Monoterpenes

Camphor () is a waxy, colorless solid with a strong aroma. It is classified as a terpenoid and a cyclic ketone. It is found in the wood of the camphor laurel (Cinnamomum camphora), a large evergreen tree found in East Asia; and in the kapur tree (Dryobalanops sp.), a tall timber tree from South East Asia. It also occurs in some other related trees in the laurel family, notably Ocotea usambarensis. Rosemary leaves (Rosmarinus officinalis) contain 0.05 to 0.5% camphor, while camphorweed (Heterotheca) contains some 5%. A major source of camphor in Asia is camphor basil (the parent of African blue

Menthol is a monoterpenoid organic compound that occurs naturally in the oils of certain plants in the mint family, such as corn mint and peppermint. It is a white or clear waxy crystalline substance that is solid at room temperature and melts slightly above. The main form of menthol occurring in nature is (−)-menthol, which is assigned the (1R,2S,5R) configuration.

Limonene () is a colorless liquid aliphatic hydrocarbon classified as a cyclic monoterpene, and is the major component in the fragrance and essential oil of citrus fruit peels, taking its name from Italian limone ("lemon").

Hinokitiol (β-thujaplicin) is a natural monoterpenoid found in the wood of trees in the family Cupressaceae. It is a tropolone derivative and one of the thujaplicins. Hinokitiol is used in oral and skin care products, and is a food additive used in Japan.

Thymol (also known as 2-isopropyl-5-methylphenol, IPMP), , is a monoterpenoid, phenol derivative of p-cymene, isomeric with carvacrol. It occurs naturally in oil of thyme and is extracted from Thymus vulgaris (common thyme), ajwain, and various other plants, as a white crystalline substance with a pleasant aromatic odor.

Geraniol is a monoterpenoid and an alcohol. It is the primary component of citronella oil and is a primary component of rose oil and palmarosa oil. It is a colorless oil, although commercial samples can appear yellow. It has low solubility in water, but it is soluble in common organic solvents.

Linalool (), also called linalol refers to two enantiomers of a naturally occurring terpene alcohol found in many flowers and spice plants. Together with geraniol, nerol, and citronellol, linalool is one of the rose alcohols. Linalool has multiple commercial applications, the majority of which are based on its pleasant scent (floral, with a touch of spiciness).

Eucalyptol (also called cineole) is a monoterpenoid colorless liquid, and a bicyclic ether. It has a fresh camphor-like odor and a spicy, cooling taste. It is insoluble in water, but miscible with organic solvents. Eucalyptol makes up about 70–90% of eucalyptus oil. Eucalyptol forms crystalline adducts with hydrohalic acids, o-cresol, resorcinol, and phosphoric acid. Formation of these adducts is useful for purification.

Borneol is a bicyclic organic compound and a terpene derivative. The hydroxyl group in this compound is placed in an endo position. The exo diastereomer is called isoborneol. Being chiral, borneol exists as enantiomers, both of which are found in nature: d-borneol (also written (+)-borneol, dextroborneol, dexborneol) and l-borneol (or (−)-borneol, levoborneol).

Thujone () is a ketone and a monoterpene that occurs predominantly in two diastereomeric (epimeric) forms: (−)-α-thujone and (+)-β-thujone.

Citral is an acyclic monoterpene aldehyde. Being a monoterpene, it is made of two isoprene units. Citral is a collective term which covers two geometric isomers that have their own separate names; the E-isomer is named geranial (trans-citral; α-citral) or citral A. The Z-isomer is named neral (cis-citral; β-citral) or citral B. These stereoisomers occur as a mixture, often not in equal proportions; e.g. in essential oil of Australian ginger, the neral to geranial ratio is 0.61.

Carvacrol, or cymophenol, C6H3(CH3)(OH)C3H7, is a monoterpenoid phenol. It has a characteristic pungent, warm odor of oregano.

Carvone is a member of a family of chemicals called terpenoids. 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.

Camphene is a bicyclic organic compound. It is one of the most pervasive monoterpenes. As with other terpenes, it is insoluble in water, flammable, colorless, and has a pungent smell. It is a minor constituent of many essential oils such as turpentine, cypress oil, camphor oil, citronella oil, neroli, ginger oil, valerian, and mango. It is produced industrially by isomerization of the more common alpha-pinene using a solid acid catalyst such as titanium dioxide.

'''p-Cymene' is a naturally occurring aromatic organic compound. It is classified as an alkylbenzene related to monocyclic monoterpenes. Its structure consists of a benzene ring para-substituted with a methyl group and an isopropyl group. p''-Cymene is insoluble in water, but miscible with organic solvents.

Myrcene, or β-myrcene, is a monoterpene. A colorless oil, it occurs widely in essential oils. It is produced mainly semi-synthetically from Myrcia, from which it gets its name. It is an intermediate in the production of several fragrances. A less-common isomeric form, having one of the three alkene units in a different position, is α-myrcene.

