Turkish Journal of Chemistry
Abstract
This study demonstrated the kinetics of nucleophilic substitution reactions of butyl methyl chlorophosphate (2) with X-anilines (XC$_{6}$H$_{4}$NH$_{2})$ and deuterated X-anilines (XC$_{6}$H$_{4}$ND$_{2})$ in MeCN at 55.0 \textpm\ 0.1 \textdegree C together with the general optimized method for the synthesis of 2 under mild conditions. Different spectroscopic characterizations revealed the formation of 2 with high purity. The free energy relationship with the substituents X in the anilines exhibited biphasic concavity upwards with a break point at X $=$ H, which induced large negative $\rho_{X}$ and small positive $\beta_{X}$ values. The deuterium kinetic isotope effects (DKIEs) were secondary inverse ($k_{H}$/$k_{D}$ \textless\ 1: 0.702--0.918) and the magnitudes were increased with the change of nucleophiles from weakly basic to strongly basic anilines. A concerted mechanism with a rate-limiting leaving group departing from the intermediate is proposed based on the selectivity parameters and the variation of DKIEs with X.
DOI
10.3906/kim-1807-123
Keywords
Phosphoryl transfer reaction, concerted mechanism, butyl methyl chlorophosphate, Hammett and Br{\o}nsted constants, deuterium kinetic isotope effects
First Page
501
Last Page
510
Recommended Citation
BARAI, HASI RANI; RAHMAN, MD. MAHBUBUR; and JOO, SANG WOO
(2019)
"Synthesis, kinetic study, and reaction mechanism: nucleophilic substitution reactions of butyl methyl chlorophosphate with substituted anilines and deuterated substituted anilines in acetonitrile,"
Turkish Journal of Chemistry: Vol. 43:
No.
2, Article 11.
https://doi.org/10.3906/kim-1807-123
Available at:
https://journals.tubitak.gov.tr/chem/vol43/iss2/11