multiple image direction vertical width 120 image1 2 but ne 2 ol.png alt1 caption1 Enol image2 Keto Enol Tautomerie3.svg alt2 caption2 Enolate image3 Brenzcatechin.svg alt3 caption3 Enediol image4 Reductic ..., by which they present keto enol tautomerism . In keto enol tautomerism, enols interconvert with ketone s or aldehyde s. The words enol and alkenol are portmanteau s of the words alkene or just ene , the suffix given to C C double bonded alkenes and alcohol which represents the enol s hydroxyl group . Keto enol tautomerism Image enol.png thumb keto enol tautomerism Keto enol tautomers br Right the enol ... side, whereas a single bond and a double bond are exchanged. This is called keto enol tautomerism . The enol form is usually unstable, does not survive long, and changes into the keto ketone . This is because ..., however, the mono enol form predominates. This is due to intramolecular hydrogen bond ing and possibly ... OHCCH sub 2 sub CHO molecules exist as the mono enol. The percentage is lower for 1,3 aldehyde ketones and diketones acetylacetone , for example, 80 enol form Citation needed date October 2010 . File ... enol tautomerism occurs the keto or enol is deprotonated and an anion, which is called the enolate ... prettytable colspan 6 Keto enol tautomerism style background color ffffff align center Image Keto Enol Tautomerie1.svg 300px align center Image Keto Enol Tautomerie2.svg 260px br Image Keto Enol Tautomerie3.svg 80px align center Image Keto Enol Tautomerie4.svg 300px Interconversion between keto form ... resonance . Left the carbanion . Interconversion between enolate and enol protonation of the enolate ... vertical nodes, leading to six red or blue regions. Image Keto Enol Tautomerie3.svg thumb left upright ... Category Alcohols Category Alkenes Category Enols ar bg ca Enol cs Enol de Enole et Enoolid es Enol fr nol gl Enol ko id Enol it Enoli he hu Enol mk nl Enol ja pl Enole pt Enol ru sr Enol fi Enoli sv Enol zh ... more details
Unreferenced date December 2009 Image Enol ether.png thumb right The structure of a typical enol ether group. An enol ether is an alkene with an alkoxy substituent . The general structure is math R 1R 2C CR 3 O R 4 math with R an alkyl or an aryl group. Enol ethers and enamine s are so called activated alkenes or electron rich alkenes because the oxygen atom donates electrons to the double bond by forming a resonance structure with the corresponding oxonium ion . This property makes them reactive substrates in certain organic reaction s such as the Diels Alder reaction . An enol ether can be considered the ether of the corresponding enolate , hence the name. Two simple enol ethers are methyl vinyl ether and 2,3 Dihydrofuran 2,3 dihydrofuran . DEFAULTSORT Enol Ether Category Functional groups de Enolether et Enooleetrid fr ther d nol zh ... more details
enzyme Name 3 oxoadipate enol lactonase EC number 3.1.1.24 CAS number 9031 04 3 IUBMB EC number 3 1 1 24 GO code 0047570 image width caption In enzymology , a 3 oxoadipate enol lactonase EC number 3.1.1.24 is an enzyme that catalysis catalyzes the chemical reaction 3 oxoadipate enol lactone H sub 2 sub O math rightleftharpoons math 3 oxoadipate Thus, the two substrate biochemistry substrates of this enzyme are 3 oxoadipate enol lactone and water H sub 2 sub O , whereas its product chemistry product is 3 oxoadipate . This enzyme belongs to the family of hydrolase s, specifically those acting on carboxylic ester bonds. The systematic name of this enzyme class is 4 carboxymethylbut 3 en 4 olide enol lactonohydrolase . Other names in common use include carboxymethylbutenolide lactonase , beta ketoadipic enol lactone hydrolase , 3 ketoadipate enol lactonase , 3 oxoadipic enol lactone hydrolase , and beta ketoadipate enol lactone hydrolase . This enzyme participates in benzoate degradation via hydroxylation . References reflist 1 cite journal author Ornston LN date 1966 title The conversion of catechol and protocatechuate to beta ketoadipate by Pseudomonas putida. II. Enzymes of the protocatechuate pathway journal J. Biol. Chem. volume 241 pages 3787&ndash 94 pmid 5916392 issue 16 cite journal author Ornston LN date 1970 title Conversion of catechol and protocatechuate to beta ketoadipate Pseudomonas putida journal Methods Enzymol. volume 17A pages 529&ndash 549 hydrolase stub Category EC 3.1.1 Category Enzymes of unknown structure ... more details
