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Pyridine-N-oxide
Pyridine-''N''-oxide is the heterocyclic compound with the formula C5H5NO. This colourless, hygroscopic solid is the product of the oxidation of pyridine. It was originally prepared using peroxyacids as the oxidising agent. The compound is used infrequently as an oxidizing reagent in organic synthesis. Structure The structure of pyridine-N-oxide is very similar to that of pyridine with respect to the parameters for the ring. The molecule is planar. The N-O distance is 1.34Å. The C-N-C angle is 124°, 7° wider than in pyridine. Synthesis The oxidation of pyridine can be achieved with a number of peracids including peracetic acid and perbenzoic acid. Oxidation can also be effected by a modified Dakin reaction using a urea-hydrogen peroxide complex, and sodium perborate or, using methylrhenium trioxide () as catalyst, with sodium percarbonate. Reactions Pyridine ''N''-oxide is five orders of magnitude less basic than pyridine, but it is isolable as a hydrochloride sal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zinc Pyrithione
Zinc pyrithione (or pyrithione zinc) is a coordination complex of zinc. It has fungistatic (inhibiting the division of fungal cells) and bacteriostatic (inhibiting bacterial cell division) properties and is used in the treatment of seborrhoeic dermatitis and dandruff. Structure of the compound The pyrithione ligands, which are formally monoanions, are chelated to Zn2+ via oxygen and sulfur centers. In the crystalline state, zinc pyrithione exists as a centrosymmetric dimer (see figure), where each zinc is bonded to two sulfur and three oxygen centers. In solution, however, the dimers dissociate via scission of one Zn-O bond. This compound was first described in the 1930s. Pyrithione is the conjugate base derived from 2-mercaptopyridine-''N''-oxide (CAS# 1121-31-9), a derivative of pyridine-''N''-oxide. Uses Medicine Zinc pyrithione can be used to treat dandruff and seborrhoeic dermatitis. It also has antibacterial properties and is effective against many pathogens fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyridine
Pyridine is a basic (chemistry), basic heterocyclic compound, 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 diamagnetism, diamagnetic and has a Magnetic susceptibility, diamagnetic susceptibility of −48.7 × 10−6 cm3·mol−1. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nicotinic Acid N-oxide
Nicotinic acid ''N''-oxide is an organic compound with the formula (HO2C)C5H4NO. It is the ''N''-oxide of nicotinic acid ((HO2C)C5H4N). It is prepared by oxidation of nicotinic acid or the hydrolysis of 3-cyanopyridine ''N''-oxide. The compound is a precursor to the popular drugs niflumic acid and pranoprofen Pranoprofen ( INN) is a nonsteroidal anti-inflammatory drug Non-steroidal anti-inflammatory drugs (NSAID) are members of a therapeutic drug class which reduces pain, decreases inflammation, decreases fever, and prevents blood clots. Side ....{{Ullmann, doi=10.1002/14356007.a22_399, chapter=Pyridine and Pyridine Derivatives, year=2000, last1=Shimizu, first1=Shinkichi, last2=Watanabe, first2=Nanao, last3=Kataoka, first3=Toshiaki, last4=Shoji, first4=Takayuki, last5=Abe, first5=Nobuyuki, last6=Morishita, first6=Sinji, last7=Ichimura, first7=Hisao, isbn=3527306730 References Amine oxides Pyridinium compounds Carboxylic acids ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dakin Reaction
The Dakin oxidation (or Dakin reaction) is an organic redox reaction in which an '' ortho''- or ''para''-hydroxylated phenyl aldehyde ( 2-hydroxybenzaldehyde or 4-hydroxybenzaldehyde) or ketone reacts with hydrogen peroxide in base to form a benzenediol and a carboxylate. Overall, the carbonyl group is oxidized, and the hydrogen peroxide is reduced. The Dakin oxidation, which is closely related to the Baeyer–Villiger oxidation, is not to be confused with the Dakin–West reaction, though both are named after Henry Drysdale Dakin. Reaction mechanism The Dakin oxidation starts with nucleophilic addition of a hydroperoxide anion to the carbonyl carbon, forming a tetrahedral intermediate (2). The intermediate collapses, causing ,2aryl migration, hydroxide elimination, and formation of a phenyl ester (3). The phenyl ester is subsequently hydrolyzed: nucleophilic addition of hydroxide from solution to the ester carbonyl carbon forms a second tetrahedral intermediate (4), w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synlett
''Synlett'' is an international scientific journal for accounts and rapid communications of original contributions of fundamental research in synthetic organic chemistry. The impact factor of this journal is 2.419 (2017). ''Nature'' featured a brief piece by the editor-in-chief An editor-in-chief (EIC), also known as lead editor or chief editor, is a publication's editorial leader who has final responsibility for its operations and policies. The highest-ranking editor of a publication may also be titled editor, managing ... of the journal in 2017, Benjamin List, where he discussed the journal's experience with the non-traditional peer review system. References Chemistry journals Thieme academic journals Publications established in 1989 {{chem-journal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Omeprazole
