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Alfred Hassner
Alfred Hassner (Hebrew: אלפרד הסנר) (born 1930) is an internationally known organic chemist. Biography Alfred Hassner was born in Czernowitz and spent WWII in hiding while he lost his father; after the war, he returned to study in Vienna and then immigrated to the USA where he continued his studies. In 1983 he moved with his wife Cyd and two children to Israel. Hassner is currently Emeritus Professor at Bar Ilan University. Scientific career After a postdoctoral at Harvard University, Hassner joined the University of Colorado Boulder in 1957 where he became a full professor in 1966. In 1975 he was called to State University of New York Binghamton as Leading Professor and in 1983 he moved to Bar Ilan University in Israel. Hassner was visiting professor at Wuerzburg University, Stanford University, Weizmann Institute of Science, University of California Berkeley, University of Nijmegen, Universite Claude Bernard Lyon, Indian Institute of Science Bangalore, Kyus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Synthesis
As a topic of chemistry, chemical synthesis (or combination) is the artificial execution of chemical reactions to obtain one or several products. This occurs by physical and chemical manipulations usually involving one or more reactions. In modern laboratory uses, the process is reproducible and reliable. A chemical synthesis involves one or more compounds (known as '' reagents'' or ''reactants'') that will experience a transformation when subjected to certain conditions. Various reaction types can be applied to formulate a desired product. This requires mixing the compounds in a reaction vessel, such as a chemical reactor or a simple round-bottom flask. Many reactions require some form of processing (" work-up") or purification procedure to isolate the final product. The amount produced by chemical synthesis is known as the ''reaction yield''. Typically, yields are expressed as a mass in grams (in a laboratory setting) or as a percentage of the total theoretical quantity that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stanford University
Stanford University, officially Leland Stanford Junior University, is a private research university in Stanford, California. The campus occupies , among the largest in the United States, and enrolls over 17,000 students. Stanford is considered among the most prestigious universities in the world. Stanford was founded in 1885 by Leland and Jane Stanford in memory of their only child, Leland Stanford Jr., who had died of typhoid fever at age 15 the previous year. Leland Stanford was a U.S. senator and former governor of California who made his fortune as a railroad tycoon. The school admitted its first students on October 1, 1891, as a coeducational and non-denominational institution. Stanford University struggled financially after the death of Leland Stanford in 1893 and again after much of the campus was damaged by the 1906 San Francisco earthquake. Following World War II, provost of Stanford Frederick Terman inspired and supported faculty and graduates' entrepreneu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steroids
A steroid is a biologically active organic compound with four rings arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes that alter membrane fluidity; and as signaling molecules. Hundreds of steroids are found in plants, animals and fungi. All steroids are manufactured in cells from the sterols lanosterol (opisthokonts) or cycloartenol (plants). Lanosterol and cycloartenol are derived from the cyclization of the triterpene squalene. The steroid core structure is typically composed of seventeen carbon atoms, bonded in four " fused" rings: three six-member cyclohexane rings (rings A, B and C in the first illustration) and one five-member cyclopentane ring (the D ring). Steroids vary by the functional groups attached to this four-ring core and by the oxidation state of the rings. Sterols are forms of steroids with a hydroxy group at position three and a skeleton derived from cholestane. '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrilium Ion
A nitrilium ion is a nitrile that has been protonated, CNHsup>+, or alkylated, CNR′sup>+. Synthesis Nitriles are only weakly basic and are poor nucleophiles, but they will attack very reactive electrophiles such as carbocations. Nitrilium salts can be prepared by reacting nitriles with trialkyloxonium salts. The nitrilium ions thus formed can then be reduced to secondary amines with sodium borohydride in diglyme. This is a convenient route to secondary amines of the form RCH2—NH—R′. As intermediates Nitrilium ions are believed to be intermediates in the hydrolysis of nitriles, the Beckmann rearrangement, the Friedel-Crafts cyclization of amines to isoquinolines, the Schmidt reaction In organic chemistry, the Schmidt reaction is an organic reaction in which an azide reacts with a carbonyl derivative, usually an aldehyde, ketone, or carboxylic acid, under acidic conditions to give an amine or amide, with expulsion of nitrogen ... with ketones, and the Ugi, Rit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cycloaddition
In organic chemistry, a cycloaddition is a chemical reaction in which "two or more Unsaturated hydrocarbon, unsaturated molecules (or parts of the same molecule) combine with the formation of a cyclic adduct in which there is a net reduction of the Multiplicity (chemistry)#Molecules, bond multiplicity". The resulting reaction is a cyclization reaction. Many but not all cycloadditions are Concerted reaction, concerted and thus pericyclic. Nonconcerted cycloadditions are not pericyclic. As a class of addition reaction, cycloadditions permit carbon–carbon bond formation without the use of a nucleophile or electrophile. Cycloadditions can be described using two systems of notation. An older but still common notation is based on the size of linear arrangements of atoms in the reactants. It uses parentheses: where the variables are the numbers of linear atoms in each reactant. The product is a cycle of size . In this system, the standard Diels-Alder reaction is a (4 + 2)-cyc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Azides