File Keto Enol Tautomerie.png thumb right 350px Keto enol tautomerism. br Left the keto form right the enol. In organic chemistry , keto enol tautomerism refers to a chemical equilibrium between a keto form a ketone or an aldehyde and an enol an alcohol . The enol and keto forms are said to be tautomers ... group C O is normally in rapid Chemical equilibrium equilibrium with an enol tautomer, which ... form predominates at equilibrium for most ketones. Nonetheless, the enol form is important for some ... nucleophile . Normally, the keto enol tautomerization chemical equilibrium is highly thermodynamically ... and acetaldehyde K enol keto 3 x10 sup 7 sup . However, it is reported that in the case of vinyl alcohol , formation of a stabilized enol form can be accomplished by controlling the water concentration ... life of the enol form can easily be increased to t sub 1 2 sub 42 minutes for first order ... of enols conversion of an acid catalyzed enol to the keto form proceeds by a two step Reaction ... is removed from the alpha carbon and bonds to the oxygen of the carbonyl carbon to form the enol ... electrons of the C C double bond of the enol are donated to a hydronium ion H sub 3 sub O sup sup ... One of the early investigators into keto enol tautomerism was Richard August Carl Emil Erlenmeyer . His ... form is, in general, more stable than its enol tautomer. As the lower energy form, the keto form is favored ... substituents, the conversion of the enol to the keto tautomer affords enantiomers . On the other ... Keto enol tautomerism is important in several areas of biochemistry . The high phosphate ... in the less stable enol form, whereas after dephosphorylation it can assume the keto form. Rare enol tautomers of the bases guanine and thymine can lead to mutation because of their altered ... s, the enol is important due to the aromatic character of the enol but not the keto form. Melting ... and reverts back to the enol in presence of a base chemistry base . The keto form can be obtained in a pure ... more details
Image Silyl enol ether.png thumb right 100px The general structure of a silyl enol ether Silyl enol ethers in organic chemistry are a class of organic compound s that share a common functional group composed of an enolate bonded through its oxygen terminus to an organosilicon group. Silyl enol ethers are important intermediates in organic synthesis . Organic synthesis Trimethylsilyl enol ethers can be prepared from ketones in presence of a strong base and trimethylsilyl chloride or a weak base and trimethylsilyl triflate. Silyl enol ether can form by capturing any enolate formed in a nucleophilic conjugate addition . ref Organic Syntheses , Coll. Vol. 9, p.564 1998 Vol. 73, p.123 1996 http www.orgsynth.org orgsyn prep.asp?prep cv9p0564 Article ref ref Organic Syntheses , Coll. Vol. 8, p.277 1993 Vol. 66, p. 43 1988 http www.orgsynth.org orgsyn prep.asp?prep cv8p0277 Article . ref A rather exotic way to generate silyl enol ethers is via the Brook rearrangement of appropriate substrates. ref Cite journal last Tong first R. last2 McDonald first2 F. E. title Mimicking Biosynthesis Total Synthesis of the Triterpene Natural Product Abudinol B from a Squalene like Precursor journal Angewandte Chemie edition Int. volume 47 issue 23 pages 4377 4379 year 2008 doi 10.1002 anie.200800749 ref Organic reactions Silyl enol ethers react as nucleophile s in Mukaiyama aldol addition Michael reaction s Alkylation s Haloketone formation with halogen s ref Organic Syntheses , Coll. Vol. 8, p.286 1993 Vol. 69, p.129 1990 http www.orgsynth.org orgsyn prep.asp?prep cv8p0286 Article ref Acyloin formation ... oxidation certain silyl enol ethers are oxidized to enone s with palladium II acetate . In the original ... II catalyzed dehydrosilylation of silyl enol ethers first Yoshihiko last Ito first2 Toshikazu ... sub 3 sub OR . References references Category Functional groups es ter sil lico de enol id Silil enol eter zh ... more details
