TY - JOUR
T1 - Kinetic studies of solvent and pressure effects on thermal isomerizations of N‐phenyl‐ and N‐methylrhodaminelactams
AU - Sueishi, Yoshimi
AU - Sugiyama, Yukie
AU - Yamamoto, Shunzo
AU - Nishimura, Norio
PY - 1993
Y1 - 1993
N2 - Solvent and pressure effects were examined for the isomerization rates of N‐phenyl‐ and N‐methylrhodaminelactams (RL‐Ph and RL‐CH3) from their zwitterionic to the spiro forms. From the pressure dependence of the reaction rate, the activation volumes were estimated to be about 5 cm3 mol−1 for RL‐Ph and 3–10 cm3 mol−1 for RL‐CH3. It is proposed that there are two rotameric isomers for the coloured zwitterionic forms, and the role of these rotamers in the kinetic effects of solvent and pressure is discussed. The results are consistent with a reaction mechanism involving heterolytic ring closure on activation.
AB - Solvent and pressure effects were examined for the isomerization rates of N‐phenyl‐ and N‐methylrhodaminelactams (RL‐Ph and RL‐CH3) from their zwitterionic to the spiro forms. From the pressure dependence of the reaction rate, the activation volumes were estimated to be about 5 cm3 mol−1 for RL‐Ph and 3–10 cm3 mol−1 for RL‐CH3. It is proposed that there are two rotameric isomers for the coloured zwitterionic forms, and the role of these rotamers in the kinetic effects of solvent and pressure is discussed. The results are consistent with a reaction mechanism involving heterolytic ring closure on activation.
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U2 - 10.1002/poc.610060806
DO - 10.1002/poc.610060806
M3 - Article
AN - SCOPUS:84985454695
SN - 0894-3230
VL - 6
SP - 478
EP - 482
JO - Journal of Physical Organic Chemistry
JF - Journal of Physical Organic Chemistry
IS - 8
ER -