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Chelidonic Acid
Chelidonic acid is a heterocyclic organic acid with a pyran skeleton. Preparation Chelidonic acid can be prepared in two steps from diethyl oxalate and acetone: : Uses Chelidonic acid is used to synthesize 4-pyrone via thermal decarboxylation. Natural occurrence Chelidonic acid was first discovered in extracts of ''Chelidonium majus''. It occurs naturally in plants of the Asparagales order. Potassium chelidonate has been found to be responsible for nyctinasty in some plants; specifically, it has been found to regulate the closing of leaves of ''Cassia mimosoides'' at nightfall. See also * Dimethyl oxalate * Dehydroacetic acid Dehydroacetic acid is an organic compound which has several industrial applications. The compound is classified as a pyrone derivative. It presents as an odorless, colorless to white crystalline powder, almost insoluble in water and moderately so ... References {{reflist 4-Pyrones Dicarboxylic acids ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meconic Acid
Meconic acid, also known as acidum meconicum and poppy acid, is a chemical substance found in certain plants of the poppy family, Papaveraceae, such as ''Papaver somniferum'' (opium poppy) and ''Papaver bracteatum''. Meconic acid constitutes about 5% of opium and can be used as an analytical marker for the presence of opium. Meconic acid has erroneously been described as a mild narcotic, but it has little or no physiological activity, and is not used medicinally. Meconic acid forms salts with alkaloids and metals. These salts as well as meconic acid esters are called meconates. Meconic acid was first isolated by Friedrich Sertürner in 1805.Friedrich Sertürner (1805(Untitled letter to the editor) ''Journal der Pharmacie für Aerzte, Apotheker und Chemisten'' (Journal of Pharmacy for Physicians, Apothecaries, and Chemists), 13 : 229–243. See also: Sertuerner (1817"Ueber das Morphium, eine neue salzfähige Grundlage, und die Mekonsäure, als Hauptbestandtheile des Opiums"(On m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterocyclic
A heterocyclic compound or ring structure is a cyclic compound that has atoms of at least two different elements as members of its ring(s). Heterocyclic chemistry is the branch of organic chemistry dealing with the synthesis, properties, and applications of these heterocycles. Examples of heterocyclic compounds include all of the nucleic acids, the majority of drugs, most biomass (cellulose and related materials), and many natural and synthetic dyes. More than half of known compounds are heterocycles. 59% of US FDA-approved drugs contain nitrogen heterocycles. Classification The study of heterocyclic chemistry focuses especially on unsaturated derivatives, and the preponderance of work and applications involves unstrained 5- and 6-membered rings. Included are pyridine, thiophene, pyrrole, and furan. Another large class of heterocycles refers to those fused to benzene rings. For example, the fused benzene derivatives of pyridine, thiophene, pyrrole, and furan are quinol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Acid
An organic acid is an organic compound with acidic properties. The most common organic acids are the carboxylic acids, whose acidity is associated with their carboxyl group –COOH. Sulfonic acids, containing the group –SO2OH, are relatively stronger acids. Alcohols, with –OH, can act as acids but they are usually very weak. The relative stability of the conjugate base of the acid determines its acidity. Other groups can lsoconfer acidity, usually weakly: the thiol group –SH, the enol group, and the phenol group. In biological systems, organic compounds containing these groups are generally referred to as organic acids. A few common examples include: * lactic acid * acetic acid * formic acid * citric acid * oxalic acid * uric acid * malic acid * tartaric acid Characteristics In general, organic acids are weak acids and do not dissociate completely in water, whereas the strong mineral acids do. Lower molecular mass organic acids such as formic and lactic ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyran
In chemistry, pyran, or oxine, is a six-membered heterocyclic, non-aromatic ring, consisting of five carbon atoms and one oxygen atom and containing two double bonds. The molecular formula is C5H6O. There are two isomers of pyran that differ by the location of the double bonds. In 2''H''-pyran, the saturated carbon is at position 2, whereas, in 4''H''-pyran, the saturated carbon is at position 4. 4''H''-Pyran was first isolated and characterized in 1962 via pyrolysis of 2-acetoxy-3,4-dihydro-2''H''-pyran. It was found too unstable, particularly in the presence of air. 4''H''-pyran easily disproportionates to the corresponding dihydropyran and the pyrylium ion, which is easily hydrolyzed in aqueous medium. Although the pyrans themselves have little significance in chemistry, many of their derivatives are important biological molecules, such as the pyranoflavonoids. The term pyran is also often applied to the saturated ring analog, which is more properly referred to as tetrahydrop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diethyl Oxalate
In organic chemistry, an ethyl group (abbr. Et) is an alkyl substituent with the formula , derived from ethane (). ''Ethyl'' is used in the International Union of Pure and Applied Chemistry's nomenclature of organic chemistry for a saturated two-carbon moiety in a molecule, while the prefix "''eth-''" is used to indicate the presence of two carbon atoms in the molecule. Ethylation Ethylation is the formation of a compound by introduction of the ethyl group. The most widely practiced example of this reaction is the ethylation of benzene with ethylene to yield ethylbenzene, a precursor to styrene, which is a precursor to polystyrene. Approximately 24.7 million tons of ethylbenzene were produced in 1999. :: Many ethyl-containing compounds are generated by electrophilic ethylation, i.e. treatment of nucleophiles with sources of Et+. Triethyloxonium tetrafluoroborate t3OF4 is such a reagent. For good nucleophiles, less electrophilic reagents are employed, such as ethyl halides. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetone
Acetone (2-propanone or dimethyl ketone), is an organic compound with the formula . It is the simplest and smallest ketone (). It is a colorless, highly volatile and flammable liquid with a characteristic pungent odour. Acetone is miscible with water and serves as an important organic solvent in its own right, in industry, home, and laboratory. About 6.7 million tonnes were produced worldwide in 2010, mainly for use as a solvent and production of methyl methacrylate (and from that PMMA) as well as bisphenol A.Acetone World Petrochemicals report, January 2010Stylianos Sifniades, Alan B. Levy, "Acetone" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005. It is a common building block in |
Organic Synthesis
Organic synthesis is a special branch of chemical synthesis and is concerned with the intentional construction of organic compounds. Organic molecules are often more complex than inorganic compounds, and their synthesis has developed into one of the most important branches of organic chemistry. There are several main areas of research within the general area of organic synthesis: ''total synthesis'', ''semisynthesis'', and ''methodology''. Total synthesis A total synthesis is the complete chemical synthesis of complex organic molecules from simple, commercially available petrochemical or natural precursors. Total synthesis may be accomplished either via a linear or convergent approach. In a ''linear'' synthesis—often adequate for simple structures—several steps are performed one after another until the molecule is complete; the chemical compounds made in each step are called synthetic intermediates. Most often, each step in a synthesis refers to a separate rea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
4-Pyrone
4-Pyrone (γ-pyrone or pyran-4-one) is an unsaturated cyclic chemical compound with the molecular formula C5H4O2. It is isomeric with 2-pyrone. Preparation 4-Pyrone is prepared via the thermal decarboxylation of chelidonic acid. Reactions 4-Pyrone and its derivatives react with amines in protic solvents to form 4-Pyridones. Derivatives 4-Pyrone forms the central core of several natural chemical compounds, including maltol, meconic acid, kojic acid, and of the important class of the Flavones. : See also * Pyrone * 4-Pyridone * Dehydroacetic acid Dehydroacetic acid is an organic compound which has several industrial applications. The compound is classified as a pyrone derivative. It presents as an odorless, colorless to white crystalline powder, almost insoluble in water and moderately so ... References {{DEFAULTSORT:Pyrone, 4- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decarboxylation
Decarboxylation is a chemical reaction that removes a carboxyl group and releases carbon dioxide (CO2). Usually, decarboxylation refers to a reaction of carboxylic acids, removing a carbon atom from a carbon chain. The reverse process, which is the first chemical step in photosynthesis, is called carboxylation, the addition of CO2 to a compound. Enzymes that catalyze decarboxylations are called decarboxylases or, the more formal term, carboxy-lyases (Enzyme Commission number, EC number 4.1.1). In organic chemistry The term "decarboxylation" usually means replacement of a carboxyl group () with a hydrogen atom: :RCO2H -> RH + CO2 Decarboxylation is one of the oldest known organic reactions. It is one of the processes assumed to accompany pyrolysis and destructive distillation. Metal salts, especially copper compounds, facilitate the reaction via the intermediacy of metal carboxylate complexes. Decarboxylation of aryl carboxylates can generate the equivalent of the correspond ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chelidonium Majus
''Chelidonium majus'', the greater celandine, is a perennial herbaceous flowering plant in the poppy family Papaveraceae. One of two species in the genus ''Chelidonium'', it is native to Europe and western Asia and introduced widely in North America. The plant known as lesser celandine (''Ficaria verna'') is not closely related, as it belongs to the buttercup family Ranunculaceae. Description Greater celandine is a perennial herbaceous plant with an erect habit, and reaches high. The blue-green leaves are pinnate with lobed and wavy margins, up to long. When injured, the plant exudes a yellow to orange latex. The flowers consist of four yellow petals, each about long, with two sepals. A double-flowered variety occurs naturally. The flowers appear from late spring to summer, May to September (in the UK), in umbelliform cymes of about 4 flowers. The seeds are small and black, borne in a long, cylindrical capsule. Each has an elaiosome, which attracts ants to disperse the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asparagales
Asparagales (asparagoid lilies) is an order (biology), order of plants in modern classification systems such as the Angiosperm Phylogeny Group (APG) and the Angiosperm Phylogeny Web. The order takes its name from the type (biology), type family (biology), family Asparagaceae and is placed in the monocots amongst the lilioid monocots. The order has only recently been recognized in classification systems. It was first put forward by herbert Huber (botanist), Huber in 1977 and later taken up in the Dahlgren system of 1985 and then the APG in 1998, 2003 and 2009. Before this, many of its families were assigned to the old order Liliales, a very large order containing almost all monocots with colorful tepals and lacking starch in their endosperm. DNA sequencing, DNA sequence analysis indicated that many of the taxa previously included in Liliales should actually be redistributed over three orders, Liliales, Asparagales, and Dioscoreales. The boundaries of the Asparagales and of its fam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
