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2-Aminopyridine
2-Aminopyridine is an organic compound with the formula H2NC5H4N. It is one of three isomeric aminopyridines. It is a colourless solid that is used in the production of the drugs piroxicam, sulfapyridine, tenoxicam, and tripelennamine. It is produced by the reaction of sodium amide with pyridine, the Chichibabin reaction. Structure Although 2-hydroxypyridine converts significantly to the pyridone tautomer, the related imine tautomer (HNC5H4NH) is less important for 2-aminopyridine. Toxicity The acute toxicity is indicated by the LD50 In toxicology, the median lethal dose, LD50 (abbreviation for "lethal dose, 50%"), LC50 (lethal concentration, 50%) or LCt50 is a toxic unit that measures the lethal dose of a toxin, radiation, or pathogen. The value of LD50 for a substance is the ... = 200 mg/kg (rat, oral). References External links MSDS {{DEFAULTSORT:Aminopyridine, 2- Aminopyridines 2-Pyridyl compounds ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aminopyridines
Aminopyridine may refer to any of several chemical compounds: * 2-Aminopyridine * 3-Aminopyridine 3-Aminopyridine is an aminopyridine. It is a colorless solid. Preparation 3-Aminopyridine is prepared by heating nicotinamide with sodium hypobromite which is in turn prepared ''in situ'' by the reaction of sodium hydroxide and bromine at 70& ... * 4-Aminopyridine (4-AP), also known as fampridine or dalfampridine {{Short pages monitor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Compound
In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The study of the properties, reactions, and syntheses of organic compounds comprise the discipline known as organic chemistry. For historical reasons, a few classes of carbon-containing compounds (e.g., carbonate salts and cyanide salts), along with a few other exceptions (e.g., carbon dioxide, hydrogen cyanide), are not classified as organic compounds and are considered inorganic. Other than those just named, little consensus exists among chemists on precisely which carbon-containing compounds are excluded, making any rigorous definition of an organic compound elusive. Although organic compounds make up only a small percentage of Earth's crust, they are of central importance because all known life is based on organic compounds. Living t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isomer
In chemistry, isomers are molecules or polyatomic ions with identical molecular formulae – that is, same number of atoms of each element – but distinct arrangements of atoms in space. Isomerism is existence or possibility of isomers. Isomers do not necessarily share similar chemical or physical properties. Two main forms of isomerism are structural or constitutional isomerism, in which ''bonds'' between the atoms differ; and stereoisomerism or spatial isomerism, in which the bonds are the same but the ''relative positions'' of the atoms differ. Isomeric relationships form a hierarchy. Two chemicals might be the same constitutional isomer, but upon deeper analysis be stereoisomers of each other. Two molecules that are the same stereoisomer as each other might be in different conformational forms or be different isotopologues. The depth of analysis depends on the field of study or the chemical and physical properties of interest. The English word "isomer" () is a back-for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Piroxicam
Piroxicam is a nonsteroidal anti-inflammatory drug (NSAID) of the oxicam class used to relieve the symptoms of painful inflammatory conditions like arthritis. Piroxicam works by preventing the production of endogenous prostaglandins which are involved in the mediation of pain, stiffness, tenderness and swelling. The medicine is available as capsules, tablets and (not in all countries) as a prescription-free gel 0.5%. It is also available in a betadex formulation, which allows a more rapid absorption of piroxicam from the digestive tract. Piroxicam is one of the few NSAIDs that can be given parenteral routes. It was patented in 1968 by Pfizer and approved for medical use in 1979. It became generic in 1992, and is marketed worldwide under many brandnames. Medical uses It is used in the treatment of certain inflammatory conditions like rheumatoid and osteoarthritis, primary dysmenorrhoea, postoperative pain; and act as an analgesic, especially where there is an inflammatory co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfapyridine
Sulfapyridine (INN; also known as sulphapyridine) is a sulfanilamide antibacterial medication. At one time, it was commonly referred to as M&B 693. Sulfapyridine is no longer prescribed for treatment of infections in humans. However, it may be used to treat linear IgA disease and has use in veterinary medicine. It is a good antibacterial drug, but its water solubility is very pH dependent. Thus there is a risk of crystallization within the bladder or urethra, which could lead to pain or blockage. As with other sulfonamides, there is a significant risk of agranulocytosis, and this, rather than the development of resistance by bacteria, is the main reason for its decline in use. History M&B 693 was one of the first generation of sulfonamide antibiotics. It was discovered by Lionel Whitby at the British firm May & Baker Ltd and logged in their Test Book on 2 November, 1937 under Code No M&B 693. During the aftermath to the disastrous convoy SC7, in October 1940, Surgeon-Lieut ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tenoxicam
