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Topic: Keto-enol tautomerism

    Note: these results are not from the primary (high quality) database.

Keto-Enol Tautomerism Enol - HO- resides on sp2 carbon of C=C www.miami.edu /chem/chm201c/notes/ch08/tsld016.htm   (9 words)

Keto/Enol Atom Types In order to handle keto/enol tautomerism, all of the sp2 hybridized carbons are reclassified as acceptors and all sp3 carbons with at least 1 hydrogen and alpha to an original donor, acceptor or hybridized atom are reclassified as donors. www.daylight.com /meetings/emug99/Delany/taut_html/tsld026.htm   (39 words)

Keto-Enol Tautomerism The enol form is less polar than the keto tautomer because of the intramolecular hydrogen bonding. However, this spacing is not present in acetylacetone, and in the keto form interactions between the methyl groups is pronounced. Tautomerism refers to an equilibrium between two different structure of the same compound. itl.chem.ufl.edu /4411L_f00/nmr/nmr.html   (495 words)

Keto-Enol Tautomerism One way of forming enols is by way of tautomerization of enolizable ketones. Enols are alkenes (en) that have a alcohol (ol) function directly attached to the alkene C-atoms. Migration of one of those enolizable H-atoms to the carbonyl-oxygen atom give the enol tautomer shown. cwx.prenhall.com /bookbind/pubbooks/bruice/chapter18/medialib/acetone_enol.html   (140 words)

Keto-Enol Tautomerism The Keto-Enol Tautomerism of 2,4-Pentanedione and Related Compounds The difference between the semi-empirical energies for the keto and enol tautomers is recorded and compared to those for the other molecules. The literature values given are actually the change in enthalpy for the gas phase conversion of keto to enol for the molecules indicated. www.molecules.org /experiments/Anderson/Anderson.html   (896 words)

ipedia.com: Aldehyde Article Equilibration of keto and enol tautomers is catalyzed by acid. www.ipedia.com /aldehyde.html   (471 words)

Guanine - Open Encyclopedia Guanine exists as tautomers (see Keto-enol tautomerism), as depicted graphically on the right. Guanine is also the name of a white amorphous substance found in the scales of certain fishes, the guano of sea-birds, and the liver and pancreas of mammals. open-encyclopedia.com /Guanine   (111 words)

Search Results for keto - Encyclopædia Britannica Acids and bases both bring about the establishment of an equilibrium between ketones (or aldehydes) and their enol forms, which contain a hydroxyl group directly attached to a doubly bonded carbon... It is manufactured from d-glucose; this is converted by means of microbiological oxidation to a keto acid, which is catalytically... The reactions of the monosaccharides can be conveniently subdivided into those associated with the aldehydo or keto group and those associated with the hydroxyl groups. www.britannica.com /search?query=keto&submit=Find&source=MWTEXT   (323 words)

Keto-Enol Tautomerism Keto-enol equilibria lie far toward the keto form. www.chem.sc.edu /faculty/salvatore/chem334/chp16/tsld046.htm   (8 words)

Chem 331 Quiz 4 Solutions, Summer, 2001 Keto-enol tautomerism, an equilibrium process, is the intercoversion of the keto form of a ketone or aldehyde and the enol form of the ketone or aldehyde. (5 pts) Explain keto-enol tautomerism and provide an example of tautomerism. The resulting enol will tautomerize to give the more stable tautomer, the ketone. web.uccs.edu /chemistry/organic_online/331quiz4soln.htm   (202 words)

Keto–enol interconversion of 2-phenacylfuran in aqueous solution and in the presence of surfactant micelles The relaxation of the enol- to its more stable keto- tautomer was monitored by stopped-flow spectrophotometry (at a wavelength near the absorption peak of the enol or enolate anion). Tautomeric constants and acid dissociation constants for the keto- and the enol- forms of some phenylacetyl- and phenacyl- heterocycles. Interestingly, the enol contents of 2PAF and 2PAT are considerably lower than that of 2PF: this can probably be attributed to external conjugation with the lone pair of electrons on the oxygen- and sulfur atoms which stabilizes the carbonyl groups of the keto forms of 2PAF and 2PAT, as previously suggested. www.arkat-usa.org /ark/journal/2002/I11_Spinelli/MS-541H/541H.asp   (3983 words)

