Ring-Chain Tautomerism.

Jones, Paul R.

doi:10.1021/cr60225a002

Cited by 108 publications

(30 citation statements)

References 174 publications

(271 reference statements)

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“…Valence tautomerism involves electronic exchanges without the repositioning of protons and is more common in transition metal complexes (Sato et al 2007). The ribose or deoxyribose in nucleosides can also participate in ring-chain tautomerism (Jones 1963), a type of tautomerism in which one of the tautomeric forms is cyclic and the interconversion is mediated by the transfer of a proton. An example of ring-chain tautomerism enables mutarotation of sugars (Baker et al 1924).…”

Section: Mechanism Of Tautomerization Of Rna Basesmentioning

confidence: 99%

Role of tautomerism in RNA biochemistry

Singh

Fedeles

Essigmann

2014

RNA

121

116

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Heterocyclic nucleic acid bases and their analogs can adopt multiple tautomeric forms due to the presence of multiple solventexchangeable protons. In DNA, spontaneous formation of minor tautomers has been speculated to contribute to mutagenic mispairings during DNA replication, whereas in RNA, minor tautomeric forms have been proposed to enhance the structural and functional diversity of RNA enzymes and aptamers. This review summarizes the role of tautomerism in RNA biochemistry, specifically focusing on the role of tautomerism in catalysis of small self-cleaving ribozymes and recognition of ligand analogs by riboswitches. Considering that the presence of multiple tautomers of nucleic acid bases is a rare occurrence, and that tautomers typically interconvert on a fast time scale, methods for studying rapid tautomerism in the context of nucleic acids under biologically relevant aqueous conditions are also discussed.

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Section: Mechanism Of Tautomerization Of Rna Basesmentioning

confidence: 99%

Role of tautomerism in RNA biochemistry

Singh

Fedeles

Essigmann

2014

RNA

121

116

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“…The kinetics of tautomeric interconversion and chemical derivatization is complex. While the relative rates of derivatization and proton transfer between tautomeric forms and the solvent affect the outcome, inherent in these methods is that the reagent used to derivatize the individual tautomeric forms must react with each tautomeric form faster than a proton can be transferred between tautomeric forms in solution [48,49], and solvent mediated proton transfer is very fast, indeed. In the case of 4-hydroxycoumarin itself, acid-catalyzed alkylation can yield either C-alkylated products (corresponding to alkylation of the chromandione tautomeric form) [50,51] or either of two O-alkylated (coumarin or chromone) products [27,29,30,52].…”

Section: Determining Tautomeric Equilibriamentioning

confidence: 99%

Warfarin: history, tautomerism and activity

Porter

2010

J Comput Aided Mol Des

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The anticoagulant drug warfarin, normally administered as the racemate, can exist in solution in potentially as many as 40 topologically distinct tautomeric forms. Only 11 of these forms for each enantiomer can be distinguished by selected computational software commonly used to estimate octanol-water partition coefficients and/or ionization constants. The history of studies on warfarin tautomerism is reviewed, along with the implications of tautomerism to its biological properties (activity, protein binding and metabolism) and chemical properties (log P, log D, pK (a)). Experimental approaches to assessing warfarin tautomerism and computational results for different tautomeric forms are presented.

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“…Many of the -and -ketocarboxylic acids we study are capable of ring-chain tautomerism [4,5] and several are known to exist predominantly or exclusively in the closed, lactol form, sometimes referred to as the "pseudoacid" [6][7][8][9][10]. A search of the X-ray literature (Cambridge Structural Database, Version 5.27, update of May, 2006) [11] reveals some 63 examples of keto-acid lactol structures, of widely varying degrees of complexity.…”

Section: Introductionmentioning

confidence: 99%

“…A search of the X-ray literature (Cambridge Structural Database, Version 5.27, update of May, 2006) [11] reveals some 63 examples of keto-acid lactol structures, of widely varying degrees of complexity. About 90% of these are derived from what are formally -keto acids, which yield five-membered lactols, the size known to be most favorable for such rings [4,12].…”

Section: Introductionmentioning

confidence: 99%

The Preferred Ring-Tautomeric Form of a Bicyclic γ-Ketocarboxylic Acid: An Equilibrium Driven by Relief of Angular Hybridization Strain

Wong¹,

Lalancette

Thompson³

2008

TOCRYJ

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(±)-2-exo-Carboxy-2-endo-methyl-7-oxobicyclo[2.2.1]heptane exists preferentially in its closed, ringtautomer form, the tricyclic lactol (C 9 H 12 O 3 ), which aggregates catemerically by forming hydroxyl-to-carbonyl hydrogen bonds [O O = 2.7667(16)Å, O-H O = 170º] among molecules screw related in b. This ring-chain equilibrium is driven by relief of angular strain at the 7-ketone, whose origin is the ketone's sp 2 hybridization vs. the angle enforced by the bicyclic system. In the analogous compound with transposed functional groups, the equilibrium favors the keto acid, which is easily isolated.

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Ring-Chain Tautomerism.

Cited by 108 publications

References 174 publications

Role of tautomerism in RNA biochemistry

Role of tautomerism in RNA biochemistry

Warfarin: history, tautomerism and activity

The Preferred Ring-Tautomeric Form of a Bicyclic γ-Ketocarboxylic Acid: An Equilibrium Driven by Relief of Angular Hybridization Strain

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