4058-71-3Relevant articles and documents
Reactive Oxygen Species-Triggered Tunable Hydrogen Sulfide Release
Chauhan, Preeti,Jos, Swetha,Chakrapani, Harinath
supporting information, p. 3766 - 3770 (2018/07/21)
A series of carbamothioates with tunable release of H2S after activation by reactive oxygen species are reported. The half-lives of H2S release could be tuned from 24 to 203 min by varying the basicity of the amine.
Anilinolysis of reactive aryl 2,4-dinitrophenyl carbonates: Kinetics and mechanism
Castro, Enrique A.,Domecq, Claudia,Santos, Jose G.
supporting information; experimental part, p. 191 - 197 (2011/10/04)
The reactions of a series of anilines with phenyl 2,4-dinitrophenyl (1), 4-nitrophenyl 2,4-dinitrophenyl (2), and bis(2,4-dinitrophenyl) (3) carbonates are subjected to a kinetic investigation in 44 wt% ethanol-water, at 25.0 ± 0.1°C and an ionic strength of 0.2 M. Under amine excess pseudo-first-order rate coefficients (kobs) are obtained. Plots of kobs against free amine concentration at constant pH are linear, with slopes kN. The BrAnsted plots (log kN vs. anilinium pKa) for the anilinolysis of 1-3 are linear, with slope (β) values of 0.52, 0.61, and 0.63, respectively. The values of these slopes and other considerations suggest that these reactions are ruled by a concerted mechanism. For these reactions, the kN values follow the reactivity sequence: 3 > 2 > 1. Namely, the reactivity increases as the number of nitro groups attached to the nonleaving group increases. Comparison of the reactions of this work with the stepwise pyridinolysis of carbonates 1-3 indicates that the zwitterionic tetrahedral intermediate (T±) formed in the pyridinolysis reactions is destabilized by the change of its pyridino moiety by an isobasic anilino group. This is attributed to the superior leaving ability from the T± intermediate of anilines, relative to isobasic pyridines, which destabilize kinetically this intermediate. The kN values for the anilinolysis of carbonates 1-3 are similar to those found in the reactions of these carbonates with secondary alicyclic amines. With the kinetic data for the anilinolysis of the title substrates and 4-methylphenyl and 4-chlorophenyl 2,4-dinitrophenyl carbonates, a multiparametric equation is derived for log kN as a function of the pKa of the conjugate acids of anilines and nonleaving groups.
Kinetics and mechanism of the anilinolysis of aryl 4-nitrophenyl carbonates in aqueous ethanol
Castro, Enrique A.,Gazitua, Marcela,Santos, Jose G.
, p. 8088 - 8092 (2007/10/03)
The reactions of anilines with 4-nitrophenyl, 4-methylphenyl, and 4-chlorophenyl 4-nitrophenyl carbonates (BNPC, MPNPC and ClPNPC, respectively) are studied kinetically in 44 wt % ethanol-water, at 25.0 °C, with an ionic strength of 0.2 M (KCl). Plots of kobsd vs [amine] are linear, with the slopes (kN) independent of pH. The Bronsted-type plots (log kN vs pKa of conjugate acids of anilines) are linear, with slopes β = 0.65, 0.85, and 0.78 for the reactions of anilines with BNPC, MPNPC, and ClPNPC, respectively. The values of the slopes for the two latter reactions are in accordance with those obtained in stepwise mechanism where breakdown to product of a zwitterionic tetrahedral intermediate is the rate-determining step. On the other hand, the β value for the reactions of BNPC is at the upper limit of those found for concerted mechanisms. The kinetic results for the reactions of anilines with BNPC correlates well with those for the concerted reactions of the same amines with 4-methylphenyl and 4-chlorophenyl 2,4-dinitrophenyl carbonates: A plot of the calculated log k N values (through a multiple parametric equation) vs the experimental log kN values is linear with unity slope and zero intercept, which confirms the concerted mechanism for the latter three reactions.
