ISSN print edition: 0366-6352
ISSN electronic edition: 1336-9075
Registr. No.: MK SR 9/7
Kinetics of cyclization of N-substituted 1-(2-nitrophenyl)-guanidines and mechanism of the cyclization reactions
P. Pazdera and M. Potáček
Department of Organic Chemistry, Faculty of Natural Sciences,
J. E. Purkyně University, CS-611 37 Brno
Abstract: Kinetic measurements of cyclization of 3-ethyl-l-(2-nitrophenyl)guanidine and 2-phenyl-l-(2-nitrophenyl)guanidine to 3-ethyl- and 3-phenylamino-l,2,4-benzotriazine 1-oxide were carried out in dependence on pH
of the reaction medium by spectrophotometry.
The rate constants kI calculated for the unimolecular order of the reaction were proved to be linearly dependent on pH of the medium. Also the
rate constants kIIfor the bimolecular order of the reaction were calculated.
From the results of this kinetic study and the published experimental
findings about the properties of 2-nitrophenylguanidines and their cyclization to substituted 3-amino-l,2,4-benzotriazine 1-oxides the mechanism of
this base-catalyzed reaction was proposed.
Full paper in Portable Document Format: 442a241.pdf
Chemical Papers 44 (2) 241–248 (1990)