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Azonine
Azonine is an unsaturated heterocycle of nine atoms, with a nitrogen replacing a carbon at one position. A variety of derivatives have been synthesised. It is considered to possess a considerable amount of aromatic stability. It and C9H9– are the largest monocyclic all-''cis'' ring systems to be aromatic and close to planar. Due to a balance between angle strain (~20°) and aromaticity, a planar conformation and distorted conformation are very close in energy and the two are observable as an equilibrium mixture in the solution phase in acetone. Furthermore, the presence of substituents or nearby cations strongly influences the conformation. See also * Azepine * Pyrrole * Cyclononatetraene * (2Z,4Z,6Z,8Z)-Thionine * Oxonine Oxonine is an unsaturated heterocycle of nine atoms, with an oxygen replacing a carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent In chemistry, the valence (US spelling) or ... R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterocyclic Compounds With 1 Ring
A heterocyclic compound or ring structure is a cyclic compound that has atoms of at least two different elements as members of its ring(s). Heterocyclic chemistry is the branch of organic chemistry dealing with the synthesis, properties, and applications of these heterocycles. Examples of heterocyclic compounds include all of the nucleic acids, the majority of drugs, most biomass (cellulose and related materials), and many natural and synthetic dyes. More than half of known compounds are heterocycles. 59% of US FDA-approved drugs contain nitrogen heterocycles. Classification The study of heterocyclic chemistry focuses especially on unsaturated derivatives, and the preponderance of work and applications involves unstrained 5- and 6-membered rings. Included are pyridine, thiophene, pyrrole, and furan. Another large class of heterocycles refers to those fused to benzene rings. For example, the fused benzene derivatives of pyridine, thiophene, pyrrole, and furan are quinol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterocycle
A heterocyclic compound or ring structure is a cyclic compound that has atoms of at least two different elements as members of its ring(s). Heterocyclic chemistry is the branch of organic chemistry dealing with the synthesis, properties, and applications of these heterocycles. Examples of heterocyclic compounds include all of the nucleic acids, the majority of drugs, most biomass (cellulose and related materials), and many natural and synthetic dyes. More than half of known compounds are heterocycles. 59% of US FDA-approved drugs contain nitrogen heterocycles. Classification The study of heterocyclic chemistry focuses especially on unsaturated derivatives, and the preponderance of work and applications involves unstrained 5- and 6-membered rings. Included are pyridine, thiophene, pyrrole, and furan. Another large class of heterocycles refers to those fused to benzene rings. For example, the fused benzene derivatives of pyridine, thiophene, pyrrole, and furan are quinol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrrole
Pyrrole is a heterocyclic aromatic organic compound, a five-membered ring with the formula C4 H4 NH. It is a colorless volatile liquid that darkens readily upon exposure to air. Substituted derivatives are also called pyrroles, e.g., ''N''-methylpyrrole, C4H4NCH3. Porphobilinogen, a trisubstituted pyrrole, is the biosynthetic precursor to many natural products such as heme. Pyrroles are components of more complex macrocycles, including the porphyrinogens and products derived therefrom, including porphyrins of heme, the chlorins, bacteriochlorins, and chlorophylls. Properties Pyrrole is a colorless volatile liquid that darkens readily upon exposure to air, and is usually purified by distillation immediately before use. Pyrrole has a nutty odor. Pyrrole is a 5-membered aromatic heterocycle, like furan and thiophene. Unlike furan and thiophene, it has a dipole in which the positive end lies on the side of the heteroatom, with a dipole moment of 1.58 D. In CDCl3, it ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclononatetraene
Cyclononatetraene is an organic compound with the formula C9H10. It was first prepared in 1969 by protonation of the corresponding aromatic anion (described below). It is unstable and isomerizes with a half-life of 50 minutes at room temperature to 3a,7a-dihydro-1''H-''indene via a thermal 6π disrotatory electrocyclic ring closing. Upon exposure to ultraviolet light, it undergoes a photochemical 8π electrocyclic ring closing to give bicyclo .1.0ona-2,4,6-triene. Cyclononatetraenyl anion Cyclononatetraenyl anion is a 10π aromatic system. Two isomers of the cyclononatetraenyl anion are known: the ''trans'',''cis'',''cis'',''cis'' isomer (" Pac-Man"-shaped) and the all-''cis'' isomer (a convex enneagon). The former is less stable and isomerizes to the latter upon warming from –40 °C to room temperature. The all-''cis'' isomer of C9H9− can be prepared by treatment of 9-chlorobicyclo .1.0ona-2,4,6-triene (1) with lithium or potassium metal. Despite the ring strain res ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
