Intramolecular participation by the thiol group in amide hydrolysis: the general acid-catalyzed pathway

1983 ◽  
Vol 61 (8) ◽  
pp. 1846-1852 ◽  
Author(s):  
Robert S. McDonald ◽  
Patricia Patterson ◽  
Ann Stevens-Whalley
Keyword(s):  
Thiol Group ◽  
General Acid ◽  
Amide Hydrolysis ◽  
Acid Catalyzed

Intramolecular nucleophilic participation by the thiol group during amide hydrolysis. Part 2. The imidazole catalysis dilemma

1992 ◽  
Vol 70 (1) ◽  
pp. 62-67 ◽  
Author(s):  
Robert S. McDonald ◽  
Patricia Patterson ◽  
June Rodwell ◽  
Ann Whalley
Keyword(s):  
Aqueous Solution ◽  
Thiol Group ◽  
Tetrahedral Intermediate ◽  
General Base ◽  
General Acid ◽  
Amide Hydrolysis ◽  
Acid Catalyzed ◽  
Rate Limiting ◽  
Imidazole Catalysis

Catalysis by imidazole and N-methylimidazole buffers of the intramolecular thiolysis of N-n-propyl 2-mercaptomethylbenzamide (forming 2-thiophthalide) has been studied in aqueous solution at 40.0 °C, μ = 1.0. Unlike other buffers previously studied, imidazole and N-methylimidazole are able to catalyze, by a general base route, formation of neutral tetrahedral intermediate; this pathway is rate limiting at pH ≤ 7.5. At higher pH, the previously reported general acid-catalyzed breakdown of this intermediate is rate limiting. The relevance of these observations to the currently accepted pathway for the acylation of papain by amide substrates is discussed. Keywords: amide hydrolysis, intramolecular, thiol participation, imidazole, papain model.

The nature of the steric effect in the general-acid-catalyzed hydrolyses of benzaldehyde acetals

1983 ◽  
Vol 48 (23) ◽  
pp. 4175-4179 ◽  
Author(s):  
James L. Jensen ◽  
Anna B. Martinez ◽  
Cheryl L. Shimazu
Keyword(s):  
Steric Effect ◽  
General Acid ◽  
Acid Catalyzed

Deuterium exchange of C-methyl protons in lumazine derivatives

1970 ◽  
Vol 48 (2) ◽  
pp. 263-270 ◽  
Author(s):  
J. M. McAndless ◽  
Ross Stewart
Keyword(s):  
Proton Magnetic Resonance ◽  
Proton Magnetic Resonance Spectroscopy ◽  
Acid Catalysis ◽  
Deuterium Exchange ◽  
Base Catalysis ◽  
Resonance Spectroscopy ◽  
Methyl Group ◽  
General Base ◽  
General Acid ◽  
Acid Catalyzed

Proton magnetic resonance spectroscopy has been used to examine the deuterium exchange of the methyl protons in two lumazine derivatives. The exchange occurs at the C-7 methyl group in 6,7,8-trimethyllumazine (2) and at the C-6 methyl group in 1,7-dihydro-6,7,8-trimethyllumazine (3). The former reaction is subject to both general acid- and general base-catalysis but the latter only to general acid-catalysis. Plausible mechanisms for the reactions of both compounds are advanced, involving in the case of 3, acid-catalyzed addition of water across the C6—N5 double bond.

scholarly journals REDUCTION OF CARBONYL SUBSTRATES BY 3-CARBOXY-N-BENZYL-1,4-DIHYDROQUINOLINE: BIFUNCTIONALITY IN THE GENERAL-ACID CATALYZED NADH MODEL REDUCTION

1979 ◽  
Vol 8 (3) ◽  
pp. 229-232 ◽  
Author(s):  
Seiji Shinkai ◽  
Tetsuya Nakano ◽  
Hisatake Hamada ◽  
Yumiko Kusano ◽  
Osamu Manabe
Keyword(s):  
Model Reduction ◽  
General Acid ◽  
Acid Catalyzed
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