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Kinetic study of nitrosation of guanidines
Author(s) -
Fernández I.,
Hervés P.,
Parajó M.
Publication year - 2008
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.1380
Subject(s) - chemistry , nitrosation , computational chemistry , organic chemistry , combinatorial chemistry
The kinetics of the nitrosation reaction of three guanidines, dicyandiamide, N , N′ ‐dimethyl‐ N ″‐cyanoguanidine and guanidine have been studied. The nitrosation rate is first order with respect to both the guanidine and acid concentration. The absence of catalysis by nucleophilic anions, the observed general acid–base catalysis and the observed deuterium isotope effect lead us to propose mechanism for the nitrosation of guanidines similar to that which operates in the case of the amides and ureas, in which a slow proton transfer is the rate determining step. From this mechanism we were able to obtain the values of the rate constants for the nitrosation and denitrosation processes. The catalytic constants in presence of buffers were also obtained and the analysis of the Brönsted slopes suggests a process with a transition state more similar to reactants than products. Copyright © 2008 John Wiley & Sons, Ltd.