Aromatic Nucleophilic Substitution. XV Stopped-flow Kinetics of the Formation and Decomposition of 1,3- and 1,1-Disubstituted Meisenheimer Complexes in the Reactions of 1-Dialkylamino-2,4-dinitronaphtalenes with Potassium Methoxide in Dimethyl Sulfoxide-Methanol

Article abstract of DOI:10.1246/bcsj.54.3009

The formation of 1,3-disubstituted anionic ? complexes, followed by 1,1-disubstituted ones was confirmed by means of absorption and NMR spectra in the reactions of 1-dialkylamino-2,4-dinitronaphthalenes with potassium methoxide in DMSO-CH3OH.The rates and activation parameters were determined by kinetic studies with use of stopped-flow and conventional spectrophotometers.The rate constants for the formation of 1,3-disubstituted one decreased in the order 1-dimethylamino->1-(N-methylbutyl)amino->1-piperidino-1-diethylamino->-2,4-dinitronaphthalenes, those fot its decomposition being comparable with each other.On the other hand , the rate constant for the formation of 1,1-disubstituted one decreased in the some order as above while that for its decomposition decreased in the order 1-dimethylamino->1-(N-methylbutyl)amino->1-diethylamino->1-piperidino-2,4-dinitronaphthalenes.The mechanism was discussed from activation parameters.