Reaction Mechanism of the Acidic Hydrolysis of Highly Twisted Amides:  Rate Acceleration Caused by the Twist of the Amide Bond

2006 ◽  
Vol 110 (30) ◽  
pp. 15000-15011 ◽  
Author(s):  
Jon I. Mujika ◽  
Elena Formoso ◽  
Jose M. Mercero ◽  
Xabier Lopez
Keyword(s):  
Reaction Mechanism ◽  
Amide Bond ◽  
Acidic Hydrolysis ◽  
Rate Acceleration ◽  
Hydrolysis Of

Water-Promoted Hydrolysis of a Highly Twisted Amide:  Rate Acceleration Caused by the Twist of the Amide Bond

2005 ◽  
Vol 127 (12) ◽  
pp. 4445-4453 ◽  
Author(s):  
Jon Iñaki Mujika ◽  
Jose Maria Mercero ◽  
Xabier Lopez
Keyword(s):  
Amide Bond ◽  
Rate Acceleration ◽  
Hydrolysis Of

A computational study on the mechanism of ynamide-mediated amide bond formation from carboxylic acids and amines

2017 ◽  
Vol 15 (30) ◽  
pp. 6367-6374 ◽  
Author(s):  
Song-Lin Zhang ◽  
Hai-Xing Wan ◽  
Zhu-Qin Deng
Keyword(s):  
Reaction Mechanism ◽  
Carboxylic Acids ◽  
Computational Study ◽  
Bond Formation ◽  
Amide Bond ◽  
Reactivity Pattern ◽  
Amide Bond Formation ◽  
Coupling Reagent ◽  
Catalytic Effects ◽  
Acid Substrate

A detailed computational study is presented on the reaction mechanism of ynamide-mediated condensation of carboxylic acids with amines to produce amides, which elucidates the reactivity pattern of the coupling reagent ynamide and discloses crucial bifunctional catalytic effects of the carboxylic acid substrate during aminolysis.

Vinyl ether hydrolysis. XVII. Oxacyclonon-2,8-diene and the question of the unorthodox reaction mechanism for 9-methoxyoxacyclonon-2-ene

1984 ◽  
Vol 62 (1) ◽  
pp. 74-76 ◽  
Author(s):  
R. A. Burt ◽  
Y. Chiang ◽  
A. J. Kresge ◽  
S. Szilagyi
Keyword(s):  
Reaction Mechanism ◽  
Vinyl Ether ◽  
Membered Ring ◽  
Specific Rate ◽  
Ether Group ◽  
Reaction Proceeds ◽  
Great Reactivity ◽  
Rate Of Hydrolysis ◽  
Acid Catalyzed ◽  
Hydrolysis Of

The acid-catalyzed hydrolysis of the nine-membered ring cyclic vinyl ether, oxacyclonon-2,8-diene, occurs with a normal isotope effect, [Formula: see text], which indicates that this reaction proceeds by the conventional vinyl ether hydrolysis mechanism involving rate-determining proton transfer to carbon. The specific rate of this reaction, [Formula: see text], may then be used to show that there is no significant ring-size effect on the rate of hydrolysis of a vinyl ether group in a nine-membered ring. The previously noted unusually great reactivity of the vinyl ether group in 9-methoxyoxacyclonon-2-ene, for which an unorthodox reaction mechanism has been claimed, must therefore be due to some other cause.

Insights into the Inhibition of Acidic Hydrolysis of Cellulose by Its Solation

2018 ◽  
Vol 6 (8) ◽  
pp. 10999-11007 ◽  
Author(s):  
Gongzhe Chen ◽  
Xicheng Wang ◽  
Yijun Jiang ◽  
Xindong Mu ◽  
Haichao Liu
Keyword(s):  
Acidic Hydrolysis ◽  
Hydrolysis Of Cellulose ◽  
Hydrolysis Of

The crystal structure of human mitochondrial 3-ketoacyl-CoA thiolase (T1): insight into the reaction mechanism of its thiolase and thioesterase activities

2014 ◽  
Vol 70 (12) ◽  
pp. 3212-3225 ◽  
Author(s):  
Tiila-Riikka Kiema ◽  
Rajesh K. Harijan ◽  
Malgorzata Strozyk ◽  
Toshiyuki Fukao ◽  
Stefan E. H. Alexson ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Reaction Mechanism ◽  
Active Site ◽  
Quaternary Structure ◽  
Fatty Acyl ◽  
Physiological Importance ◽  
Loop Domain ◽  
Solution Studies ◽  
Hydrolysis Of ◽  
Insight Into

