Names | |||
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Preferred IUPAC name 2-Methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one | |||
Other names 2-Methyl-5-(prop-1-en-2-yl)cyclohex-2-enone 2-Methyl-5-(1-methylethenyl)-2-cyclohexenone [1] Δ6:8(9)-p-Menthadien-2-one 1-Methyl-4-isopropenyl-Δ6-cyclohexen-2-one Carvol (obsolete) | |||
Identifiers | |||
3D model (JSmol) |
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ChEBI | |||
ChEMBL | |||
ChemSpider | |||
ECHA InfoCard | 100.002.508 | ||
KEGG | |||
PubChem CID | |||
RTECS number |
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UNII |
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CompTox Dashboard (EPA) | |||
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Properties | |||
C10H14O | |||
Molar mass | 150.22 g/mol | ||
Appearance | Clear, colorless liquid | ||
Density | 0.96 g/cm3 | ||
Melting point | 25.2 °C (77.4 °F; 298.3 K) | ||
Boiling point | 231 °C (448 °F; 504 K) (91 °C @ 5 mmHg) | ||
Insoluble (cold) Slightly soluble (hot)/soluble in trace amounts | |||
Solubility in ethanol | Soluble | ||
Solubility in diethyl ether | Soluble | ||
Solubility in chloroform | Soluble | ||
Chiral rotation ([α]D) | −61° (R)-Carvone 61° (S)-Carvone | ||
−92.2×10−6 cm3/mol | |||
Hazards | |||
Occupational safety and health (OHS/OSH): | |||
Main hazards | Flammable | ||
GHS labelling: | |||
Danger | |||
H304, H315, H317, H411 | |||
P261, P264, P270, P272, P273, P280, P301+P310, P301+P312, P302+P352, P321, P330, P331, P332+P313, P333+P313, P362, P363, P391, P405, P501 | |||
NFPA 704 (fire diamond) | |||
Safety data sheet (SDS) | External MSDS | ||
Related compounds | |||
Related ketone | menthone dihydrocarvone carvomenthone | ||
Related compounds | limonene, menthol, p-cymene, carveol | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Carvone is a member of a family of chemicals called terpenoids. [2] Carvone is found naturally in many essential oils, but is most abundant in the oils from seeds of caraway (Carum carvi), spearmint (Mentha spicata), and dill. [3]
Both carvones are used in the food and flavor industry. [3] R-(−)-Carvone is also used for air freshening products and, like many essential oils, oils containing carvones are used in aromatherapy and alternative medicine. S-(+)-Carvone has shown a suppressant effect against high-fat diet induced weight gain in mice. [4]
As the compound most responsible for the flavor of caraway, dill and spearmint, carvone has been used for millennia in food. [3] Wrigley's Spearmint Gum and spearmint flavored Life Savers are major users of natural spearmint oil from Mentha spicata .[ citation needed ] Caraway seed is extracted with alcohol to make the European drink Kümmel.[ citation needed ]
S-(+)-Carvone is also used to prevent premature sprouting of potatoes during storage, being marketed in the Netherlands for this purpose under the name Talent. [3]
R-(−)-Carvone has been approved by the U.S. Environmental Protection Agency for use as a mosquito repellent. [5]
Carvone is available inexpensively in both enantiomerically pure forms, making it an attractive starting material for the asymmetric total synthesis of natural products. For example, (S)-(+)-carvone was used to begin a 1998 synthesis of the terpenoid quassin: [6]
Carvone forms two mirror image forms or enantiomers: R-(−)-carvone, has a sweetish minty smell, like spearmint leaves. Its mirror image, S-(+)-carvone, has a spicy aroma with notes of rye, like caraway seeds. [7] [8] The fact that the two enantiomers are perceived as smelling different is evidence that olfactory receptors must respond more strongly to one enantiomer than to the other. Not all enantiomers have distinguishable odors. Squirrel monkeys have also been found to be able to discriminate between carvone enantiomers. [9]
The two forms are also referred to, in older texts, by their optical rotations of laevo (l) referring to R-(−)-carvone, and dextro (d) referring to S-(+)-carvone. Modern naming refers to levorotatory isomers with the sign (-) and dextrorotatory isomers with the sign (+) in the systematic name.
