Related Research Articles
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 organic chemistry is the branch of organic chemistry dealing with the synthesis, properties, and applications of organic heterocycles.
Chalcone is the organic compound C6H5C(O)CH=CHC6H5. It is an α,β-unsaturated ketone. A variety of important biological compounds are known collectively as chalcones or chalconoids. They are widely known bioactive substances, fluorescent materials, and chemical intermediates.
A betaine in chemistry is any neutral chemical compound with a positively charged cationic functional group that bears no hydrogen atom, such as a quaternary ammonium or phosphonium cation, and with a negatively charged functional group, such as a carboxylate group that may not be adjacent to the cationic site. Historically, the term was reserved for trimethylglycine (TMG), which is involved in methylation reactions and detoxification of homocysteine. This is a modified amino acid consisting of glycine with three methyl groups serving as methyl donor for various metabolic pathways.
Pyrazole is an organic compound of azole group with the formula C3H3N2H. It is a heterocycle characterized by a 5-membered ring of three carbon atoms and two adjacent nitrogen atoms, which are in ortho-substitution. Pyrazole is a weak base, with pKb 11.5 (pKa of the conjugate acid 2.49 at 25 °C). Pyrazoles are also a class of compounds that have the ring C3N2 with adjacent nitrogen atoms. Notable drugs containing a pyrazole ring are celecoxib (celebrex) and the anabolic steroid stanozolol.
Benzoxazole is an aromatic organic compound with a molecular formula C7H5NO, a benzene-fused oxazole ring structure, and an odor similar to pyridine. Although benzoxazole itself is of little practical value, many derivatives of benzoxazoles are commercially important.
Pyridazine is an aromatic, heterocyclic, organic compound with the molecular formula C4H4N2. It contains a six-membered ring with two adjacent nitrogen atoms. It is a colorless liquid with a boiling point of 208 °C. It is isomeric with two other diazine rings, pyrimidine and pyrazine.
A cyclic compound is a term for a compound in the field of chemistry in which one or more series of atoms in the compound is connected to form a ring. Rings may vary in size from three to many atoms, and include examples where all the atoms are carbon, none of the atoms are carbon, or where both carbon and non-carbon atoms are present. Depending on the ring size, the bond order of the individual links between ring atoms, and their arrangements within the rings, carbocyclic and heterocyclic compounds may be aromatic or non-aromatic; in the latter case, they may vary from being fully saturated to having varying numbers of multiple bonds between the ring atoms. Because of the tremendous diversity allowed, in combination, by the valences of common atoms and their ability to form rings, the number of possible cyclic structures, even of small size numbers in the many billions.
In chemistry, mesoionic compounds are one in which a heterocyclic structure is dipolar and where both the negative and the positive charges are delocalized. A completely uncharged structure cannot be written and mesoionic compounds cannot be represented satisfactorily by any one mesomeric structure. Mesoionic compounds are a subclass of betaines. Examples are sydnones and sydnone imines, münchnones, and mesoionic carbenes.
Sydnones are mesoionic heterocyclic chemical compounds possessing a 1,2,3-oxadiazole core with a keto group in the 5 position. Like other mesoionic compounds they are di-polar, possessing both positive and negative charges which are delocalized across the ring. Recent computational studies have indicated that sydnones and other similar mesoionic compounds are nonaromatic, "though well-stabilized in two separate regions by electron and charge delocalization." Sydnones are heterocyclic compounds named after the city of Sydney, Australia.
1-Methylimidazole or N-methylimidazole is an aromatic heterocyclic organic compound with the formula CH3C3H3N2. It is a colourless liquid that is used as a specialty solvent, a base, and as a precursor to some ionic liquids. It is a fundamental nitrogen heterocycle and as such mimics for various nucleoside bases as well as histidine and histamine.
Thiete is a heterocyclic compound containing an unsaturated four-membered ring with three carbon atoms and one sulfur atom. It is more commonly encountered not on its own, but in anellated derivatives, several of which have been synthesized. Thietes are generally not very stable.
