Imidazole Catalysis. II. The Reaction of Substituted Imidazoles with Phenyl Acetates in Aqueous Solution

Bruice, Thomas C.; Schmir, Gaston L.

doi:10.1021/ja01534a040

Cited by 182 publications

(74 citation statements)

References 10 publications

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“…The hydrolysis catalyzed by 2-methylimidazole was also stated by previous investigators (14) to be first order in both catalyst and substrate, with a rate constant of 7.0 X lO-?l mole-I s-'. The solvent was 28.5% (v/v) ethanol-water, and the temperature was 30.0 "C. No catalysis could be detected in the present investigation, from which it is concluded that the rate constant is less than loA4 1 mole-1s-l.…”

Section: Catalysis By Imidazole and Its Derivativessupporting

confidence: 58%

KINETICS OF THE CATALYZED HYDROLYSIS OF p-NITROPHENYL ACETATE

Sacher¹,

Laidler²

1964

Can. J. Chem.

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Catalytic constants have been determined for the hydrolysis a t 20 OC of p-nitrophenyl acetate in 9.56% (w/w) dioxane-water mixtures; catalysts used were hydroxide ions, imidazole and 2-methylimidazole, various substituted pyridines, serine, histidine and histidylhistidine. In the case of hydroxide ion catalysis, the rate coilstant falls off a t high catalyst concentrations, and this is attributed to the establishment of a n equilibrium involving the anion of the substrate. The results with the various catalysts indicate that there is no simplecorrelation between catalytic efficiency and pK or nucleophilicity. In the imidazole series there is evidence of steric hindrance when a group is present in a position next t o the functional group. There is a n indication of bifunctional catalysis in the hydrolysis by 2-(8-hydroxyethy1)pyridine and 4-(r-hydroxypropyl)pyridine, both of which are much more effective than pyridine.

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Section: Catalysis By Imidazole and Its Derivativessupporting

confidence: 58%

KINETICS OF THE CATALYZED HYDROLYSIS OF p-NITROPHENYL ACETATE

Sacher¹,

Laidler²

1964

Can. J. Chem.

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“…[25] The electronic properties of the nitrogen ligand also appears to be important, as the higher activity observed with 2 b compared to 6 is likely due to differences between the coordinating nitrogen of the oxazoline and imidazole groups respectively, as reflected in the lower basicity of the former. [26] We then considered whether the bridging groups, X, significantly influence the Lewis acidity of the metal in the palladacycles studied for catalyst activity. To investigate this, the same method used for the synthesis of triphenylphosphine adduct 3 b was used to generate small-scale samples of oxazoline complexes 3 a, 3 c, 3 d and 3 f (Scheme 4), together with a corresponding complex 11 derived from the imidazole analogue 6.…”

Section: Rationalisation Of Reactivity Trendsmentioning

confidence: 99%

An Investigation into the Allylic Imidate Rearrangement of Trichloroacetimidates Catalysed by Cobalt Oxazoline Palladacycles

Nomura

Richards

2007

Chemistry A European J

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Dimeric palladacycles, di-mu-X-bis[{eta(5)-(S)-((p)R)-2-[2'-(4'-methylethyl)oxazolinyl]cyclopentadienyl,1-C,3'-N}(eta(4)-tetraphenylcyclobutadiene)cobalt]dipalladium (COP-X), containing bridging groups X=OAc, Cl, Br, I, O(2)CCF(3), p-O(2)CC(6)H(4)F, were synthesised and compared as catalysts for the asymmetric allylic imidate rearrangement of (E)-Cl(3)CC(=NH)OCH(2)CH=CHR with R=nPr. The enantiomeric excess of the product (S)-Cl(3)CC(=O)NHCHRCH=CH(2) was essentially invariant of X (93-96%) and the yield increased in the sequence I

