Kinetic Studies of the Formation of Number of Spiropyrrolidine

The rate of reaction between Schiff bases (N-Benzylidene-4-Picolyamine) and its derivatives with Chalcone(2-benzylidine-1-tetralone) to form spiropyrrolidine have been studied in DMF. This study occurred in two steps: The first step involved following the formation of intermediate by Fluorescence. The study indicated a pseudo first order dependence with rates 3,4-Dimethoxy> p-OCH3 > p-CH3 > H > P-Cl > P-NO2 at any temperature (298-318 K). The effect of substituents on the rate showed that electronic factors, inductive, conjugative and steric factors play reasonable role on the stability of the intermediates. The second step involved the disappearance of intermediate (cyclization process) to form the final product (spiropyrrolidine). This step was followed by UV technique and indicated a first order dependence with rates P-NO2 > p-Cl > H > p-CH3 > p-OCH3 > 3,4-Dimethoxy. A suitable mechanism for this type of reaction, which is consistent with the results, has been postulated.