100.000.648 | ||
EC Number |
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KEGG | |||
PubChem CID | |||
RTECS number |
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UNII | |||
CompTox Dashboard (EPA) | |||
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Properties | |||
C7H6O3 | |||
Molar mass | 138.122 g/mol | ||
Appearance | Colorless to white crystalline powder | ||
Odor | Odorless | ||
Density | 1.443 g/cm3 (20 °C) [2] | ||
Melting point | 158.6 °C (317.5 °F; 431.8 K) | ||
Boiling point | 211 °C (412 °F; 484 K) at 20 mmHg [2] [3] | ||
Sublimes at 76 °C [3] | |||
Solubility | Soluble in ether, CCl4, benzene, propanol, acetone, ethanol, oil of turpentine, toluene | ||
Solubility in benzene | |||
Solubility in chloroform | |||
Solubility in methanol |
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Solubility in olive oil | 2.43 g/100 g (23 °C) [3] | ||
Solubility in acetone | 39.6 g/100 g (23 °C) [3] | ||
log P | 2.26 | ||
Vapor pressure | 10.93 mPa [3] | ||
Acidity (pKa) | |||
UV-vis (λmax) | 210 nm, 234 nm, 303 nm (4 mg/dL in ethanol) [3] | ||
−72.23·10−6 cm3/mol | |||
Refractive index (nD) | 1.565 (20 °C) [2] | ||
2.65 D | |||
Thermochemistry | |||
Std enthalpy of formation (ΔfH⦵298) | −589.9 kJ/mol | ||
Std enthalpy of combustion (ΔcH⦵298) | -3.025 MJ/mol [6] | ||
Pharmacology | |||
A01AD05 ( WHO ) B01AC06 ( WHO ) D01AE12 ( WHO ) N02BA01 ( WHO ) S01BC08 ( WHO ) | |||
Hazards | |||
Occupational safety and health (OHS/OSH): | |||
Eye hazards | Severe irritation | ||
Skin hazards | Mild irritation | ||
GHS labelling: [7] | |||
Danger | |||
H302, H318 | |||
P280, P305+P351+P338 | |||
NFPA 704 (fire diamond) | |||
Flash point | 157 °C (315 °F; 430 K) closed cup [3] | ||
540 °C (1,004 °F; 813 K) [3] | |||
Lethal dose or concentration (LD, LC): | |||
LD50 (median dose) | 480 mg/kg (mice, oral) | ||
Safety data sheet (SDS) | MSDS [ dead link ] | ||
Related compounds | |||
Related compounds | Methyl salicylate, Benzoic acid, Phenol, Aspirin, 4-Hydroxybenzoic acid, Magnesium salicylate, Choline salicylate, Bismuth subsalicylate, Sulfosalicylic acid, Salicylate synthase | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Salicylic acid is an organic compound with the formula HOC6H4COOH. [3] A colorless (or, white), bitter-tasting solid, it is a precursor to and a metabolite of acetylsalicylic acid (aspirin). [3] It is a plant hormone, [8] and has been listed by the EPA Toxic Substances Control Act (TSCA) Chemical Substance Inventory as an experimental teratogen. [9] The name is from Latin salix for willow tree, from which it was initially identified and derived. It is an ingredient in some anti-acne products. Salts and esters of salicylic acid are known as salicylates. [3]
Salicylic acid as a medication is commonly used to remove the outermost layer of the skin. As such, it is used to treat warts, psoriasis, acne vulgaris, ringworm, dandruff, and ichthyosis. [3] [10] [11]
Similar to other hydroxy acids, salicylic acid is an ingredient in many skincare products for the treatment of seborrhoeic dermatitis, acne, psoriasis, calluses, corns, keratosis pilaris, acanthosis nigricans, ichthyosis, and warts. [12]
Salicylic acid is used as a food preservative, a bactericide, and an antiseptic. [13] [14]
Salicylic acid is used in the production of other pharmaceuticals, including 4-aminosalicylic acid, sandulpiride, and landetimide (via salethamide). [15] It is also used in picric acid production. [16]
Salicylic acid has long been a key starting material for making acetylsalicylic acid (ASA or aspirin). [8] ASA is prepared by the acetylation of salicylic acid with the acetyl group from acetic anhydride or acetyl chloride. [17] ASA is the standard to which all the other non-steroidal anti-inflammatory drugs (NSAIDs) are compared. In veterinary medicine, this group of drugs is mainly used for treatment of inflammatory musculoskeletal disorders. [18]
Bismuth subsalicylate, a salt of bismuth and salicylic acid, "displays anti-inflammatory action (due to salicylic acid) and also acts as an antacid and mild antibiotic". [3] It is an active ingredient in stomach-relief aids such as Pepto-Bismol and some formulations of Kaopectate.
