Unreferenced stub auto yes date December 2009 Reaction shot is a term used in motion picture film production production and cinematography referring to a basic unit of film grammar. It is a shot which cuts away from the main scene in order to show the reaction of a character to it. A reaction shot usually implies the display of some sort of emotion on the face of the actor being shown, and is thus most commonly a close up shot although a group of actors may be shown reacting together . A reaction shot is also generally bereft of dialogue , though this is not an absolute rule. Its main purpose is to show an emotional response to the immediately preceding action or words of another character in the scene, or to an event in the immediately preceding scene which may or may not involve another actor e.g., an explosion, monster, empty room, etc. The assumption behind the logic of the reaction shot is that the emotional reaction of the actor being depicted will either advance the story, reveal character traits of the character in the reaction shot, or emphasize character traits of another character that were displayed in the action or dialog present in the preceding shot. A completely unemotional reaction may also be important if it provides information to the audience or is unexpected in the context of the scene. Reaction shots can be especially critical in comedy , as the reaction of an actor or actors to a dramatic incident provides a psychological cue to the audience about how to respond to that incident themselves. In some cases, the deliberate avoidance of showing a reaction shot can be used by a filmmaker to dramatic effect for instance, if the filmmaker wishes to conceal a character s motivations by hiding their reaction to a particular event. DEFAULTSORT Reaction Shot Category Film techniques Film term stub ... more details
merge from Wharton olefin synthesis discuss Talk Wharton reaction Merger candidate date September 2011 The Wharton reaction is the chemical reaction of , epoxide epoxy ketone s with hydrazine to give allylic alcohol s. Ref Wharton1961A Ref Wharton1961B Ref Chamberlin1991 It can be used to synthesize carenol compounds. Image Wharton Reaction Scheme.png center 350px The Wharton reaction Dupuy has developed an improved procedure. Ref Dupuy1989 Reaction mechanism The Reaction mechanism mechanism of the Wharton reaction begins with reaction of the ketone 1 with hydrazine to form a hydrazone 2 . Rearrangement of the hydrazone gives intermediate 3 , which can decompose giving off nitrogen gas forming the desired product 4 . Stork et al. have investigated the mechanism of the final decomposition and found that it can proceed by an ionic mechanism or a radical mechanism depending on reaction temperature, solvent used, and structure of intermediate 3 . Ref Stork1977 Image Wharton Reaction Mechanism.png center 600px The mechanism of the Wharton reaction Notice that the alcohol retains the configuration of the starting epoxide. The reaction is named after Peter Stanley Wharton. References Note Wharton1961A Phillip Simon Wharton Wharton, P. S. Bohlen, D. H. J. Org. Chem. 1961 , 26 , 3615. Note Wharton1961B Wharton, P. S. J. Org. Chem. 1961 , 26 , 4781. Note Chamberlin1991 Chamberlin, A. R. Sall, D. J. Comp. Org. Syn. 1991 , 8 , 927 929. Review Note Dupuy1989 Dupuy, C. Luche, J. L. Tetrahedron journal Tetrahedron 1989 , 45 , 3437. Note Stork1977 Stork, G. A. et al. J. Am. Chem. Soc. 1977 , 99 , 7067. See also Eschenmoser fragmentation Grob fragmentation Wolff Kishner reduction Category Organic redox reactions Category Name reactions es Reacci n de Wharton zh ... more details
chem stub Reactionbox verifiedrevid Reference Type ring condensation NamedAfter W. Pfitzinger Section1 Reactionbox Conditions Solvent protic Reaction Reactionbox Reaction Reactant1 ketone or aldehyde Reactant2 isatin Reactant3 potassium hydroxide Product1 quinoline 4 carboxylic acid Sideproduct1 water The Pfitzinger reaction also known as the Pfitzinger Borsche reaction is the chemical reaction of isatin with base and a carbonyl compound to yield substituted quinoline 4 carboxylic acid s. ref Pfitzinger, W. J. Prakt. Chem. 1886 , 33 , 100. ref ref Pfitzinger, W. J. Prakt. Chem. 1888 , 38 , 582. ref Image Pfitzinger Reaction Scheme.png center 400px The Pfitzinger reaction Several reviews have been published. ref Manske, R. H. Chem. Rev. 1942 , 30 , 126. Review ref ref Bergstrom, F. W. Chem. Rev. 1944 , 35 , 152. Review ref ref Shvekhgeimer, M. G. A. Chemistry of Heterocyclic Compounds 2004 , 40 , 257 294. Review, DOI 10.1023 B COHC.0000028623.41308.e5 ref Reaction mechanism Image Pfitzinger Reaction Mechanism.png center 650px The mechanism of the Pfitzinger reaction The reaction of isatin with a base such as potassium hydroxide hydrolysis hydrolyses the amide bond to give the keto acid 2 . This intermediate can be isolated, but is typically not. A ketone or aldehyde will react with the aniline to give the imine 3 and the enamine 4 . The enamine will cyclize and dehydrate to give the desired quiniline 5 . Variations Halberkann variant Image Pfitzinger Halberkann Modification Scheme.png center 350px The Halberkann variant of the Pfitzinger reaction Reaction of N acyl isatins with base gives 2 Hydroxyl hydroxy quinoline 4 carboxylic acid s. ref Halberkann, J. Chemische Berichte Ber. 1921 , 54 , 3090. ref References Reflist See also Camps quinoline synthesis Friedl nder synthesis Niementowski quinazoline synthesis Category Carbon carbon bond forming reactions Category Condensation reactions Category Quinoline forming reactions Category Name reactions de Pfitzinger Reakti ... more details