Omeprazole, sold under the brand names Prilosec and Losec, among others, is a medication used in the treatment of gastroesophageal reflux disease (GERD), peptic ulcer disease, and Zollinger–Ellison syndrome. It is also used to prevent upper gastrointestinal bleeding in people who are at high risk. Omeprazole is a proton-pump inhibitor (PPI) and its effectiveness is similar to other PPIs. It can be taken by mouth or by injection into a vein. It is also available in the fixed-dose combination medication omeprazole/sodium bicarbonate as Zegerid. Common side effects include nausea, vomiting, headaches, abdominal pain, and increased intestinal gas. Serious side effects may include ''Clostridium difficile'' colitis, an increased risk of pneumonia, an increased risk of bone fractures, and the potential of masking stomach cancer. It is unclear if it is safe for use in pregnancy. It works by blocking the release of stomach acid. Omeprazole was patented in 1978, and approved for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pranoprofen
Pranoprofen ( INN) is a nonsteroidal anti-inflammatory drug Non-steroidal anti-inflammatory drugs (NSAID) are members of a therapeutic drug class which reduces pain, decreases inflammation, decreases fever, and prevents blood clots. Side effects depend on the specific drug, its dose and duration of ... (NSAID) used in ophthalmology. References Nonsteroidal anti-inflammatory drugs {{Musculoskeletal-drug-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Niflumic Acid
Niflumic acid is a drug used for joint and muscular pain. It is categorized as an inhibitor of cyclooxygenase-2. In experimental biology, it has been employed to inhibit chloride channel Chloride channels are a superfamily of poorly understood ion channels specific for chloride. These channels may conduct many different ions, but are named for chloride because its concentration ''in vivo'' is much higher than other anions. Several ...s. It has also been reported to act on GABA-A and NMDA channels and to block T-type calcium channels. References Aminopyridines Anilines Trifluoromethyl compounds Calcium channel blockers GABAA receptor positive allosteric modulators NMDA receptor antagonists Aromatic acids Chloride channel blockers {{musculoskeletal-drug-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nicotinic Acid
Niacin, also known as nicotinic acid, is an organic compound and a form of vitamin B3, an essential human nutrient. It can be manufactured by plants and animals from the amino acid tryptophan. Niacin is obtained in the diet from a variety of whole and processed foods, with highest contents in fortified packaged foods, meat, poultry, red fish such as tuna and salmon, lesser amounts in nuts, legumes and seeds. Niacin as a dietary supplement is used to treat pellagra, a disease caused by niacin deficiency. Signs and symptoms of pellagra include skin and mouth lesions, anemia, headaches, and tiredness. Many countries mandate its addition to wheat flour or other food grains, thereby reducing the risk of pellagra. The amide derivative nicotinamide (niacinamide) is a component of the coenzymes nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP+). Although niacin and nicotinamide are identical in their vitamin activity, nicotinamid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pergamon Press
Pergamon Press was an Oxford-based publishing house, founded by Paul Rosbaud and Robert Maxwell, that published scientific and medical books and journals. Originally called Butterworth-Springer, it is now an imprint of Elsevier. History The core company, Butterworth-Springer, started in 1948 to bring the "Springer know-how and techniques of aggressive publishing in science"Joe Haines (1988) ''Maxwell'', Houghton Mifflin, p. 137. to Britain. Paul Rosbaud was the man with the knowledge. When Maxwell acquired the company in 1951, Rosbaud held a one-quarter share. They changed the house name to Pergamon Press, using a logo that was a reproduction of a Greek coin from Pergamon. Maxwell and Rosbaud worked together growing the company until May 1956, when, according to Joe Haines, Rosbaud was sacked. When Pergamon Press started it had only six serials and two books. Initially the company headquarters was in Fitzroy Square in West End of London. In 1959, the company moved into He ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphorus Oxychloride
Phosphoryl chloride (commonly called phosphorus oxychloride) is a colourless liquid with the formula . It hydrolyses in moist air releasing phosphoric acid and fumes of hydrogen chloride. It is manufactured industrially on a large scale from phosphorus trichloride and oxygen or phosphorus pentoxide. It is mainly used to make phosphate esters such as tricresyl phosphate. Structure Like phosphate, is tetrahedral in shape. It features three P−Cl bonds and one strong P=O double bond, with an estimated bond dissociation energy of 533.5 kJ/mol. On the basis of bond length and electronegativity, the Schomaker-Stevenson rule suggests that the double bond form is dominant, in contrast with the case of . The P=O bond involves the donation of the lone pair electrons on oxygen ''p''-orbitals to the antibonding combinations associated with phosphorus-chlorine bonds, thus constituting ''π'' bonding. Phosphoryl chloride exists as neutral molecules in the solid, liquid and gas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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