Kinetic evidence for the formation of monocationic N,N'-Disubstituted Phthalamide in tertiary Amine-Catalyzed hydrolysis of N-Substituted Phthalimides

• Main Authors: Ariffin, Azhar, Khan, M.N., Sim, Y.L.
• Format: Article
• Published: 2007
• Subjects: QD Chemistry
• Online Access: http://eprints.um.edu.my/8052/; http://pubs.acs.org/doi/pdfplus/10.1021/jo701295n

A kinetic study on the aqueous cleavage of N-(2-methoxyphenyl)phthalimide (1) and N-(2-hydroxyphenyl)-phthalimide (2), under the buffers of N-methylmorphohne, reveals the equilibrium presence of monocationic amide (Ctam) formed due to nucleophilic reactions of N-methylmorpholine with 1 and 2. Pseudo-first-order rate constants for the reactions of water and HO- with Ctam (formed through nucleophilic reaction of N-methylmorpholine with 1) are 4.60 x 10(-5) s(-1) and 47.9 M-1 s(-1), respectively. But the cleavage of Ctam, formed through nucleophilic reaction of N-methylmorpholine with 2, involves intramolecular general base (2(')-0(-) group of Ctam)-assisted water attack at carbonyl carbon of cationic amide group of Ctam in or before the rate-determining step.