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Isoxazolidine
An oxazolidine is a five-membered ring compound consisting of three carbon atoms, a nitrogen atom and an oxygen atom. The O atom and NH group are the 1 and 3 positions, respectively. In oxazolidine derivatives, there is always a carbon atom between the O and N atoms (or it would be an ''isoxazolidine''). All of the carbon atoms in oxazolidines are reduced (compare to oxazole and oxazoline). Some of their derivatives, the 2,4-Oxazolidinedione, oxazolidinediones, are used as anticonvulsants. Oxazolidines were first synthesized over 100 years ago. Monooxazolidines Oxazolidines that are the precursor to bisoxazolidines are in effect mono-oxazolidines. They are also used as moisture scavengers in polyurethane and other systems. Dioxooxazolidines Oxazolidines where the carbon centers at the 1 and 3 positions are carbonyl group, carbonyls are called dioxooxazolidines. Some of these are commercial fungicides including chlozolinate, vinclozolin, and famoxadone. Bisoxazolidines Bisoxazol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isoxazolidine
An oxazolidine is a five-membered ring compound consisting of three carbon atoms, a nitrogen atom and an oxygen atom. The O atom and NH group are the 1 and 3 positions, respectively. In oxazolidine derivatives, there is always a carbon atom between the O and N atoms (or it would be an ''isoxazolidine''). All of the carbon atoms in oxazolidines are reduced (compare to oxazole and oxazoline). Some of their derivatives, the 2,4-Oxazolidinedione, oxazolidinediones, are used as anticonvulsants. Oxazolidines were first synthesized over 100 years ago. Monooxazolidines Oxazolidines that are the precursor to bisoxazolidines are in effect mono-oxazolidines. They are also used as moisture scavengers in polyurethane and other systems. Dioxooxazolidines Oxazolidines where the carbon centers at the 1 and 3 positions are carbonyl group, carbonyls are called dioxooxazolidines. Some of these are commercial fungicides including chlozolinate, vinclozolin, and famoxadone. Bisoxazolidines Bisoxazol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrone-olefin (3+2) Cycloaddition
The nitrone-olefin (3+2) cycloaddition reaction is the combination of a nitrone with an alkene or alkyne to generate an isoxazoline or isoxazolidine via a +2cycloaddition process. This reaction is a 1,3-dipolar cycloaddition, in which the nitrone acts as the 1,3-dipole, and the alkene or alkyne as the dipolarophile. Mechanism and stereochemistry When nitrones are combined with either alkenes or alkynes, +2cycloaddition leads to the formation of a new C–C bond and a new C–O bond. The cycloadditions is stereospecific with respect to the configuration of the alkene; however, diastereoselectivity in reactions of C-substituted nitrones is often low. Regioselectivity is controlled by the dominant frontier orbitals interacting during the reaction, and substrates with electronically distinct substituents tend to react with high regioselectivity. Intramolecular versions of the reaction have been used to synthesize complex polyclic carbon frameworks. Reduction of the N–O linkage l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexamethylene Diisocyanate
Hexamethylene diisocyanate (HDI) is the organic compound with the formula (CH2)6(NCO)2. It is classified as an diisocyanate. It is a colorless liquid. It has sometimes been called HMDI but this not usually done to avoid confusion with Hydrogenated MDI. Synthesis Compared to other commercial diisocyanates, HDI is produced in relatively small quantities, accounting for (with isophorone diisocyanate) only 3.4% of the global diisocyanate market in the year 2000. It is produced by phosgenation of hexamethylene diamine. Applications Aliphatic diisocyanates are used in specialty applications, such as enamel coatings which are resistant to abrasion and degradation by ultraviolet light. These properties are particularly desirable in, for instance, the exterior paint applied to aircraft and vessels. HDI is also sold oligomerized as the trimer or biuret which are used in automotive refinish coatings. Although more viscous in these forms, it reduces the volatility and toxicity. At least 3 c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Union Of Pure And Applied Chemistry
The International Union of Pure and Applied Chemistry (IUPAC ) is an international federation of National Adhering Organizations working for the advancement of the chemical sciences, especially by developing nomenclature and terminology. It is a member of the International Science Council (ISC). IUPAC is registered in Zürich, Switzerland, and the administrative office, known as the "IUPAC Secretariat", is in Research Triangle Park, North Carolina, United States. This administrative office is headed by IUPAC's executive director, currently Lynn Soby. IUPAC was established in 1919 as the successor of the International Congress of Applied Chemistry for the advancement of chemistry. Its members, the National Adhering Organizations, can be national chemistry societies, national academies of sciences, or other bodies representing chemists. There are fifty-four National Adhering Organizations and three Associate National Adhering Organizations. IUPAC's Inter-divisional Committee on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diisocyanate