The Pr vost reaction is chemical reaction in which an alkene is converted by iodine and the silver salt chemistry salt of benzoic acid to a Vicinal chemistry vicinal diol with anti addition anti stereochemistry. ref cite journal author Charles Pr vost journal Comptes rendus volume 196 pages 1129 year 1933 title Sur un complexe iodo argento benzo que et son application l oxydation des combinaisons thyl niques en glycols url http gallica.bnf.fr ark 12148 bpt6k3148d f1129.table ref ref Charles Pr vost C.A. 27, 3195 1933 ref ref Wilson, C. V. Org. React. 1950 , 9 , 350. Review ref The reaction was discovered by the French chemist Charles Pr vost 1899 1983 . Image Prevost Reaction Scheme.png center 500px The Pr vost reactionReaction mechanism The reaction between silver benzoate 1 and iodine is very fast and produces a very reactive iodinium benzoate intermediate 2 . The reaction of the iodinium salt 2 with an alkene gives another short lived iodinium salt 3 . Nucleophilic substitution SN2 reaction S sub N sub 2 by the benzoate salt gives the ester 4 . Another silver ion causes the anchimeric assistance neighboring group substitution of the benzoate ester to gives the oxonium ion oxonium salt 5 . A second SN2 reaction S sub N sub 2 substitution by the benzoate anion give the desired diester 6 . Image Prevost Reaction Mechanism.png center 600px The mechanism of the Pr vost reaction In the final step hydrolysis of the ester groups gives the anti diol. This outcome is the opposite of that of the related Woodward cis hydroxylation which gives syn addition . References Reflist See also Woodward cis hydroxylation DEFAULTSORT Prevost Reaction Category Organic redox reactions Category Substitution reactions Category Name reactions de Pr vost Hydroxylierung zh ... more details
The Del pine reaction is the organic synthesis of primary amine s 4 by reaction of a benzyl or alkyl halide s 1 with hexamethylenetetramine 2 followed by acid chemistry acid hydrolysis of the quaternary ammonium salt 3 . ref M. Del pine Bull.Soc.Chim.Fr. . 1895 , 13, S. 352 361 ref ref Alexander R. Surrey Name Reactions in Organic Chemistry . 2nd Edition, Academic Press, 1961 ref It is named after the French chemist St phane Marcel Del pine 1871 1965 . Image Delepine2.png 495px center Delepin reaction Advantages of this reaction are selective access to the primary amine without side reaction s from easily accessible reactants with short reaction times and relatively mild reaction conditions. An example is the synthesis of 2 bromoallylamine from 2,3 dibromopropene. ref OrgSynth title 2 Bromoallylamine author Albert T. Bottini, Vasu Dev, and Jane Klinck collvol 5 collvolpages 121 year 1973 prep cv5p0121 ref Reaction mechanism The benzyl halide or alkyl halide 1 reacts with hexamethylenetetramine to a quaternary ammonium salt 3 , each time just alkylating one nitrogen atom. By reflux ing in concentrated ethanolic hydrochloric acid solution this salt is converted to the primary amine together with formaldehyde as the acetal with ethanol and ammonium chloride . References references DEFAULTSORT Delepine Reaction Category Substitution reactions Category Name reactions de Del pine Reaktion ru zh ... more details
The Bosch reaction is a chemical reaction between carbon dioxide and hydrogen that produces elemental carbon graphite , water and a 10 return of invested heat . This reaction requires the introduction of iron as a catalyst and requires a temperature level of 530 730 degrees Celsius. ref Messerschmid, Ernst and Reinhold Bertrand. Space Stations. Springer. 1999. ref The overall reaction is as follows CO sub 2 sub gas g 2 H sub 2 sub g C solid s 2 H sub 2 sub O g The above reaction is actually the result of two reactions. The first reaction, the reverse water gas shift reaction , is a fast one. CO sub 2 sub H sub 2 sub CO H sub 2 sub O The second reaction controls the reaction rate . CO H sub 2 sub C H sub 2 sub O The overall reaction produces 2.3× 10 sup 3 sup joule s for every gram of carbon produced at 650 C. Reaction temperatures are in the range of 450 to 600 C. The reaction can be accelerated in the presence of an iron , cobalt or nickel catalyst . Ruthenium also serves to speed up the reaction. Together with the Sabatier reaction the Bosch reaction is studied as a way to remove carbon dioxide and to generate clean water aboard a space station ref http oregonstate.edu atwaterj