|
Lactone
Lactones are cyclic carboxylic esters, containing a 1-oxacycloalkan-2-one structure (), or analogues having unsaturation or heteroatoms replacing one or more carbon atoms of the ring. Lactones are formed by intramolecular esterification of the corresponding hydroxycarboxylic acids, which takes place spontaneously when the ring that is formed is five- or six-membered. Lactones with three- or four-membered rings (α-lactones and β-lactones) are very reactive, making their isolation difficult. Special methods are normally required for the laboratory synthesis of small-ring lactones as well as those that contain rings larger than six-membered. Nomenclature Lactones are usually named according to the precursor acid molecule (''aceto'' = 2 carbon atoms, ''propio'' = 3, ''butyro'' = 4, ''valero'' = 5, ''capro'' = 6, etc.), with a ''-lactone'' suffix and a Greek letter prefix that specifies the number of carbon atoms in the heterocycle — that is, the distance between the relevant -OH ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lactone Types
Lactones are cyclic carboxylic esters, containing a 1-oxacycloalkan-2-one structure (), or analogues having unsaturation or heteroatoms replacing one or more carbon atoms of the ring. Lactones are formed by intramolecular esterification of the corresponding hydroxycarboxylic acids, which takes place spontaneously when the ring that is formed is five- or six-membered. Lactones with three- or four-membered rings (α-lactones and β-lactones) are very reactive, making their isolation difficult. Special methods are normally required for the laboratory synthesis of small-ring lactones as well as those that contain rings larger than six-membered. Nomenclature Lactones are usually named according to the precursor acid molecule (''aceto'' = 2 carbon atoms, ''propio'' = 3, ''butyro'' = 4, ''valero'' = 5, ''capro'' = 6, etc.), with a ''-lactone'' suffix and a Greek letter prefix that specifies the number of carbon atoms in the heterocycle — that is, the distance between the relevant -OH ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ascorbic Acid
Vitamin C (also known as ascorbic acid and ascorbate) is a water-soluble vitamin found in citrus and other fruits and vegetables, also sold as a dietary supplement and as a topical 'serum' ingredient to treat melasma (dark pigment spots) and wrinkles on the face. It is used to prevent and treat scurvy. Vitamin C is an essential nutrient involved in the repair of tissue, the formation of collagen, and the enzymatic production of certain neurotransmitters. It is required for the functioning of several enzymes and is important for immune system function. It also functions as an antioxidant. Most animals are able to synthesize their own vitamin C. However, apes (including humans) and monkeys (but not all primates), most bats, some rodents, and certain other animals must acquire it from dietary sources. There is some evidence that regular use of supplements may reduce the duration of the common cold, but it does not appear to prevent infection. It is unclear whether supp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclopentadecanolide
Cyclopentadecanolide is a natural macrolide lactone and a synthetic musk. Natural occurrence Cyclopentadecanolide occurs in small quantities in angelica root essential oil and is responsible for its musklike odor. Production Cyclopentadecanolide is produced synthetically by ring expansion of cyclotetradecanone. Another synthesis route is the depolymerization of polyesters of 15-hydroxypentadecanoic acid. Uses Cyclopentadecanolide is used as a musklike perfume fixative in fine fragrances and as a flavoring agent A flavoring (or flavouring), also known as flavor (or flavour) or flavorant, is a food additive used to improve the taste or smell of food. It changes the perceptual impression of food as determined primarily by the chemoreceptors of the gustat .... It is a substitute for the extremely expensive animal musk. References {{reflist Flavors Lactones Perfume ingredients ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macrolide
The Macrolides are a class of natural products that consist of a large macrocyclic lactone ring to which one or more deoxy sugars, usually cladinose and desosamine, may be attached. The lactone rings are usually 14-, 15-, or 16-membered. Macrolides belong to the polyketide class of natural products. Some macrolides have antibiotic or antifungal activity and are used as pharmaceutical drugs. Rapamycin is also a macrolide and was originally developed as an antifungal, but is now used as an immunosuppressant drug and is being investigated as a potential longevity therapeutic. Macrolides are bacteriostatic in that they suppress or inhibit bacterial growth rather than killing bacteria completely. Definition In general, any macrocyclic lactone having greater than 8-membered rings are candidates for this class. The macrocycle may contain amino nitrogen, amide nitrogen (but should be differentiated from cyclopeptides), an oxazole ring, or a thiazole ring. Benzene rings are exclude ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kavain
Kavain is the main kavalactone found mostly in the roots of the kava plant. Pharmacology Kavain has anticonvulsive properties, attenuating vascular smooth muscle contraction through interactions with voltage-dependent and channels. How this effect is mediated and to what extent this mechanism is involved in the anxiolytic and analgesic effects of kavalactones on the central nervous system is unknown. The recent finding that kavain can reversibly inhibit both monoamine oxidase A and monoamine oxidase B suggests that kavain may exert some of its effects by modulating serotonin, norepinephrine, and dopamine signaling. However, the precise mechanisms underlying the psychotropic, sedative, and anxiolytic actions of kavain and related kavalactones are still debated. Direct binding to the benzodiazepine/flumazenil binding site of the GABA-A receptor does not occur with kavain enantiomers. Many studies involved kava extracts from different plant parts and are, therefore, not applica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carboxylic Ester