In organic chemistry, isocyanate is the functional group with the formula . Organic compounds that contain an isocyanate group are referred to as isocyanates. An organic compound with two isocyanate groups is known as a diisocyanate. Diisocyanates are manufactured for the production of polyurethanes, a class of polymers. Isocyanates should not be confused with cyanate esters and isocyanides, very different families of compounds. The cyanate (cyanate ester) functional group () is arranged differently from the isocyanate group (). Isocyanides have the connectivity , lacking the oxygen of the cyanate groups. Structure and bonding In terms of bonding, isocyanates are closely related to carbon dioxide (CO2) and carbodiimides (C(NR)2). The C−N=C=O unit that defines isocyanates is planar, and the N=C=O linkage is nearly linear. In phenyl isocyanate, the C=N and C=O distances are respectively 1.195 and 1.173 Å. The C-N=C angle is 134.9° and the N=C=O angle is 173.1°. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Furan
Furan is a heterocyclic organic compound, consisting of a five-membered aromatic ring with four carbon atoms and one oxygen atom. Chemical compounds containing such rings are also referred to as furans. Furan is a colorless, flammable, highly volatile liquid with a boiling point close to room temperature. It is soluble in common organic solvents, including alcohol, ether, and acetone, and is slightly soluble in water. Its odor is "strong, ethereal; chloroform-like". It is toxic and may be carcinogenic in humans. Furan is used as a starting point for other speciality chemicals. History The name "furan" comes from the Latin ''furfur'', which means bran. ( Furfural is produced from bran.) The first furan derivative to be described was 2-furoic acid, by Carl Wilhelm Scheele in 1780. Another important derivative, furfural, was reported by Johann Wolfgang Döbereiner in 1831 and characterised nine years later by John Stenhouse. Furan itself was first prepared by Heinrich Lim ... [...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 has ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benzoxazole
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. Being a heterocyclic compound, benzoxazole finds use in research as a starting material for the synthesis of larger, usually bioactive structures. Its aromaticity makes it relatively stable, although as a heterocycle, it has reactive sites which allow for functionalization. Occurrence and applications It is found within the chemical structures of pharmaceutical drugs such as flunoxaprofen and tafamidis. Benzoxazole derivatives are also of interest for optical brighteners in laundry detergents.E. Smulders, E. Sung "Laundry Detergents, 2. Ingredients and Products" in ''Ullmann's Encyclopedia of Industrial Chemistry'', Wiley-VCH, Weinheim, 2012. Benzoxazoles belong to the group of well-known antifungal agents with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thiazole
Thiazole, or 1,3-thiazole, is a heterocyclic compound that contains both sulfur and nitrogen. The term 'thiazole' also refers to a large family of derivatives. Thiazole itself is a pale yellow liquid with a pyridine-like odor and the molecular formula C3H3NS. The thiazole ring is notable as a component of the vitamin thiamine (B1). Molecular and electronic structure Thiazoles are members of the azoles, heterocycles that include imidazoles and oxazoles. Thiazole can also be considered a functional group. Oxazoles are related compounds, with sulfur replaced by oxygen. Thiazoles are structurally similar to imidazoles, with the thiazole sulfur replaced by nitrogen. Thiazole rings are planar and aromatic. Thiazoles are characterized by larger pi-electron delocalization than the corresponding oxazoles and have therefore greater aromaticity. This aromaticity is evidenced by the chemical shift of the ring protons in proton NMR spectroscopy (between 7.27 and 8.77 ppm), clearly indicating ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Imidazole
Imidazole (ImH) is an organic compound with the formula C3N2H4. It is a white or colourless solid that is soluble in water, producing a mildly alkaline solution. In chemistry, it is an aromatic heterocycle, classified as a diazole Diazole refers to either one of a pair of isomeric chemical compounds with molecular formula C3H4N2, having a five-membered ring consisting of three carbon atoms and two nitrogen atoms. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isoxazole
Isoxazole is an electron-rich azole with an oxygen atom next to the nitrogen. It is also the class of compounds containing this ring. Isoxazolyl is the univalent radical derived from isoxazole. Occurrence Isoxazole rings are found in some natural products, such as ibotenic acid and muscimol. Synthesis Isoxazole can be synthesised via a variety of methods. Examples include via a 1,3-dipolar cycloaddition of nitrile oxides with alkynes; or the reaction of hydroxylamine with 1,3-diketones or derivatives of propiolic acid. Photochemistry The photolysis of isoxazole was first reported in 1966. Due to the weak N-O bond, the isoxazole ring tends to collapse under UV irradiation, rearranging to oxazole through azirine intermediate. Meanwhile, the azirine intermediate can react with nucleophiles, especially carboxylic acids. Given the photoreactions, isoxazole group is developed as a native photo-cross-linker for photoaffinity labeling and chemoproteomic studies. Pharmaceuticals and h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