h2o gen.htm Methods of water production ref The reaction is also used to produce graphite for radiocarbon dating with Accelerator Mass Spectrometry . It is named after the German chemist Carl Bosch . Citation needed date March 2008 The Bosch reaction is being investigated for use in maintaining space station life support. Though the Bosch reaction would present a completely closed hydrogen and oxygen cycle which only produces atomic carbon as waste, difficulties maintaining its higher required temperature and properly handling carbon deposits mean significantly more research will be required ... carbon tends to foul the catalyst s surface, which is detrimental to the reaction s efficiency ... A carbon dioxide reduction unit using Bosch reaction Category Organic redox reactions Category ... more details
Unreferenced date August 2010 In theoretical physics , Back reaction is often necessary to calculate the behavior of a Elementary particle particle or an object in an external field. When the particle is considered to be infinitely light or have an infinitesimal charge, it is said that we deal with a probe and the back reaction is neglected. However, a real object also carries a mass and charges itself. They modify the original environment for example, they help to curve the space in general relativity and this modification the back reaction has to be taken into account when a more accurate calculation is performed. In Cosmology the term Back reaction is used for the measure of the non commutativity of the averaging procedure and the dynamical evolution of space time. The existence of an isotropy scale is determined be the length scale at which the Back reaction parameter vanishes. The existence of such scale still needs experimental confirmation. Category Theoretical physics phys stub ... more details
Image EliminationReactionCyclohexene.svg frame right Elimination reaction of cyclohexanol to cyclohexene ... ref An elimination reaction is a type of organic reaction in which two substituent s are removed ... as the E2 reaction , and the two step mechanism is known as the E1 reaction . The numbers do not have to do with the number of steps in the mechanism, but rather the kinetics of the reaction, bimolecular ... the reverse of an addition reaction . When the substrate is asymmetric, regioselectivity is determined ... Kelk Ingold Sir Christopher Ingold proposed a model to explain a peculiar type of chemical reaction the E2 mechanism. E2 stands for bimolecular elimination. The fundamental elements of the reaction ... The reaction rate , influenced by both the alkyl halide and the base bimolecular , is second order reaction second order . Because E2 mechanism results in formation of a pi bond, the two leaving groups ... with higher energy. The reaction mechanism involving staggered conformation is more favorable ... effect is larger than 1. E2 is very similar to the SN2 reaction S sub N sub 2 reaction mechanism. Image E2 Elimination Reaction.png center 500px Scheme 1. E2 reaction mechanism An example of this type of reaction in scheme 1 is the reaction of isobutyl bromide with potassium alkoxide ethoxide in ethanol . The reaction products are isobutylene , ethanol and potassium bromide . E1 mechanism This section is linked from E1 E1 is a model to explain a particular type of chemical elimination reaction ... atom tertiary alkyl halides, but is possible with some secondary alkyl halides. The reaction rate ... step aka rate determining step . Therefore first order reaction first order kinetics apply unimolecular . Reaction usually occurs in complete absence of base or presence of only a weak base acidic conditions and high temperature . E1 reactions are in competition with SN1 reaction S sub N sub 1 reaction s because they share a common carbocationic intermediate. A deuterium isotope effect is absent ... more details
Image Samariumiodide.jpg thumb 170px right Barbier reaction with samarium II iodide The Barbier reaction is an organic reaction between an alkyl halide and a carbonyl group as an electrophilic substrate in the presence of magnesium , aluminium , zinc , indium , tin or its salts. The reaction product is a primary, secondary or tertiary alcohol . The reaction is similar to the Grignard reaction but the crucial difference is that the Barbier reaction is a one pot synthesis whereas a Grignard reagent is prepared separately before addition of the carbonyl compound. ref cite journal author Barbier, P ... in many cases to run the reaction in water which makes the procedure part of green chemistry . The Barbier reaction is named after Victor Grignard s teacher Philippe Barbier . Examples of Barbier reactions are the reaction of propargylic bromide with butanal with zinc metal in water ref cite journal title Zn Mediated Regioselective Barbier Reaction of Propargylic Bromides in THF aq. NH4Cl Solution ... BarbierReaction1.png 507px center Barbier reaction center small With a substituted alkyne instead of a terminal alkyne the allene product is favoured small center the intramolecular Barbier reaction with samarium II iodide ref cite journal title Preparation of oxo substituted chloro ethers and their reaction ... 