Moss

Terpenes are a general term for all polymers of isoprene and their derivatives, formula (C5H8)n. Acarids are a class of compounds that are ubiquitous in the plant kingdom and are rare in the animal kingdom. In addition to their presence in the form of anthracene hydrocarbons, a wide variety is formed in the form of various oxygen-containing derivatives, including alcohols, aldehydes, ketones, carboxylic acids, esters, and anthracenes. Secondly, there are nitrogen-containing derivatives, and a small number of sulfur-containing derivatives exist. According to the number of isoprene units included in the molecule, the quinones can be classified into: monoterpenes, sesquiterpenes, diterpenes, sesquiterpenes, triterpenes, tetraterpenes, and polyterpenes. For some compounds synthesized from isoprene in the source, but the number of carbon atoms in the molecule is not 5 multiples, it is called terpenoid. In life activities, terpenoids have important functions especially in plants. For example, gibberellin, abscisic acid and insect preservative are important hormones. Carotenoids and chlorophyll are important photosynthetic pigments, plastids and pans.醌 is an important electron donor in the photosynthetic chain and the respiratory chain, and sterol is a component of the biofilm. One and the sesquiterpenes are the main components of the volatile oil, the second is the main substance forming the resin, the third is the important substance for forming the plant saponin and the resin, and the four cockroaches are mainly the fat-soluble pigments widely distributed in the plants. In nature, terpenoids are widely distributed, and some have physiological activities. For example, scorpionins and mountain tracts have the effect of aphids, artemisinins have anti-malarial effects, and andrographolide has antibacterial effects. The following are some of the chemical reactions associated with terpenoids, which are important for determining the chemical structure of terpenoids. (I) Oxidation reactions Different oxidants In different cases, different groups of oxime components can be oxidized to form different products. For example, chromic acid can oxidize carbon methyl and gem-carbon dimethyl to acetic acid; the oxidation of ozone is a valuable reaction to cleave double bonds, and the position of the double bond in the structure of the steroid component can be determined by the product of the ozonation reaction. . Lead tetraacetate is also a reagent for oxidizing double bonds and has been widely used in the chemical research of terpenoids. (2) Dehydrogenation Dehydrogenation is considered to be one of the oxidation reactions and is a valuable reaction in the study of the chemical structure of anthraquinones, especially cyclic anthraquinones. The anthraquinone component is heated with sulfur or selenium in an inert gas stream (200 ° C ~ 300 ° C), and the carbon skeleton of the ring is converted into an aromatic hydrocarbon derivative by dehydrogenation. Sometimes the complex ring may be cracked, and sometimes there may be The cyclization reaction is present at the same time. (3) Addition reaction The double bond in the quinone component can be reacted with a hydrohalic acid such as hydriodic acid or hydrogen chloride in a glacial acetic acid solution to form a crystalline addition product. It also absorbs bromine (in glacial acetic acid or diethyl ether-ethanol solution) to form bromide with certain physical and chemical properties. If mixed glacial acetic acid and sodium nitrite are shaken, nitrous oxide or pseudo nitrous oxide is formed to give a special color. If the unsaturated terpene component is added with pentylene nitrite and concentrated hydrochloric acid and shaken to keep the temperature low, and then add a small amount of ethanol or glacial acetic acid, there is a quinone chloride nitroso derivative, which also has a special color. Such nitroso derivatives (including nitrous oxides and nitrosonitro derivatives) are mostly blue or blue-green, and they are easily polymerized to form a colorless dipolymer, but the dipolymer is heated to melt or When made into a solution, it can be converted into a blue or blue-green single molecule compound. The nitrosonitro derivative can be condensed with a primary or secondary amine (usually hexahydropyridine) to form a nitrosamine, and has a good crystal shape and a certain physical and chemical constant for the unsaturated anthracene. Censorship. If the steroid component has a conjugated double bond, it can react with the butylene dianhydride to form a crystalline addition product by Diels-Alder, thereby demonstrating the presence of a conjugated double bond. (iv) Wagner-Meerweein rearrangement of terpenoids is sometimes acted upon by reagents (such as acids) to alter the carbon frame or to transfer functional groups in the molecule. In particular, Wagner-Meerweein rearrangement occurs frequently in the elimination, addition or nucleophilic substitution reactions of bicyclic guanidine compounds.