Ab Initio Study on the Keto-Enol Tautomerism of the -Substituted Acetaldehydes XH2CCH=O (X = H, BH2, CH3, NH2, OH, F, CN, NC, and Cl): Comparison with the Tautomerism in -Substituted Acetaldimines and Acetyl Derivatives -substituted acetaldehydes XH, OH, F, CN, NC, and Cl) to investigate the substituent effects on the keto-enol tautomerisms. Ab Initio Study on the Keto-Enol Tautomerism of the -Substituted Acetaldehydes XH2CCH=O (X = H, BH2, CH3, NH2, OH, F, CN, NC, and Cl): Comparison with the Tautomerism in -Substituted Acetaldimines and Acetyl Derivatives All substituents except F stabilize the enol form relative to its keto counterpart as shown by the reduction of the energy gaps between the former and the latter forms. pubs.acs.org /cgi-bin/abstract.cgi/jpcafh/1999/103/i17/abs/jp9839910.html   (345 words)

Keto-Enol Tautomerism of Dimedone Studied by Dynamic NMR Kinetic information of the solution keto-enol tautomerism for dimedone in DMSO, in the temperature range of 25-85 deg. The keto-enol tautomeric equilibrium of dimedone has been investigated by high-resolution 13C NMR spectroscopy. The data are discussed in terms of the different motional environments that result from the geometric restrictions imposed by hydrogen bonding in the crystal structure www.s-a-s.org /journal/96/asv50n11/ASv50n11_mr5.html   (143 words)

Keto-enol tautomerism, acid- and base-catalyzed (from acid-base reaction) --  Encyclopædia Britannica More results on "Keto-enol tautomerism, acid- and base-catalyzed (from acid-base reaction)" when you join. The interconversion between the two forms is called keto–enol tautomerism. Keto-enol tautomerism, acid- and base-catalyzed (from acid-base reaction) --  Encyclopædia Britannica www.britannica.com /eb/article-49255?hook=498898   (886 words)

Keto-Enol Tautomerism Any ketone that has at least one hydrogen atom attached to one of the C-atoms that are directly connected to the carbonyl C-atom is an "enolizable" ketone since equilibration between H-C-C=O and C=C-OH is possible. You can see the structure of the enol in the following item. cwx.prenhall.com /bookbind/pubbooks/bruice2/chapter19/medialib/acetone_keto.html   (85 words)

Model of (R)-2-Methylcyclohexanone and enol The keto-enol tautomerization is catalyzed by both proton acids and bases. When the enol reverts back to the ketone, both enantiomers will be produced - the ketone has racemized during this process. For acid catalysis, the proton adds to the oxygen of the carbonyl group and then another is removed from the alpha carbon to give the enol. wps.prenhall.com /wps/media/objects/341/349454/methylcyclohexanone.html   (148 words)

section6 Results show that in the keto form the negative charge density on N7 and N3 atoms are -0.0614 and -0.1786 respectively while in the enol form it is -0.1757, -0.3978, -0.2415 and -0.2263 for the N7, O6, N1 and N3 atoms respectively. Negative charge density is higher on N3 in the keto form whereas in the enol form the negative charge density is significant on all the four atoms. The variation of SER spectra with pH for hydroxyquinoline is attributed to the adsorption of the molecules on the bare and the chlorinated silver surfaces whose surface density depends on the sol pH. www.ijvs.com /volume4/edition2/section6.html   (4640 words)

Keto-Enol Tautomerism The keto form is the more stable (Why?) www.cns.uni.edu /~macmilla/mcmurry/mcmurry_chapter_22/sld004.htm   (8 words)

11th Hour - Organic Chemistry I & II Since the equilibrium normally favors the keto form, any reaction that looks, on paper, to yield an enol will likely produce the keto form as the major product as in the case of hydration of an alkyne. Even in samples of what one believes to be "pure" carbonyl compounds like aldehydes and ketones, there is a small amount or enol present in equilibrium. The equilibrium is dynamic in that, although only a small amount of the material present may be in the enol form at any instant in time, the individual molecules "take turns" at being the enol. www.blackwellpublishing.com /11thhour/book6/oc1ch4.html   (191 words)

