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Verbenol
Verbenol (2-pine-4-ol) is a group of stereoisomeric bicyclic monoterpene alcohols. These compounds have been found to be active components of insect pheromones and essential oils. Isomers Four stereoisomers of verbenol are known. For the ''cis'' isomer, the two methyl groups (-CH3) are on the same side of the carbon ring as the hydroxy group (-OH), and for the ''trans'' isomer, they are on the opposite sides. Again, there are enantiomers of each form that exhibit optical activity, that is, turn the plane of linearly polarized light as it passes through the substance or its solution. ''trans''-Verbenol is a mountain pine beetle pheromone that attracts insects to a tree. ''cis''-Verbenol is an aggregation pheromone of ''Ips'' typographus and ''Dendroctonus ponderosae'' Hopkins. Enantiomeric composition Typically, verbenol and related cyclic monoterpenes are available as non‐racemic mixtures of their enantiomers. There are methods to increase enantiomeric excess In stereochemist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bicyclic
In chemistry, a bicyclic molecule () is a molecule that features two joined rings. Bicyclic structures occur widely, for example in many biologically important molecules like α-thujene and camphor. A bicyclic compound can be carbocyclic (all of the ring atoms are carbons), or heterocyclic (the rings' atoms consist of at least two elements), like DABCO. Moreover, the two rings can both be aliphatic (''e.g.'' decalin and norbornane), or can be aromatic (''e.g.'' naphthalene), or a combination of aliphatic and aromatic (''e.g.'' tetralin). Three modes of ring junction are possible for a bicyclic compound: * In spirocyclic compounds, the two rings share only one single atom, the spiro atom, which is usually a quaternary carbon. An example of a spirocyclic compound is the photochromic switch spiropyran. * In fused/condensed bicyclic compounds, two rings share two adjacent atoms. In other words, the rings share one covalent bond, ''i.e.'' the so-called bridgehead atoms are directly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monoterpene
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. Biosynthesis Monoterpenes are derived biosynthetically from units of isopentenyl pyrophosphate, which is formed from acetyl-CoA via the intermediacy of mevalonic acid in the HMG-CoA reductase pathway. An alternative, unrelated biosynthesis pathway of IPP is known in some bacterial groups and the plastids of plants, the so-called MEP-(2-methyl-D-erythritol-4-phosphate) pathway, which is initiated from C5 sugars. In both pathways, IPP is isomerized to DMAPP by the enzyme isopentenyl pyrophosphate isomerase. Geranyl pyrophosphate is the precurso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alcohols
In chemistry, an alcohol is a type of organic compound that carries at least one hydroxyl () functional group bound to a saturated carbon atom. The term ''alcohol'' originally referred to the primary alcohol ethanol (ethyl alcohol), which is used as a drug and is the main alcohol present in alcoholic drinks. An important class of alcohols, of which methanol and ethanol are the simplest examples, includes all compounds which conform to the general formula . Simple monoalcohols that are the subject of this article include primary (), secondary () and tertiary () alcohols. The suffix ''-ol'' appears in the IUPAC chemical name of all substances where the hydroxyl group is the functional group with the highest priority. When a higher priority group is present in the compound, the prefix ''hydroxy-'' is used in its IUPAC name. The suffix ''-ol'' in non-IUPAC names (such as paracetamol or cholesterol) also typically indicates that the substance is an alcohol. However, some compound ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pheromones
A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavior of the receiving individuals. There are ''alarm pheromones'', ''food trail pheromones'', ''sex pheromones'', and many others that affect behavior or physiology. Pheromones are used by many organisms, from basic unicellular prokaryotes to complex multicellular eukaryotes. Their use among insects has been particularly well documented. In addition, some vertebrates, plants and ciliates communicate by using pheromones. The ecological functions and evolution of pheromones are a major topic of research in the field of chemical ecology. Background The portmanteau word "pheromone" was coined by Peter Karlson and Martin Lüscher in 1959, based on the Greek φερω ''pheroo'' ('I carry') and ὁρμων ''hormon'' ('stimulating'). Pheromones ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Essential Oils
An essential oil is a concentrated hydrophobic liquid containing volatile (easily evaporated at normal temperatures) chemical compounds from plants. Essential oils are also known as volatile oils, ethereal oils, aetheroleum, or simply as the oil of the plant from which they were extracted, such as oil of clove. An essential oil is essential in the sense that it contains the essence of the plant's fragrance—the characteristic fragrance of the plant from which it is derived. The term "essential" used here does ''not'' mean indispensable or usable by the human body, as with the terms essential amino acid or essential fatty acid, which are so called because they are nutritionally required by a living organism. Essential oils are generally extracted by distillation, often by using steam. Other processes include expression, solvent extraction, '' sfumatura'', absolute oil extraction, resin tapping, wax embedding, and cold pressing. They are used in perfumes, cosmetics, soaps, air ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methyl Group
In organic chemistry, a methyl group is an alkyl derived from methane, containing one carbon atom bonded to three hydrogen atoms, having chemical formula . In formulas, the group is often abbreviated as Me. This hydrocarbon group occurs in many organic compounds. It is a very stable group in most molecules. While the methyl group is usually part of a larger molecule, bounded to the rest of the molecule by a single covalent bond (), it can be found on its own in any of three forms: methanide anion (), methylium cation () or methyl radical (). The anion has eight valence electrons, the radical seven and the cation six. All three forms are highly reactive and rarely observed. Methyl cation, anion, and radical Methyl cation The methylium cation () exists in the gas phase, but is otherwise not encountered. Some compounds are considered to be sources of the cation, and this simplification is used pervasively in organic chemistry. For example, protonation of methanol gives an elect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydroxy Group
