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Isocrotonic Acid
Isocrotonic acid (also known as quartenylic acid; formally named (''Z'')-2-butenoic acid) is the ''cis'' isomer of crotonic acid. It is an oil, possessing a smell similar to that of brown sugar. It boils at 171.9 °C, concomitant with conversion into crotonic acid. Isomerization is complete when the ''cis'' acid is heated to 170–180 °C in a sealed tube. Rudolph Fittig and Hugo Erdmann showed that the γ-phenyl structural analog of isocrotonic acid forms α-naphthol when dehydrated, an observation that provided useful evidence in understanding the nature of naphthalene.{{cite journal, first1 = Rudolph, last1 = Fittig, first2 = Hugo, last2 = Erdmann, authorlink1 = Rudolph Fittig, authorlink2 = Hugo Erdmann, journal = Ber. Dtsch. Chem. Ges. ''Chemische Berichte'' (usually abbreviated as ''Ber.'' or ''Chem. Ber.'') was a German-language scientific journal of all disciplines of chemistry founded in 1868. It was one of the oldest scientific journals in chemistry, u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Merck Index
''The Merck Index'' is an encyclopedia of chemicals, drugs and biologicals with over 10,000 monograph on single substances or groups of related compounds published online by the Royal Society of Chemistry. History The first edition of the Merck's Index was published in 1889 by the German chemical company Emanuel Merck and was primarily used as a sales catalog for Merck's growing list of chemicals it sold. The American subsidiary was established two years later and continued to publish it. During World War I the US government seized Merck's US operations and made it a separate American "Merck" company that continued to publish the Merck Index. In 2012 the Merck Index was licensed to the Royal Society of Chemistry. An online version of The Merck Index, including historic records and new updates not in the print edition, is commonly available through research libraries. It also includes an appendix with monographs on organic named reactions. The 15th edition was published in A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carboxylic Acid
In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group () attached to an R-group. The general formula of a carboxylic acid is or , with R referring to the alkyl, alkenyl, aryl, or other group. Carboxylic acids occur widely. Important examples include the amino acids and fatty acids. Deprotonation of a carboxylic acid gives a carboxylate anion. Examples and nomenclature Carboxylic acids are commonly identified by their trivial names. They at oftentimes have the suffix ''-ic acid''. IUPAC-recommended names also exist; in this system, carboxylic acids have an ''-oic acid'' suffix. For example, butyric acid (C3H7CO2H) is butanoic acid by IUPAC guidelines. For nomenclature of complex molecules containing a carboxylic acid, the carboxyl can be considered position one of the parent chain even if there are other substituents, such as 3-chloropropanoic acid. Alternately, it can be named as a "carboxy" or "carboxylic acid" substituent on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crotonic Acid
Crotonic acid ((2''E'')-but-2-enoic acid) is a short-chain unsaturated carboxylic acid, described by the formula CH3CH=CHCO2H. It is called crotonic acid because it was erroneously thought to be a saponification product of croton oil. It crystallizes as colorless needles from hot water. The ''cis''-isomer of crotonic acid is called isocrotonic acid. Crotonic acid is soluble in water and many organic solvents. Its odor is similar to butyric acid. Production Crotonic acid may be obtained by several methods: *by oxidation of crotonaldehyde: : *by Knoevenagel condensation of acetaldehyde with malonic acid in pyridine: : *or by alkaline hydrolysis of allyl cyanide after the intramolecular rearrangement of the double bond: : *Furthermore, it is formed during the distillation of 3-hydroxybutyric acid: : Properties Crotonic acid crystallizes in the monoclinic crystal system in the space group P21/a (space group 14, position 3) with the lattice parameters , , and . The uni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angelic Acid
Angelic acid is a monocarboxylic unsaturated organic acid, mostly found in the plants of the family Apiaceae. It is a volatile solid with a biting taste and pungent sour odor. It is the '' cis'' isomer of 2-methyl-2-butenoic acid, which easily converts to the ''trans'' isomer, tiglic acid, upon heating or reaction with inorganic acids. The reverse transformation occurs much less readily. The salts and esters of angelic acid are called angelates. Angelic acid esters are the active components of herbal medicine used against a wide range of various health disturbances including pains, fever, gout, heartburn, etc. Name and discovery Angelic acid was first isolated by the German pharmacist Ludwig Andreas Buchner (1813–1897) in 1842 from the roots of the garden plant angelica (''Angelica archangelica''), which gave the acid its name. Occurrence Angelic acid occurs in the roots of many plants, especially of the family Apiaceae. These plants include ''Angelica archangelica'', '' Peuc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IUPAC Nomenclature Of Organic Chemistry
