Sesquiterpenes are quinones containing three isoprene units, generally of the general formula CH, most of which conform to the isoprene rule. The sesquiterpenoids are widely distributed and are most abundant in the magnoliales, rutales, cornales, and asterales plants. The sesquiterpene is mostly present in volatile oils in the form of oxygen-containing derivatives such as alcohols, ketones, lactones, etc. It is the main component of the high-boiling part of the volatile oil, and has strong aroma and biological activity, and is a medicine, food, and cosmetics. An important raw material for industry. There are many sesquiterpenoids, and the most one of the terpenoids is in terms of number and type of structural skeleton. The sesquiterpene compounds are classified according to the number of carbon rings of their structure, such as acyclic, monocyclic, bicyclic, tricyclic and tetracyclic. It is also classified according to the size of the ring, such as the five, six, and seven-member rings, up to the eleven-yuan ring. For example, it is easy to recognize their physical and chemical properties and physiological activities such as sesquiterpene alcohol, aldehyde, lactone and the like. Some common sesquiterpenoids are listed below: (1) Farnesol is an open-chain sesquiterpene which is found in the volatile oils of various aromatic plants such as lemongrass, orange blossom, and rose. An oily liquid is a precious spice. It also has insect juvenile hormone activity. Excessive insect hormones can inhibit the metamorphosis and maturation of insects. (2) germacone. Also known as the big yak ketone, it is present in the volatile oil of the leaves of Xing'an Rhododendron (Manshan Red), which is a 10-membered ring of monocyclic sesquiterpenes. Manchurian red volatile oil has antitussive, expectorant and antiasthmatic effects, and can be used for the treatment of chronic bronchitis. The main component of azadirachtin is 56-57 ° C. (3) Guaiazulene. It is a sesquiterpene component in the volatile oil of the genus guaiac wood, the volatile oil of geranium, and the like. It is a blue needle crystal with a melting point of 31 ° C. It has anti-inflammatory effect and can promote the healing of burns or burn wounds. It is one of the main components of domestic burn cream. Figure 1 shows the structure of the guaiac wood.
    
    
    
        
    
    
    
        
            
                
                
                    
                        
                        
                        
                        
                        
                        
                            
                                
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                                    Amino compound
                                    
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                                    Oxy-containing amino compound
                                    
                                    
                                    Cycloalkylamines, aromatic monoamines, aromatic polyamines and derivatives and salts thereof
                                    
                                    
                                    Acyclic monoamines, polyamines and their derivatives and salts
                                    
                                    
                                    Amide compound
                                    
                                    
                                    Sulfonic acid amino compound
                                    
                                    
                                
 
                                
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                                    Alcohols, phenols, phenolic compounds and derivatives
                                    
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                                    2-cycloalcohol
                                    
                                    
                                    Halogenated, sulfonated, nitrated or nitrosated derivatives of alcohols
                                    
                                    
                                    Extremely halogenated, sulfonated, nitrated or nitrosated derivatives of phenols
                                    
                                    
                                    Phenol and its halogenated, sulfonated, nitrated or nitrosated derivatives
                                    
                                    
                                    Acyclic alcohol
                                    
                                    
                                
 
                                
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                                    Nitrogen-containing compound
                                    
                                    
                                
 
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                                    Nitrile compound
                                    
                                    
                                
 
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                                    Organic derivative of hydrazine or hydrazine
                                    
                                    
                                
 
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                                    Terpenoid
                                    
                                    
                                
 
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                                    Ether compounds and their derivatives
                                    
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                                    Ether, ether alcohol
                                    
                                    
                                    Halogenation, sulfonation, nitration or nitrosation of ethers, ether alcohols, ether phenols
                                    
                                    
                                
 
                                
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                                    Aldehyde
                                    
                                    
                                
 
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                                    Carboxylic compounds and derivatives
                                    
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                                    Cyclic carboxylic acid
                                    
                                    
                                    Halogenation, sulfonation, nitration or nitrosation of carboxylic acids
                                    
                                    
                                    Halogenation, sulfonation, nitration or nitration of carboxylic anhydrides
                                    
                                    
                                    Carboxylic acid halide
                                    
                                    
                                    Carboxylic esters and their derivatives
                                    
                                    
                                    Salt of carboxylic acid ester and its derivatives
                                    
                                    
                                    Acyclic carboxylic acid
                                    
                                    
                                
 
                                
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                                    Hydrocarbon compounds and their derivatives
                                    
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                                    Aromatic hydrocarbon
                                    
                                    
                                    Cyclic hydrocarbon
                                    
                                    
                                    Hydrocarbon sulfonate
                                    
                                    
                                    Hydrocarbon halide
                                    
                                    
                                    Hydrocarbon nitrite
                                    
                                    
                                    Acyclic hydrocarbon
                                    
                                    
                                
 
                                
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                                    Ketone compound
                                    
                                    
                                
 
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                                    Alkyl ureas and their derivatives and salts
                                    
                                    
                                
 
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                                    Inorganic acid ester
                                    
                                    
                                
 
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                                    Heterocyclic compound
                                    
                                    
                                
 
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                                    Diazo, azo or azo compound
                                    
                                    
                                
 
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                                    Organosilicon compound
                                    
                                    
                                
 
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                                    Organometallic compound
                                    
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                                    Organic palladium
                                    
                                    
                                    Organic germanium, cobalt, strontium, barium, gallium, germanium, germanium, germanium, germanium, etc.
                                    
                                    
                                    Organic calcium
                                    
                                    
                                    Zirconium
                                    
                                    
                                    Organic potassium
                                    
                                    
                                    Organic
                                    
                                    
                                    Organic lithium
                                    
                                    
                                    Organic
                                    
                                    
                                    Organic aluminum
                                    
                                    
                                    Organotin
                                    
                                    
                                    Organic manganese
                                    
                                    
                                    Organic sodium
                                    
                                    
                                    Organic nickel
                                    
                                    
                                    Organic titanium
                                    
                                    
                                    Organic iron
                                    
                                    
                                    Organic copper
                                    
                                    
                                    Organotin
                                    
                                    
                                    Organic zinc
                                    
                                    
                                    Organic
                                    
                                    
                                    Organic
                                    
                                    
                                    Organic germanium, mercury, silver, platinum, etc.
                                    
                                    
                                    Organic germanium, antimony, bismuth, tungsten, antimony, bismuth, lead, vanadium, molybdenum, chromium, antimony, etc.
                                    
                                    
                                
 
                                
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                                    Organic sulfur compound
                                    
                                    
                                
 
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                                    Organic phosphine compound
                                    
                                    
                                
 
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                                    Organometallic salt
                                    
                                    
                                
 
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                                    Organic fluorine compound
                                    
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                                    Fluorobenzoic acid series
                                    
                                    
                                    Fluorobenzonitrile series
                                    
                                    
                                    Fluorobenzaldehyde series
                                    
                                    
                                    Fluorobenzyl alcohol series
                                    
                                    
                                    Fluoroanisole series
                                    
                                    
                                    Fluoroaniline series
                                    
                                    
                                    Fluorophenylacetic acid series
                                    
                                    
                                    Fluorophenol series
                                    
                                    
                                    Fluorobenzoic acid series
                                    
                                    
                                    Fluoronitrobenzene series
                                    
                                    
                                    Fluoropyridine series
                                    
                                    
                                    Potassium fluoroborate series
                                    
                                    
                                    Fluorobenzyl alcohol series
                                    
                                    
                                    Fluorotoluene series
                                    
                                    
                                    Fluorine red series
                                    
                                    
                                    Fluoroethane series
                                    
                                    
                                    Fluoropropane series