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Longifolene
Longifolene is the common (or trivial) chemical name of a naturally occurring, oily liquid hydrocarbon found primarily in the high-boiling fraction of certain pine resins. The name is derived from that of a pine species from which the compound was isolated, Chemically, longifolene is a tricyclic sesquiterpene. This molecule is chiral, and the enantiomer commonly found in pines and other higher plants exhibits a positive optical rotation of +42.73°. The other enantiomer (optical rotation −42.73°) is found in small amounts in certain fungi and liverworts. Longifolene is also one of two most abundant aroma constituents of lapsang souchong tea, because the tea is smoked over pinewood fires. Occurrence and syntheses Terpentine obtained from ''Pinus longifolia'' (obsolete name for ''Pinus roxburghii'' Sarg.) contains as much as 20% of longifolene. The laboratory synthesis of longifolene has attracted much syntheses. Biosynthesis The biosynthesis of longifolene begins wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Longifolene Biosynthesis Mechanism
Longifolene is the common (or trivial) chemical name of a naturally occurring, oily liquid hydrocarbon found primarily in the high-boiling fraction of certain pine resins. The name is derived from that of a pine species from which the compound was isolated, Chemically, longifolene is a tricyclic sesquiterpene. This molecule is chiral, and the enantiomer commonly found in pines and other higher plants exhibits a positive optical rotation of +42.73°. The other enantiomer (optical rotation −42.73°) is found in small amounts in certain fungi and liverworts. Longifolene is also one of two most abundant aroma constituents of lapsang souchong tea, because the tea is smoked over pinewood fires. Occurrence and syntheses Terpentine obtained from ''Pinus longifolia'' (obsolete name for ''Pinus roxburghii'' Sarg.) contains as much as 20% of longifolene. The laboratory synthesis of longifolene has attracted much syntheses. Biosynthesis The biosynthesis of longifolene begins with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Longifolene Total Synthesis By Corey
Longifolene is the common (or trivial) chemical name of a naturally occurring, oily liquid hydrocarbon found primarily in the high-boiling fraction of certain pine resins. The name is derived from that of a pine species from which the compound was isolated, Chemically, longifolene is a tricyclic sesquiterpene. This molecule is chiral, and the enantiomer commonly found in pines and other higher plants exhibits a positive optical rotation of +42.73°. The other enantiomer (optical rotation −42.73°) is found in small amounts in certain fungi and liverworts. Longifolene is also one of two most abundant aroma constituents of lapsang souchong tea, because the tea is smoked over pinewood fires. Occurrence and syntheses Terpentine obtained from ''Pinus longifolia'' (obsolete name for ''Pinus roxburghii'' Sarg.) contains as much as 20% of longifolene. The laboratory synthesis of longifolene has attracted much syntheses. Biosynthesis The biosynthesis of longifolene begins wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Farnesyl Diphosphate
Farnesyl pyrophosphate (FPP), also known as farnesyl diphosphate (FDP), is an intermediate in the biosynthesis of terpenes and terpenoids such as sterols and carotenoids. It is also used in the synthesis of CoQ (part of the electron transport chain), as well as dehydrodolichol diphosphate (a precursor of dolichol, which transports proteins to the ER lumen for ''N''-glycosylation). Biosynthesis Farnesyl pyrophosphate synthase (a prenyl transferase) catalyzes sequential condensation reactions of dimethylallyl pyrophosphate Dimethylallyl pyrophosphate (DMAPP; or alternatively, dimethylallyl diphosphate (DMADP); also isoprenyl pyrophosphate) is an isoprenoid precursor. It is a product of both the mevalonate pathway and the MEP pathway of isoprenoid precursor biosynt ... with 2 units of 3-isopentenyl pyrophosphate to form farnesyl pyrophosphate, as is shown in the following two steps: * Dimethylallyl pyrophosphate reacts with 3-isopentenyl pyrophosphate to form geranyl pyrop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polycyclic Nonaromatic Hydrocarbons
Polycyclic may refer to: * Polycyclic compound, a cyclic compound with more than one hydrocarbon loop or ring structures, including: ** Polycyclic musks ** Polycyclic aromatic hydrocarbon *** Chlorinated polycyclic aromatic hydrocarbon *** Contorted polycyclic aromatic hydrocarbon * Polycyclic group In mathematics, a polycyclic group is a solvable group that satisfies the maximal condition on subgroups (that is, every subgroup is finitely generated). Polycyclic groups are finitely presented, which makes them interesting from a computational ..., in mathematics, a solvable group that satisfies the maximal condition on subgroups * Polycyclic spawning, when an animal reproduces multiple times during its lifespan {{disambig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydroboration
In organic chemistry, hydroboration refers to the addition of a hydrogen-boron bond to certain double and triple bonds involving carbon (, , , and ). This chemical reaction is useful in the organic synthesis of organic compounds. Hydroboration produces organoborane compounds that react with a variety of reagents to produce useful compounds, such as alcohols, amines, or alkyl halides. The most widely known reaction of the organoboranes is oxidation to produce alcohols typically by hydrogen peroxide. This type of reaction has promoted research on hydroboration because of its mild condition and a wide scope of tolerated alkenes. Another research subtheme is metal-catalysed hydroboration. The development of this technology and the underlying concepts were recognized by the Nobel Prize in Chemistry to Herbert C. Brown. He shared the prize with Georg Wittig in 1979 for his pioneering research on organoboranes as important synthetic intermediates. Addition of a H-B bond to C-C double ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Borane