442px center Barbier reaction the reaction of an allyl bromide with formaldehyde in THF ... 502px center Barbier reaction center small The Barbier reaction is accompanied by an allylic rearrangement to a terminal alkene small center or another allyl bromide in a reaction with benzaldehyde ... Aqueous Barbier Grignard Reaction author Gary W. Breton, John H. Shugart, Christine A. Hughey ... 464px center Barbier reaction center small The observed diastereoselectivity for this reaction is erythro threo 83 17 small center Related reactions Grignard reaction , Nozaki Hiyama Kishi reaction External links Barbier reaction University of Connecticut http orgchem.chem.uconn.edu ... more details
Image E1cB.svg right frame The E1cB reaction mechanism. The E1cB elimination reaction is a special type of elimination reaction in organic chemistry . This reaction mechanism explains the formation of alkene s from mostly alkyl halide s through a carbanion intermediate given specified reaction conditions .... The reaction takes place around a orbital hybridization sp sup 3 sup sp sup 3 sup carbon to carbon ... bond is formed. When the first step to the carbanion is slow and the second step fast the reaction ... reversibly then the reaction mechanism is E1cB sub r sub . In the E1cB sub anion sub variation ... of the leaving group and the stability of the carbanion determine whether or not the reaction is reversible. Image E1cBexample.gif right frame The E1cB reaction mechanism. Reaction of 1 methyl 2 2 fluoroethyl pyridinium iodide with hydroxide. A named reaction displaying E1cB elimination ... reaction mechanisms E2, E1, E1cB is often difficult and involves the study of chemical kinetics , kinetic isotope effect s, substituent effects and computational chemistry . The reaction of 1 methyl ... reaction because the carbanion is stabilized by the resonance effect with the enamine . ref cite journal title Evidence of a Borderline Region between E1cb and E2 Elimination Reaction Mechanisms A Combined ... and the reaction proceeds by a concerted reaction concerted one step elimination reaction E2 reaction mechanism . When the leaving group in the methylated pyridine compound is chlorine instead of fluoride the reaction mechanism is also E2 because now the carbon to chloride bond is too ... ja0517062 ref In this report, a photochemically induced decarboxylation reaction generates a carbanion intermediate, which subsequently eliminates a beta leaving group. The reaction is unique from ... step is irreversible, and should thus be classified as E1cB sub I sub . References reflist Reaction mechanisms Category Elimination reactions Category Reaction mechanisms ca Reacci d eliminaci E1cB ... more details
The Varrentrapp reaction is an organic reaction involving the chemical decomposition of an , saturation chemistry unsaturated carboxylic acid acid into two other acid fragments by action of molten alkali . This reaction pioneered by F. Varrentrapp in 1840 ref F. Varrentrapp, Ann., 36, 196 1840 ref has been of some importance in structure elucidation of certain fatty acid s but has no practical synthetic use. ref Organic reactions in strong alkalis I Fission of ethylenic acids the varrentrapp reaction Tetrahedron journal Tetrahedron , Volume 8, Issues 3 4, 1960 , Pages 221 238 R. G. Ackman, Patrick Linstead, B. J. Wakefield and B. C. L. Weedon doi 10.1016 0040 4020 60 80031 2 ref ref A Mechanism for the Cleavage of Unsaturated Acids with Molten Alkali William A. Bonner, Robert T. Rewick J. Am. Chem. Soc. 1962 84 12 2334 2337. DOI 10.1021 ja00871a013 ref The original 1840 Varrentrapp reaction concerned the conversion of oleic acid to palmitic acid , acetic acid and hydrogen gas Image VarrentrappReaction.svg 600px center The Varrentrap reaction the reaction conditions are harsh medium molten potassium hydroxide at temperatures in the range of 250 to 300 C . Likewise cinnamic acid is converted to benzoic acid . The reaction mechanism for this reaction is outlined below. Although the alkene group in the fatty acid can be located at more than one position in the chain, this does not affect the nature of the reaction products. This is because the double bond always migrates to the position next to the carboxylic acid group prior to cleavage. The next step is nucleophilic addition of a hydroxyl anion to the double bond of 1 followed by proton migration to intermediate 3 . The next step is cleavage to enolate 4a and aldehyde 4b . The enolate on acidic workup will form acetic acid .... The hydride transfer is akin the Cannizzaro reaction . Image VarrentrappMechanism3.svg 600px center Varrentrapp reaction mechanism References Reflist Category Elimination reactions Category ... more details