enzyme Name oxaloacetate tautomerase EC number 5.3.2.2 CAS number 37318 45 9 IUBMB EC number 5 3 2 2 GO code 0050163 image width caption In enzymology , an oxaloacetate tautomerase EC number 5.3.2.2 is an enzyme that catalysis catalyzes the chemical reaction keto oxaloacetate math rightleftharpoons math enol oxaloacetate Hence, this enzyme has one substrate biochemistry substrate , keto oxaloacetate , and one product chemistry product , enol oxaloacetate . This enzyme belongs to the family of isomerase s, specifically those intramolecular oxidoreductase s interconverting keto and enol groups. The systematic name of this enzyme class is oxaloacetate keto enol isomerase . This enzyme is also called oxalacetic keto enol isomerase . References reflist 1 cite journal author Annett RG, Kosicki GW date 1969 title Oxalacetate keto enol tautomerase. Purification and characterization journal J. Biol. Chem. volume 244 pages 2059&ndash 67 pmid 5781999 issue 8 isomerase stub Intramolecular oxidoreductases Category EC 5.3.2 Category Enzymes of unknown structure ... more details
Thioenols also known as alkenthiols are alkene s with a thiol group affixed to one of the carbon atoms composing the double bond . Alkenes with a thiol group on both sides of the double bond are called enedithiols . Deprotonation Deprotonated anions of thioenols are called thioenolates . The C C double bond with adjacent alcohol gives thioenols and enedithiols their chemical characteristics, by which they present keto enol tautomerism . In keto enol tautomerism, thioenols interconvert with thioketone s or thioaldehyde s. The words thioenol and alkenthiol come from the words alkene or just ene , the suffix given to C C double bonded alkenes and thiol which represents the thioenol s thiol group . Thioketo thioenol tautomerism Thioenols interconvert with thio carbonyl compound s that have an hydrogen , like thioketone s and thioaldehyde s. The compound is Deprotonation deprotonated on one side and Protonation protonated on another side, whereas a single bond and a double bond are exchanged. This is called keto enol tautomerism . See also Enol External links http www.nrcresearchpress.com doi abs 10.1139 v98 027 Canadian journal of chemistry Category Sulfur compounds ... more details
enzyme Name phenylpyruvate tautomerase EC number 5.3.2.1 CAS number 9023 54 5 IUBMB EC number 5 3 2 1 GO code 0050178 image width caption In enzymology , a phenylpyruvate tautomerase EC number 5.3.2.1 is an enzyme that catalysis catalyzes the chemical reaction keto phenylpyruvate math rightleftharpoons math enol phenylpyruvate Hence, this enzyme has one substrate biochemistry substrate , keto phenylpyruvate , and one product chemistry product , enol phenylpyruvate . This enzyme belongs to the family of isomerase s, specifically those intramolecular oxidoreductase s interconverting keto and enol groups. The systematic name of this enzyme class is phenylpyruvate keto enol isomerase . This enzyme is also called phenylpyruvic keto enol isomerase . This enzyme participates in tyrosine metabolism and phenylalanine metabolism . Structural studies As of late 2007, 7 tertiary structure structures have been solved for this class of enzymes, with Protein Data Bank PDB accession codes PDB link 1GYJ , PDB link 1GYX , PDB link 1GYY , PDB link 2GDG , PDB link 2OOH , PDB link 2OOW , and PDB link 2OOZ . References reflist 1 cite journal author Blasi F, Fragomele F, Covelli I date 1969 title Thyroidal phenylpyruvate tautomerase. Isolation and characterization journal J. Biol. Chem. volume 244 pages 4864&ndash 70 pmid 5824560 issue 18 cite journal author Knox WE date 1955 title p Hydroxyphenylpyruvate enol keto tautomerase journal Methods Enzymol. volume 2 pages 289&ndash 295 cite journal author KNOX WE, PITT BM date 1957 title Enzymic catalysis of the keto enol tautomerization of phenylpyruvic acids journal J. Biol. Chem. volume 225 pages 675&ndash 88 pmid 13416270 issue 2 isomerase stub Intramolecular oxidoreductases Category EC 5.3.2 Category Enzymes of known structure ... more details