In chemical nomenclature, the IUPAC nomenclature of organic chemistry is a method of naming organic chemical compounds as recommended by the International Union of Pure and Applied Chemistry (IUPAC). It is published in the '' Nomenclature of Organic Chemistry'' (informally called the Blue Book). Ideally, every possible organic compound should have a name from which an unambiguous structural formula can be created. There is also an IUPAC nomenclature of inorganic chemistry. To avoid long and tedious names in normal communication, the official IUPAC naming recommendations are not always followed in practice, except when it is necessary to give an unambiguous and absolute definition to a compound. IUPAC names can sometimes be simpler than older names, as with ethanol, instead of ethyl alcohol. For relatively simple molecules they can be more easily understood than non-systematic names, which must be learnt or looked over. However, the common or trivial name is often substanti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cis–trans Isomerism
''Cis''–''trans'' isomerism, also known as geometric isomerism or configurational isomerism, is a term used in chemistry that concerns the spatial arrangement of atoms within molecules. The prefixes "''cis''" and "''trans''" are from Latin: "this side of" and "the other side of", respectively. In the context of chemistry, ''cis'' indicates that the functional groups (substituents) are on the same side of some plane, while ''trans'' conveys that they are on opposing (transverse) sides. ''Cis''–''trans'' isomers are stereoisomers, that is, pairs of molecules which have the same formula but whose functional groups are in different orientations in three-dimensional space. ''Cis-trans'' notation does not always correspond to ''E''–''Z'' isomerism, which is an '' absolute'' stereochemical description. In general, ''cis''–''trans'' stereoisomers contain double bonds that do not rotate, or they may contain ring structures, where the rotation of bonds is restricted or prevente ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crotonic Acid
Crotonic acid ((2''E'')-but-2-enoic acid) is a short-chain unsaturated carboxylic acid, described by the formula CH3CH=CHCO2H. It is called crotonic acid because it was erroneously thought to be a saponification product of croton oil. It crystallizes as colorless needles from hot water. The ''cis''-isomer of crotonic acid is called isocrotonic acid. Crotonic acid is soluble in water and many organic solvents. Its odor is similar to butyric acid. Production Crotonic acid may be obtained by several methods: *by oxidation of crotonaldehyde: : *by Knoevenagel condensation of acetaldehyde with malonic acid in pyridine: : *or by alkaline hydrolysis of allyl cyanide after the intramolecular rearrangement of the double bond: : *Furthermore, it is formed during the distillation of 3-hydroxybutyric acid: : Properties Crotonic acid crystallizes in the monoclinic crystal system in the space group P21/a (space group 14, position 3) with the lattice parameters , , and . The uni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isomerization
In chemistry, isomerization or isomerisation is the process in which a molecule, polyatomic ion or molecular fragment is transformed into an isomer with a different chemical structure. Enolization is an example of isomerization, as is tautomerization. When the isomerization occurs intramolecularly it may be called a rearrangement reaction. When the activation energy for the isomerization reaction is sufficiently small, both isomers will exist in a temperature-dependent equilibrium with each other. Many values of the standard free energy difference, \Delta G^\circ, have been calculated, with good agreement between observed and calculated data. Examples and applications Alkanes Skeletal isomerization occurs in the cracking process, used in the petrochemical industry. As well as reducing the average chain length, straight-chain hydrocarbons are converted to branched isomers in the process, as illustrated the following reaction of ''n''-butane to ''i''-butane. :\overset -> ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 lab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hugo Erdmann
Hugo Wilhelm Traugott Erdmann (8 May 1862 – 25 June 1910) was the German chemist who discovered, together with his doctoral advisor Jacob Volhard, the Volhard-Erdmann cyclization. In 1898 he was the first who coined the term ''noble gas'' (the original noun is in German). Erdmann invented the name Thiozone in 1908, hypothesizing that S3 made up a large proportion of liquid sulfur. In collaboration with Rudolph Fittig, Erdmann found that dehydration of γ-phenyl structural analog of isocrotonic acid produced α-naphthol, an observation that provided evidence in understanding the nature of naphthalene Naphthalene is an organic compound with formula . It is the simplest polycyclic aromatic hydrocarbon, and is a white crystalline solid with a characteristic odor that is detectable at concentrations as low as 0.08 ppm by mass. As an aromat .... Bibliography Books written by Erdmann: # See also * German inventors and discoverers References * * Notes 1862 b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Structural Analog
A structural analog (analogue in modern traditional English; Commonwealth English), also known as a chemical analog or simply an analog, is a compound having a structure similar to that of another compound, but differing from it in respect to a certain component. It can differ in one or more atoms, functional groups, or substructures, which are replaced with other atoms, groups, or substructures. A structural analog can be imagined to be formed, at least theoretically, from the other compound. Structural analogs are often isoelectronic. Despite a high chemical similarity, structural analogs are not necessarily functional analogs and can have very different physical, chemical, biochemical, or pharmacological properties. In drug discovery, either a large series of structural analogs of an initial lead compound are created and tested as part of a structure–activity relationship study or a database is screened for structural analogs of a lead compound. Chemical analogues of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