Unreferenced date April 2010 Weidel s reaction may refer to either a chemical reaction showing the presence of uric acid or xanthine bodies, or to a Chemical test test now considered obsolete based on that reaction invented by the Austria n chemist Hugo Weidel . A solution of the suspected substance in chlorine water with a little nitric acid is evaporated in a water bath , and then exposed to the vapor of ammonia the presence of xanthine is indicated when a red or purple color develops. Category Chemical tests Category Name reactions zh Weidel ... more details
In chemical kinetics , the order of reaction with respect to certain reactant is defined as the Exponentiation ... goldbook O04322.pdf IUPAC s Goldbook definition of order of reaction ref For example, given a chemical reaction 2A B C with a rate equation r k A sup 2 sup B sup 1 sup The reaction order with respect to A in this case is 2 and with respect to B in this case is 1 the overall reaction order is 2 1 3. It is not necessary that the order of a reaction be a whole number &ndash zero and fractional values of order are possible &ndash but they tend to be integers. Reaction orders can be determined only by experiment . Their knowledge allows conclusions about the reaction mechanism . The reaction order is not necessarily related to the stoichiometry of the reaction, unless the reaction is elementary reaction elementary . Complex reactions may or may not have reaction orders ... of reaction rates in solution , 1990, VCH Publishers ref The alkaline hydrolysis of ethyl acetate is a complex reaction CH sub 3 sub COOC sub 2 sub H sub 5 sub OH sup &minus sup CH sub 3 sub COO ... chemical equation In the reaction of diazonium salt aryldiazonium ions with nucleophiles in aqueous ... sub 2 sub sup sup Reactions can also have an undefined reaction order with respect to a reactant for example, one cannot talk about reaction order in the rate equation found when dealing with a bimolecular reaction between reactions on surfaces adsorbed molecules math r k frac K 1K 2C AC B 1 K 1C .... First order If a reaction has a single reactant and the value of the exponent is one, then it is said to be a first order reaction. Most of the N mineralization models follow the first order kinectic in soil. K 2.303 t log A A This is used for first order reaction Zero order Zero order reactions are often seen for thermal chemical decomposition s where the reaction rate is independent of the concentration of the reactant changing the concentration has no effect on the speed of the reaction ... more details
The Passerini reaction is a chemical reaction involving an isocyanide , an aldehyde or ketone , and a carboxylic acid to form a acyloxy amide . ref Passerini, M. Simone, L. Gazz. Chim. Ital. 1921 , 51 , 126 129. ref ref Passerini, M. Ragni, G. Gazz. Chim. Ital. 1931 , 61 , 964 969. ref ref cite journal author Banfi, L. Riva, R. journal Org. React. year 2005 volume 65 pages 1 140 doi 10.1002 0471264180.or065.01 title The Passerini Reaction . ref File Passerini reaction.svg 498px center The Passerini reaction This organic reaction was discovered by Mario Passerini in 1921 in Florence , Italy . It is the first isocyanide based multi component reaction developed, and currently plays a central role ... ref Reaction mechanism Two different reaction pathways have been hypothesized. Ionic mechanism In polar solvents such as methanol or water molecule water , the reaction proceeds by protonation ... the desired ester 5 Fact date January 2008 . Image Passerini Reaction Mechanism.png 500px center The mechanism of the Passerini reaction Concerted mechanism In non polar solvents and at high concentration a concerted mechanism is likely ref The Passirini Reaction L. Banfi, R.Riva in Organic Reactions ... center Trimolecular Passerini reaction mechanism This mechanism involves a trimolecular reaction ... bonding. The second step of the Passerini reaction is an acyl transfer to the neighboring hydroxyl group. There is support for this reaction mechanism the reaction proceeds in relatively non polar solvent s in line with transition state and the reaction kinetics depend on all three reactant s. This reaction ... multicomponent reaction s for instance one preceded by a Horner Wadsworth Emmons reaction and forming a depsipeptide ref A Flexible Six Component Reaction To Access Constrained Depsipeptides Based on a Dihydropyridinone ... 10.1021 jo701978v ref Image SixComponentreactionParavidino2007.svg center 500px Six component reaction ... ja1113003 ref See also Ugi reaction References Reflist Category Carbon carbon bond forming reactions ... more details
Cleanup date May 2011 The Barton Reaction involves the photolysis of a nitrite to form a nitroso alcohol . It is named for the British chemist Sir Derek Harold Richard Barton . ref Cite doi 10.1021 ja01480a030 ref The mechanism is believed to involve a homolytic RO NO cleavage, followed by hydrogen abstraction and free radical recombination. ref GoldBookRef title Barton Reaction url http www.iupac.org goldbook B00599.pdf ref File Barton reaction mechanism.svg 500px Barton reaction A related reaction is the Hofmann L ffler reaction involving haloamines. References references L szl K rti , Barbara Czak Strategic Applications of Named Reactions in Organic Synthesis Elsevier Academic Press, Burlington San Diego London 2005, 1. Edition ISBN 0 12 369483 3. Category Free radical reactions Category Name reactions ar de Barton Reaktion es Reacci n de Barton ja pt Rea o de Barton zh ... more details
