5309-92-2Relevant academic research and scientific papers
Kinetics and Mechanism of the Aminolysis of Phenyl Thionoacetate in Aqueous Solution
Castro, Enrique A.,Ibanez, Fernando,Santos, Jose G.,Ureta, Carmen
, p. 4908 - 4912 (2007/10/02)
The reactions of a series of secondary alicyclic amines with the title substrate have been subjected to a kinetic study in water at 25 deg C, ionic strength 0.2 M.Pseudo-first-order rate coefficients (kobsd) are found throughout, under amine ex
Kinetics and Mechanism of the Aminolysis of 4-Nitrophenyl Dithioacetate
Castro, Enrique A.,Ibanez, Fernando,Santos, Jose G.,Ureta, Carmen
, p. 7024 - 7028 (2007/10/02)
The reaction of the title substrate with a series of secondary alicyclic amines has been the subject of a kinetic study in aqueous solution, 25 deg C, ionic strength 0.2 M (KCl).With the amine in excess, pseudo-first-order rate constants (k(obsd)) are observed.The order in amine varies from 1 to 2 depending on the basicity of the amine and reaction conditions.A reaction scheme is deduced on the basis of the existence of zwitterionic (T(+/-)) and anionic (T(-)) tetrahedral intermediates.Proton transfer from T(+/-) to an amine or base (to yield T(-)) seems to compete with 4-nitrothiophenoxide (NPS(-)) expulsion from T(+/-).The pKa of T(+/-) and all the rate microconstants of the scheme are estimated.The rates of expulsion of NPS(-) and amine from T(+/-) are smaller than those from analogous T(+/-) formed in the aminolyses of O-ethyl S-(4-nitrophenyl)dithiocarbonate and 4-nitrophenyl thiolacetate.It is claimed that substitution of Me by RO (R = alkyl) or S(-) by O(-) in T(+/-) destablizes this intermediate.