Other derivatives include methyl salicylate, used as a liniment to soothe joint and muscle pain, and choline salicylate, which is used topically to relieve the pain of mouth ulcers. [3] [19] [20] Aminosalicylic acid is used to induce remission in ulcerative colitis, and has been used as an antitubercular agent often administered in association with isoniazid. [21]
Sodium salicylate is a useful phosphor in the vacuum ultraviolet spectral range, with nearly flat quantum efficiency for wavelengths between 10 and 100 nm. [22] It fluoresces in the blue at 420 nm. It is easily prepared on a clean surface by spraying a saturated solution of the salt in methanol followed by evaporation.[ citation needed ]
Salicylic acid modulates COX-1 enzymatic activity to decrease the formation of pro-inflammatory prostaglandins. Salicylate may competitively inhibit prostaglandin formation.
Salicylic acid, when applied to the skin surface, works by causing the cells of the epidermis to slough off more readily, preventing pores from clogging up, and allowing room for new cell growth. Salicylic acid inhibits the oxidation of uridine-5-diphosphoglucose (UDPG) competitively with NADH and noncompetitively with UDPG. It also competitively inhibits the transferring of glucuronyl group of uridine-5-phosphoglucuronic acid to the phenolic acceptor. [23]
The wound-healing retardation action of salicylates is probably due mainly to its inhibitory action on mucopolysaccharide synthesis. [5]
If high concentrations of salicylic ointment are used topically, high levels of salicylic acid can enter the blood, requiring hemodialysis to avoid further complications. [24]
Cosmetic applications of the drug pose no significant risk. [25] Even in a worst-case use scenario in which one was using multiple salicylic acid-containing topical products, the aggregate plasma concentration of salicylic acid was well below what was permissible for acetylsalicylic acid (aspirin). [25] Since oral aspirin (which produces much higher salicylic acid plasma concentrations than dermal salicylic acid applications) poses no significant adverse pregnancy outcomes in terms of frequency of stillbirth, birth defects or developmental delay, use of salicylic acid containing cosmetics is safe for pregnant women. [25] Salicylic acid is present in most fruits and vegetables as for example in greatest quantities in berries and in beverages like tea.
Salicylic acid is biosynthesized from the amino acid phenylalanine. In Arabidopsis thaliana , it can be synthesized via a phenylalanine-independent pathway.
Commercial vendors prepare sodium salicylate by treating sodium phenolate (the sodium salt of phenol) with carbon dioxide at high pressure (100 atm) and high temperature (115 °C) – a method known as the Kolbe-Schmitt reaction. Acidifying the product with sulfuric acid gives salicylic acid:
At the laboratory scale, it can also be prepared by the hydrolysis of aspirin (acetylsalicylic acid) [26] or methyl salicylate (oil of wintergreen) with a strong acid or base; these reactions reverse those chemicals' commercial syntheses.
Upon heating, salicylic acid converts to phenyl salicylate: [27] [8]
Further heating gives xanthone. [8]
Salicylic acid as its conjugate base is a chelating agent, with an affinity for iron(III). [28]
Salicylic acid slowly degrades to phenol and carbon dioxide at 200–230 °C: [29]
All isomers of chlorosalicylic acid and of dichlorosalicylic acid are known. 5-Chlorosalicylic acid is produced by direct chlorination of salicylic acid. [8]
Willow has long been used for medicinal purposes. Dioscorides, whose writings were highly influential for more than 1,500 years, [30] used 'Itea' (which was possibly a species of willow) as a treatment for 'painful intestinal obstructions,' birth control, for 'those who spit blood,' to remove calluses and corns and, externally, as a 'warm pack for gout.' William Turner, in 1597, repeated this, saying that willow bark, 'being burnt to ashes, and steeped in vinegar, takes away corns and other like risings in the feet and toes.' [31] Some of these cures may describe the action of salicylic acid, which can be derived from the salicin present in willow. It is, however, a modern myth that Hippocrates used willow as a painkiller. [32]
Hippocrates, Galen, Pliny the Elder, and others knew that decoctions containing salicylate could ease pain and reduce fevers. [33] [34]
It was used in Europe and China to treat these conditions. [35] This remedy is mentioned in texts from Ancient Egypt, Sumer, and Assyria. [36]
The Cherokee and other Native Americans use an infusion of the bark for fever and other medicinal purposes. [37] In 2014, archaeologists identified traces of salicylic acid on seventh-century pottery fragments found in east-central Colorado. [38]
The Reverend Edward Stone, a vicar from Chipping Norton, Oxfordshire, England, reported in 1763 that the bark of the willow was effective in reducing a fever. [39]
An extract of willow bark, called salicin, after the Latin name for the white willow ( Salix alba ), was isolated and named by German chemist Johann Andreas Buchner in 1828. [41] A larger amount of the substance was isolated in 1829 by Henri Leroux, a French pharmacist. [42] Raffaele Piria, an Italian chemist, was able to convert the substance into a sugar and a second component, which on oxidation becomes salicylic acid. [43] [44] Salicylic acid was also isolated from the herb meadowsweet ( Filipendula ulmaria , formerly classified as Spiraea ulmaria) by German researchers in 1839. [45] Their extract caused digestive problems such as gastric irritation, bleeding, diarrhea, and even death when consumed in high doses.