Orphan date February 2009 The Benary reaction is an organic reaction . In 1931 Erich B nary ref Erich B nary, Chemische Berichte Ber. 63, 1573 1930 64, 2543 1931 ref discovered that N , N dialkylamino vinyl ketones reacted with Grignard reagents in a Nucleophilic conjugate addition 1,4 addition to give enone , unsaturated ketones , , unsaturated aldehyde s and , unsaturated ester s as well as poly unsaturated ketone s and aldehydes ref N f et al., Helv. Chem. Acta. 57, 1309 1317 1974 ref after hydrolysis of the reaction intermediate and elimination of a dialkylated amine. File Mechanism Benary reaction.svg frameless upright 3 Mechanism of the Benary reaction References reflist DEFAULTSORT Benary Reaction Category Substitution reactions Category Carbon carbon bond forming reactions Category Name reactions reaction stub ar de Benary Reaktion es Reacci n de Benary nl B nary synthese zh B nary ... more details
A reaction video is a genre of short amateur video that captures the reaction of an individual or group of individuals as they encounter a particular text, usually a short media clip . History and Examples The first massively popular reaction videos emerged in mid 2007, when thousands of YouTube rs uploaded their reactions, often a combination of laughter and retching to a trailer for a particularly graphic adult film called 2 Girls 1 Cup . The trailer has spawned many reaction videos on the Internet, some of which have attracted many millions of views. In 2008, another batch of reaction videos emerged around the viral video Scarlet Takes a Tumble, a video in which an obese woman sings and dances and then falls off a coffee table. That same year, Twilight 2008 film Twilight fans uploaded reaction videos that captured their affect as they watched the trailer for the film for the first time. References references Category Internet Category Internet memes ... more details
Image Neosalvarsan.svg thumb Neosalvarsan The Abelin reaction is a qualitative reaction for demonstrating the presence of arsphenamine and neoarsphenamine in blood and urine . It is named for Issak Abelin , Swiss physiologist. ref WhoNamedIt synd 131 ref References reflist Eponymous medical signs for infectious disease Category Blood tests med diagnostic stub ... more details
Image Aldehyde2.png thumb right 100px The formyl group A formylation reaction in organic chemistry is the catch all name for any organic reaction in which an organic compound is functionalized with a formyl group CH O . Aromatic formylation reactions via electrophilic aromatic substitution include Dimethylformamide and phosphorus oxychloride in the Vilsmeier Haack reaction Hexamine in the Duff reaction and the Sommelet reaction Carbon monoxide and hydrochloric acid in the Gattermann Koch reaction Anionic cyanides in the Gattermann aldehyde synthesis . This method synthetizes phenolic aldehydes by treatment of an aromatic compound with hydrogen chloride and hydrogen cyanide or another metallic cyanide as zinc cyanide in the presence of Lewis acid catalysts Image Gattermann aldehyde synthesis.png center 450px Gattermann aldehyde synthesis Chloroform in the Reimer Tiemann reaction dichloromethyl methyl ether in Rieche formylation In biological systems, formylation is one of the processes of posttranslational modification in which a formyl group is added to the N terminus of a protein. See also Hydroformylation DEFAULTSORT Formylation Reaction Category Substitution reactions de Formylierung fr Formylation nl Formylering ja pl Formylowanie zh ... more details
The Stetter reaction is an organic reaction involving the nucleophile catalyzed conjugate addition of an aldehyde to a Michael acceptor such as an enone . Ref Stetter The reaction product is a 1,4 dicarbonyl compound. The active catalyst can be a combination of a thiazolium salt and a base chemistry base which forms an N heterocyclic carbene in situ or cyanide anion. It was found by Dr. Hermann Stetter in 1976. Ref List Image Stetter overview.png center 400px Scheme 1. Stetter reaction overview Reaction mechanism Key in the reaction mechanism is the conversion of the aldehyde carbonyl group from an electrophile to a nucleophile in an umpolung process. This is accomplished by deprotonation of the quaternary thiazolium salt 1 by base to the thiazolium ylide 2 which reacts in a nucleophilic addition with the aldehyde 3 to the tetrahedral intermediate 4 . After a 1,2 rearrangement reaction of the methylene proton in 4 to oxygen the resulting carbanion 5 is able to react with enone 6 in a Michael reaction to adduct 7 . A hydrogen migration takes place to 8 after which the thiazolium group is expelled generating