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Jakob Meisenheimer
Jakob Meisenheimer (14 June 1876 – 2 December 1934) was a German chemist. He made numerous contributions to organic chemistry, the most famous being his proposed structure for a group of compounds now named Meisenheimer complex. He also proposed the mechanism of the Beckmann rearrangement. Later in his career, he reported the synthesis of the pyridine-N-oxide Pyridine-''N''-oxide is the heterocyclic compound with the formula C5H5NO. This colourless, hygroscopic solid is the product of the oxidation of pyridine. It was originally prepared using peroxyacids as the oxidising agent. The compound is used .... References * {{DEFAULTSORT:Meisenheimer, Jakob 1876 births 1934 deaths 20th-century German chemists Academic staff of the University of Greifswald Scientists from Frankfurt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Griesheim (Frankfurt Am Main)
Griesheim () is a quarter of Frankfurt am Main, Germany. It is part of the ''Ortsbezirk West''. Griesheim had been an independent town until 1928, the year of its suburbanisation. It is located between Nied The Nied (; ) is a river in Lorraine, France, and Saarland, Germany. It is a left tributary of the Saar. It is formed where two streams converge: the ''Nied allemande'' ("German Nied") and the ''Nied française'' ("French Nied"), which join in ..., Sossenheim, Bockenheim, Gallus and Schwanheim. References External links Geschichtsverein Griesheim„Griesheim, Gemeinde Frankfurt am Main“, in: Historisches Ortslexikon Districts of Frankfurt {{Hesse-geo-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemist
A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin ''alchemist'') is a scientist trained in the study of chemistry. Chemists study the composition of matter and its properties. Chemists carefully describe the properties they study in terms of quantities, with detail on the level of molecules and their component atoms. Chemists carefully measure substance proportions, chemical reaction rates, and other chemical properties. In Commonwealth English, pharmacists are often called chemists. Chemists use their knowledge to learn the composition and properties of unfamiliar substances, as well as to reproduce and synthesize large quantities of useful naturally occurring substances and create new artificial substances and useful processes. Chemists may specialize in any number of subdisciplines of chemistry. Materials scientists and metallurgists share much of the same education and skills with chemists. The work of chemists is often related to t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1934 Deaths
Events January–February * January 1 – The International Telecommunication Union, a specialist agency of the League of Nations, is established. * January 15 – The 8.0 1934 Nepal–Bihar earthquake, Nepal–Bihar earthquake strikes Nepal and Bihar with a maximum Mercalli intensity scale, Mercalli intensity of XI (''Extreme''), killing an estimated 6,000–10,700 people. * January 26 – A 10-year German–Polish declaration of non-aggression is signed by Nazi Germany and the Second Polish Republic. * January 30 ** In Nazi Germany, the political power of federal states such as Prussia is substantially abolished, by the "Law on the Reconstruction of the Reich" (''Gesetz über den Neuaufbau des Reiches''). ** Franklin D. Roosevelt, President of the United States, signs the Gold Reserve Act: all gold held in the Federal Reserve is to be surrendered to the United States Department of the Treasury; immediately following, the President raises the statutory gold price from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1876 Births
Events January–March * January 1 ** The Reichsbank opens in Berlin. ** The Bass Brewery Red Triangle becomes the world's first registered trademark symbol. * February 2 – The National League of Professional Base Ball Clubs is formed at a meeting in Chicago; it replaces the National Association of Professional Base Ball Players. Morgan Bulkeley of the Hartford Dark Blues is selected as the league's first president. * February 2 – Third Carlist War – Battle of Montejurra: The new commander General Fernando Primo de Rivera marches on the remaining Carlist stronghold at Estella, where he meets a force of about 1,600 men under General Carlos Calderón, at nearby Montejurra. After a courageous and costly defence, Calderón is forced to withdraw. * February 14 – Alexander Graham Bell applies for a patent for the telephone, as does Elisha Gray. * February 19 – Third Carlist War: Government troops under General Primo de Rivera drive through the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angewandte Chemie
''Angewandte Chemie'' (, meaning "Applied Chemistry") is a weekly peer-reviewed scientific journal that is published by Wiley-VCH on behalf of the German Chemical Society (Gesellschaft Deutscher Chemiker). Publishing formats include feature-length reviews, short highlights, research communications, minireviews, essays, book reviews, meeting reviews, correspondences, corrections, and obituaries. This journal contains review articles covering all aspects of chemistry. According to the ''Journal Citation Reports'', the journal had a 2021 impact factor of 16.823. Editions The journal appears in two editions with separate volume and page numbering: a German edition, ''Angewandte Chemie'' ( (print), (online)), and a fully English-language edition, ''Angewandte Chemie International Edition'' ( (print), (online)). The editions are identical in content with the exception of occasional reviews of German-language books or German translations of IUPAC recommendations. Business model ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyridine-N-oxide