Trihydridoboron, also known as borane or borine, is an unstable and highly reactive molecule with the chemical formula . The preparation of borane carbonyl, BH3(CO), played an important role in exploring the chemistry of boranes, as it indicated the likely existence of the borane molecule. However, the molecular species BH3 is a very strong Lewis acid. Consequently, it is highly reactive and can only be observed directly as a continuously produced, transitory, product in a flow system or from the reaction of laser ablated atomic boron with hydrogen. Structure and properties BH3 is a trigonal planar molecule with D3h symmetry. The experimentally determined B–H bond length is 119 pm. In the absence of other chemical species, it reacts with itself to form diborane. Thus, it is an intermediate in the preparation of diborane according to the reaction: :BX3 +BH4− → HBX3− + (BH3) (X=F, Cl, Br, I) :2 BH3 → B2H6 The standard enthalpy of dimerization of BH3 is estim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1,2-rearrangement
A 1,2-rearrangement or 1,2-migration or 1,2-shift or Frank C. Whitmore, Whitmore 1,2-shift is an organic reaction where a substituent moves from one atom to another atom in a chemical compound. In a 1,2 shift the movement involves two adjacent atoms but moves over larger distances are possible. In the example below the substituent R moves from carbon atom C2 to C3. The rearrangement is Intramolecular reaction, intramolecular and the starting compound and reaction product are structural isomers. The 1,2-rearrangement belongs to a broad class of chemical reactions called rearrangement reactions. A rearrangement involving a hydrogen atom is called a 1,2-hydride shift. If the substituent being rearranged is an alkyl group, it is named according to the alkyl group's anion: i.e. 1,2-methanide shift, 1,2-ethanide shift, etc. Reaction mechanism A 1,2-rearrangement is often initialised by the formation of a reactive intermediate such as: *a carbocation by Heterolysis (chemistry), hete ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1,3-hydride Shift
A sigmatropic reaction in organic chemistry is a pericyclic reaction wherein the net result is one σ-bond is changed to another σ-bond in an uncatalyzed intramolecular reaction. The name ''sigmatropic'' is the result of a compounding of the long-established sigma designation from single carbon–carbon bonds and the Greek word ''tropos'', meaning turn. In this type of rearrangement reaction, a substituent moves from one part of a π-bonded system to another part in an intramolecular reaction with simultaneous rearrangement of the π system. True sigmatropic reactions are usually uncatalyzed, although Lewis acid catalysis is possible. Sigmatropic reactions often have transition-metal catalysts that form intermediates in analogous reactions. The most well-known of the sigmatropic rearrangements are the ,3 Cope rearrangement, Claisen rearrangement, Carroll rearrangement, and the Fischer indole synthesis. Overview of sigmatropic shifts Woodward–Hoffman sigmatropic shift nomencla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alkene
In organic chemistry, an alkene is a hydrocarbon containing a carbon–carbon double bond. Alkene is often used as synonym of olefin, that is, any hydrocarbon containing one or more double bonds.H. Stephen Stoker (2015): General, Organic, and Biological Chemistry'. 1232 pages. Two general types of monoalkenes are distinguished: terminal and internal. Also called α-olefins, terminal alkenes are more useful. However, the International Union of Pure and Applied Chemistry (IUPAC) recommends using the name "alkene" only for acyclic hydrocarbons with just one double bond; alkadiene, alkatriene, etc., or polyene for acyclic hydrocarbons with two or more double bonds; cycloalkene, cycloalkadiene, etc. for cyclic ones; and "olefin" for the general class – cyclic or acyclic, with one or more double bonds. Acyclic alkenes, with only one double bond and no other functional groups (also known as mono-enes) form a homologous series of hydrocarbons with the general formula with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Farnesyl Pyrophosphate
Farnesyl pyrophosphate (FPP), also known as farnesyl diphosphate (FDP), is an intermediate in the biosynthesis of terpenes and terpenoids such as sterols and carotenoids. It is also used in the synthesis of CoQ (part of the electron transport chain), as well as dehydrodolichol diphosphate (a precursor of dolichol, which transports proteins to the ER lumen for ''N''-glycosylation). Biosynthesis Farnesyl pyrophosphate synthase (a prenyl transferase) catalyzes sequential condensation reactions of dimethylallyl pyrophosphate with 2 units of 3-isopentenyl pyrophosphate to form farnesyl pyrophosphate, as is shown in the following two steps: * Dimethylallyl pyrophosphate reacts with 3-isopentenyl pyrophosphate to form geranyl pyrophosphate: * Geranyl pyrophosphate then reacts with another molecule of 3-isopentenyl pyrophosphate to form farnesyl pyrophosphate Pharmacology The above reactions are inhibited by bisphosphonates (used for osteoporosis). Farnesyl pyrophosphate is a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or exemplified by the odors of gasoline and lighter fluid. They occur in a diverse range of molecular structures and phases: they can be gases (such as methane and propane), liquids (such as hexane and benzene), low melting solids (such as paraffin wax and naphthalene) or polymers (such as polyethylene and polystyrene). In the fossil fuel industries, ''hydrocarbon'' refers to the naturally occurring petroleum, natural gas and coal, and to their hydrocarbon derivatives and purified forms. Combustion of hydrocarbons is the main source of the world's energy. Petroleum is the dominant raw-material source for organic commodity chemicals such as solvents and polymers. Most anthropogenic (human-generated) emissions of greenhouse gas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