the 1,4 diketone 9 and completing the catalytic cycle . Image Stetter mechanism.png 500px center Scheme 2. Stetter reaction mechanism The Stetter reaction is related to the Benzoin ... The Stetter reaction produces classically difficult to access 1,4 dicarbonyl compounds and related ... reaction is the preparation of 2,5 undecanedione from heptanal and 3 buten 2 one as shown below ... Just as with benzoin condensations the reaction can be carried out as an intramolecular asymmetric ... of a hydrobenzofuranone shown below. Ref Liu The base in this reaction is Sodium bis trimethylsilyl ... asymmetric Stetter reaction Related Baylis Hillman reaction References Note Stetter Review. Catalyzed ... via Desymmetrization of Cyclohexadienones Using the Intramolecular Stetter Reaction ... of the hydroxyl group by Dess Martin periodinane . DEFAULTSORT Stetter Reaction Category Addition ... more details
The Guerbet reaction , named after Marcel Guerbet 1861 1938 , is an organic reaction converting a primary aliphatic alcohol into its alkylated Dimer chemistry dimer alcohol with loss of one equivalent of water. ref cite journal title Condensation de l alcool isopropylique avec son d riv sod formation du m thylisobutylcarbinol et du dim thyl 2.4 heptanol 6 author Marcel Guerbet journal Comptes rendus de l Acad mie des sciences volume 149 issue pages 129 132 year 1909 url http gallica.bnf.fr ark 12148 bpt6k3103r f129.table doi ref This reaction requires a catalyst and elevated temperatures. Image GuerbetReaction.png center 400px Guerbet Reaction The original 1899 publication concerned the conversion of N Butanol n butanol to 2 ethyl 1 hexanol . The alcohols derived from this reaction are called Guerbet alcohols . Application of long chained aliphatic alcohols gives access to surfactant s. The reaction requires alkali metal hydroxides or alkoxide s and hydrogenation catalysts such as Raney Nickel at higher temperature 220 C and pressure. Reaction mechanism The reaction mechanism for this reaction is a four step sequence. In the first step the alcohol is organic oxidation oxidized to the aldehyde . These intermediates then react in an Aldol condensation to the vinyl aldehyde which the hydrogenation catalyst then reduces to the alcohol. ref cite journal title On the mechanism of the Guerbet reaction author S. Veibel and J. I. Nielsen journal Tetrahedron journal Tetrahedron volume ... center 400px Guerbet Reaction Mechanism The Cannizzaro reaction is a competing reaction ... acid . Another side reaction is the Tishchenko reaction . Scope New catalyst systems are actively ... tert butoxide as a base in P Xylene p xylene . ref cite journal title Guerbet Reaction of Primary ... center Guerbet Reaction Scope See also Two related reactions in the production of butadiene are the Lebedev process and the Ostromisslenskii reaction . References Reflist External links A Review of Guerbet ... more details
Other uses Strip disambiguation A stripping reaction is a term used to describe two separate physical processes In nuclear physics a stripping reaction is a nuclear reaction in which part of the incident Atomic nucleus nucleus combines with the target nucleus, and the remainder proceeds with most of its original momentum in almost its original direction. This reaction was first described by Stuart Thomas Butler in 1950. ref name Butler Butler, S.T. 1950 Physical Review 80 1950 1095, 1951. Proc. R. Soc. A 208 36 ref Deuteron stripping reactions have been extensively used to study nuclear reactions and structure, this occurs where the incident nucleus is a deuteron and only a proton emerges from the target nucleus. A simple one step stripping reaction can be represented as A a B b A b x sub a sub A x sub b sub b where A represents the target core, b represents the projectile core, and x is the transferred mass which may represent any number of particles. In chemistry a stripping reaction is a chemical process, studied in a molecular beam , in which the reaction products are scattered forward with respect to the moving centre of mass of the system. ref name IUPAC IUPAC Compendium of Chemical Terminology 2nd Edition 1997 http www.iupac.org goldbook S06057.pdf Stripping reaction ref References reflist disambig Category Nuclear physics Category Chemical reactions ... more details
