Heterocyclic compound

A heterocyclic compound is a type of organic compound having a cyclic structure in a molecule, and the atoms constituting the ring contain one or more other atoms such as nitrogen, sulfur, oxygen, and the like in addition to carbon. A single heterocyclic compound, such as furan, thiazole, or pyridine, containing two or more rings, and a fused heterocyclic compound such as quinoline, anthracene, and the like. The most stable and most common is a five- or six-membered heterocyclic ring. Simple heterocycles can be combined with benzene or with additional heterocycles to form bicyclic, tricyclic or more complex ring systems. Some heterocyclic rings have the characteristics of aromatic compounds, such as easy replacement reactions, difficult addition reactions, and are relatively stable to oxidants. Heterocyclic compounds are widely found in nature, such as nucleic acids, most vitamins, chlorophyll, heme, most alkaloids, pigments, and the like. Some heterocyclic compounds have aromaticity, such as coumarone in plants, jasmonone, civetone in animals, and the like. Many of the synthetic pesticides are such compounds, such as the herbicide atrazine, the herbicide, the wheat straw, the insecticide fluorogram, the quetiapine, the sterilizing agent, the chlorpyrifos and the like. Simple heterocyclic compounds are important raw materials for organic chemicals. The cyclic compounds in which the atoms constituting the ring system contain a hetero atom such as O, S, N or the like in addition to the carbon atom are collectively referred to as a heterocyclic compound. According to this definition, cyclic dianhydrides, cyclic imides, lactones, lactides, cyclic anhydrides, lactams, cyclic ethers and the like are also strictly referred to as heterocyclic compounds, but since the properties of these compounds are similar to those of aliphatics, It is easy to be obtained by ring-opening compound ring-bonding, and it is also easy to open-loop into a chain compound, which is generally discussed in aliphatic chemistry. Therefore, a heterocyclic compound generally refers to a heterocyclic compound, that is, an aromatic heterocyclic compound, in which the ring system is relatively stable and has a different degree of aromaticity. Organic heterocyclic compounds are a large class of organic compounds, such as open-chain, carbocyclic and heterocyclic, which are numerous and large in number, accounting for about 1/3 of all known organic compounds, and are ubiquitous in the biological world. It is closely related to the growth, development, reproduction, and inheritance and variation of living things. Common heterocyclic compounds include oxoprene (furan), thiophene (thiophene), nitroxyl (pyrrole), benzene (pyridine), nitrogen naphthalene (quinoline), hydrazine (carbazole) and the like. These heterocyclic compounds are widely used in organic synthesis or as medicines, agricultural chemicals, solvents, and the like. It is a colorless liquid or crystal with special odor. Its specific gravity is less than or close to water. It is toxic, soluble in some organic solvents and slightly soluble in water. In case of fire, high heat, oxidant and strong acid can cause burning or explosion, and at the same time, toxic sulfur oxide or nitrous oxide gas is precipitated. Oxime can form peroxides in the air and can cause an explosion when distilled. In the management of dangerous goods, according to the danger of fire, explosion and poison, it is classified as flammable liquid, flammable solid and organic poison; respectively; in storage, the first two are dangerous according to Class A and Class B fire, the latter Fire management according to Class C fire hazard. When the fire is on, it can be saved with foam, dry powder, misty water, 1211, carbon dioxide and other fire extinguishing agents.