Mandelate racemase is a bacterial enzyme which catalyzes the interconversion of the enantiomers of mandelate via an enol intermediate. It is a member of the enolase superfamily of enzymes, along with muconate lactonizing enzyme and enolase . External links MeshName mandelate racemase EC number 5.1.2.2 Racemases and epimerases Enzyme stub Category EC 5.1.2 ... more details
DISPLAYTITLE C sub 20 sub H sub 23 sub NO sub 4 sub The molecular formula C sub 20 sub H sub 23 sub NO sub 4 sub molar mass 341.40 g mol may refer to Efaproxiral , an allosteric effector of hemoglobin Dihydrocodeinone enol acetate Naltrexone MolFormDisambig ... more details
name HEZ 2006 f The Stereochemistry of Allenic Enol Tautomerism Independent Generation and Reactivity ... of an enol leads to the less stable of two, a priori , diastereomers . In this example ref name Linder there are two different reactions which afford the enol as a transient intermediate. One is the treatment of an &alpha bromoketone with dilute HI in acetone . The second is the reaction of an enol ... to proceed via the enol as an intermediate. Interestingly this is an example with extreme stereoselectivity ... of the stereochemistry of kinetic protonation of an enol ref name Linder With an Acid catalysis .... Equilibration of the Diastereomers via the Common Enol. Image Equilibr.gif center 550px The contrasting ... enol Figure 3 show the ketonization results for the two Phenyl Pyridyl diastereomers. In the exo ... stereochemistry. ref name HEZ 2002 Figure 3. Two Phenyl Pyridyl Enol Diastereomers. Image PhenylPyridyl.gif center 550px A Typical example an enol generated from an alpha bromoketone Figure 4. The Example of Ketonization of the Enol of 4 Phenyl 1 Benzoylcyclohexane. Image 4 Ph 1 Bz Enol.gif center 600px In this example the enol intermediate is generated from either the cis or the trans stereoisomer ... more details
Image Diacetyl structure.png thumb right 100px Diacetyl , the simplest diketone A diketone is a molecule containing two ketone Functional group groups . The simpliest diketone is diacetyl , also known as 2,3 butanedione. Diacetyl, acetylacetone , and hexane 2,5 dione are examples of 1,2 , 1,3 , and 1,4 diketones, respectively. Dimedone is an example of a cyclic diketone. Reactions 1,3 Diketones, such as acetylacetone, are particularly prone to form stable enol enols or enolate enolates because of Conjugated system conjugation of the enol or enolate with the other carbonyl group, and the stability gained in forming a six membered ring, hydrogen bonded in the case of the enol or containing the counter ion in the case of the enolate . Image acacH.png 400px Scheme 1. Tautomerism of 2,4 pentanedione The conjugate base derived from 1,3 ketones form complexes with metal ions. Diketones with one or two methylene groups separating the carbonyl groups typically coexist with their enolization enol tautomer s. The reactions of such dicarbonyls are very similar to those of simple ketones. In the DeMayo reaction 1,3 diketones react with alkenes in a photochemical pericyclic reaction to form substituted 1,5 diketones. EU Regulation In 2004, the EU conducted an examination of certain flavoring Food additive additives grouped together as Flavouring Group Evaluation FGE.11 . This group included diketones. ref http www.efsa.europa.eu EFSA Scientific Opinion afc opinionflav ej166 en1.pdf Opinion of the Scientific Panel on Food Additives, Flavourings, Processing Aids and Materials in contact with Food , EFSA Journal 2004 166, 1 44 ref As part of that study, the EU found that acetylacetone pentane 2,4 dione FL 07.191 was genotoxic in vivo and in vitro , and deleted it from the register of permitted flavoring substances. ref http eur lex.europa.eu LexUriServ site en oj 2005 l 128 l 12820050521en00730076.pdf COMMISSION DECISION of 18 May 2005 amending Decision 1999 217 EC as regards the re ... more details
