|
Baylis–Hillman Reaction
The Baylis–Hillman reaction is a carbon-carbon bond forming reaction between the α-position of an activated alkene and a carbon electrophile such as an aldehyde. Employing a nucleophilic catalyst, such as a tertiary amine and phosphine, this reaction provides a densely functionalized product (e.g. functionalized allyl alcohol in the case of aldehyde as the electrophile). It is named for Anthony B. Baylis and Melville E. D. Hillman, two of the chemists who developed this reaction while working at Celanese. This reaction is also known as the Morita–Baylis–Hillman reaction or MBH reaction, as K. Morita had published earlier work on it. DABCO is one of the most frequently used tertiary amine catalysts for this reaction. In addition, nucleophilic amines such as DMAP and DBU as well as phosphines have been found to successfully catalyze this reaction. MBH reaction has several advantages as a useful synthetic method: 1) It is an atom-economic coupling of easily prepared starting ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Celanese
Celanese Corporation, formerly known as Hoechst Celanese, is an American technology and specialty materials company headquartered in Irving, Texas. A Fortune 500 corporation, the company is the world’s leading producer of acetic acid, producing about 1.95 million tonnes per year, representing approximately 25% of global production. Celanese is also the world's largest producer of vinyl acetate monomer (VAM). Celanese operates 25 production plants and six research centers in 11 countries, mainly in North America, Europe, and Asia. The company owns and operates the world's three largest acetic acid plants: one in the Clear Lake area of Pasadena, Texas, one on Jurong Island in Singapore, and a third in Nanjing, China. History In 1918, the American Cellulose & Chemical Manufacturing Company (known as Amcelle) was founded in New York City by Swiss chemist Camille Dreyfus. The American Cellulose and Chemical Manufacturing Co. Ltd plant in Cumberland, Maryland, was set up dur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brook Rearrangement
In organic chemistry the Brook rearrangement refers to any [1,''n''] carbon to oxygen silyl migration. The Rearrangement reaction, rearrangement was first observed in the late 1950s by Canadian chemist Adrian Gibbs Brook (1924–2013), after which the reaction is named. These migrations can be promoted in a number of different ways, including thermally, photolytically or under basic/acidic conditions. In the forward direction, these silyl migrations produce silyl ethers as products which is driven by the stability of the oxygen-silicon bond. The silyl substituents can be Aliphatic compound, aliphatic or Aromatic compound, aromatic, and if the silicon is a center of Chirality (chemistry), chirality, the migration occurs with retention at this center. This migration occurs through a transition state where silicon is penta-Coordination complex, coordinate and bears a partial negative charge. If a center of chirality is present at the carbon center to which the silyl group is attached ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secondary Amine Cat MBH
Secondary may refer to: Science and nature * Secondary emission, of particles ** Secondary electrons, electrons generated as ionization products * The secondary winding, or the electrical or electronic circuit connected to the secondary winding in a transformer * Secondary (chemistry), a term used in organic chemistry to classify various types of compounds * Secondary color, color made from mixing primary colors * Secondary mirror, second mirror element/focusing surface in a reflecting telescope * Secondary craters, often called "secondaries" * Secondary consumer, in ecology * An obsolete name for the Mesozoic in geosciences * Secondary feathers, flight feathers attached to the ulna on the wings of birds Society and culture * Secondary (football), a position in American football and Canadian football * Secondary dominant in music * Secondary education, education which typically takes place after six years of primary education ** Secondary school, the type of school at th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fu DMAP MBH
Fu or FU may refer to: In arts and entertainment *Fool Us, Penn & Teller's magic-competition television show *Fǔ, a type of ancient Chinese vessel * Fu (poetry) (赋), a Chinese genre of rhymed prose *'' FU: Friendship Unlimited'', a 2017 Marathi film * Fu Manchu, a fictional character first featured in a series of novels by English author Sax Rohmer * Shaq Fu, video game * Francis Urquhart, the main character in the novel ''House of Cards'' by Michael Dobbs, and in the UK television series In music *The F.U.'s, an American band *'' F.U. Don't Take It Personal'', an album by American hip hop group Fu-Schnickens *'' F.U.E.P.'', an EP by Lily Allen * "FU" (song), a song by Miley Cyrus from her album ''Bangerz'' *''F.U. EP'', a 2002 EP by Gob *"F.U.", a song by Little Mix from their 2016 album '' Glory Days'' *"F-U", a song by Yo Gotti from his 2013 album '' I Am'' *"F.U.", a song by Avril Lavigne from her seventh studio album ''Love Sux'' In language * Fu (character) (福), meani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
P-Chiral Phosphine
''P''-Chiral phosphines are organophosphorus compounds of the formula PRR′R″, where R, R′, R″ = H, alkyl, aryl, etc. They are a subset of chiral phosphines, a broader class of compounds where the stereogenic center can reside at sites other than phosphorus. P-chirality exploits the high barrier for inversion of phosphines, which ensures that enantiomers of PRR'R" do not racemize readily. The inversion barrier is relatively insensitive to substituents for triorganophosphines. By contrast, most amines of the type NRR′R″ undergo rapid pyramidal inversion. Research themes Most chiral phosphines are C2-symmetric diphosphines. Famous examples are DIPAMP and BINAP. These chelating ligands support catalysts used in asymmetric hydrogenation and related reactions. DIPAMP is prepared by coupling the ''P''-chiral methylphenylanisylphosphine. ''P''-Chiral phosphines are of particular interest in asymmetric catalysis. ''P''-Chiral phosphines have been investigated for two ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ICD MBH Asymmetric