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“…From solvation energies of a titratable compound we determined the electrostatic energy contributions only and ignored [77] benzoic acids 2-methylpyridine 5.33 5.67 5.68 [77] benzoic acid 3.26 3.49 4.22 [76] 4-methylpyridine 5.59 5.84 6.02 [77] p-methylbenzoic acid 4.91 4.25 4.37 [76] 2-aminopyridine 6.27 6.57 6.82 [77] m-methylbenzoic acid 4.10 3.51 4.22 [76] 4-aminopyridine 9.47 10.01 9.11 [77] p-chlorobenzoic acid 3.12 3.69 3.98 [76] 3-chloropyridine 2.92 3.66 2.84 [77] phenols imidazoles phenol 9.99 9.95 9.98 [51] imidazole 7.82 7.98 7.00 [78] m-aminophenol 10.18 10.25 9.87 [51] 2-methylimidazole 7.69 8.18 7.80 [78] o-aminophenol 10.64 10.39 9.78 [a] 4-methylimidazole 7.44 7.34 7.45 [79] m-chlorophenol 9.72 9.25 9.02 [51] 2-aminoimidazole 8.98 8.79 8.50 [78] o-chlorophenol 8.89 8.72 8.56 [51] 2-chloroimidazole 2.73 3.03 3.55 [78] [a] Calculated using Advanced Chemistry Development (ACD) Software Solaris V4. 67 (1994-2003, ACD).…”

Section: Solvation Energiesmentioning

confidence: 99%

Accurate pK_a Determination for a Heterogeneous Group of Organic Molecules

Busch¹,

Knapp²

2004

ChemPhysChem

108

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Single-molecule studies that allow to compute pKa values, proton affinities (gas-phase acidity/basicity) and the electrostatic energy of solvation have been performed for a heterogeneous set of 26 organic compounds. Quantum mechanical density functional theory (DFT) using the Becke-half&half and B3LYP functionals on optimized molecular geometries have been carried out to investigate the energetics of gas-phase protonation. The electrostatic contribution to the solvation energies of protonated and deprotonated compounds were calculated by solving the Poisson equation using atomic charges generated by fitting the electrostatic potential derived from the molecular wave functions in vacuum. The combination of gas-phase and electrostatic solvation energies by means of the thermodynamic cycle enabled us to compute pKa values for the 26 compounds, which cover six distinct chemical groups (carboxylic acids, benzoic acids, phenols, imides, pyridines and imidazoles). The computational procedure for determining pKa values is accurate and transferable with a root-mean-square deviation of 0.53 and 0.57 pKa units and a maximum error of 1.0 pKa and 1.3 pKa units for Becke-half&half and B3LYP DFT functionals, respectively.

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Imidazole Catalysis. II. The Reaction of Substituted Imidazoles with Phenyl Acetates in Aqueous Solution

Cited by 182 publications

References 10 publications

KINETICS OF THE CATALYZED HYDROLYSIS OF p-NITROPHENYL ACETATE

KINETICS OF THE CATALYZED HYDROLYSIS OF p-NITROPHENYL ACETATE

An Investigation into the Allylic Imidate Rearrangement of Trichloroacetimidates Catalysed by Cobalt Oxazoline Palladacycles

Accurate pK_a Determination for a Heterogeneous Group of Organic Molecules

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Imidazole Catalysis. II. The Reaction of Substituted Imidazoles with Phenyl Acetates in Aqueous Solution

Cited by 182 publications

References 10 publications

KINETICS OF THE CATALYZED HYDROLYSIS OF p-NITROPHENYL ACETATE

KINETICS OF THE CATALYZED HYDROLYSIS OF p-NITROPHENYL ACETATE

An Investigation into the Allylic Imidate Rearrangement of Trichloroacetimidates Catalysed by Cobalt Oxazoline Palladacycles

Accurate pKa Determination for a Heterogeneous Group of Organic Molecules

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Accurate pK_a Determination for a Heterogeneous Group of Organic Molecules