In 1874 the Scottish physician Thomas MacLagan experimented with salicin as a treatment for acute rheumatism, with considerable success, as he reported in The Lancet in 1876. [46] Meanwhile, German scientists tried sodium salicylate with less success and more severe side effects. [47] [48]
In 1979, salicylates were found to be involved in induced defenses of tobacco against tobacco mosaic virus. [49] In 1987, salicylic acid was identified as the long-sought signal that causes thermogenic plants, such as the voodoo lily, Sauromatum guttatum , to produce heat. [50]
Salicylic acid occurs in plants as free salicylic acid and its carboxylated esters and phenolic glycosides. Several studies suggest that humans metabolize salicylic acid in measurable quantities from these plants. [51] High-salicylate beverages and foods include beer, coffee, tea, numerous fruits and vegetables, sweet potato, nuts, and olive oil. [19] Meat, poultry, fish, eggs, dairy products, sugar, breads and cereals have low salicylate content. [19] [52]
Some people with sensitivity to dietary salicylates may have symptoms of allergic reaction, such as bronchial asthma, rhinitis, gastrointestinal disorders, or diarrhea, so may need to adopt a low-salicylate diet. [19]
Salicylic acid is a phenolic phytohormone, and is found in plants with roles in plant growth and development, photosynthesis, transpiration, and ion uptake and transport. [53] Salicylic acid is involved in endogenous signaling, mediating plant defense against pathogens. [54] It plays a role in the resistance to pathogens (i.e. systemic acquired resistance) by inducing the production of pathogenesis-related proteins and other defensive metabolites. [55] SA's defense signaling role is most clearly demonstrated by experiments which do away with it: Delaney et al. 1994, Gaffney et al. 1993, Lawton et al. 1995, and Vernooij et al. 1994 each use Nicotiana tabacum or Arabidopsis expressing nahG , for salicylate hydroxylase. Pathogen inoculation did not produce the customarily high SA levels, SAR was not produced, and no pathogenesis-related (PR) genes were expressed in systemic leaves. Indeed, the subjects were more susceptible to virulent – and even normally avirulent – pathogens. [53]
Exogenously, salicylic acid can aid plant development via enhanced seed germination, bud flowering, and fruit ripening, though too high of a concentration of salicylic acid can negatively regulate these developmental processes. [56]
The volatile methyl ester of salicylic acid, methyl salicylate, can also diffuse through the air, facilitating plant-plant communication. [57] Methyl salicylate is taken up by the stomata of the nearby plant, where it can induce an immune response after being converted back to salicylic acid. [58]
A number of proteins have been identified that interact with SA in plants, especially salicylic acid binding proteins (SABPs) and the NPR genes (nonexpressor of pathogenesis-related genes), which are putative receptors. [59]
Aspirin, also known as acetylsalicylic acid (ASA), is a nonsteroidal anti-inflammatory drug (NSAID) used to reduce pain, fever, and inflammation, and as an antithrombotic. Specific inflammatory conditions that aspirin is used to treat include Kawasaki disease, pericarditis, and rheumatic fever.
Non-steroidal anti-inflammatory drugs (NSAID) are members of a therapeutic drug class which reduces pain, decreases inflammation, decreases fever, and prevents blood clots. Side effects depend on the specific drug, its dose and duration of use, but largely include an increased risk of gastrointestinal ulcers and bleeds, heart attack, and kidney disease.