In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry, alcohols and carboxylic acids contain one or more hydroxy groups. Both the negatively charged anion , called hydroxide, and the neutral radical , known as the hydroxyl radical, consist of an unbonded hydroxy group. According to IUPAC definitions, the term ''hydroxyl'' refers to the hydroxyl radical () only, while the functional group is called a ''hydroxy group''. Properties Water, alcohols, carboxylic acids, and many other hydroxy-containing compounds can be readily deprotonated due to a large difference between the electronegativity of oxygen (3.5) and that of hydrogen (2.1). Hydroxy-containing compounds engage in intermolecular hydrogen bonding increasing the electrostatic attraction between molecules and thus to higher boiling and melting points than found for compounds that lack this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enantiomer
In chemistry, an enantiomer ( /ɪˈnænti.əmər, ɛ-, -oʊ-/ ''ih-NAN-tee-ə-mər''; from Ancient Greek ἐνάντιος ''(enántios)'' 'opposite', and μέρος ''(méros)'' 'part') – also called optical isomer, antipode, or optical antipode – is one of two stereoisomers that are non-superposable onto their own mirror image. Enantiomers are much like one's right and left hands, when looking at the same face, they cannot be superposed onto each other. No amount of reorientation will allow the four unique groups on the chiral carbon (see Chirality (chemistry)) to line up exactly. The number of stereoisomers a molecule has can be determined by the number of chiral carbons it has. Stereoisomers include both enantiomers and diastereomers. Diastereomers, like enantiomers, share the same molecular formula and are non-superposable onto each other however, they are not mirror images of each other. A molecule with chirality rotates plane-polarized light. A mixture of equals a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Activity
Optical rotation, also known as polarization rotation or circular birefringence, is the rotation of the orientation of the plane of polarization about the optical axis of linearly polarized light as it travels through certain materials. Circular birefringence and circular dichroism are the manifestations of optical activity. Optical activity occurs only in chiral materials, those lacking microscopic mirror symmetry. Unlike other sources of birefringence which alter a beam's state of polarization, optical activity can be observed in fluids. This can include gases or solutions of chiral molecules such as sugars, molecules with helical secondary structure such as some proteins, and also chiral liquid crystals. It can also be observed in chiral solids such as certain crystals with a rotation between adjacent crystal planes (such as quartz) or metamaterials. When looking at the source of light, the rotation of the plane of polarization may be either to the right (dextrorotatory ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mountain Pine Beetle
The mountain pine beetle (''Dendroctonus ponderosae'') is a species of bark beetle native to the forests of western North America from Mexico to central British Columbia. It has a hard black exoskeleton, and measures approximately , about the size of a grain of rice. In western North America, a recent outbreak of the mountain pine beetle and its microbial associates has affected wide areas of lodgepole pine forest, including more than of forest in British Columbia. The outbreak in the Rocky Mountain National Park in Colorado began in 1996 and has caused the destruction of millions of acres/hectares of ponderosa and lodgepole pine trees. At the peak of the outbreak in 2009, over were affected. The outbreak then declined due to better environmental conditions and the fact that many vulnerable trees had been already destroyed. Mountain pine beetles inhabit ponderosa, whitebark, lodgepole, Scots, jack, limber, Rocky Mountain bristlecone, and Great Basin bristlecone pine tre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enantiomeric Excess
In stereochemistry, enantiomeric excess (ee) is a measurement of purity used for chiral substances. It reflects the degree to which a sample contains one enantiomer in greater amounts than the other. A racemic mixture has an ee of 0%, while a single completely pure enantiomer has an ee of 100%. A sample with 70% of one enantiomer and 30% of the other has an ee of 40% (70% − 30%). Definition Enantiomeric excess is defined as the absolute difference between the mole fraction of each enantiomer: :\ ee = , F_R - F_S, where :\ F_R + F_S = 1 In practice, it is most often expressed as a percent enantiomeric excess. The enantiomeric excess can be determined in another way if we know the amount of each enantiomer produced. If one knows the moles of each enantiomer produced then: Enantiomeric excess is used as one of the indicators of the success of an asymmetric synthesis. For mixtures of diastereomers, there are analogous definitions and uses for diastereomeric excess an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pheromones
A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavior of the receiving individuals. There are ''alarm pheromones'', ''food trail pheromones'', ''sex pheromones'', and many others that affect behavior or physiology. Pheromones are used by many organisms, from basic unicellular prokaryotes to complex multicellular eukaryotes. Their use among insects has been particularly well documented. In addition, some vertebrates, plants and ciliates communicate by using pheromones. The ecological functions and evolution of pheromones are a major topic of research in the field of chemical ecology. Background The portmanteau word "pheromone" was coined by Peter Karlson and Martin Lüscher in 1959, based on the Greek φερω ''pheroo'' ('I carry') and ὁρμων ''hormon'' ('stimulating'). Pheromones ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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