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Acromelic Acid A
Acromelic acid A (ACRO A) is a toxic compound that is part of a group known as kainoids, characterized by a structure bearing a pyrrolidine dicarboxylic acid, represented by kainic acid. Acromelic acid A has the molecular formula . It has been isolated from a Japanese poisonous mushroom, ''Clitocybe acromelalga''. Acromelic acid is responsible for the poisonous aspects of the mushroom because of its potent neuroexcitatory and neurotoxic properties. Ingestion of the Clitocybe acromelalga, causes allodynia which can continue for over a month. The systemic administration of acromelic acid A in rats results in selective loss of interneurons in the lower spinal cord, without causing neuronal damage in the hippocampus and other regions. Structure and isoforms Acromelic acids represent a group of compounds found in various forms. Five distinct molecules have been identified, including two isoforms designated acromelic acid A and B. Acromelic acid C-E are recognized toxic analogs. Acro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kainic Acid
Kainic acid, or kainate, is an acid that naturally occurs in some seaweed. Kainic acid is a potent neuroexcitatory amino acid agonist that acts by activating receptors for glutamate, the principal excitatory neurotransmitter in the central nervous system. Glutamate is produced by the cell's metabolic processes and there are four major classifications of glutamate receptors: NMDA receptors, AMPA receptors, kainate receptors, and the metabotropic glutamate receptors. Kainic acid is an agonist for kainate receptors, a type of ionotropic glutamate receptor. Kainate receptors likely control a sodium channel that produces excitatory postsynaptic potentials (EPSPs) when glutamate binds. Kainic acid is commonly injected into laboratory animal models to study the effects of Ablative brain surgery, experimental ablation. Kainic acid is a direct agonist of the glutamic kainate receptors and large doses of concentrated solutions produce immediate neuronal death by overstimulating neurons to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epoxide
In organic chemistry, an epoxide is a cyclic ether, where the ether forms a three-atom ring: two atoms of carbon and one atom of oxygen. This triangular structure has substantial ring strain, making epoxides highly reactive, more so than other ethers. They are produced on a large scale for many applications. In general, low molecular weight epoxides are colourless and nonpolar, and often volatile. Nomenclature A compound containing the epoxide functional group can be called an epoxy, epoxide, oxirane, and ethoxyline. Simple epoxides are often referred to as oxides. Thus, the epoxide of ethylene (C2H4) is ethylene oxide (C2H4O). Many compounds have trivial names; for instance, ethylene oxide is called "oxirane". Some names emphasize the presence of the epoxide functional group, as in the compound ''1,2-epoxyheptane'', which can also be called ''1,2-heptene oxide''. A polymer formed from epoxide precursors is called an ''epoxy''. However, few if any of the epoxy groups i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spinal Interneuron
A spinal interneuron, found in the spinal cord, relays signals between (afferent) sensory neurons, and (efferent) motor neurons. Different classes of spinal interneurons are involved in the process of sensory-motor integration. Most interneurons are found in the grey column, a region of grey matter in the spinal cord. Structure The grey column of the spinal cord appears to have groups of small neurons, often referred to as spinal interneurons, that are neither primary sensory cells nor motor neurons. The versatile properties of these spinal interneurons cover a wide range of activities. Their functions include the processing of sensory input, the modulation of motor neuron activity, the coordination of activity at different spinal levels, and the relay of sensory or proprioceptive data to the brain. There has been extensive research on the identification and characterization of the spinal cord interneurons based on factors such as location, size, structure, connectivity, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toxin
A toxin is a naturally occurring poison produced by metabolic activities of living cells or organisms. They occur especially as proteins, often conjugated. The term was first used by organic chemist Ludwig Brieger (1849–1919), derived from '' toxic''. Toxins can be small molecules, peptides, or proteins that are capable of causing disease on contact with or absorption by body tissues interacting with biological macromolecules such as enzymes or cellular receptors. They vary greatly in their toxicity, ranging from usually minor (such as a bee sting) to potentially fatal even at extremely low doses (such as botulinum toxin). Terminology Toxins are often distinguished from other chemical agents strictly based on their biological origin. Less strict understandings embrace naturally occurring inorganic toxins, such as arsenic. Other understandings embrace synthetic analogs of naturally occurring organic poisons as toxins, and may or may not embrace naturally oc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Absorption (pharmacology)
Absorption is the journey of a drug travelling from the site of administration to the site of action. The drug travels by some route of administration ( oral, topical-dermal, etc.) in a chosen dosage form (e.g., tablets, capsules, or in solution). Absorption by some other routes, such as intravenous therapy, intramuscular injection, enteral nutrition, is even more straightforward and there is less variability in absorption and bioavailability is often near 100%. Intravascular administration does not involve absorption, and there is no loss of drug. The fastest route of absorption is inhalation. Absorption is a primary focus in drug development and medicinal chemistry, since a drug must be absorbed before any medicinal effects can take place. Moreover, the drug's pharmacokinetic profile can be easily and significantly changed by adjusting factors that affect absorption. Dissolution Oral ingestion is the most common route of administration of pharmaceuticals. Passing thro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reductive Amination