S-(+)-Carvone is the principal constituent (60–70%) of the oil from caraway seeds (Carum carvi), [10] which is produced on a scale of about 10 tonnes per year. [3] It also occurs to the extent of about 40–60% in dill seed oil (from Anethum graveolens), and also in mandarin orange peel oil. R-(−)-Carvone is also the most abundant compound in the essential oil from several species of mint, particularly spearmint oil ( Mentha spicata ), which is composed of 50–80% R-(−)-carvone. [11] Spearmint is a major source of naturally produced R-(−)-carvone. However, the majority of R-(−)-carvone used in commercial applications is synthesized from R-(+)-limonene. [12] The R-(−)-carvone isomer also occurs in kuromoji oil. Some oils, like gingergrass oil, contain a mixture of both enantiomers. Many other natural oils, for example peppermint oil, contain trace quantities of carvones.
Caraway was used for medicinal purposes by the ancient Romans, [3] but carvone was probably not isolated as a pure compound until Franz Varrentrapp (1815–1877) obtained it in 1849. [2] [13] It was originally called carvol by Schweizer. Goldschmidt and Zürrer identified it as a ketone related to limonene, [14] and the structure was finally elucidated by Georg Wagner (1849–1903) in 1894. [15]
The dextro-form, S-(+)-carvone is obtained practically pure by the fractional distillation of caraway oil. The levo-form obtained from the oils containing it usually requires additional treatment to produce high purity R-(−)-carvone. This can be achieved by the formation of an addition compound with hydrogen sulfide, from which carvone may be regenerated by treatment with potassium hydroxide in ethanol and then distilling the product in a current of steam. Carvone may be synthetically prepared from limonene via limonene nitrosochloride which may be formed by treatment of limonene with isoamyl nitrite in glacial acetic acid. This compound is then converted into carvoxime, which can be achieved by refluxing with DMF in isopropanol. Refluxing carvoxime with 5% oxalic acid yields carvone. [16] This procedure affords R-(−)-carvone from R-(+)-limonene. The major use of d-limonene is as a precursor to S-(+)-carvone. The large scale availability of orange rinds, a byproduct in the production of orange juice, has made limonene cheaply available, and synthetic carvone correspondingly inexpensively prepared. [17]
The biosynthesis of carvone is by oxidation of limonene.
There are three double bonds in carvone capable of reduction; the product of reduction depends on the reagents and conditions used. [2] Catalytic hydrogenation of carvone (1) can give either carvomenthol (2) or carvomenthone (3). Zinc and acetic acid reduce carvone to give dihydrocarvone (4). MPV reduction using propan-2-ol and aluminium isopropoxide effects reduction of the carbonyl group only to provide carveol (5); a combination of sodium borohydride and CeCl3 (Luche reduction) is also effective. Hydrazine and potassium hydroxide give limonene (6) via a Wolff–Kishner reduction.
Oxidation of carvone can also lead to a variety of products. [2] In the presence of an alkali such as Ba(OH)2, carvone is oxidised by air or oxygen to give the diketone 7. With hydrogen peroxide the epoxide 8 is formed. Carvone may be cleaved using ozone followed by steam, giving dilactone 9, while KMnO4 gives 10.
As an α,β;-unsaturated ketone, carvone undergoes conjugate additions of nucleophiles. For example, carvone reacts with lithium dimethylcuprate to place a methyl group trans to the isopropenyl group with good stereoselectivity. The resulting enolate can then be allylated using allyl bromide to give ketone 11. [18]
In the body, in vivo studies indicate that both enantiomers of carvone are mainly metabolized into dihydrocarvonic acid, carvonic acid and uroterpenolone. [19] (–)-Carveol is also formed as a minor product via reduction by NADPH. (+)-Carvone is likewise converted to (+)-carveol. [20] This mainly occurs in the liver and involves cytochrome P450 oxidase and (+)-trans-carveol dehydrogenase.
Mentha is a genus of plants in the family Lamiaceae. The exact distinction between species is unclear; it is estimated that 13 to 24 species exist. Hybridization occurs naturally where some species' ranges overlap. Many hybrids and cultivars are known.
Spearmint, also known as garden mint, common mint, lamb mint and mackerel mint, is a species of mint, Mentha spicata (, native to Europe and southern temperate Asia, extending from Ireland in the west to southern China in the east. It is naturalized in many other temperate parts of the world, including northern and southern Africa, North America, and South America. It is used as a flavouring in food and herbal teas. The aromatic oil, called oil of spearmint, is also used as a flavoring and sometimes as a scent.
Caraway, also known as meridian fennel and Persian cumin, is a biennial plant in the family Apiaceae, native to western Asia, Europe, and North Africa.
Menthol is an organic compound, more specifically a monoterpenoid, made synthetically or obtained from the oils of corn mint, peppermint, or other mints. It is a waxy, clear or white crystalline substance, which is solid at room temperature and melts slightly above.