In organic chemistry, an acetyl group is a functional group denoted by the chemical formula −COCH3 and the structure −C(=O)−CH3. It is sometimes represented by the symbol Ac. In IUPAC nomenclature, an acetyl group is called an ethanoylgroup.
Willows, also called sallows and osiers, of the genus Salix, comprise around 350 species of typically deciduous trees and shrubs, found primarily on moist soils in cold and temperate regions.
Filipendula ulmaria, commonly known as meadowsweet or mead wort, is a perennial herbaceous plant in the family Rosaceae that grows in damp meadows. It is native throughout most of Europe and Western Asia. It has been introduced and naturalised in North America.
Felix Hoffmann was a German chemist notable for re-synthesising diamorphine, which was popularized under the Bayer trade name of "heroin". He is also credited with synthesizing aspirin, though whether he did this under his own initiative or under the instruction of Arthur Eichengrün is contested.
Salix alba, the white willow, is a species of willow native to Europe and western and central Asia. The name derives from the white tone to the undersides of the leaves.
Methyl salicylate (oil of wintergreen or wintergreen oil) is an organic compound with the formula C8H8O3. It is the methyl ester of salicylic acid. It is a colorless, viscous liquid with a sweet, fruity odor reminiscent of root beer (in which it is used as a flavoring), but often associatively called "minty", as it is an ingredient in mint candies. It is produced by many species of plants, particularly wintergreens. It is also produced synthetically, used as a fragrance and as a flavoring agent.
Bismuth subsalicylate, sold generically as pink bismuth and under brand names including Pepto-Bismol, Pepti-Calm and BisBacter, is a medication used to treat temporary discomfort of the stomach and gastrointestinal tract. This includes an upset stomach, heartburn or other similar symptoms.
A prodrug is a pharmacologically inactive medication or compound that, after intake, is metabolized into a pharmacologically active drug. Instead of administering a drug directly, a corresponding prodrug can be used to improve how the drug is absorbed, distributed, metabolized, and excreted (ADME).
The Kolbe–Schmitt reaction or Kolbe process is a carboxylation chemical reaction that proceeds by treating phenol with sodium hydroxide to form sodium phenoxide, then heating sodium phenoxide with carbon dioxide under pressure, then treating the product with sulfuric acid. The final product is an aromatic hydroxy acid which is also known as salicylic acid.
Salicin is an alcoholic β-glucoside. Salicin is produced in willow (Salix) bark. It is a biosynthetic precursor to salicylaldehyde.
Phenyl salicylate, or salol, is the organic compound with the formula C6H5O2C6H4OH. It is a white solid. It is occasionally used in sunscreens and as an antiseptic.
Copper(II) aspirinate is an aspirin chelate of copper(II) cations (Cu2+). It is used to treat rheumatoid arthritis.
Sodium salicylate is a sodium salt of salicylic acid. It can be prepared from sodium phenolate and carbon dioxide under higher temperature and pressure. Historically, it has been synthesized by refluxing methyl salicylate with an excess of sodium hydroxide.
Edward Stone (1702–1768) was a Church of England cleric who discovered the active ingredient of aspirin.
Aspirin, an organic compound that does not occur in nature, was first synthesised in 1899.
Salicylate poisoning, also known as aspirin poisoning, is the acute or chronic poisoning with a salicylate such as aspirin. The classic symptoms are ringing in the ears, nausea, abdominal pain, and a fast breathing rate. Early on, these may be subtle, while larger doses may result in fever. Complications can include swelling of the brain or lungs, seizures, low blood sugar, or cardiac arrest.
Salicylic acid is used as a medicine to help remove the outer layer of the skin. As such it is used to treat warts, skin tags, calluses, psoriasis, dandruff, acne, ringworm, and ichthyosis. For conditions other than warts, it is often used together with other medications. It is applied to the area affected.
Lysine acetylsalicylate, also known as aspirin DL-lysine or lysine aspirin, is a more soluble form of acetylsalicylic acid (aspirin). As with aspirin itself, it is a nonsteroidal anti-inflammatory drug (NSAID) with analgesic, anti-inflammatory, antithrombotic and antipyretic properties. It is composed of the ammonium form of the amino acid lysine paired with the conjugate base of aspirin.
Noch ist es mir aber nicht geglückt, den bittern Bestandtheil der Weide, den ich Salicin nennen will, ganz frei von allem Färbestoff darzustellen.[I have still not succeeded in preparing the bitter component of willow, which I will name salicin, completely free from colored matter]
Piria mentions "Hydrure de salicyle" (hydrogen salicylate, i.e., salicylic acid).