Citronellal or rhodinal (C10H18O) is a monoterpenoid aldehyde, the main component in the mixture of terpenoid chemical compounds that give citronella oil its distinctive lemon scent.

Nerol is a monoterpenoid alcohol found in many essential oils such as lemongrass and hops. It was originally isolated from neroli oil, hence its name. This colourless liquid is used in perfumery. Like geraniol, nerol has a sweet rose odor but it is considered to be fresher. Esters and related derivatives of nerol are referred to as neryl, e.g., neryl acetate.

Citronellol, or dihydrogeraniol, is a natural acyclic monoterpenoid. Both enantiomers occur in nature. (+)-Citronellol, which is found in citronella oils, including Cymbopogon nardus (50%), is the more common isomer. (−)-Citronellol is widespread, but particularly abundant in the oils of rose (18–55%) and Pelargonium geraniums.

Pinene is a collection of unsaturated bicyclic monoterpenes. Two geometric isomers of pinene are found in nature, α-pinene and β-pinene. Both are chiral, and both contain a strained four-membered ring. As the name suggests, pinenes are found in pines. Specifically, pinene is the major component of the liquid extracts of conifers. Pinenes are also found in many non-coniferous plants such as camphorweed (Heterotheca) and big sagebrush (Artemisia tridentata).

chemical compound

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.

Sabinene is a natural bicyclic monoterpene with the molecular formula C10H16. It is isolated from the essential oils of a variety of plants including Marjoram, holm oak (Quercus ilex) and Norway spruce (Picea abies). It has a strained ring system with a cyclopentane ring fused to a cyclopropane ring.

Menthone is a chemical compound of the monoterpene class of naturally occurring organic compounds found in a number of essential oils, one that presents with minty flavor. It is a specific pair of stereoisomers of the four possible such isomers for the chemical structure, 2-isopropyl-5-methylcyclohexanone. Of those, the stereoisoomer '''l-menthone'—formally, the (2S,5R)-trans'' isomer of that structure, as shown at right—is the most abundant in nature. Menthone is structurally related to menthol, which has a secondary alcohol (>C-OH) in place of the carbon-oxygen double bond (carbonyl group) p

Safranal is an organic compound isolated from saffron, the spice consisting of the stigmas of crocus flowers (Crocus sativus). It is the constituent primarily responsible for the aroma of saffron.

Terpineol is any of four isomeric monoterpenoids. Terpenoids are terpene that are modified by the addition of a functional group, in this case, an alcohol. Terpineols have been isolated from a variety of sources such as cardamom, cajuput oil, pine oil, and petitgrain oil. Four isomers exist: α-terpineol, β-terpineol, γ-terpineol, and terpinen-4-ol. β-Terpineol and γ-terpineol differ only by the location of the double bond. Terpineol is usually a mixture of these isomers with α-terpineol as the major constituent.

Verbenone is a natural organic compound classified as a terpene that is found naturally in a variety of plants. The chemical has a pleasant characteristic odor. Besides being a natural constituent of plants, it and its analogs are insect pheromones. In particular, verbenone when formulated in a long-lasting matrix has an important role in the control of bark beetles such as the mountain pine beetle and the Southern pine bark beetle.

α-Pinene is an organic compound of the terpene class. It is one of the two isomers of pinene, the other being β-pinene. An alkene, it contains a strained four-membered ring. It is found in the oils of many species of coniferous trees, notably Pinus and Picea species. It is also found in the essential oil of rosemary (Rosmarinus officinalis) and Satureja myrtifolia (also known as Zoufa in some regions). Both enantiomers are known in nature; (1S,5S)- or (−)-α-pinene is more common in European pines, whereas the (1R,5R)- or (+)-α-isomer is more common in North America. The enantiomers' racemic mi

The terpinenes are a group of isomeric hydrocarbons that are classified as monoterpenes. They each have the same molecular formula and carbon framework, but they differ in the position of carbon-carbon double bonds. α-Terpinene has been isolated from cardamom and marjoram oils, and from other natural sources. β-Terpinene has no known natural source but has been prepared from sabinene. γ-Terpinene and δ-terpinene (also known as terpinolene) have been isolated from a variety of plant sources. They are all colorless liquids with a turpentine-like odor.

chemical compound

β-Pinene is a monoterpene, an organic compound found in plants. It is the less abundant of the two isomers of pinene, the other being α-pinene. It is a colorless liquid soluble in alcohol, but not water. It has a woody-green pine-like smell.

pair of enantiomers

Pulegone is a naturally occurring organic compound obtained from the essential oils of a variety of plants such as Nepeta cataria (catnip), Mentha piperita, and pennyroyal. It is classified as a monoterpenoid, which means that it is an oxidized derivative of a terpene, a large class of naturally occurring C10 hydrocarbons.

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.

Ocimenes are a group of isomeric hydrocarbons. The ocimenes are monoterpenes found within a variety of plants and fruits. α-Ocimene and the two β-ocimenes differ in the position of the isolated double bond: it is terminal in the alpha isomer. α-Ocimene is cis-3,7-dimethyl-1,3,7-octatriene. β-Ocimene is trans-3,7-dimethyl-1,3,6-octatriene. β-Ocimene exists in two stereoisomeric forms, cis and trans, with respect to the central double bond.