In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides are fatty acid esters of glycerol; they are important in biology, being one of the main classes of lipids and comprising the bulk of animal fats and vegetable oils. Esters typically have a pleasant smell; those of low molecular weight are commonly used as fragrances and are found in essential oils and pheromones. They perform as high-grade solvents for a broad array of plastics, plasticizers, resins, and lacquers, and are one of the largest classes of synthetic lubricants on the commercial market. Polyesters are important plastics, with monomers linked by ester moieties. Phosphoesters form the backbone of DNA molecules. Nitrate esters, such as nitroglycerin, are known for their explosive properties. '' Nomenclature Etymol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Esterification
In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides are fatty acid esters of glycerol; they are important in biology, being one of the main classes of lipids and comprising the bulk of animal fats and vegetable oils. Esters typically have a pleasant smell; those of low molecular weight are commonly used as fragrances and are found in essential oils and pheromones. They perform as high-grade solvents for a broad array of plastics, plasticizers, resins, and lacquers, and are one of the largest classes of synthetic lubricants on the commercial market. Polyesters are important plastics, with monomers linked by ester moieties. Phosphoesters form the backbone of DNA molecules. Nitrate esters, such as nitroglycerin, are known for their explosive properties. '' Nomenclature Etymology The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardenolide
A cardenolide is a type of steroid. Many plants contain derivatives, collectively known as cardenolides, including many in the form of cardenolide glycosides (cardenolides that contain structural groups derived from sugars). Cardenolide glycosides are often toxic; specifically, they are heart-arresting. Cardenolides are toxic to animals through inhibition of the enzyme Na+/K+‐ATPase, which is responsible for maintaining the sodium and potassium ion gradients across the cell membranes. Etymology The term derives from ''card-'' "heart" (from Greek καρδία ''kardiā'') and the suffix ''-enolide'', referring to the lactone ring at C17. Cardenolides are a class of steroids (or aglycones if viewed as cardiac glycoside constituents), and cardenolides are a subtype of this class (see MeSH D codes list). Structure Cardenolides are C(23)-steroids with methyl groups at C-10 and C-13 and a five-membered lactone (specifically a butenolide) at C-17. They are aglycone constituents of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wilhelm Rudolph Fittig
Wilhelm Rudolph Fittig (6 December 183519 November 1910) was a German chemist. He discovered the pinacol coupling reaction, mesitylene, diacetyl and biphenyl. Fittig studied the action of sodium on ketones and hydrocarbons. He discovered the Fittig reaction or Wurtz–Fittig reaction for the synthesis of alkylbenzenes, he proposed a diketone structure for benzoquinone and isolated phenanthrene from coal tar. He discovered and synthesized the first lactones and investigated structures of piperine naphthalene and fluorene. Career Fittig studied chemistry at the University of Göttingen, graduating as Ph.D. with a dissertation on acetone in 1858, under the supervision of Heinrich Limpricht and Friedrich Wöhler. He subsequently held several appointments at Göttingen, becoming Wöhler's assistant in 1858, privatdozent in 1860 and extraordinary professor in 1870. In 1870 he was appointed full professor at University of Tübingen and in 1876 at Strassburg, where the laboratories were ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coumarin
Coumarin () or 2''H''-chromen-2-one is an aromatic organic chemical compound with formula . Its molecule can be described as a benzene molecule with two adjacent hydrogen atoms replaced by a lactone-like chain , forming a second six-membered heterocycle that shares two carbons with the benzene ring. It can be placed in the benzopyrone chemical class and considered as a lactone. Coumarin is a colorless crystalline solid with a sweet odor resembling the scent of vanilla and a bitter taste. It is found in many plants, where it may serve as a chemical defense against predators. By inhibiting synthesis of vitamin K, a related compound is used as the prescription drug warfarin – an anticoagulant – to inhibit formation of blood clots, deep vein thrombosis, and pulmonary embolism. Etymology Coumarin is derived from ''coumarou'', the French word for the tonka bean. The word ''tonka'' for the tonka bean is taken from the Galibi (Carib) tongue spoken by natives of French G ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bufadienolide
Bufadienolide is a chemical compound with steroid structure. Its derivatives are collectively known as bufadienolides, including many in the form of bufadienolide glycosides (bufadienolides that contain structural groups derived from sugars). These are a type of cardiac glycoside, the other being the cardenolide glycosides. Both bufadienolides and their glycosides are toxic; specifically, they can cause an atrioventricular block, bradycardia (slow heartbeat), ventricular tachycardia (a type of rapid heartbeat), and possibly lethal cardiac arrest. Etymology The term derives from the toad genus ''Bufo'' that contains bufadienolide glycosides, the suffix ''-adien-'' that refers to the two double bonds in the lactone ring, and the ending ''-olide'' that denotes the lactone structure. Consequently, related structures with only one double bond are called ''bufenolides'', and the saturated equivalent is ''bufanolide''. Classification According to MeSH, bufadienolides and bufanolides ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phthalides
Phthalide is an organic chemical compound with the molecular formula C8H6O2. A white solid, it is the simplest benzo lactone. It is prepared from hydroxymethylbenzoic acid. Phthalides The phthalide core is found a variety of more complex chemical compounds including dyes (such as phenolphthalein Phenolphthalein ( ) is a chemical compound with the chemical formula, formula carbon, C20hydrogen, H14oxygen, O4 and is often written as "HIn", "HPh", "phph" or simply "Ph" in shorthand notation. Phenolphthalein is often used as an indicator in ...), fungicides (such as tetrachlorophthalide, often referred to simply as "phthalide"), and natural oils (such as butylphthalide). Examples File:phenolphthalein.svg, Phenolphthalein File:tetrachlorophthalide.svg, Tetrachlorophthalide FIle:Butylphthalide.svg, Butylphthalide References {{reflist Phthalides, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
