Kinetics and Mechanism of the Cyclization of Methyl (2-Cyano-4,6-dinitrophenylsulfanyl)acetate Producing Methyl 3-Amino-5,7-dinitrobenzo[b]thiophene-2-carboxylate

摘要

Base-catalyzed ring closure of methyl (2-cyano-4,6-dinitrophenylsulfanyl)acetate produces methyl 3-amino-,5,7-dinitrobenzo[b]thiophene-2-carboxylate. This means that the carbanion initially formed attacks cyano group and not nitro group. The kinetics of this cyclization reaction has been studied in methanolic buffers of tert-amine/tert-ammonium chloride, and the reaction mechanism was suggested. The reaction is subject to general base catalysis. The found value of the Bronsted coefficient is p = 0.9 ± 0.1, which indicates a late transition state of the rate-limiting proton transfer.