enol acetate exerts some of its effect by being a prodrug for a stronger opioid, namely ... time can antagonise or cause potentiation. Dihydrocodeinone enol acetate is a Schedule I controlled ... more details
enol ether . Key in explaining the difference in reactivity is the electron density on the ... enol phosphates formed in good yields ca. 90 in the Perkow reaction can be used as phosphorylation ... more details
Image EnolLake.jpg thumb 300px Lago Enol seen from La Picota Image Lago Ercina.JPG thumb 300px Lago Ercina. The Lakes of Covadonga el. 1134 m. are of two glacial lake s located on the region of Asturias , Spain . These lakes, often also called Lakes of Enol or simply Los Lagos , are Lake Enol and Lake Ercina located in the Picos de Europa range and they are the original center of the Picos de Europa National Park , created in 1918. Vuelta a Espa a The road ascending from Covadonga to the lakes is a popular climb in professional road bicycle racing , having been used by Vuelta a Espa a many times in the last 25 years. Lagos de Covadonga is the most important climb in the modern history of the Vuelta . The road that leads to the lakes starts at Covadonga and is 12.6 kilometres long at an average gradient of 7.3 height gain 1056 m . http www.lavuelta.com 07 ingles recorrido etapa4.html?e 4 The most demanding section is La Huesera , 7 kilometres from the top of the climb, with an average gradient of 15 during 800 meters. It was featured for the first time in 1983 with the victory of Marino Lejarreta . Winners of the Lakes of Covadonga stage class wikitable Year Name Country 1983 Vuelta a Espa a 1983 Marino Lejarreta ESP 1984 Vuelta a Espa a 1984 Raimund Dietzen GER 1985 Vuelta a Espa a 1985 Pedro Delgado ESP 1986 Vuelta a Espa a 1986 Robert Millar GBR 1987 Vuelta a Espa a 1987 Lucho Herrera COL 1988 Vuelta a Espa a 1989 Alvaro Pino ESP 1991 Vuelta a Espa a 1991 Lucho Herrera COL 1992 Vuelta a Espa a 1992 Pedro Delgado ESP 1993 Vuelta a Espa a 1993 Oliverio Rinc n COL 1994 Vuelta a Espa a 1994 Laurent Jalabert FRA 1996 Vuelta a Espa a 1996 Laurent Jalabert FRA 1997 Vuelta a Espa a 1997 Pavel Tonkov RUS 2000 Vuelta a Espa a 2000 Andrei Zintchenko RUS 2001 Vuelta a Espa a ... Asturias geo stub cycling stub ast Llagos d Enol es Lagos de Covadonga eu Covadongako aintzirak fr Lacs de Covadonga gl Lagos de Enol it Laghi di Enol nl Meren van Covadonga ... more details
The Camps quinoline synthesis also known as the Camps cyclization is a chemical reaction whereby an o acylaminoacetophenone is transformed into two different hydroxyquinolines products A and B using hydroxide ion. ref Camps, R. Chemische Berichte Ber. 1899 , 22 , 3228. ref ref Camps, R. Arch. Pharm. 1899 , 237 , 659. ref ref Camps, R. Arch. Pharm. 1901 , 239 , 591. ref ref Manske, R. H. F. Chem. Rev. 1942 , 30 , 127. Review ref Image Camps Quinoline Synthesis Scheme.png center 500px The Camps quinoline synthesis The relative proportions of the hydroxyquinolines A and B produced are dependent upon the reaction conditions and structure of the starting material. Although the reaction product is commonly depicted as a quinoline the Keto enol tautomerism enol form , it is believed that the Keto enol tautomerism keto form predominates in both the solid state and in solution, making the compound a quinolone ref name jones . An example of the Camps reaction is given below ref name jones Sequential Cu Catalyzed Amidation Base Mediated Camps Cyclization A Two Step Synthesis of 2 Aryl 4 quinolones from o Halophenones Jones, C. P. Anderson, K. W. Buchwald, S. L. J. Org. Chem. Article 2007 72 21 7968 7973. DOI 10.1021 jo701384n ref Image CampsApplication.svg center 500px Camps quinoline synthesis References Reflist See also Conrad Limpach synthesis Doebner reaction Category Quinoline forming reactions Category Name reactions es S ntesis de quinolinas de Camps nl Camps chinolinesynthese zh Camps ... more details
