Kinetic evidence for the formation of monocationic N,N'-disubstituted phthalamide in tertiary amine-catalyzed hydrolysis of N-substituted phthalimides.
A kinetic study on the aqueous cleavage of N-(2-methoxyphenyl)phthalimide (1) and N-(2-hydroxyphenyl)phthalimide (2), under the buffers of N-methylmorpholine, 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'-O- group of Ctam)-assisted water attack at carbonyl carbon of cationic amide group of Ctam in or before the rate-determining step.
Sim
Yoke-Leng
YL
Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia.
Ariffin
Azhar
A
Khan
M Niyaz
MN
D000588:Amines / Q000737:chemistry*; D002384:Catalysis; D002412:Cations / Q000138:chemical synthesis / Q000737:chemistry; D006868:Hydrolysis; D007700:Kinetics; D015394:Molecular Structure; D010797:Phthalimides / Q000138:chemical synthesis* / Q000737:chemistry; D014867:Water / Q000737:chemistry
D000588:Amines; D002412:Cations; D010797:Phthalimides; D014867:Water