Intramolecular Catalysis of Hydrolytic Reactions. III. Intramolecular Catalysis by Carboxylate Ion in the Hydrolysis of Methyl Hydrogen Phthalate<sup>1,2</sup>

Bender, Myron L.; Chloupek, Frank J.; Neveu, Maurice C.

doi:10.1021/ja01553a016

Cited by 52 publications

(30 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the literature, there are some early reports about the "acid anhydride" character of aspirin, [22] confirmed by other authors who claimed the anhydride intermediate was involved in the mechanism of hydrolysis of aspirin to acetic acid and salicylate. [23] However, later independent works by Fersht, [24] Jencks [25] and Kemp [26] demonstrated through elegant experiments that, while aspirin can actually exist in the anhydride form, the latter is not involved in the mechanism of solvolysis (either by water or alcohols), which instead proceeds under intramolecular general base catalysis provided by the vicinal carboxylate moiety (Scheme 1). The anhydride intermediate is thought not to play a role in solvolysis of aspirin because the greater nucleophilicity of the phenoxide anion with respect to solvent favors the intramolecular reaction reforming aspirin.…”

mentioning

confidence: 99%

Mechanistic Insights into Cyclooxygenase Irreversible Inactivation by Aspirin

Tosco¹,

Lazzarato²

2009

ChemMedChem

View full text Add to dashboard Cite

A mechanistic hypothesis for the acetylation of cyclooxygenase (COX) by aspirin is proposed on the basis of a QM/MM study. This mechanism is consistent with previous experimental findings by other investigators. Ser 530 appears to be acetylated under intramolecular general base catalysis provided by the carboxylate moiety of aspirin, while Tyr 385 plays a crucial role in orienting and polarizing the acetyl group.

show abstract

mentioning

confidence: 99%

Mechanistic Insights into Cyclooxygenase Irreversible Inactivation by Aspirin

Tosco¹,

Lazzarato²

2009

ChemMedChem

View full text Add to dashboard Cite

show abstract

“…This mechanism has been set out in its most acceptable form by Bender (Scheme 1) [9]. This hypothesis was supported by the same authors [10], which showed that a small amount of labelled oxygen from solvent 18 2 H O appears in the salicylic acid produced. Only Garrett has seriously questioned this mechanism.…”

Section: Introductionmentioning

confidence: 80%

Stability Studies of Lysine Acetylsalicylate (Aspirin Derivative): Mechanisms of Hydrolysis

Kamal¹,

Benlyamani²,

Serdaoui³

et al. 2012

OJPC

View full text Add to dashboard Cite

To control the stability of the lysine acetylsalicylate compound (LAS) in aqueous solution, some studies of the hydronium ion-catalyzed, hydroxide ion-catalyzed, and spontaneous reactions of this active ingredient in water solutions have been carried out. The pH-rate profile (log k obs = f(pH)), shows that the hydrolysis reaction of the LAS, is conducted by a catalysis acid-base mechanism, with multiple reaction pathways. The rate constants, k H , k OH and k 0 to the reaction pathways catalyzed by H 3 O + , HO -ions and to the spontaneous reaction, for the hydrolysis reaction of the reagent LAS, were determined. The results show that the studied compound LAS is unstable in basic medium and the hydrolysis reaction catalyzed by HO -ions is predominant.For a known acidity (pH  10), studies conducted for different temperatures of the medium, clearly indicate, that the experimental rate constant k obs ,depends on the temperature according to the Arrhenius equation. The activation parameters: activation energy (E a ), enthalpy (ΔH ≠ ) and entropy (ΔS ≠ ), for the transition state were determined, The very negative value obtained for the activation parameter ΔS*, first indicates that in the transition state there is gain in order, then this late state, resembles the products and that probably for the mechanism of the LAS hydrolysis reaction catalyzed by HO -ions, the rate-determining step is a bimolecular reaction. Finally from all these results, the mechanism for the reaction pathway catalyzed by HO -ions has been elucidated.

show abstract

“…The data in 'rable VI reveal that there is little or no' reaction of fumaramic acid with cellulose under the reaction conditions used (samples [1][2][3][4]. Maleamic acid, under the same conditions and the same concentration (samples 5b, 6b), give significant reaction, with DS values of 0.07 and 0.08, respectivelv.…”

Section: Ester Bond To a Cid And Basementioning

confidence: 97%

“…How can these stabilities . [2] have shown that the hydrolysis of methyl hydrogen phthalate occurs through intramolecular catalysis by the carboxytate ion. Therefore, at pH 2.0 -2.5, the ester bonds formed should be stable to hydrolysis since the unesterified carboxyl groups are non-ionized.…”

Section: Stability Of Ester Bonds Formed To Acidic and Basicmentioning

confidence: 99%

The Reactions of Cellulose with Amic Acids and Anhydride /Ammonia

Johnson

Cuculo

1973

Textile Research Journal

View full text Add to dashboard Cite

Reported is the generality of two new, recently reported reactions for the esterification of cellulosic fabrics using amic acids or anhydride/ammonia in aqueous solution. A study is made of amic acid structure and extent of formation of the cellulose half-acid ester, the main reaction product. The formation of crosslinked cellulose, a minor product, is also discussed. A series of amic acids, including the isomer pair, maleamic and fumaramic acids, as well as several anhydrides (with ammonia) were reacted with cellulosic fabrics. The results are interpreted to support a hypothesis which requires a unique combination of structural and environmental features for reaction to occur. Effects of pH, catalyst, and presence of moisture on extent of reaction were also studied. Resistance to acid and basic hydrolysis as well as the relative strength retention of treated fabric was determined. Comment is made on the potential utility of the modified fabrics.

show abstract

Intramolecular Catalysis of Hydrolytic Reactions. III. Intramolecular Catalysis by Carboxylate Ion in the Hydrolysis of Methyl Hydrogen Phthalate^1,2

Abstract: cago through whose courtesy the mass spectrometer under AEC Contract At(ll-1)92 was made available. We thank the Simonize Co. for its contribution to the departmental fund for research.Chicago 16, III.

Cited by 52 publications

References 9 publications

Mechanistic Insights into Cyclooxygenase Irreversible Inactivation by Aspirin

Mechanistic Insights into Cyclooxygenase Irreversible Inactivation by Aspirin

Stability Studies of Lysine Acetylsalicylate (Aspirin Derivative): Mechanisms of Hydrolysis

The Reactions of Cellulose with Amic Acids and Anhydride /Ammonia

Contact Info

Product

Resources

About

Intramolecular Catalysis of Hydrolytic Reactions. III. Intramolecular Catalysis by Carboxylate Ion in the Hydrolysis of Methyl Hydrogen Phthalate1,2

Abstract: cago through whose courtesy the mass spectrometer under AEC Contract At(ll-1)92 was made available. We thank the Simonize Co. for its contribution to the departmental fund for research.Chicago 16, III.

Cited by 52 publications

References 9 publications

Mechanistic Insights into Cyclooxygenase Irreversible Inactivation by Aspirin

Mechanistic Insights into Cyclooxygenase Irreversible Inactivation by Aspirin

Stability Studies of Lysine Acetylsalicylate (Aspirin Derivative): Mechanisms of Hydrolysis

The Reactions of Cellulose with Amic Acids and Anhydride /Ammonia

Contact Info

Product

Resources

About

Intramolecular Catalysis of Hydrolytic Reactions. III. Intramolecular Catalysis by Carboxylate Ion in the Hydrolysis of Methyl Hydrogen Phthalate^1,2