Characterization of Keto-Enol Tautomerism of Acetyl Derivatives from the Analysis of Energy, Chemical Potential, and Hardness Characterization of Keto-Enol Tautomerism of Acetyl Derivatives from the Analysis of Energy, Chemical Potential, and Hardness enol equilibria in 10 acetyl derivatives (CH, OCHO, F, Cl and Br). We present a theoretical study of the substituent effects on keto pubs.acs.org /cgi-bin/jtext?jpcafh/104/i07/abs/jp9930797   (88 words)

CHEM 261 Organic Chemistry 1 - Keto-enol Tautomerism CHEM 261 Organic Chemistry 1 - Keto-enol Tautomerism www.chem.umass.edu /~adams/chem261/261handouts/ketoenol.html   (8 words)

Keto/Enol Node Ordering The introduction of keto/enol tautomerism requires ordering carbon atoms relative to the hetero atoms; oxygen, nitrogen, sulfur, etc... www.daylight.com /meetings/emug99/Delany/taut_html/tsld027.htm   (27 words)

Abstract of Article Abstract The keto-enol tautomerism of α-carbonylcyclododecanones has been studied by means of Conformational Effect on the Keto-enol Tautomerism of α-Carbonylcyclododecanones The result shows that the effects of substituent, temperature and solvent on the tautomerism agreed with the known rules, while their enol contents were much lower than those of the corresponding α-carbonylcyclohexanones, which is illustrated reasonably by the conformational effect. sioc-journal.cn /yjhx/qikan/epaper/zhaiyao.asp?bsid=791   (95 words)

Chromatography Forum I guess it must be some other process impurities simply based on that keto-enol tautomerism can't resolved well under chromatographic conditions. some of our project mates telling that there exhibits a keto enol tautomerism exhibits and so the results. If you can collect peak fractions and reinject them, and if the two peaks are tautomers, wouldn't you see approximately the same ratio of the two peaks for the reinjected sample regardless of the fraction injected? www.lcresources.com /discus/messages/5134/4291.html?ThursdayApril120040608am   (535 words)

AAS Biographical Memoirs - Raymond James Wood Le Fevre 1905-1986 Examined were, inter alia, oxygen, sulphur and nitrogen containing heterocycles, monoterpenes, oximes, 'iodoxybenzene', substituted benzocinnoline 6-oxides, 2,2'-dipyridyl, 'diphenylmaleinitrile', substituted aryl nitro compounds, 1,4-dioxan and the temperature dependence of its structure, species with possible keto-enol tautomerism, and solute intermolecular interactions. Other topics that interested Le Fèvre in his first decade in Sydney included the thermotropy of spiro-pyrans and thermochromism of methyleneanthrones; the a priori calculation of atomic polarisations from spectroscopic data; and the influence of molecular shape and of medium characteristics on the dielectric relaxation times of dipolar solutes. In parallel with the above programmes and substantially with colleagues already named, Le Fèvre continued his long-standing interest in the elucidation of problems of molecular structure and geometry using dipole moments, often in conjunction with infrared and electronic spectral data. www.asap.unimelb.edu.au /bsparcs/aasmemoirs/lefevre.htm   (10274 words)

chemistry I've recently learned a little more about the Keto-Enol Tautomerism. How can you not love a reaction like this? www2.hanover.edu /student/gerdon/chemistry.html   (326 words)

Keto-enol tautomerism - Wikipedia, the free encyclopedia In organic chemistry, keto-enol tautomerism refers to an equilibrium between a ketone and an enol. Keto-enol tautomerism is important in several areas of biochemistry. The high phosphate-transfer potential of phosphoenolpyruvate results from the fact that the phosphorylated compound is "trapped" in the less stable enol form, whereas after dephosphorylation it can assume the keto form. en.wikipedia.org /wiki/Keto-enol_tautomerism   (326 words)

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