The International Classification of Diseases (ICD) is a globally used diagnostic tool for epidemiology, health management and clinical purposes. The ICD is maintained by the World Health Organization (WHO), which is the directing and coordinating authority for health within the United Nations System. The ICD is originally designed as a health care classification system, providing a system of diagnostic codes for classifying diseases, including nuanced classifications of a wide variety of signs, symptoms, abnormal findings, complaints, social circumstances, and external causes of injury or disease. This system is designed to map health conditions to corresponding generic categories together with specific variations, assigning for these a designated code, up to six characters long. Thus, major categories are designed to include a set of similar diseases. The ICD is published by the WHO and used worldwide for morbidity and mortality statistics, reimbursement systems, and automa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sultam Allene MBH
In organic chemistry, the sulfonamide functional group (also spelled sulphonamide) is an organosulfur group with the structure . It consists of a sulfonyl group () connected to an amine group (). Relatively speaking this group is unreactive. Because of the rigidity of the functional group, sulfonamides are typically crystalline; for this reason, the formation of a sulfonamide is a classic method to convert an amine into a crystalline derivative which can be identified by its melting point. Many important drugs contain the sulfonamide group. A sulfonamide (compound) is a chemical compound that contains this group. The general formula is or , where each R is some organic group; for example, "methanesulfonamide" (where R = methane, R' = R" = hydrogen) is . Any sulfonamide can be considered as derived from a sulfonic acid by replacing a hydroxyl group () with an amine group. In medicine, the term "sulfonamide" is sometimes used as a synonym for sulfa drug, a derivat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sultam MBH
In organic chemistry, the sulfonamide functional group (also spelled sulphonamide) is an organosulfur group with the structure . It consists of a sulfonyl group () connected to an amine group (). Relatively speaking this group is unreactive. Because of the rigidity of the functional group, sulfonamides are typically crystalline; for this reason, the formation of a sulfonamide is a classic method to convert an amine into a crystalline derivative which can be identified by its melting point. Many important drugs contain the sulfonamide group. A sulfonamide (compound) is a chemical compound that contains this group. The general formula is or , where each R is some organic group; for example, "methanesulfonamide" (where R = methane, R' = R" = hydrogen) is . Any sulfonamide can be considered as derived from a sulfonic acid by replacing a hydroxyl group () with an amine group. In medicine, the term "sulfonamide" is sometimes used as a synonym for sulfa drug, a derivat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tandem MBH Cyclization
Tandem, or in tandem, is an arrangement in which a team of machines, animals or people are lined up one behind another, all facing in the same direction. The original use of the term in English was in ''tandem harness'', which is used for two or more draft horses, or other draft animals, harnessed in a single line one behind another, as opposed to a pair, harnessed side by side, or a team of several pairs. The tandem harness allows additional animals to provide pulling power for a vehicle designed for a single animal. The English word ''tandem'' derives from the Latin adverb , meaning ''at length'' or ''finally''. It is a word play, using the Latin phrase (referring to time, not position) for English "at length, lengthwise". Tandem bicycles are named for their tandem seating, a more common arrangement than side-by-side " sociable" seating. ''Tandem'' can also be used more generally to refer to any group of persons or objects working together, not necessarily in line. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Michael Addition
In organic chemistry, the Michael reaction or Michael addition is a reaction between a Michael donor (an enolate or other nucleophile) and a Michael acceptor (usually an α,β-unsaturated carbonyl) to produce a Michael adduct by creating a carbon-carbon bond at the acceptor's β-carbon. It belongs to the larger class of conjugate additions and is widely used for the mild formation of carbon-carbon bonds. The Michael addition is an important atom-economical method for diastereoselective and enantioselective C–C bond formation, and many asymmetric variants exist : In this general Michael addition scheme, either or both of R and R' on the nucleophile (the Michael donor) represent electron-withdrawing substituents such as acyl, cyano, nitro, or sulfone groups, which make the adjacent methylene hydrogen acidic enough to form a carbanion when reacted with the base, ''B:''. For the alkene (the Michael acceptor), the R" substituent is usually a carbonyl, which makes the compound ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multicomponent Reaction
In chemistry, a multi-component reaction (or MCR), sometimes referred to as a "Multi-component Assembly Process" (or MCAP), is a chemical reaction where three or more compounds react to form a single product. By definition, multicomponent reactions are those reactions whereby more than two reactants combine in a sequential manner to give highly selective products that retain majority of the atoms of the starting material. History and Types Multicomponent Reactions Multicomponent reactions have been known for over 150 years. The first documented multicomponent reaction was the Strecker synthesis of α-amino cyanides in 1850 from which α-amino acids could be derived. A multitude of MCRs exist today, of which the isocyanide based MCRs are the most documented. Other MCRs include free-radical mediated MCRs, MCRs based on organoboron compounds and metal-catalyzed MCRs. Isocyanide based MCRs are most frequently exploited because the isocyanide is an extraordinary functional group. It ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
