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Auguste Georges Darzens
Auguste Georges Darzens (12 July 1867 in Moscow, Russia – 10 September 1954) was a Russian-born French organic chemist. Biography From 1886 he studied at the École Polytechnique in Paris under Louis Édouard Grimaux. In 1895 he received his agrégation in physics and in 1899 his medical doctorate. From 1913 to 1937, he was a professor of chemistry at the École Polytechnique. In the meantime, from 1897 to 1920, he served as director of a research laboratory at LT Piver, a perfumery outfit. In 1904, he discovered the Darzens reaction, a chemical reaction also known as the Darzens condensation and Darzens glycidic ester condensation.Darzens, G., Compt. Rend. 1904, 139, 1214 Other reactions named after him include the Darzens tetralin synthesis, Darzens halogenation and the Darzens synthesis of unsaturated ketones. His book, "''Initiation chimique''" (1909), was translated into English in 1913 and published with the title of "Chemistry". [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Georges Auguste Darzens
Georges may refer to: Places *Georges River, New South Wales, Australia *Georges Quay (Dublin) *Georges Township, Fayette County, Pennsylvania Other uses *Georges (name) *Georges (novel), ''Georges'' (novel), a novel by Alexandre Dumas *Georges (song), "Georges" (song), a 1977 song originally recorded by Pat Simon and covered by Sylvie Vartan *Georges (store), a department store in Melbourne, Australia from 1880 to 1995 *Georges (Green Card character), Georges (''Green Card'' character) People with the surname *Eugenia Georges, American anthropologist *Karl Ernst Georges (1806–1895), German classical philologist and lexicographer, known for his edition of Latin-German dictionaries. See also *École secondaire Georges-P.-Vanier, a high school in Hamilton, Ontario, Canada *École secondaire Georges-Vanier in Laval, Quebec, Canada *French cruiser Georges Leygues, French cruiser ''Georges Leygues'', commissioned in 1937 *French frigate Georges Leygues (D640), French frigate ''G ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Darzens Reaction
The Darzens reaction (also known as the Darzens condensation or glycidic ester condensation) is the chemical reaction of a ketone or aldehyde with an α- haloester in the presence of a base to form an α,β-epoxy ester, also called a "glycidic ester". This reaction was discovered by the organic chemist Auguste Georges Darzens in 1904. : Reaction mechanism The reaction process begins when a strong base is used to form a carbanion at the halogenated position. Because of the ester, this carbanion is a resonance-stabilized enolate, which makes it relatively easy to form. This nucleophilic structure attacks another carbonyl component, forming a new carbon–carbon bond. These first two steps are similar to a base-catalyzed aldol reaction. The oxygen anion in this aldol-like product then does an intramolecular SN2 attack on the formerly-nucleophilic halide-bearing position, displacing the halide to form an epoxide. This reaction sequence is thus a condensation reaction since there i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Academic Staff Of École Polytechnique
An academy (Attic Greek: Ἀκαδήμεια; Koine Greek Ἀκαδημία) is an institution of secondary or tertiary higher learning (and generally also research or honorary membership). The name traces back to Plato's school of philosophy, founded approximately 385 BC at Akademia, a sanctuary of Athena, the goddess of wisdom and skill, north of Athens, Greece. Etymology The word comes from the ''Academy'' in ancient Greece, which derives from the Athenian hero, ''Akademos''. Outside the city walls of Athens, the gymnasium was made famous by Plato as a center of learning. The sacred space, dedicated to the goddess of wisdom, Athena, had formerly been an olive grove, hence the expression "the groves of Academe". In these gardens, the philosopher Plato conversed with followers. Plato developed his sessions into a method of teaching philosophy and in 387 BC, established what is known today as the Old Academy. By extension, ''academia'' has come to mean the accumulation, dev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1954 Deaths
Events January * January 1 – The Soviet Union ceases to demand war reparations from West Germany. * January 3 – The Italian broadcaster RAI officially begins transmitting. * January 7 – Georgetown-IBM experiment: The first public demonstration of a machine translation system is held in New York, at the head office of IBM. * January 10 – BOAC Flight 781, a de Havilland Comet jet plane, disintegrates in mid-air due to metal fatigue, and crashes in the Mediterranean near Elba; all 35 people on board are killed. * January 12 – Avalanches in Austria kill more than 200. * January 15 – Mau Mau leader Waruhiu Itote is captured in Kenya. * January 17 – In Yugoslavia, Milovan Đilas, one of the leading members of the League of Communists of Yugoslavia, is relieved of his duties. * January 20 – The US-based National Negro Network is established, with 46 member radio stations. * January 21 – The first nuclear-powered subm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1867 Births
