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Tetramethoxymethane
Tetramethoxymethane is a chemical compound which is formally formed by complete methylation of the hypothetical orthocarbonic acid C(OH)4 (orthocarboxylic acid violates the Erlenmeyer rule and is unstable in free state). Preparation The obvious synthetic route from tetrachloromethane does not yield the desired product.R. H. De Wolfe, ''Carboxylic ortho acid derivatives: preparation and synthetic applications'', Organic Chemistry, Vol. 14, Academic Press, Inc. New York – London, 1970, . The original preparation of the tetramethoxymethane was therefore based on chloropicrin: Because of the unpleasant properties of the chloropicrin, other tetrasubstituted reactive methane derivatives were investigated as starting material for tetramethoxymethane. For example, trichloromethanesulfenyl chloride (also used as a chemical warfare agent and easily accessible from carbon bisulfide and chlorine) was used: A less problematic synthesis is based on trichloroacetonitrile, with yiel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetraethoxymethane
Tetraethoxymethane is a chemical compound which is formally formed by complete ethylation of the hypothetical orthocarbonic acid C(OH)4 (orthocarboxylic acid violates the Erlenmeyer Rule, Erlenmeyer rule and is unstable in free state). History Tetraethoxymethane was described the first time in 1864.H. Bassett, ''Ueber das vierfach-basische kohlensaure Aethyl'', Ann. 132, 54 (1864), . Synthesis The preparation of tetraethoxymethane from the highly toxic trichloronitromethane is known in the literatureEuropäische Patentschrift EP 0881212 B1''Production method of aminobenzene compound'' Erfinder: H. Hashimoto et al., Anmelder: Takeda Chemical Industries, Ltd., veröffentlicht am 30. Oktober 2001. and achieves only yields of 46-49 to 58%: The obvious synthetic route from tetrachloromethane does not provide the desired product, as in the homologous tetramethoxymethane.R.H. De Wolfe, ''Carboxylic ortho acid derivatives: preparation and synthetic applications'', Organic Chemistry, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orthocarbonic Acid
Orthocarbonic acid (methanetetrol) is the name given to a hypothetical compound with the chemical formula or . Its molecular structure consists of a single carbon atom bonded to four hydroxy groups. It would be therefore a fourfold alcohol. In theory it could lose four protons to give the hypothetical oxocarbon anion (orthocarbonate), and is therefore considered an oxoacid of carbon. The compound has also been given the nickname of "Hitler's Acid" due to the Ball-and-stick model of the compound resembling the Swastika symbol. Orthocarbonic acid is highly unstable. Calculations show that it decomposes spontaneously into carbonic acid and water: : H4CO4 -> H2CO3 + H2O Orthocarbonic acid is one of the group of '' ortho acids'' that have the general structure of .The term ''ortho acid'' is also used to refer to the most hydroxylated acid in a set of oxoacids. Researchers predict that orthocarbonic acid is stable at high pressure; hence it may form in the interior of the ice gi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mol (unit)
The mole, symbol mol, is the unit of amount of substance in the International System of Units (SI). The quantity amount of substance is a measure of how many elementary entities of a given substance are in an object or sample. The mole is defined as containing exactly elementary entities. Depending on what the substance is, an elementary entity may be an atom, a molecule, an ion, an ion pair, or a subatomic particle such as an electron. For example, 10 moles of water (a chemical compound) and 10 moles of mercury (a chemical element), contain equal amounts of substance and the mercury contains exactly one atom for each molecule of the water, despite the two having different volumes and different masses. The number of elementary entities in one mole is known as the Avogadro number, which is the approximate number of nucleons ( protons or neutrons) in one gram of ordinary matter. The previous definition of a mole was simply the number of elementary entities equal to that of 12 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synthesis (journal)
''Synthesis'' is a scientific journal published from 1969 to the present day by Thieme. Its stated purpose is the "advancement of the science of synthetic chemistry". From August 2006, selected articles are offered free of charge. The impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a scientometric index calculated by Clarivate that reflects the yearly mean number of citations of articles published in the last two years in a given journal, as i ... of this journal is 2.867 (2018).Journal Citation Reports, 2018 References Chemistry journals English-language journals Thieme academic journals {{chem-journal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbonate Esters
In organic chemistry, a carbonate ester (organic carbonate or organocarbonate) is an ester of carbonic acid. This functional group consists of a carbonyl group flanked by two alkoxy groups. The general structure of these carbonates is and they are related to esters (), ethers () and also to the inorganic carbonates. Monomers of polycarbonate (e.g. Makrolon or Lexan) are linked by carbonate groups. These polycarbonates are used in eyeglass lenses, compact discs, and bulletproof glass. Small carbonate esters like dimethyl carbonate, ethylene carbonate, propylene carbonate are used as solvents, dimethyl carbonate is also a mild methylating agent. Structures Carbonate esters have planar OC(OC)2 cores, which confers rigidity. The unique O=C bond is short (1.173 Å in the depicted example), while the C-O bonds are more ether-like (the bond distances of 1.326 Å for the example depicted). Carbonate esters can be divided into three structural classes: acyclic, cyclic, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fungicide
