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

RS McDonald, P Patterson, J Rodwell…

Index: McDonald, Robert S.; Patterson, Patricia; Rodwell, June; Whalley, Ann Canadian Journal of Chemistry, 1992 , vol. 70, # 1 p. 62 - 67

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Abstract

Catalysis by imidazole and N-methylimidazole buffers of the intramolecular thiolysis of Nn- 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 ...