Ascaridole is a natural organic compound classified as a bicyclic monoterpenoid that has an unusual bridging peroxide functional group. It is a colorless liquid with a pungent smell and taste that is soluble in most organic solvents. Like other low molecular weight organic peroxides, it is unstable and prone to rapid decomposition when heated or treated with organic acids. Ascaridole determines the specific flavor of the Chilean tree boldo and is a major constituent of the oil of Mexican tea (wormseed). It is a component of natural medicine, tonic drinks and food flavoring in Latin American cu

3-Carene is a bicyclic monoterpene consisting of fused cyclohexene and cyclopropane rings. It occurs as a constituent of turpentine, with a content as high as 42% depending on the source. Carene has a sweet and pungent odor, best described as a combination of fir needles, musky earth, and damp woodlands.

Cuminaldehyde (4-isopropylbenzaldehyde) is a natural organic compound with the molecular formula C10H12O. It is a benzaldehyde with an isopropyl group substituted in the 4-position.

Myrcenol is an organic compound, specifically a terpenoid. It is most notable as one of the fragrant components of lavender oil.

Fenchol or 1,3,3-trimethyl-2-norbornanol is a monoterpenoid and an isomer of borneol. It is a colorless or white solid. It occurs widely in nature.

Bornane (or camphane) is a compound closely related to norbornane.

Piperitone is a natural monoterpene ketone which is a component of some essential oils. Both stereoisomers, the D-form and the L-form, are known. The D-form has a peppermint-like aroma and has been isolated from the oils of plants from the genera Cymbopogon, Andropogon, and Mentha. The L-form has been isolated from Sitka spruce.

Phellandrenes are organic compounds with the formula . They have a similar molecular structure and similar chemical properties. α-Phellandrene and β-phellandrene are cyclic monoterpenes and are double-bond isomers. In α-phellandrene, both double bonds are endocyclic, and in β-phellandrene, one of them is exocyclic. Both are insoluble in water, but miscible with organic solvents.

Picrocrocin is a monoterpene glycoside precursor of safranal. It is found in the spice saffron, which comes from the crocus flower. Picrocrocin has a bitter taste, and is the chemical most responsible for the taste of saffron.

Rhodinol is the chemical compound 3,7-dimethyloct-7-en-1-ol. As the (3S) isomer it is CAS 6812-78-8, and as the racemate it is CAS 141-25-3.

Thujene (or α-thujene) is a natural organic compound classified as a monoterpene. It is found in the essential oils of a variety of plants, and contributes pungency to the flavor of some herbs such as Summer savory.

Terpinen-4-ol is an isomer of terpineol with the chemical formula C10H18O. A primary constituent of tea tree oil, it is obtained as an extract from the leaves, branches, and bark of Melaleuca alternifolia Cheel. Despite considerable basic and preliminary clinical research of terpinen-4-ol and tea tree oil, its biological properties and potential for clinical uses have not been established as of 2019. It may be a factor in the contact dermatitis of tea tree oil when used topically.

Grandisol is a natural organic compound with the molecular formula C10H18O. It is a monoterpene containing a cyclobutane ring, an alcohol group, an alkene group and two chiral centers (one of which is quaternary).

chemical compound

chemical compound

Thymoquinone is a phytochemical compound found in the plant Nigella sativa. It is also found in select cultivated Monarda fistulosa plants, which can be steam distilled to produce an essential oil. Thymoquinone is also a major oxidation product of both thymol and its structural isomer, carvacrol.

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.

Perillaldehyde, perillic aldehyde or perilla aldehyde, is a natural organic compound found most abundantly in the annual herb perilla, but also in a wide variety of other plants and essential oils. It is a monoterpenoid containing an aldehyde functional group.

chemical compound

Perillartine, also known as perillartin and perilla sugar, is a semisynthetic sweetener that is about 2000 times as sweet as sucrose. It is mainly used in Japan. Perillartine is the oxime of perillaldehyde, which is extracted from plants of the genus Perilla (Lamiaceae).

Chrysanthenone (C10H14O) is a terpenoid. It can be produced from its isomer verbenone in a photochemical rearrangement reaction.

Menthofuran is an organic compound found in a variety of essential oils including that of pennyroyal (Mentha pulegium). It is highly toxic and believed to be the primary toxin in pennyroyal responsible for its potentially fatal effects. After ingestion of menthofuran, it is metabolically activated to chemically reactive intermediates that are hepatotoxic.

Halomon is a polyhalogenated monoterpene first isolated from the marine red algae Portieria hornemannii. Halomon has attracted research interest because of its promising profile of selective cytotoxicity that suggests its potential use as an antitumor agent.

chemical compound

Hydroxycitronellal (7-hydroxy-3,7-dimethyloctanal) is an odorant used in perfumery. Its molecular formula is C10H20O2.