Tenoxicam, sold under the brand name Mobiflex among others, is a nonsteroidal anti-inflammatory drug (NSAID). It is used to relieve inflammation, swelling, stiffness, and pain associated with rheumatoid arthritis, osteoarthritis, ankylosing spondylitis (a type of arthritis involving the spine), tendinitis (inflammation of a tendon), bursitis (inflammation of a bursa, a fluid-filled sac located around joints and near the bones), and periarthritis of the shoulders or hips (inflammation of tissues surrounding these joints). Tenoxicam belongs to the class of NSAIDs known as oxicams. It was patented in 1974 by Roche and approved for medical use in 1987. It is available as a prescription-only drug in the United Kingdom and other countries, but not in the US. Outside the United Kingdom, tenoxicam is also marketed under brand names including Tilatil, Tilcitin, and Alganex. Contraindications The drug is contraindicated for patients who are seniors who have been given anesthe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tripelennamine
Tripelennamine, sold under the brand name Pyribenzamine by Novartis, is a drug that is used as an antipruritic and first-generation antihistamine. It can be used in the treatment of asthma, hay fever, rhinitis, and urticaria, but is now less common as it has been replaced by newer antihistamines. The drug was patented at CIBA, which merged with Geigy into Ciba-Geigy, and eventually becoming Novartis. Medical uses Where and when it is/was in common use, tripelennamine is used much like other mildly-anticholinergic antihistamines to treat conditions of the upper respiratory tract arising from illnesses and hay fever. It can be used alone or in combination with other agents to have the desired effect. Cough medicines of the general formula tripelennamine + codeine/dihydrocodine/hydrocodone ± expectorant ± decongestant(s) are popular where available. Among these are the Pyribenzamine cough syrups which contain codeine, with and without decongestants, listed in the 1978 ''Physicia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Amide
Sodium amide, commonly called sodamide (systematic name sodium azanide), is the inorganic compound with the formula . It is a salt composed of the sodium cation and the azanide anion. This solid, which is dangerously reactive toward water, is white, but commercial samples are typically gray due to the presence of small quantities of metallic iron from the manufacturing process. Such impurities do not usually affect the utility of the reagent. conducts electricity in the fused state, its conductance being similar to that of NaOH in a similar state. has been widely employed as a strong base in organic synthesis. Preparation and structure Sodium amide can be prepared by the reaction of sodium with ammonia gas, but it is usually prepared by the reaction in liquid ammonia using iron(III) nitrate as a catalyst. The reaction is fastest at the boiling point of the ammonia, c. −33 °C. An electride, , is formed as a reaction intermediate. : is a salt-like material and as such, c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyridine
Pyridine is a basic heterocyclic organic compound with the chemical formula . It is structurally related to benzene, with one methine group replaced by a nitrogen atom. It is a highly flammable, weakly alkaline, water-miscible liquid with a distinctive, unpleasant fish-like smell. Pyridine is colorless, but older or impure samples can appear yellow, due to the formation of extended, unsaturated polymeric chains, which show significant electrical conductivity. The pyridine ring occurs in many important compounds, including agrochemicals, pharmaceuticals, and vitamins. Historically, pyridine was produced from coal tar. As of 2016, it is synthesized on the scale of about 20,000 tons per year worldwide. Properties Physical properties The molecular electric dipole moment is 2.2 debyes. Pyridine is diamagnetic and has a diamagnetic susceptibility of −48.7 × 10−6 cm3·mol−1. The standard enthalpy of formation is 100.2 kJ·mol−1 in the liquid phase ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chichibabin Reaction
The Chichibabin reaction (pronounced ' (chē')-chē-bā-bēn) is a method for producing 2-aminopyridine derivatives by the reaction of pyridine with sodium amide. It was reported by Aleksei Chichibabin in 1914. The following is the overall form of the general reaction: : The direct amination of pyridine with sodium amide takes place in liquid ammonia. Following the Addition-elimination reaction, addition elimination mechanism first a nucleophilic addition, nucleophilic NH2− is added while a hydride (H−) is leaving. Ciganek describes an example of an intramolecular Chichibabin reaction in which a nitrile group on a fused ring is the source of nitrogen in amination. Mechanism : It is widely accepted that the Chichibabin reaction mechanism is an addition-elimination reaction that proceeds through an σ-adduct (Meisenheimer complex, Meisenheimer adduct) intermediate (the third structure). First, the nucleophilic NH2− group adds to the δ+ ring carbon atom pushing electrons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tautomer
Tautomers () are structural isomers (constitutional isomers) of chemical compounds that readily interconvert. The chemical reaction interconverting the two is called tautomerization. This conversion commonly results from the relocation of a hydrogen atom within the compound. The phenomenon of tautomerization is called tautomerism, also called desmotropism. Tautomerism is for example relevant to the behavior of amino acids and nucleic acids, two of the fundamental building blocks of life. Care should be taken not to confuse tautomers with depictions of "contributing structures" in chemical resonance. Tautomers are distinct chemical species that can be distinguished by their differing atomic connectivities, molecular geometries, and physicochemical and spectroscopic properties, whereas resonance forms are merely alternative Lewis structure (valence bond theory) depictions of a single chemical species, whose true structure is best described as the "average" of the idealized, hypothe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