The Rubottom oxidation is the chemical reaction of enol silane s with m chloroperoxybenzoic acid to give silyl protecting group protected hydroxy ketone s. Ref Brook1974 Ref Hassner1975 Ref Rubottom1974 Image Rubottom Oxidation Scheme.png center 300px The Rubottom oxidation Reaction mechanism Redox Oxidation of the enolsilane 1 with m chloroperoxybenzoic acid initially gives an epoxysilane 2 . Rearrangement through a zwitterionic intermediate 3 gives the desired hydroxy ketone 4 . Image Rubottom Oxidation Mechanism.png center 600px The reaction mechanism of the Rubottom oxidation Scope and Limitations Although silyl enol ethers are the most common substrates for the Rubottom oxidation, peracids can be used to oxidize a variety of stabilized anions in addition to silyl enol ethers. Ketone and ester enolates, nitrile anions, imino anions, and silyl ketene acetals are all within the scope of the reaction. Site selective oxidation of these substrates depends on the selective deprotonation of the parent neutral compounds selectivity is typically achieved by enforcing kinetic or thermodynamic control through the use of an irreversible lithium diisopropylamide or reversible alkoxide base for deprotonation, respectively. Alternative oxidants include hypervalent iodine reagents such as iodobenzene diacetate, molecular oxygen, metal oxides most notably osmium tetroxide , and N sulfonyloxaziridines. Ref Ciganek References Note Brook1974 Brook, A. G. Macrae, D. M. J. Organometal. Chem. 1974 , 77 , C19. Note Hassner1975 Hassner, A. Reuss, R. H. Pinnick, H. W. J. Org. Chem. 1975 , 40 , 3427 3429. DOI 10.1021 jo00911a027 Note Rubottom1974 Rubottom, G. M. et al. Tetrahedron Lett. 1974 , 4319. Note Ciganek Chen, B. C. Zhou, P. Davis, F. A. Ciganek, E. Organic Reactions Org. React. 2003 , 62 , 1. doi http dx.doi.org 10.1002 0471264180.or062.01 10.1002 0471264180.or062.01 Category Organic redox reactions Category Name reactions ja zh ... more details
The Fujimoto Belleau reaction is a chemical reaction that forms cyclic substituted , unsaturated ketone s from enol lactone s. The reaction is named after the two chemists George I. Fujimoto and Bernard Belleau . Image Fujimoto Belleau Reaction Scheme.png center 500px The Fujimoto Belleau reaction The reaction is a Grignard reaction, followed by a H shift, an tautomer enol keto tautomerisation and an Aldol addition reaction. The last step is an elimination Aldol condensation reaction with an E sub 1 sub CB mechanism. Image Fujimoto belleau mechanism.jpg center mechanism of the reaction References cite journal title Labeling of Steroids in the 4 Position author George I. Fujimoto journal J. Am. Chem. Soc. volume 73 issue 4 pages 1856 1856 year 1951 url doi 10.1021 ja01148a518 cite journal title The Reaction of Methylmagnesium Iodide with 1 Hydroxy 3,4 dihydro 2 naphthyl butyric Acid Lactone author Bernard Belleau journal J. Am. Chem. Soc. volume 73 issue 11 pages 5441 5443 year 1951 url doi 10.1021 ja01155a504 Weill Raynal, J. Synthesis 1969 , 49. Category Addition reactions Category Carbon carbon bond forming reactions Category Condensation reactions reaction stub Category Name reactions ar es Reacci n de Fujimoto Belleau nl Fujimoto Belleau reactie zh Fujimoto Belleau ... more details
Image Acylsilane.PNG thumb right size The structure of a typical acylsilane. Acylsilanes are a group of chemical compound s sharing a common functional group with the general structure R CO SiR sub 3 sub . Acylsilanes are starting compounds in the Brook rearrangement with vinyl lithium compounds to silyl enol ether s Ref Innocenti . References Note Innocenti The reactivity of and iodo propenoylsilanes an alternative access to polyunsaturated acylsilanes Alessandro Degl Innocenti, Antonella Capperucci, Patrizia Scafato,Antonella Telesca Arkivoc 0 005A 2000 http www.arkat usa.org ark journal 2000 I04 General 0 005A 0051.asp Article Category functional groups nl Acylsilaan ja ... more details