In chemistry, azide is a linear, polyatomic anion with the formula and structure . It is the conjugate base of hydrazoic acid . Organic azides are organic compounds with the formula , containing the azide functional group. The dominant application of azides is as a propellant in air bags. Preparation Sodium azide is made industrially by the reaction of nitrous oxide, with sodium amide in liquid ammonia as solvent: : Many inorganic azides can be prepared directly or indirectly from sodium azide. For example, lead azide, used in detonators, may be prepared from the metathesis reaction between lead nitrate and sodium azide. An alternative route is direct reaction of the metal with silver azide dissolved in liquid ammonia. Some azides are produced by treating the carbonate salts with hydrazoic acid. Bonding Azide is isoelectronic with carbon dioxide , cyanate , nitrous oxide , nitronium ion and cyanogen fluoride NCF. Per valence bond theory, azide can be described by sever ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudohalogen
Pseudohalogens are polyatomic analogues of halogens, whose chemistry, resembling that of the true halogens, allows them to substitute for halogens in several classes of chemical compounds. Pseudohalogens occur in pseudohalogen molecules, inorganic molecules of the general forms ''Ps''–''Ps'' or ''Ps''–X (where ''Ps'' is a pseudohalogen group), such as cyanogen; pseudohalide anions, such as cyanide ion; inorganic acids, such as hydrogen cyanide; as ligands in coordination complexes, such as ferouscyanide; and as functional groups in organic molecules, such as the nitrile group. Well-known pseudohalogen functional groups include cyanide, cyanate, thiocyanate, and azide. Common pseudohalogens and their nomenclature Many pseudohalogens are known by specialized common names according to where they occur in a compound. Well-known ones include (the true halogen chlorine is listed for comparison): Au− is considered to be a pseudohalogen ion due to its disproportionation reactio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Regioselective
In chemistry, regioselectivity is the preference of chemical bonding or breaking in one direction over all other possible directions. It can often apply to which of many possible positions a reagent will affect, such as which proton a strong base will abstract from an organic molecule, or where on a substituted benzene ring a further substituent will be added. A specific example is a halohydrin formation reaction with 2-propenylbenzene: : Because of the preference for the formation of one product over another, the reaction is selective. This reaction is regioselective because it selectively generates one constitutional isomer rather than the other. Various examples of regioselectivity have been formulated as rules for certain classes of compounds under certain conditions, many of which are named. Among the first introduced to chemistry students are Markovnikov's rule for the addition of protic acids to alkenes, and the Fürst-Plattner rule for the addition of nucleophiles t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kyushu Institute Of Technology
is one of the 87 national universities in Japan. Located in Fukuoka Prefecture on the island of Kyushu, it is dedicated to education and research in the fields of science and technology. It is earlier abbreviated to KIT and is now officially abbreviated to Kyutech. The founder was Matsumoto Kenjiro, second son of Yasukawa Keiichiro, and the links with the Yaskawa Electric Corporation (founded in 1915) remain strong to this day. The centenary of the opening of the Tobata campus is being celebrated in 2009, with Founder's Day on May 28, 2009. One of its famous alumnus is "Mr. Tornado", the severe storms researcher Tetsuya "Ted" Fujita. He graduated in 1943 and was an associate professor until 1953 when he was invited to the University of Chicago. History The university was granted government permission to be founded in 1907 as a private training school for engineers called ''Meiji Senmon Gakkō'' (Meiji Vocational School), toward the end of the Meiji period. The first campu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indian Institute Of Science
The Indian Institute of Science (IISc) is a public, deemed, research university for higher education and research in science, engineering, design, and management. It is located in Bengaluru, in the Indian state of Karnataka. The institute was established in 1909 with active support from Jamsetji Tata and thus is also locally known as the ''"Tata Institute"''. It is ranked among the most prestigious academic institutions in India and has the highest citation per faculty among all the universities in the world. It was granted the deemed to be university status in 1958 and the Institute of Eminence status in 2018. History After an accidental meeting between Jamsetji Tata and Swami Vivekananda, on a ship in 1893 where they discussed Tata's plan of bringing the steel industry to India, Tata wrote to Vivekananda five years later: "I trust, you remember me as a fellow-traveller on your voyage from Japan to Chicago. I very much recall at this moment your views on the growth of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Claude Bernard University Lyon 1
Claude Bernard University Lyon 1 (french: link=no, Université Claude-Bernard Lyon 1, UCBL) is one of the three public universities of Lyon, France. It is named after the French physiologist Claude Bernard and specialises in science and technology, medicine, and sports science. It was established in 1971 by the merger of the 'faculté des sciences de Lyon' with the 'faculté de médecine'. The main administrative, teaching and research facilities are located in Villeurbanne, with other campuses located in Gerland, Rockefeller, and Laennec in the 8th arrondissement of Lyon. Attached to the University are the Hospices Civils de Lyon, including the 'Centre Hospitalier Lyon-Sud', which is the largest teaching hospital in the Rhône-Alpes regions of France, region and the second-largest in France. The university has been independent since January 2009. In 2020 it managed an annual budget of over €420 million and had 2857 faculty. History On 17 March 1808, Napoleon I founded t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
