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D. Seebach
Dieter Seebach is a German chemist known for his synthesis of biopolymers and dendrimers, and for his contributions to stereochemistry. He was born on 31 October 1937 in Karlsruhe. He studied chemistry at the University of Karlsruhe (TH) under the supervision of Rudolf Criegee and at Harvard University with Elias James Corey, Elias Corey finishing in 1969. After his habilitation he became professor for organic chemistry at the University of Giessen. After six years he was appointed professor at the ETH Zurich where he worked until he retired in 2003. Work Seebach worked on dendrimer chemistry and on the synthesis of beta-peptides. The development of the umpolung, a polarity inversion of the carbonyl group, with 1,3-Propanedithiol, 1,3-propanedithiol together with Corey had a big influence on organic synthesis, and subsequently the Corey-Seebach reaction was named after them. The Fráter–Seebach alkylation, a diastereoselective reaction of beta-hydroxy esters, is named after hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Karlsruhe
Karlsruhe ( , , ; South Franconian: ''Kallsruh'') is the third-largest city of the German state (''Land'') of Baden-Württemberg after its capital of Stuttgart and Mannheim, and the 22nd-largest city in the nation, with 308,436 inhabitants. It is also a former capital of Baden, a historic region named after Hohenbaden Castle in the city of Baden-Baden. Located on the right bank of the Rhine near the French border, between the Mannheim/ Ludwigshafen conurbation to the north and Strasbourg/Kehl to the south, Karlsruhe is Germany's legal center, being home to the Federal Constitutional Court (''Bundesverfassungsgericht''), the Federal Court of Justice (''Bundesgerichtshof'') and the Public Prosecutor General of the Federal Court of Justice (''Generalbundesanwalt beim Bundesgerichtshof''). Karlsruhe was the capital of the Margraviate of Baden-Durlach (Durlach: 1565–1718; Karlsruhe: 1718–1771), the Margraviate of Baden (1771–1803), the Electorate of Baden (1803–1806), th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta-peptide
Beta-peptides (β-peptides) are peptides derived from β-amino acids, in which the amino group is attached to the β-carbon (i.e. the carbon two atoms away from the carboxylate group). The parent β-amino acid is β-alanine (H2NCH2CH2CO2H), a common natural substance, but most examples feature substituents in place of one or more C-H bonds. β-peptides usually do not occur in nature. β-peptide-based antibiotics are being explored as ways of evading antibiotic resistance. Early studies in this field were published in 1996 by the group of Dieter Seebach and that of Samuel Gellman. Structure As there are two carbons available for substitution, β-amino acids have four sites (chirality included; as opposed to two in α-amino acids) for attaching the organic residue group. Accordingly, two main types β-amino acids exist differing by which carbon the residue is attached to: ones with the organic residue (R) next to the amine are called β3 and those with position next to the carbon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dithiane
A dithiane is a heterocyclic compound composed of a cyclohexane core structure wherein two methylene bridges (-- units) are replaced by sulfur centres. The three isomeric parent heterocycles are 1,2-dithiane, 1,3-dithiane and 1,4-dithiane. 1,3-Dithianes 1,3-Dithianes are protecting group of some carbonyl-containing compounds due to their inertness to many conditions. They form by treatment of the carbonyl compound with 1,3-propanedithiol under conditions that remove water from the system. The protecting group can be removed with mercuric reagents, a process that exploits the high affinity of Hg(II) for thiolates. 1,3-Dithianes are also employed in umpolung reactions, such as the Corey–Seebach reaction:T. W. Green, P. G. M. Wuts, "Protective Groups in Organic Synthesis" Wiley-Interscience, New York, 1999. . : Typically, in organic synthesis, ketones and aldehydes are protected as their dioxolane Dioxolane is a heterocyclic acetal with the chemical formula (CH2)2O2CH2. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chiral Column Chromatography
Chiral column chromatography is a variant of column chromatography that is employed for the separation of enantiomers, e. g. in racemates. The stationary phase contains a single enantiomer of a chiral compound. The chiral stationary phase can be prepared by attaching a chiral compound to the surface of an achiral support such as silica gel. Common chiral stationary phases are based on oligosaccharides such as cellulose or cyclodextrin (in particular with β-cyclodextrin, a seven sugar ring molecule). The principle can be also applied to the fabrication of monolithic HPLC columns or gas chromatography Gas chromatography (GC) is a common type of chromatography used in analytical chemistry for separating and analyzing compounds that can be vaporized without decomposition. Typical uses of GC include testing the purity of a particular substance, ... columns. References Chromatography Stereochemistry {{chemistry-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DMPU
