Efficient Rate Enhancement Due to Intramolecular General Base (IGB) Assistance in the Hydrolysis of N-(o-Hydroxyphenyl)phthalimide

Abstract

The rates of the hydrolyses of N-(o-hydroxyphenyl)phthalimide (1) and N-(o-methoxyphenyl)phthalimide (2), studied at different pH, show that the hydrolysis of 1 involves intramolecular general base (IGB) assistance where the o-O- group of ionized 1 acts as IGB and H2O as the reactant. The rate enhancement due to the IGB-assisted reaction of H2O with ionized 1 is>8x10(4)-fold. Pseudo-first-order rate constant for the reaction of water with 2 is approximately 2x10(3)-fold smaller than the first-order rate constant (0.10 s-1) for pH-independent hydrolysis of 1 within the pH range of 9.60-10.10. Second-order rate constants (kOH) for hydroxide ion-assisted hydrolysis of ionized 1 and 2 are 3.0 and 29.1 M-1 s-1, respectively. The solvent deuterium kinetic isotope effect (dKIE) on the rate of alkaline hydrolysis of 1 and 2 reveals that the respective values of kOH/kOD are 0.84 and 0.78, where kOD represents the second-order rate constant for DO--assisted cleavage of these imides (1 and 2). The value of kwH2O/kdD2O is 2.04, with kwH2O and kdD2O representing pseudo-first-order rate constants for the reactions of ionized 1 with H2O and D2O, respectively.

Effects of nonionic micelles on the rate of alkaline hydrolysis of N-(2′-methoxyphenyl)phthalimide (1): Kinetic and rheometric evidence for a transition from spherical to rodlike micelles under the typical reaction conditions

“…The rate of hydrolysis of 1, studied within [NaOH] ranging from 2.0 to 5.0 mM at constant ionic strength of 1.0 M (by NaCl) in the absence of micelles, obeys the following rate law [19] Rate ¼ k OH ½HO À ½1 ð 2Þ…”

“…Synthesis of 1 has been reported earlier [19], while all other chemicals used were commercial products of highest available purity. Stock solutions of 1 (0.005 M and 0.01 M) were prepared in acetonitrile.…”

Kinetics and mechanism of tertiary amine‐catalyzed cleavage of N′‐morpholino‐N‐(2′‐methoxyphenyl)phthalamide: Kinetic evidence for the presence of a reactive intermediate on the reaction path

“…(a) The values of δ 2 and δ 3 at 290 nm are 2200 [12] and 5530 [12] M −1 cm −1 , respectively. These results coupled with the spectrophotometric detection of 2 in the cleavage of 1 at ≥0.005 M HCl [10] encouraged us to carry out a kinetic run on the cleavage of 1 at near neutral pH with a hope to detect spectrophotometrically the probable intermediacy of 2 through a minimum in the plot of Abs versus t at 290 nm.…”

First Synthesis of Bi‐ and Tricyclic α,β‐Unsaturated δ‐Oxacaprolactams from Cyclic Imines via Ring‐Closing Metathesis

“…82-83°C. [21] A mixture of 2-aminophenol (4.80 g, 44.00 mmol) and phthalic anhydride (6.52 g, 44.00 mmol) in acetic acid (100 mL) was refluxed for two hours and put in cooled water. The suspension was filtered and the aqueous filtrate was extracted with chloroform.…”

“…187-230°C (238-240°C). [21] 2-[2-(1,3-Dioxo-1,3-dihydroisoindole-2-yl)phenoxy]-2-methylpropionaldehyde (5): A solution of dione 4 (1.19 g, 5.00 mmol) in anhydrous acetonitrile (50 mL) was cooled to 0°C. tBuOK (0.62 g, 5.55 mmol) was added in small amounts and stirred, while the reaction mixture was warmed up to room temperature.…”