The Mukaiyama aldol addition is an organic reaction and a type of aldol reaction between a silyl enol ether and an aldehyde catalyzed by a Lewis acid . ref Mukaiyama, T. Kobayashi, S. Org. React. 1994 , 46 , 1. doi 10.1002 0471264180.or046.01 ref This choice of reactants allows for a crossed aldol reaction between an aldehyde and a ketone or a different aldehyde without self condensation of the aldehyde . For this reason the reaction is used extensively in organic synthesis . In its original scope the Lewis acid titanium chloride was used in stochiometric amounts but truly catalytic systems exist as well. The reaction is also optimized for asymmetric synthesis . The archetypical reaction published by Teruaki Mukaiyama in 1973 ref New aldol type reaction Teruaki Mukaiyama, Koichi Narasaka and Kazuo Banno Chemistry Letters Vol.2 1973 , No.9 pp.1011 1014 doi 10.1246 cl.1973.1011 ref is that of the silyl enol ether of cyclohexanone with benzaldehyde with one equivalent of titanium tetrachloride in dichloromethane . At room temperature it produces a diastereomeric mixture of threo 63 and erythro 19 hydroxyketone as well as 6 of the exocyclic enone Aldol condensation condensation product . A subsequent paper in 1974 ref REACTION OF ENOL ACETATE WITH ACETAL AND CARBONYL COMPOUND IN THE PRESENCE OF LEWIS ACID Teruaki Mukaiyama, Toshio Izawa and Kazuhiko Saigo Chemistry Letters Vol.3 1974 , No.4 pp.323 326 doi 10.1246 cl.1974.323 ref dealt with the reaction between isopropenyl acetate the adduct of acetone and acetic acid and benzaldehyde with various Lewis acids such as aluminium .... Then in another 1974 paper ref Reactions of silyl enol ethers with carbonyl compounds .... Chem. Soc. 1974 96 24 pp 7503 7509 DOI 10.1021 ja00831a019 ref returning to silyl enol ethers the reaction ... the enol as a nucleophile and the initial reaction product is a titanium chelate which breaks down .... A typical reaction involving two ketones is that between acetophenone as the enol and acetone ... more details
. Intramolecular Aglycon Delivery IAD methods Carbon tethering Acid catalysed tethering on enol ... OAc protecting group is transformed into an enol ether by the Tebbe reagent Cp sub 2 sub Ti CH sub 2 sub , and then the glycosyl acceptor is tethered to the enol ether under acid catalysed conditions ... File Acid catalyzed tethering.png thumb 600px Iodonium tethering on enol ethers This method is similar ... into an enol ether by the Tebbe reagent . However, in this approach, N Iodosuccinimide N Chlorosuccinimide NIS is used to tether the glycosyl acceptor to the enol ether, and in a second step ... s catalyst PPh sub 3 sub sub 3 sub RhCl and butyl lithium. The resulting enol ether is then reacted ... more details
about a class of chemical compounds the chemical company Enamine Ltd Image Enamine 2D skeletal.png thumb right 200px The general structure of an enamine An enamine is an saturation chemistry unsaturated compound derived by the reaction of an aldehyde or ketone with a secondary amine followed by loss of H sub 2 sub O. ref cite book author Clayden, Jonathan authorlink editor others title Organic chemistry edition language publisher Oxford University Press location Oxford, Oxfordshire year 2001 origyear pages pages chapter chapter isbn 0 19 850346 6 oclc doi url http www.organic chemistry.org books reviews 0198503466.shtm accessdate ref ref Housecroft3rd ref The word enamine is derived from the affix en , used as the suffix of alkene , and the root amine . This can be compared with enol , which is a functional group containing both alkene en and alcohol ol . Enamines are considered to be nitrogen analogs of enols. ref http pharmaxchange.info press 2011 04 imines and enamines nitrogen analogs of enols and enolates Imines and Enamines PharmaXChange.info ref If one of the nitrogen substituents is a hydrogen atom, H, it is the tautomer ic form of an imine . This usually will rearrange to the imine however there are several exceptions such as aniline . The enamine imine tautomerism may be considered analogous to the keto enol tautomerism . In both cases, a hydrogen atom switches its location between the heteroatom oxygen or nitrogen and the second carbon atom. Enamines are both good nucleophiles and good bases. References reflist 2 See also Thorpe reaction Category Functional groups Category Enamines de Enamine es Enamina fr namine gl Enamina id Enamina it Enammina hu Enaminok nl Enamine ja pl Enaminy pt Enamina ru sr Enamin fi Enamiinit sv Enamin zh ... more details