Crystal structures of human mitochondrial 3-ketoacyl-CoA thiolase (hT1) in the apo form and in complex with CoA have been determined at 2.0 Å resolution. The structures confirm the tetrameric quaternary structure of this degradative thiolase. The active site is surprisingly similar to the active site of theZoogloea ramigerabiosynthetic tetrameric thiolase (PDB entries 1dm3 and 1m1o) and different from the active site of the peroxisomal dimeric degradative thiolase (PDB entries 1afw and 2iik). A cavity analysis suggests a mode of binding for the fatty-acyl tail in a tunnel lined by the Nβ2–Nα2 loop of the adjacent subunit and the Lα1 helix of the loop domain. Soaking of the apo hT1 crystals with octanoyl-CoA resulted in a crystal structure in complex with CoA owing to the intrinsic acyl-CoA thioesterase activity of hT1. Solution studies confirm that hT1 has low acyl-CoA thioesterase activity for fatty acyl-CoA substrates. The fastest rate is observed for the hydrolysis of butyryl-CoA. It is also shown that T1 has significant biosynthetic thiolase activity, which is predicted to be of physiological importance.

Theoretical study on the reaction mechanism for the hydrolysis of esters and amides under acidic conditions

Tetrahedron ◽  
2007 ◽  
Vol 63 (5) ◽  
pp. 1264-1269 ◽  
Author(s):  
Kenzi Hori ◽  
Yutaka Ikenaga ◽  
Kouichi Arata ◽  
Takanori Takahashi ◽  
Kenji Kasai ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Theoretical Study ◽  
Acidic Conditions ◽  
Hydrolysis Of Esters ◽  
Hydrolysis Of

SUBSTITUTION AT OCTAHEDRAL CENTERS: II. EFFECT OF SALTS UPON THE RATE OF HYDROLYSIS OF THE HALOPENTAMMINECHROMIUM(III) IONS

1961 ◽  
Vol 39 (11) ◽  
pp. 2371-2379 ◽  
Author(s):  
T. P. Jones ◽  
W. E. Harris ◽  
W. J. Wallace
Keyword(s):  
Charge Transfer ◽  
Transfer Effect ◽  
Ion Pair ◽  
Pair Formation ◽  
Sodium Salts ◽  
Rate Acceleration ◽  
Rate Of Hydrolysis ◽  
A Charge ◽  
Hydrolysis Of ◽  
Octahedral Configuration

A study of the hydrolysis of the halopentamminechromium(III) ions in the presence of the sodium salts of weak acids reveals a rate acceleration due to specific ion-pair formation. The acceleration is due partly to a charge-transfer effect and partly to the fact that the ion helps to maintain the octahedral configuration of the complex in the transition state. It is concluded that the reaction occurs by dissociation, but without collapse of the structure to a five-co-ordinated intermediate.

DC Polarographic and Spectrophotometric Determination of Ampicillin Capsules

1980 ◽  
Vol 63 (5) ◽  
pp. 1049-1051
Author(s):  
Juan A Squella ◽  
Luis J Nunez-Vergara ◽  
Maximo Aros
Keyword(s):  
Absorption Band ◽  
Spectrophotometric Determination ◽  
Degradation Product ◽  
Uv Absorption ◽  
Acidic Hydrolysis ◽  
Average Recovery ◽  
Polarographic Wave ◽  
Spectrophotometric Methods ◽  
Hydrolysis Of

Abstract Polarographic and spectrophotometric methods are proposed for the determination of ampicillin in capsules. Acidic hydrolysis of ampicillin with 1% HCHO in 0.3N HCl yields a degradation product identified as 2-hydroxy-3-phenyl-6-methylpyrazine. This compound has a well defined UV absorption band at 380 nm and a polarographic wave at –0.55 V vs SCE, which can be used for analytical purposes. Individual capsule assays, composite assays, and recovery studies are described. The average recovery values and standard deviations (SD) for UV and polarographic determinations were 99.20% (SD 0.95) and 100.85% (SD 1.09), respectively

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