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Ullmann Condensation
The Ullmann condensation or Ullmann-type reaction is the copper-promoted conversion of aryl halides to aryl ethers, aryl thioethers, aryl nitriles, and aryl amines. These reactions are examples of cross-coupling reactions. Ullmann-type reactions are comparable to Buchwald–Hartwig reactions but usually require higher temperatures. Traditionally these reaction requires high-boiling polar solvents such as ''N''-methylpyrrolidone, nitrobenzene, or dimethylformamide and high temperatures (often in excess of 210 °C) with stoichiometric amounts of copper. Aryl halide were required to be activated by electron-withdrawing groups. Traditional Ullmann style reactions used "activated" copper powder, e.g. prepared in situ by the reduction of copper sulfate by zinc metal in hot water. The methodology improved with the introduction of soluble copper catalysts supported by diamines and acetylacetonate ligands. Ullmann ether synthesis: C-O coupling Illustrative of the traditional Ullm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fritz Ullmann
Fritz Ullmann (July 2, 1875 in Fürth – March 17, 1939 in Berlin) was a German chemist. Ullmann was born in Fürth and started studying chemistry in Nuremberg, but received his PhD of the University of Geneva for work with Carl Gräbe in 1895. After some time in Geneva he went to Berlin in 1905. Ullmann taught technical chemistry during 1905-1913 and 1922-1925 at the ''Technischen Hochschule Berlin'' now ''Technische Universität Berlin'', first as part of the ordinary teaching staff, later on as a professor. In 1900 he introduced dimethyl sulfate as an alkylating agent. Between 1914 and 1922, when he was back in Geneva, he published the first edition of the "Enzyklopädie der Technischen Chemie" in 12 volumes () in English the ''Ullmann's Encyclopedia of Industrial Chemistry'', a publication that exists to this day. He was married to Irma Goldberg who was his assistant from 1905 to 1910 at his laboratory. They named after themselves the following reactions: the Ullmann rea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenanthroline
1,10-Phenanthroline (phen) is a heterocyclic organic compound. It is a white solid that is soluble in organic solvents. The 1,10 refer to the location of the nitrogen atoms that replace CH's in the hydrocarbon called phenanthrene. Abbreviated "phen", it is used as a ligand in coordination chemistry, forming strong complexes with most metal ions.Luman, C.R. and Castellano, F.N. (2003) "Phenanthroline Ligands" in Comprehensive Coordination Chemistry II. Elsevier. . It is often sold as the monohydrate. Synthesis Phenanthroline may be prepared by two successive Skraup reactions of glycerol with ''o''-phenylenediamine, catalyzed by sulfuric acid, and an oxidizing agent, traditionally aqueous arsenic acid or nitrobenzene. Dehydration of glycerol gives acrolein which condenses with the amine followed by a cyclization. Coordination chemistry In terms of its coordination properties, phenanthroline is similar to 2,2'-bipyridine (bipy) with the advantage that the two nitrogen donors ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Irma Goldberg
Irma Goldberg (born 1871) was one of the first female organic chemists to have and sustain a successful career, her work even being quoted in her own name in standard textbooks. Life Education Born in Moscow to a Russian-Jewish family, she later traveled to Geneva in the 1890s to study chemistry at Geneva University. Early research, Ullmann reaction Her early research included the development of a process to remove sulfur and phosphorus from acetylene. Her first article on the derivatives of benzophenone, coauthored by German chemist Fritz Ullmann, was published in 1897. She also researched and wrote a paper (published in 1904) on using copper as a catalyst for the preparation of a phenyl derivative of thiosalicylic acid, a process known as the Ullmann reaction; Goldberg is the only woman scientist unambiguously recognized for her own named reaction: the amidation (Goldberg) reaction. This modification to previous forms of the method was a great improvement, and was extremely ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Berichte Der Deutschen Chemischen Gesellschaft
''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, until it merged with ''Recueil des Travaux Chimiques des Pays-Bas'' to form ''Chemische Berichte/Recueil'' in 1997. ''Chemische Berichte/Recueil'' was then merged with other European journals in 1998 to form ''European Journal of Inorganic Chemistry''. History Founded in 1868 as ''Berichte der Deutschen Chemischen Gesellschaft'' (, CODEN BDCGAS), it operated under this title until 1928 (Vol. 61). The journal was then split into: * ''Berichte der Deutschen Chemischen Gesellschaft, A: Vereins-Nachrichten'' (, CODEN BDCAAS), and * ''Berichte der Deutschen Chemischen Gesellschaft, B: Abhandlungen'' (, CODEN BDCBAD). Vol. 78 and 79 (1945–1946) were omitted and not published due to World War II. The journal was renamed ''Chemische Berichte'' (, CODEN CHBEAM) in 19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