The Sakurai reaction also known as the Hosomi Sakurai reaction is the chemical reaction of carbon electrophile s such as a ketone shown here with allylic silane s catalyzed by strong Lewis acid s. ref Hosomi, A. Sakurai, H. Tetrahedron Lett. 1976 , 1295. ref ref Hosomi, A. et al. Chem. Letters 1976 , 941. ref ref Hosomi, A. et al. J. Am. Chem. Soc. 1977 , 1977 , 99 , 1673. ref ref Hosomi, A. Acc. Chem. Res. 1988 , 21 , 200 206. Review ref ref Fleming, I. et al. Org. React. 1989 , 37 , 57 575. Review ... Akira Hosomi and Hideki Sakurai . File Sakurai Reaction Scheme.png center 350px The Sakurai reaction Lewis acid activation is essential for complete reaction. Strong Lewis acids such as titanium tetrachloride ... the Hosomi reaction. The reaction is a type of electrophilic allyl shift with formation of an intermediate ... silicon effect . The reaction has been applied in a Sakurai Prins Ritter multicomponent reaction with in step two a Prins reaction and in step three a Ritter reaction ref A Sakurai Prins Ritter Sequence ... intermediate 2. This oxonium ion reacts in a Hosomi Sakurai reaction with allyltrimethylsilane ... oxonium intermediate 4 and a Prins reaction follows to 5 whereby the transient carbocation is captured first by acetonitrile and then by water in a Ritter reaction . In this sketch R is a cyclohexyl ... Various Reactions The Hosomi Sakurai reaction can be performed on a number of functional groups. An electrophilic ... groups that can be used in the Hosomi Sakurai reaction. Mechanism The proposed mechanism for the Hosomi Sakurai reaction using a ketone is displayed above. The mechanisms for all Hosomi Sakurai ... Stabilization As displayed in the mechanism, the Hosomi Sakurai reaction goes through a secondary ... is essential for the reaction to go to completion. See also Grignard reaction References reflist External links Hosomi Sakurai reaction www.organic chemistry.org http www.organic chemistry.org namedreactions ... Sakurai Reaction Category Addition reactions Category Carbon carbon bond forming reactions Category ... more details
Image Activation2 updated.svg thumb 300px Diagram of a catalytic reaction, showing the energy niveau depending on the reaction coordinate. For a catalysed reaction, the activation energy is lower. In chemistry , a reaction coordinate ref GoldBookRef file R05168 title reaction coordinate ref is an abstract one dimensional coordinate which represents progress along a reaction pathway . It is usually a geometric parameter that changes during the conversion of one or more molecular entity molecular entities . These coordinates can sometimes represent a real coordinate system such as bond length , bond angle ... , although, for more complex reactions especially, this can be difficult and non geometric parameters are used, e.g., bond order . Reaction coordinates are often plotted against Thermodynamic free energy free energy to demonstrate in some schematic form the potential energy profile an intersection of a potential energy surface associated to the reaction. In the formalism of transition state theory the reaction coordinate is that coordinate in set of curvilinear coordinates obtained from the conventional ones for the reactants which, for each reaction step, leads smoothly from the configuration of the reactants through that of the transition state to the configuration of the product chemistry products . The reaction coordinate is typically chosen to follow the path along the gradient path of shallowest ascent deepest descent of potential energy from reactants to products. For example, in the homolytic dissociation of molecular hydrogen , an apt coordinate system to choose would be the coordinate corresponding to the bond length . Notes and references reflist atomic physics stub chem stub Category Physical chemistry Category Quantum chemistry Category Theoretical chemistry Category Computational chemistry Category Molecular physics ca Coordenada de reacci et Reaktsioonikoordinaat es Coordenada de reacci n fr Coordonn e de r action it Coordinata di reazione hu Reakci koordin ta ... more details
The Gattermann reaction , named for the German chemist Ludwig Gattermann , in organic chemistry refers to a reaction of hydrocyanic acid with an aromatic compound, in this case benzene , under catalysis with Friedel Crafts catalyst aluminium chloride .Catalyst used is Copper Powder in HX X Cl or Br in the case of reaction of Benzene Diazonium Chloride commonly known as BDC instead. ref cite journal author L. Gattermann, W. Berchelmann title Synthese aromatischer Oxyaldehyde journal Berichte der deutschen chemischen Gesellschaft year 1898 volume 31 issue 2 pages 1765 1769 doi 10.1002 cber.18980310281 ref The reaction is similar to the Friedel Crafts reaction Image Gattermann I.png 300px center Image Gattermann II.png 600px center It may include the reaction where a diazonium salt is converted to an aryl halide by using copper powder and hydrochloric acid as opposed to using cuprous salt of the halide as in the Sandmeyer reaction . ref cite journal author L. Gattermann title Untersuchungen ber Diazoverbindungen journal Berichte der deutschen chemischen Gesellschaft year 1890 volume 23 issue 1 pages 1218 1228 doi 10.1002 cber.189002301199 url http gallica.bnf.fr ark 12148 bpt6k90720c f1220.chemindefer ref Although in many articles and books this reaction is also called Gatterman reaction. ref cite book title Organic Chemistry author R. N. Morrison, R. T. Boyd page 869 ref See also Friedel Crafts reaction Houben Hoesch reaction References Reflist Category Substitution reactions Category Name reactions de Gattermann Synthese nl Gattermann reactie ja ru zh ... more details
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