Thiazolines are a group of isomeric 5-membered heterocyclic compounds containing both sulfur and nitrogen in the ring. Although unsubstituted thiazolines are rarely encountered themselves, their derivatives are more common and some are bioactive. For example, in a common post-translational modification, cysteine residues are converted into thiazolines.
In chemistry, a ring is an ambiguous term referring either to a simple cycle of atoms and bonds in a molecule or to a connected set of atoms and bonds in which every atom and bond is a member of a cycle. A ring system that is a simple cycle is called a monocycle or simple ring, and one that is not a simple cycle is called a polycycle or polycyclic ring system. A simple ring contains the same number of sigma bonds as atoms, and a polycyclic ring system contains more sigma bonds than atoms.
Münchnone (synonyms: 1,3-oxazolium-5-oxide; 1,3-oxazolium-5-olate; anhydro-5-hydroxy-1,3-oxazolium hydroxide; 5-hydroxy-1,3-oxazolium hydroxide, inner salt; oxido-oxazolium) is a mesoionic heterocyclic aromatic chemical compound, with the molecular formula C3H3NO2. The name refers to the city of Munich, Germany (German: München), where the compound and its derivatives were first discovered and studied.
The Minisci reaction is a named reaction in organic chemistry. It is a nucleophilic radical substitution to an electron deficient aromatic compound, most commonly the introduction of an alkyl group to a nitrogen containing heterocycle. The reaction was published in 1971 by F. Minisci. In the case of N-Heterocycles, the conditions must be acidic to ensure protonation of said heterocycle. A typical reaction is that between pyridine and pivalic acid with silver nitrate, sulfuric acid and ammonium persulfate to form 2-tert-butylpyridine. The reaction resembles Friedel-Crafts alkylation but with opposite reactivity and selectivity.
José Elguero Bertolini is a Spanish chemist best known for his contributions to heterocyclic chemistry. He is Honorary Research Professor at the Medicinal Chemistry Institute of the Spanish Council for Scientific Research (CSIC).
Montréalone is a mesoionic heterocyclic chemical compound. It is named for the city of Montréal, Canada, which is the location of McGill University, where it was first discovered.
A ring forming reaction or ring-closing reaction in organic chemistry is a general term for a variety of reactions that introduce one or more rings into a molecule. A heterocycle forming reaction is such a reaction that introduces a new heterocycle. Important classes of ring forming reactions include annulations and cycloadditions.
Heteropentalenes are class of heterocyclic compound. Heteropentalenes have one, two or more heteroatoms on the ring. It consists of two pentagonal rings. Heteropentalenes with 10 pi electrons show aromaticity. Some of heteropentalenes are mesomeric betaines. However those heteropentalenes are not mesoionic
In organic chemistry, a diazapentalene is any of the heterocyclic compounds having molecular formula C6H6N2 whose structure is two fused two pentagonal rings of six carbon atoms and two nitrogen atoms. That is, it is a heteropentalene, with two nitrogens substituted in for carbons. There are several different constitutional isomers. Each diazapentalene has 10 pi electrons and shows aromaticity. Some of the diazapentalenes are mesomeric betaines, however these diazapentalenes are not mesoionic.
References
- ↑ Ollis, W.David; Stanforth, Stepher P.; Ramsden, Christopher A. (1985). "Heterocyclic mesomeric betaines". Tetrahedron. 41 (12): 2239–2329. doi:10.1016/S0040-4020(01)96625-6.
- ↑ Kawase, Masami (2009). "The Chemistry of Bioactive Mesoionic Heterocycles". Bioactive Heterocycles VII. Topics in Heterocyclic Chemistry. Vol. 16. Springer. pp. 135–152. doi:10.1007/7081_2007_096. ISBN 978-3-642-00335-6.
 | This article about an aromatic compound is a stub. You can help Wikipedia by expanding it. |