Pyridine-''N''-oxide is the heterocyclic compound with the formula C5H5NO. This colourless, hygroscopic solid is the product of the oxidation of pyridine. It was originally prepared using peroxyacids as the oxidising agent. The compound is used infrequently as an oxidizing reagent in organic synthesis. Structure The structure of pyridine-N-oxide is very similar to that of pyridine with respect to the parameters for the ring. The molecule is planar. The N-O distance is 1.34Å. The C-N-C angle is 124°, 7° wider than in pyridine. Synthesis The oxidation of pyridine can be achieved with a number of peracids including peracetic acid and perbenzoic acid. Oxidation can also be effected by a modified Dakin reaction using a urea-hydrogen peroxide complex, and sodium perborate or, using methylrhenium trioxide () as catalyst, with sodium percarbonate. Reactions Pyridine ''N''-oxide is five orders of magnitude less basic than pyridine, but it is isolable as a hydrochloride salt, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Annalen Der Chemie
''Justus Liebigs Annalen der Chemie'' (often cited as just ''Liebigs Annalen'') was one of the oldest and historically most important journals in the field of organic chemistry worldwide. It was established in 1832 and edited by Justus von Liebig with Friedrich Wöhler and others until Liebig's death in 1873. In 1997 the journal merged with ''Recueil des Travaux Chimiques des Pays-Bas'' to form ''Liebigs Annalen/Recueil''. In 1998 it was absorbed by ''European Journal of Organic Chemistry'' by merger of a number of other national European chemistry journals. Title history * ''Annalen der Pharmacie'', 1832–1839 * ''Annalen der Chemie und Pharmacie'', 1840–1873 (, CODEN JLACBF) * ''Justus Liebig's Annalen der Chemie und Pharmacie'', 1873–1874 (, CODEN JLACBF) * ''Justus Liebig's Annalen der Chemie'', 1874–1944 & 1947–1978 (, CODEN JLACBF) * ''Liebigs Annalen der Chemie'', 1979–1994 (, CODEN LACHDL) * ''Liebigs Annalen'', 1995–1996 (, CODEN LANAEM) * ''Lie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Chemistry
Organic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that contain carbon atoms.Clayden, J.; Greeves, N. and Warren, S. (2012) ''Organic Chemistry''. Oxford University Press. pp. 1–15. . Study of structure determines their structural formula. Study of properties includes physical and chemical properties, and evaluation of chemical reactivity to understand their behavior. The study of organic reactions includes the chemical synthesis of natural products, drugs, and polymers, and study of individual organic molecules in the laboratory and via theoretical ( in silico) study. The range of chemicals studied in organic chemistry includes hydrocarbons (compounds containing only carbon and hydrogen) as well as compounds based on carbon, but also containing other elements, especially oxygen, nitrogen, sulfur, phosphorus (i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beckmann Rearrangement
The Beckmann rearrangement, named after the German chemist Ernst Otto Beckmann (1853–1923), is a rearrangement of an oxime functional group to substituted amides. The rearrangement has also been successfully performed on haloimines and nitrones. Cyclic oximes and haloimines yield lactams. The Beckmann rearrangement is often catalyzed by acid; however, other reagents have been known to promote the rearrangement. These include tosyl chloride, thionyl chloride, phosphorus pentachloride, phosphorus pentoxide, triethylamine, sodium hydroxide, trimethylsilyl iodide among others. The Beckmann fragmentation is another reaction that often competes with the rearrangement, though careful selection of promoting reagent and solvent conditions can favor the formation of one over the other, sometimes giving almost exclusively one product. The rearrangement occurs stereospecifically for ketoximes and N-chloro/N-fluoro imines, with the migrating group being anti-periplanar to the leaving ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
German Empire
The German Empire (),Herbert Tuttle wrote in September 1881 that the term "Reich" does not literally connote an empire as has been commonly assumed by English-speaking people. The term literally denotes an empire – particularly a hereditary empire led by an emperor, although has been used in German to denote the Roman Empire because it had a weak hereditary tradition. In the case of the German Empire, the official name was , which is properly translated as "German Empire" because the official position of head of state in the constitution of the German Empire was officially a "presidency" of a confederation of German states led by the King of Prussia who would assume "the title of German Emperor" as referring to the German people, but was not emperor of Germany as in an emperor of a state. –The German Empire" ''Harper's New Monthly Magazine''. vol. 63, issue 376, pp. 591–603; here p. 593. also referred to as Imperial Germany, the Second Reich, as well as simply Germany, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meisenheimer Complex
A Meisenheimer complex or Jackson–Meisenheimer complex in organic chemistry is a 1:1 reaction adduct between an arene carrying electron withdrawing groups and a nucleophile. These complexes are found as reactive intermediates in nucleophilic aromatic substitution but stable and isolated Meisenheimer salts are also known. Background The early development of this type of complex takes place around the turn of the 19th century. In 1886 Janovski observed an intense violet color when he mixed ''meta''-dinitrobenzene with an alcoholic solution of alkali. In 1895 Cornelis Adriaan Lobry van Troostenburg de Bruyn investigated a red substance formed in the reaction of trinitrobenzene with potassium hydroxide in methanol. In 1900 Jackson and Gazzolo reacted trinitroanisole with sodium methoxide and proposed a quinoid structure for the reaction product. : In 1902 Jakob Meisenheimer observed that by acidifying their reaction product, the starting material was recovered. With three electro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