Reductive amination (also known as reductive alkylation) is a form of amination that converts a carbonyl group to an amine via an intermediate imine. The carbonyl group is most commonly a ketone or an aldehyde. It is a common method to make amines and is widely used in green chemistry since it can be done catalytically in One-pot synthesis, one-pot under mild conditions. In biochemistry, Dehydrogenase, dehydrogenase enzymes use reductive amination to produce the amino acid Glutamic acid, glutamate. Additionally, there is ongoing research on alternative synthesis mechanisms with various metal catalysts which allow the reaction to be less energy taxing, and require milder reaction conditions. Investigation into biocatalysts, such as imine reductases, have allowed for higher selectivity in the reduction of chiral amines which is an important factor in pharmaceutical synthesis. Reaction process Reductive amination occurs between a carbonyl such as an aldehyde or ketone and an amine i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrrolidine
Pyrrolidine, also known as tetrahydropyrrole, is an organic compound with the molecular formula (CH2)4NH. It is a cyclic secondary amine, also classified as a saturated heterocycle. It is a colourless liquid that is miscible with water and most organic solvents. It has a characteristic odor that has been described as "ammoniacal, fishy, shellfish-like". In addition to pyrrolidine itself, many substituted pyrrolidines are known. Production and synthesis Industrial production Pyrrolidine is prepared industrially by the reaction of 1,4-butanediol and ammonia at a temperature of 165–200 °C and a pressure of 17–21 MPa in the presence of a cobalt- and nickel oxide catalyst, which is supported on alumina. : The reaction is carried out in the liquid phase in a continuous tube- or tube bundle reactor, which is operated in the cycle gas method. The catalyst is arranged as a fixed-bed and the conversion is carried out in the downflow mode. The product is obtained after m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2,6-Dichloropyridine
2,6-Dichloropyridine is a chloropyridine with the formula C5H3Cl2N. A white solid, it is one of six isomers of dichloropyridine. It serves as a precursor to the antibiotic enoxacin, as well as the drug and anpirtoline and the antifungal liranaftate. Synthesis 2,6-Dichoropyridine is produced by reaction of pyridine with chlorine. 2-Chloropyridine 2-Chloropyridine is an aryl chloride with the formula C5H4ClN. It is a colorless liquid that is mainly used to generate fungicides and insecticides in industry. It also serves to generate antihistamines and antiarrythymics for pharmaceutical purpo ... is an intermediate. Toxicity The is 115 mg/kg (oral, mice). References Chloropyridines Disubstituted pyridines {{organic-compound-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catechol
Catechol ( or ), also known as pyrocatechol or 1,2-dihydroxybenzene, is an organic compound with the molecular formula . It is the ''ortho'' isomer of the three isomeric benzenediols. This colorless compound occurs naturally in trace amounts. It was first discovered by destructive distillation of the plant extract catechin. About 20,000 tonnes of catechol are now synthetically produced annually as a commodity organic chemical, mainly as a precursor to pesticides, flavors, and fragrances. Small amounts of catechol occur in fruits and vegetables. Isolation and synthesis Catechol was first isolated in 1839 by Edgar Hugo Emil Reinsch (1809–1884) by distilling it from the solid tannic preparation catechin, which is the residuum of catechu, the boiled or concentrated juice of ''Mimosa catechu'' ('' Acacia catechu''). Upon heating catechin above its decomposition point, a substance that Reinsch first named ''Brenz-Katechusäure'' (burned catechu acid) sublimated as a white efflo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glutamic Acid
Glutamic acid (symbol Glu or E; known as glutamate in its anionic form) is an α- amino acid that is used by almost all living beings in the biosynthesis of proteins. It is a non-essential nutrient for humans, meaning that the human body can synthesize enough for its use. It is also the most abundant excitatory neurotransmitter in the vertebrate nervous system. It serves as the precursor for the synthesis of the inhibitory gamma-aminobutyric acid (GABA) in GABAergic neurons. Its molecular formula is . Glutamic acid exists in two optically isomeric forms; the dextrorotatory -form is usually obtained by hydrolysis of gluten or from the waste waters of beet-sugar manufacture or by fermentation.Webster's Third New International Dictionary of the English Language Unabridged, Third Edition, 1971. Its molecular structure could be idealized as HOOC−CH()−()2−COOH, with two carboxyl groups −COOH and one amino group −. However, in the solid state and mildly acidic water s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Condensation
Condensation is the change of the state of matter from the gas phase into the liquid phase, and is the reverse of vaporization. The word most often refers to the water cycle. It can also be defined as the change in the state of water vapor to liquid water when in contact with a liquid or solid surface or cloud condensation nuclei within the atmosphere. When the transition happens from the gaseous phase into the solid phase directly, the change is called deposition. Condensation is usually associated with water. Initiation Condensation is initiated by the formation of atomic/molecular clusters of that species within its gaseous volume—like rain drop or snow flake formation within clouds—or at the contact between such gaseous phase and a liquid or solid surface. In clouds, this can be catalyzed by water-nucleating proteins, produced by atmospheric microbes, which are capable of binding gaseous or liquid water molecules. Reversibility scenarios A few distinct rev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pummerer Rearrangement
The Pummerer rearrangement is an organic reaction whereby an alkyl sulfoxide rearranges to an α- acyloxy–thioether (monothioacetal-ester) in the presence of acetic anhydride. The stoichiometry of the reaction is: :RS(O)CHR'2 + Ac2O → RSC(OAc)R'2 + AcOH Synthetic implementation Aside from acetic anhydride, trifluoroacetic anhydride and trifluoromethanesulfonic anhydride have been employed as activators. Common nucleophiles besides acetates are arenes, alkenes, amides, and phenols. The usage of α-acyl sulfoxides and Lewis acids, such as TiCl4 and SnCl4, allow the reaction to proceed at lower temperatures (0 °C). Thionyl chloride can be used in place of acetic anhydride to trigger the elimination for forming the electrophilic intermediate and supplying chloride as the nucleophile to give an α-chloro-thioether: Other anhydrides and acyl halides can give similar products. Inorganic acids can also give this reaction. This product can be converted to alde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