(2Z,4Z,6Z,8Z)-Thionine
(2''Z'',4''Z'',6''Z'',8''Z'')-Thionine or Thionine is an unsaturated heterocycle of nine atoms, with a sulfur replacing a carbon at one position. Thionine is a partially aromatic compound. D. O. Tymoshenko See also * * * * |
Oxonine
Oxonine is an unsaturated heterocycle of nine atoms, with an oxygen replacing a carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent In chemistry, the valence (US spelling) or valency (British spelling) of an element is the measure of its combining capacity with o ... at one position. Oxonine is a nonaromatic compound. D. O. Tymoshenko See also * Azonine * Furan * Cyclononatetraene * Oxepin * (2Z,4Z,6Z,8Z)-ThionineReferences Oxygen heterocycles Heterocyclic compounds with 1 ring Fully conjugated nonaromatic rings Nine-membered rings {{Heterocyclic-stub ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrogen
Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at seventh in total abundance in the Milky Way and the Solar System. At standard temperature and pressure, two atoms of the element bond to form N2, a colorless and odorless diatomic gas. N2 forms about 78% of Earth's atmosphere, making it the most abundant uncombined element. Nitrogen occurs in all organisms, primarily in amino acids (and thus proteins), in the nucleic acids ( DNA and RNA) and in the energy transfer molecule adenosine triphosphate. The human body contains about 3% nitrogen by mass, the fourth most abundant element in the body after oxygen, carbon, and hydrogen. The nitrogen cycle describes the movement of the element from the air, into the biosphere and organic compounds, then back into the atmosphere. Many industrially ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon
Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon makes up only about 0.025 percent of Earth's crust. Three isotopes occur naturally, C and C being stable, while C is a radionuclide, decaying with a half-life of about 5,730 years. Carbon is one of the few elements known since antiquity. Carbon is the 15th most abundant element in the Earth's crust, and the fourth most abundant element in the universe by mass after hydrogen, helium, and oxygen. Carbon's abundance, its unique diversity of organic compounds, and its unusual ability to form polymers at the temperatures commonly encountered on Earth, enables this element to serve as a common element of Carbon-based life, all known life. It is the second most abundant element in the human body by mass (about 18.5%) after oxygen. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Azepine
Azepines are unsaturated heterocycles of seven atoms, with a nitrogen replacing a carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon makes ... at one position. See also * Azepane * Benzazepines * Diazepine * Oxepin * Borepin Azepines {{Heterocyclic-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrogen Heterocycles
Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at seventh in total abundance in the Milky Way and the Solar System. At standard temperature and pressure, two atoms of the element bond to form N2, a colorless and odorless diatomic gas. N2 forms about 78% of Earth's atmosphere, making it the most abundant uncombined element. Nitrogen occurs in all organisms, primarily in amino acids (and thus proteins), in the nucleic acids ( DNA and RNA) and in the energy transfer molecule adenosine triphosphate. The human body contains about 3% nitrogen by mass, the fourth most abundant element in the body after oxygen, carbon, and hydrogen. The nitrogen cycle describes the movement of the element from the air, into the biosphere and organic compounds, then back into the atmosphere. Many industrially import ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Simple Aromatic Rings
Simple aromatic rings, also known as simple arenes or simple aromatics, are aromatic organic compounds that consist only of a conjugated planar ring system. Many simple aromatic rings have trivial names. They are usually found as substructures of more complex molecules (" substituted aromatics"). Typical simple aromatic compounds are benzene, indole, and pyridine. Simple aromatic rings can be heterocyclic if they contain non-carbon ring atoms, for example, oxygen, nitrogen, or sulfur. They can be monocyclic as in benzene, bicyclic as in naphthalene, or polycyclic as in anthracene. Simple monocyclic aromatic rings are usually five-membered rings like pyrrole or six-membered rings like pyridine. Fused/condensed aromatic rings consist of monocyclic rings that share their connecting bonds. Heterocyclic aromatic rings The nitrogen (N)-containing aromatic rings can be separated into basic aromatic rings that are easily protonated, and form aromatic cations and salts (e.g., pyridini ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
