ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

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

M. Pešková, J. Hanusek, and V. Macháček

Department of Organic Chemistry, Faculty of Chemical Technology, University of Pardubice, CZ-532 10 Pardubice

E-mail: Marketa.Peskova@upce.cz

Received: 6 February 2003

Abstract: 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 Brønsted coefficient is β = 0.9 ± 0.1, which indicates a late transition state of the rate-limiting proton transfer.

Full paper in Portable Document Format: 582a133.pdf

Chemical Papers 58 (2) 133–138 (2004)