Simple enols

HART, H.

doi:10.1021/cr60322a003

Cited by 141 publications

(48 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[1] It typically manifests itself in the oxo/hydroxy olefin, [2][3][4][5] amide/ hydroxy imine [6][7][8] and the degenerate carboxy/hydroxycarbonyl proton-shift equilibria, but also in phenol/cyclohexadienone, [9][10] 2-pyridinone/2-hydroxypyridine [11][12][13][14][15][16] and 2-quinolinone/2-hydroxyquinoline [16][17][18] equilibria (Scheme 1).…”

Section: Introductionmentioning

confidence: 99%

The Tautomeric Persistence of Electronically and Sterically Biased 2‐Quinolinones

2008

View full text Add to dashboard Cite

One dozen of tailormade model 3‐fluoro‐2(1H)‐quinolinones were synthesized in order to be investigated by UV‐, IR‐ and NMR spectroscopic techniques. All of these compounds were found to exist predominantly, if not exclusively, in the lactam (carboxamide, 1,2‐dihydro‐2‐oxoquinoline) form. No tautomeric lactim (iminol, azaphenol) structure was detected. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

show abstract

Section: Introductionmentioning

confidence: 99%

The Tautomeric Persistence of Electronically and Sterically Biased 2‐Quinolinones

2008

View full text Add to dashboard Cite

show abstract

“…Despite the fact that the concentration of enol form in water solutions is very small (K = 10 -6 at 298 K [9]), we can envisage two pathways of reaction of propanone with the amino groups coordinated to the metal ion (M), as shown in Scheme 3; considering our experimental observations, together with fact that for cobalt(III) a coordination number of 6 is typical, and the data of our previous work concerning template synthesis in the cobalt(III)-dithiooxamide-methanal (glyoxal) triple systems [1], according to which OH -and H 2 O are coordinated to cobalt(III), six possible products can be suggested for the triple system under examination as shown in Scheme 4. …”

Section: Resultsmentioning

confidence: 99%

Soft template synthesis in the cobalt(III)–1,2-diaminoethane-1,2-dithione–propanone triple system on a K[CoFe(CN)6]-gelatin-immobilized matrix

Михайлов

Kazymova

2008

Transition Met Chem

View full text Add to dashboard Cite

Complexation of Co III , in the form of K[CoFe(CN) 6 ]-gelatin-immobilized matrix, in contact with aqueous-alkaline solutions (pH * 12) containing 1,2-diaminoethane-1,2-dithione and propanone, has been studied. Template synthesis leading to a chelate Co III coordination compound with a tetradentate N,N,S,S-donor ligand identified as 4,4,6-trimethyl-1,9-diamino-1,9-dimercapto-3,7-diazanon-3-en-2,8-dithione and hydroxy co-ligand occurs under these specific conditions. 1,2-Diaminoethane-1,2-dithione and propanone are the ligand synthons in this process.

show abstract

“…Since the tautomeric equilibria in excited states can be very different from those in the ground state, it is in many cases possible to induce an isomerization between two tautomeric forms by light. [72][73][74][75][76][77][78][79] Already in 1961, Yang and Rivas showed that the keto form of ortho-methylbenzophenone (Fig. 3.6) can undergo excited-state tautomerism into the corresponding enol form in alcohol solutions.…”

mentioning

confidence: 99%

Computational Studies of Photobiological Keto-Enol Reactions and Chromophores

Falklöf¹

2015

Linköping Studies in Science and Technology. Dissertations

View full text Add to dashboard Cite

This thesis presents computational chemistry studies of keto-enol reactions and chromophores of photobiological significance.The first part of the thesis is concerned with two protein-bound chromophores that, depending on the chemical conditions, can exist in a number of different ketonic and enolic forms. The first chromophore is astaxanthin, which occurs in the protein complex responsible for the deep-blue color of lobster carapace. By investigating how different forms of astaxanthin absorb UV-vis radiation of different wavelengths, a model is presented that explains the origin of the dramatic color change from deep-blue to red upon cooking of live lobsters.The second chromophore is the oxyluciferin light emitter of fireflies, which is formed in the catalytic center of the enzyme firefly luciferase. To date, there is no consensus regarding which of the possible ketonic and enolic forms is the key contributor to the light emission. In the thesis, the intrinsic tendency of oxyluciferin to prefer one particular form over other possible forms is established through calculation of keto-enol and acid-base excited-state equilibrium constants in aqueous solution.The second part of the thesis is concerned with two families of biological photoreceptors: the blue-light-absorbing LOV-domain proteins and the red-lightabsorbing phytochromes. Based on the ambient light environment, these proteins regulate physiological and developmental processes by switching between inactive and active conformations. In both families, the conversion of the inactive into the active conformation is triggered by a chemical reaction of the respective chromophore.The LOV-domain proteins bind a flavin chromophore and regulate processes such as chloroplast relocation and phototropism in plants. An important step in the activation of these photoreceptors is a singlet-triplet transition between two electronically excited states of the flavin chromophore. In the thesis, this transition is used as a prototype example for illustrating, for the first time, the ability of first-principles methods to calculate rate constants of inter-excited state phosphorescence events.Phytochromes, in turn, bind bilin chromophores and are active in the regulation of processes like seed germination and flowering time in plants. Following two systematic studies identifying the best way to model the UV-vis absorption iii iv and fluorescence spectra of these photoreceptors, it is demonstrated that steric interactions between the chromophore and the apoprotein play a decisive role for how phytochromes are activated by light. Populärvetenskaplig sammanfattningSolljusär en förutsättning för liv på jorden. Växter använder solljus som energikälla för att kunna bilda näring till sig själva ochäven syre till andra organismer. Iögonen hos människor och djur finns specialdesignade celler som omvandlar ljus till elektriska impulser, som sedan tolkas till en bild av syncentrat i hjärnan. Djur har utvecklat mekanismer för att med hjälp av ljus kunna kamouflera sig, locka till s...

show abstract

Simple enols

Cited by 141 publications

References 17 publications

The Tautomeric Persistence of Electronically and Sterically Biased 2‐Quinolinones

The Tautomeric Persistence of Electronically and Sterically Biased 2‐Quinolinones

Soft template synthesis in the cobalt(III)–1,2-diaminoethane-1,2-dithione–propanone triple system on a K[CoFe(CN)6]-gelatin-immobilized matrix

Computational Studies of Photobiological Keto-Enol Reactions and Chromophores

Contact Info

Product

Resources

About