Kinetic studies of solvent and pressure effects on thermal isomerizations of N‐phenyl‐ and N‐methylrhodaminelactams

Yoshimi Sueishi, Yukie Sugiyama, Shunzo Yamamoto, Norio Nishimura

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)478-482
Number of pages5
JournalJournal of Physical Organic Chemistry
Volume6
Issue number8
DOIs
Publication statusPublished - 1993

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Organic Chemistry

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