enzyme Name dopachrome isomerase EC number 5.3.3.12 CAS number 130122 81 5 IUBMB EC number 5 3 3 12 GO code 0004167 image width caption In enzymology , a L dopachrome isomerase EC number 5.3.3.12 is an enzyme that catalysis catalyzes the chemical reaction L dopachrome math rightleftharpoons math 5,6 dihydroxyindole 2 carboxylate Hence, this enzyme has one substrate biochemistry substrate , L dopachrome , and one product chemistry product , 5,6 dihydroxyindole 2 carboxylate . This enzyme belongs to the family of isomerase s, specifically those intramolecular oxidoreductase s transposing C C bonds. The systematic name of this enzyme class is L dopachrome keto enol isomerase . Other names in common use include dopachrome tautomerase , tyrosinase related protein 2 , TRP 1 , TRP2 , TRP 2 , tyrosinase related protein 2 , dopachrome Delta7,Delta2 isomerase , dopachrome Delta isomerase , dopachrome conversion factor , dopachrome isomerase , dopachrome oxidoreductase , dopachrome rearranging enzyme , DCF , DCT , dopachrome keto enol isomerase , and L dopachrome methyl ester tautomerase . This enzyme participates in tyrosine metabolism and melanogenesis . References reflist 1 cite journal author Jara JR, Lozano JA date Pt 2 title Molecular mechanism for catalysis by a new zinc enzyme, dopachrome tautomerase journal Biochem. J. volume 313 pages 447&ndash 53 pmid 8573077 pmc 1216928 cite journal author Pawelek JM date 1990 title Dopachrome conversion factor functions as an isomerase journal Biochem. Biophys. Res. Commun. volume 166 pages 1328&ndash 33 pmid 2106316 doi 10.1016 0006 291X 90 91011 G issue 3 cite journal author Joshua GW, Selkirk ME, Zhang Y, Meyer DJ date Pt 3 title Rapid purification and characterization of L dopachrome methyl ester tautomerase macrophage migration inhibitory factor from Trichinella spiralis, Trichuris muris and Brugia pahangi journal Biochem. J. volume 335 pages 495&ndash 8 pmid 9794786 pmc 1219807 isomerase stub Intramolecular oxidoreductases C ... more details
Chembox Watchedfields changed verifiedrevid 458774030 ImageFile Dibenzoylmethane.svg ImageSize ImageAlt IUPACName 1,3 diphenylpropane 1,3 dione OtherNames 2 Benzoylacetophenone Section1 Chembox Identifiers CASNo Ref cascite correct CAS CASNo 120 46 7 PubChem 8433 SMILES C1 CC C C C1 C O CC O C2 CC CC C2 Section2 Chembox Properties Formula C sub 15 sub H sub 12 sub O sub 2 sub MolarMass 224.25 g mol Appearance Density MeltingPt 77 78 C ref name Spectro http dx.doi.org 10.1016 j.saa.2009.12.040 , Jan Zawadiak, Marek Mrzyczek Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 75 2010 pp. 925 929 ref BoilingPt Solubility Section3 Chembox Hazards MainHazards FlashPt Autoignition 1,3 diphenylpropane 1,3 dione dibenzoylmethane, DBM is an aromatic diketone 1,3 diketone , acac acetylacetone acac derivative, where both methyl groups have been substituted by phenyl groups. It is white solid melting 77 78 C. Similarly to acac, DBM exist as two tautomeric forms, however keto enol equilibrium of DBM is strongly shifted to the enol form. It is result of formation of intra molecular hydrogen bond, which is conjugated with phenyl rings. ref name Spectro The resonance assisted hydrogen bond is responsible for high photostability of such compounds, and therefore, some derivates of DBM e.g. Avobenzone have found application as sunscreen s. References references Category Ketones Category Chelating agents Category Ligands fa pl Dibenzoilometan ... more details
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