In chemistry, a molecule or ion is called chiral if it cannot be superposed on its mirror image by any combination of rotations, translations, and some conformational changes. This geometric property is called chirality. The terms are derived from Ancient Greek χείρ (cheir) 'hand'; which is the canonical example of an object with this property.
Linalool refers to two enantiomers of a naturally occurring terpene alcohol found in many flowers and spice plants. Linalool has multiple commercial applications, the majority of which are based on its pleasant scent. A colorless oil, linalool is classified as an acyclic monoterpenoid. In plants, it is a metabolite, a volatile oil component, an antimicrobial agent, and an aroma compound. Linalool has uses in manufacturing of soaps, fragrances, food additives as flavors, household products, and insecticides. Esters of linalool are referred to as linalyl, e.g. linalyl pyrophosphate, an isomer of geranyl pyrophosphate.
Enantioselective synthesis, also called asymmetric synthesis, is a form of chemical synthesis. It is defined by IUPAC as "a chemical reaction in which one or more new elements of chirality are formed in a substrate molecule and which produces the stereoisomeric products in unequal amounts."
Anethole is an organic compound that is widely used as a flavoring substance. It is a derivative of phenylpropene, a type of aromatic compound that occurs widely in nature, in essential oils. It is in the class of phenylpropanoid organic compounds. It contributes a large component of the odor and flavor of anise and fennel, anise myrtle (Myrtaceae), liquorice (Fabaceae), magnolia blossoms, and star anise (Schisandraceae). Closely related to anethole is its isomer estragole, abundant in tarragon (Asteraceae) and basil (Lamiaceae), that has a flavor reminiscent of anise. It is a colorless, fragrant, mildly volatile liquid. Anethole is only slightly soluble in water but exhibits high solubility in ethanol. This trait causes certain anise-flavored liqueurs to become opaque when diluted with water; the ouzo effect.
Limonene is a colorless liquid aliphatic hydrocarbon classified as a cyclic monoterpene, and is the major component in the oil of citrus fruit peels. The D-isomer, occurring more commonly in nature as the fragrance of oranges, is a flavoring agent in food manufacturing. It is also used in chemical synthesis as a precursor to carvone and as a renewables-based solvent in cleaning products. The less common L-isomer has a piny, turpentine-like odor, and is found in the edible parts of such plants as caraway, dill, and bergamot orange plants.
Spearmint is a flavour that is either naturally or artificially created to taste like the oil of the herbaceous Mentha spicata (spearmint) plant.
Orange oil is an essential oil produced by cells within the rind of an orange fruit. In contrast to most essential oils, it is extracted as a by-product of orange juice production by centrifugation, producing a cold-pressed oil. It is composed of mostly d-limonene, and is often used in place of pure d-limonene. D-limonene can be extracted from the oil by distillation.
Humulene, also known as α-humulene or α-caryophyllene, is a naturally occurring monocyclic sesquiterpene (C15H24), containing an 11-membered ring and consisting of 3 isoprene units containing three nonconjugated C=C double bonds, two of them being triply substituted and one being doubly substituted. It was first found in the essential oils of Humulus lupulus (hops), from which it derives its name. Humulene is an isomer of β-caryophyllene, and the two are often found together as a mixture in many aromatic plants.
Carveol is a natural unsaturated, monocyclic monoterpenoid alcohol that is a constituent of spearmint essential oil in the form of cis-(−)-carveol. It is a colorless fluid soluble in oils, but insoluble in water and has an odor and flavor that resemble those of spearmint and caraway. Consequently, it is used as a fragrance in cosmetics and as a flavor additive in the food industry.
Monoterpenes are a class of terpenes that consist of two isoprene units and have the molecular formula C10H16. Monoterpenes may be linear (acyclic) or contain rings (monocyclic and bicyclic). Modified terpenes, such as those containing oxygen functionality or missing a methyl group, are called monoterpenoids. Monoterpenes and monoterpenoids are diverse. They have relevance to the pharmaceutical, cosmetic, agricultural, and food industries.
Fenchone is an organic compound classified as a monoterpenoid and a ketone. It is a colorless oily liquid. It has a structure and an odor similar to those of camphor. Fenchone is a constituent of absinthe and the essential oil of fennel. Fenchone is used as a flavor in foods and in perfumery.
In enzymology, a carveol dehydrogenase (EC 1.1.1.243) is an enzyme that catalyzes the chemical reaction
In enzymology, a (R)-limonene 6-monooxygenase (EC 1.14.13.80) is an enzyme that catalyzes the chemical reaction
In enzymology, a (S)-limonene 6-monooxygenase (EC 1.14.13.48) is an enzyme that catalyzes the chemical reaction
The enzyme (4S)-limonene synthase catalyzes the chemical reaction