Fungicides are biocidal chemical compounds or biological organisms used to kill parasitic fungi or their spores. A fungistatic inhibits their growth. Fungi can cause serious damage in agriculture, resulting in critical losses of yield, quality, and profit. Fungicides are used both in agriculture and to fight fungal infections in animals. Chemicals used to control oomycetes, which are not fungi, are also referred to as fungicides, as oomycetes use the same mechanisms as fungi to infect plants. Fungicides can either be contact, translaminar or systemic. Contact fungicides are not taken up into the plant tissue and protect only the plant where the spray is deposited. Translaminar fungicides redistribute the fungicide from the upper, sprayed leaf surface to the lower, unsprayed surface. Systemic fungicides are taken up and redistributed through the xylem vessels. Few fungicides move to all parts of a plant. Some are locally systemic, and some move upwardly. Most fungicides that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Muscle Relaxant
A muscle relaxant is a drug that affects skeletal muscle function and decreases the muscle tone. It may be used to alleviate symptoms such as muscle spasms, pain, and hyperreflexia. The term "muscle relaxant" is used to refer to two major therapeutic groups: neuromuscular blockers and spasmolytics. Neuromuscular blockers act by interfering with transmission at the neuromuscular end plate and have no central nervous system (CNS) activity. They are often used during surgical procedures and in intensive care and emergency medicine to cause temporary paralysis. Spasmolytics, also known as "centrally acting" muscle relaxant, are used to alleviate musculoskeletal pain and spasms and to reduce spasticity in a variety of neurological conditions. While both neuromuscular blockers and spasmolytics are often grouped together as muscle relaxant, [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antiemetic
An antiemetic is a drug that is effective against vomiting and nausea. Antiemetics are typically used to treat motion sickness and the side effects of opioid analgesics, general anaesthetics, and chemotherapy directed against cancer. They may be used for severe cases of gastroenteritis, especially if the patient is dehydrated. Some antiemetics previously thought to cause birth defects appear safe for use by pregnant women in the treatment of morning sickness and the more serious hyperemesis gravidarum. __TOC__ Types * 5-HT3 receptor antagonists block serotonin receptors in the central nervous system and gastrointestinal tract. As such, they can be used to treat post-operative and cytotoxic drug nausea & vomiting. However, they can also cause constipation or diarrhea, dry mouth, and fatigue. ** Dolasetron (Anzemet) can be administered in tablet form or in an injection. ** Granisetron (Kytril, Sancuso) can be administered in tablet (Kytril), oral solution (Kytril), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sedative
A sedative or tranquilliser is a substance that induces sedation by reducing irritability or excitement. They are CNS depressants and interact with brain activity causing its deceleration. Various kinds of sedatives can be distinguished, but the majority of them affect the neurotransmitter gamma-aminobutyric acid (GABA). In spite of the fact that each sedative acts in its own way, most produce relaxing effects by increasing GABA activity. This group is related to hypnotics. The term ''sedative'' describes drugs that serve to calm or relieve anxiety, whereas the term ''hypnotic'' describes drugs whose main purpose is to initiate, sustain, or lengthen sleep. Because these two functions frequently overlap, and because drugs in this class generally produce dose-dependent effects (ranging from anxiolysis to loss of consciousness) they are often referred to collectively as ''sedative-hypnotic'' drugs. Sedatives can be used to produce an overly-calming effect ( alcohol being th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neuroleptics
Antipsychotics, also known as neuroleptics, are a class of psychotropic medication primarily used to manage psychosis (including delusions, hallucinations, paranoia or disordered thought), principally in schizophrenia but also in a range of other psychotic disorders. They are also the mainstay together with mood stabilizers in the treatment of bipolar disorder. Prior research has shown that use of any antipsychotic is associated with smaller brain tissue volumes, including white matter reduction and that this brain shrinkage is dose dependent and time dependent. A more recent controlled trial suggests that second generation antipsychotics combined with intensive psychosocial therapy may potentially prevent pallidal brain volume loss in first episode psychosis. The use of antipsychotics may result in many unwanted side effects such as involuntary movement disorders, gynecomastia, impotence, weight gain and metabolic syndrome. Long-term use can produce adverse effects suc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecular Building Blocks
Building block is a term in chemistry which is used to describe a virtual molecular fragment or a real chemical compound the molecules of which possess reactive functional groups. Building blocks are used for bottom-up modular assembly of molecular architectures: nano-particles, metal-organic frameworks, organic molecular constructs, supra-molecular complexes. Using building blocks ensures strict control of what a final compound or a (supra)molecular construct will be. Building blocks for medicinal chemistry In medicinal chemistry, the term defines either imaginable, virtual molecular fragments or chemical reagents from which drugs or drug candidates might be constructed or synthetically prepared. Virtual building blocks Virtual building blocks are used in drug discovery for drug design and virtual screening, addressing the desire to have controllable molecular morphologies that interact with biological targets. Of special interest for this purpose are the building block ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