Events January–March * January 1 – The Covington–Cincinnati Suspension Bridge opens between Cincinnati, Ohio, and Covington, Kentucky, in the United States, becoming the longest single-span bridge in the world. It was renamed after its designer, John A. Roebling, in 1983. * January 8 – African-American men are granted the right to vote in the District of Columbia. * January 11 – Benito Juárez becomes Mexican president again. * January 30 – Emperor Kōmei of Japan dies suddenly, age 36, leaving his 14-year-old son to succeed as Emperor Meiji. * January 31 – Maronite nationalist leader Youssef Bey Karam leaves Lebanon aboard a French ship for Algeria. * February 3 – ''Shōgun'' Tokugawa Yoshinobu abdicates, and the late Emperor Kōmei's son, Prince Mutsuhito, becomes Emperor Meiji of Japan in a brief ceremony in Kyoto, ending the Late Tokugawa shogunate. * February 7 – West Virginia University is established in Morgantown, West Virginia. * Febru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Darzens Halogenation
Darzens halogenation is the chemical synthesis of alkyl halides from alcohols via the treatment upon reflux of a large excess of thionyl chloride or thionyl bromide (SOX2) in the presence of a small amount of a nitrogen base, such as a tertiary amine or pyridine or its corresponding hydrochloride or hydrobromide salt. The reaction is named after its creator, Auguste Georges Darzens, who first reported it in 1911. The addition of the amine and use of a large excess of the thionyl halide as compared to the usual halogenation protocol makes this reaction effective for a wide range of alcohols including those that are difficult to halogenate, such as cyclohexanol, which normally decomposes to form cyclohexene if reacted with only SOCl2. The reaction takes place through an SN2 mechanism but is also often used in the description of SNi mechanisms. For example, ethanol Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Reaction
A chemical reaction is a process that leads to the IUPAC nomenclature for organic transformations, chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and breaking of chemical bonds between atoms, with no change to the Atomic nucleus, nuclei (no change to the elements present), and can often be described by a chemical equation. Nuclear chemistry is a sub-discipline of chemistry that involves the chemical reactions of unstable and radioactive Chemical element, elements where both electronic and nuclear changes can occur. The substance (or substances) initially involved in a chemical reaction are called reagent, reactants or reagents. Chemical reactions are usually characterized by a chemical change, and they yield one or more Product (chemistry), products, which usually have properties different from the reactants. Reactions often consist of a sequence o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bull
A bull is an intact (i.e., not castrated) adult male of the species ''Bos taurus'' (cattle). More muscular and aggressive than the females of the same species (i.e., cows), bulls have long been an important symbol in many religions, including for sacrifices. These animals play a significant role in beef ranching, dairy farming, and a variety of sporting and cultural activities, including bullfighting and bull riding. Due to their temperament, handling requires precautions. Nomenclature The female counterpart to a bull is a cow, while a male of the species that has been castrated is a ''steer'', '' ox'', or ''bullock'', although in North America, this last term refers to a young bull. Use of these terms varies considerably with area and dialect. Colloquially, people unfamiliar with cattle may refer to both castrated and intact animals as "bulls". A wild, young, unmarked bull is known as a ''micky'' in Australia.Sheena Coupe (ed.), ''Frontier Country, Vol. 1'' (Weldon R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moscow
Moscow ( , US chiefly ; rus, links=no, Москва, r=Moskva, p=mɐskˈva, a=Москва.ogg) is the capital and largest city of Russia. The city stands on the Moskva River in Central Russia, with a population estimated at 13.0 million residents within the city limits, over 17 million residents in the urban area, and over 21.5 million residents in the metropolitan area. The city covers an area of , while the urban area covers , and the metropolitan area covers over . Moscow is among the world's largest cities; being the most populous city entirely in Europe, the largest urban and metropolitan area in Europe, and the largest city by land area on the European continent. First documented in 1147, Moscow grew to become a prosperous and powerful city that served as the capital of the Grand Duchy that bears its name. When the Grand Duchy of Moscow evolved into the Tsardom of Russia, Moscow remained the political and economic center for most of the Tsardom's history. When th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physics
Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which relates to the order of nature, or, in other words, to the regular succession of events." Physics is one of the most fundamental scientific disciplines, with its main goal being to understand how the universe behaves. "Physics is one of the most fundamental of the sciences. Scientists of all disciplines use the ideas of physics, including chemists who study the structure of molecules, paleontologists who try to reconstruct how dinosaurs walked, and climatologists who study how human activities affect the atmosphere and oceans. Physics is also the foundation of all engineering and technology. No engineer could design a flat-screen TV, an interplanetary spacecraft, or even a better mousetrap without first understanding the basic laws of physic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