''N'',''N''′-Dimethylpropyleneurea (DMPU) is a cyclic urea sometimes used as a polar, aprotic organic solvent. In 1985, Dieter Seebach showed that it is possible to replace the suspected carcinogen hexamethylphosphoramide Hexamethylphosphoramide, often abbreviated HMPA, is a phosphoramide (an amide of phosphoric acid) with the formula This colorless liquid is a useful reagent in organic synthesis. Structure and reactivity HMPA is the oxide of the highly basic ter ... (HMPA) with DMPU. References Further reading * * Solvents Green chemistry {{organic-compound-stub Amide solvents Amides Ureas Nitrogen heterocycles Heterocyclic compounds with 1 ring ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fráter–Seebach Alkylation
In organic chemistry, the Fráter–Seebach alkylation (also known as Seebach–Fráter alkylation or Fráter–Seebach reaction) is a diastereoselective alkylation of chiral beta-hydroxy esters using strong base (chemistry), bases. The reaction was first published by Georg Fráter in 1979; in 1980, Dieter Seebach reported about a similar reaction with malic acid ester. Outline and mechanism Chiral beta-hydroxy esters can be treated with two equivalents of a strong base (lithium diisopropylamide, lithium diisopropylamide (LDA) or Lithium bis(trimethylsilyl)amide, lithium bis(trimethylsilyl)amide (LHMDS) are popular choices) to both remove the proton on the alcohol and Enolization, enolize the ester. An alkylating agent (methyl iodide in the case of Fráter's publication) is then added. This attacks from the opposite face of the chiral hydroxyl group to avoid steric hindrance as shown below in the 6-membered transition state with Chelation, chelating metal ions. This reaction has ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journal Of Organic Chemistry
''The Journal of Organic Chemistry'', colloquially known as ''JOC'', is a peer-reviewed scientific journal for original contributions of fundamental research in all branches of theory and practice in organic and bioorganic chemistry. It is published by the publishing arm of the American Chemical Society, with 24 issues per year. According to the ''Journal Citation Reports'', the journal had a 2017 impact factor of 4.805 and it is the journal that received the most cites (100,091 in 2017) in the field of organic chemistry. According to Web of Knowledge (and as December 2012), eleven papers from the journal have received more than 1,000 citations, with the most cited paper having received 7,967 citations. The current editor-in-chief is Scott J. Miller from Yale University. Indexing ''J. Org. Chem.'' is currently indexed in: See also *Organic Letters *Organometallics ''Organometallics'' is a biweekly journal published by the American Chemical Society. Its area of focus is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elias J
Sir Patrick Elias, PC (born 28 March 1947), is a retired Lord Justice of Appeal.Privy Council appointment of Sir Patrick Elias , 3 March 2009, Prime Minister's Office, Press Notices Early life and education Patrick Elias was born in Cardiff and received his undergraduate degree, with first-class honours, at in 1969, where he was a member of both the rugby and cricket teams. He was called to the |
1,3-Propanedithiol
1,3-Propanedithiol is the chemical compound with the formula HSCH2CH2CH2SH. This dithiol is a useful reagent in organic synthesis. This liquid, which is readily available commercially, has an intense stench. Use in organic synthesis 1,3-Propanedithiol is mainly used for the protection of aldehydes and ketones via their reversible formation of dithianes. A prototypical reaction is its formation of 1,3-dithiane from formaldehyde. The reactivity of this dithiane illustrates the concept of umpolung. Alkylation gives thioethers, e.g. 1,5-dithiacyclooctane. The unpleasant odour of 1,3-propanedithiol has encouraged the development of alternative reagents that generate similar derivatives. 1,3-Propanedithiol is used in the synthesis of tiapamil. Use in inorganic synthesis 1,3-Propanedithiol reacts with metal ions to form chelate rings. Illustrative is the synthesis of the derivative diiron propanedithiolate hexacarbonyl upon reaction with triiron dodecacarbonyl: :Fe3(CO)12 + C3H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbonyl
In organic chemistry, a carbonyl group is a functional group composed of a carbon atom double-bonded to an oxygen atom: C=O. It is common to several classes of organic compounds, as part of many larger functional groups. A compound containing a carbonyl group is often referred to as a carbonyl compound. The term carbonyl can also refer to carbon monoxide as a ligand in an inorganic or organometallic complex (a metal carbonyl, e.g. nickel carbonyl). The remainder of this article concerns itself with the organic chemistry definition of carbonyl, where carbon and oxygen share a double bond. Carbonyl compounds In organic chemistry, a carbonyl group characterizes the following types of compounds: Other organic carbonyls are urea and the carbamates, the derivatives of acyl chlorides chloroformates and phosgene, carbonate esters, thioesters, lactones, lactams, hydroxamates, and isocyanates. Examples of inorganic carbonyl compounds are carbon dioxide and carbonyl sulfide. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
