Fused-Fluoran Leuco Dyes with Large Color-Change Derived from Two-Step Equilibrium: Iso-Aminobenzopyranoxanthenes

Yoshinao Shirasaki, Yuta Okamoto, Atsuya Muranaka, Shinichiro Kamino, Daisuke Sawada, Daisuke Hashizume, Masanobu Uchiyama

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Fluorans are popular leuco dyes that are used in various applications, such as carbonless-copy papers and thermal papers. Here, we describe unique leuco dyes in which two fluoran units are fused into a C2h structure (iso-aminobenzopyranoxanthenes; iso-ABPXs). iso-ABPXs exhibited a large two-step color change (colorless/pink and pink/blue-green) due to opening-closing of two spirolactone rings. The two-step equilibrium among the colorless, pink, and blue-green forms could be well controlled by adjusting acid concentration, solvent, and/or temperature.

Original languageEnglish
Pages (from-to)12046-12051
Number of pages6
JournalJournal of Organic Chemistry
Issue number23
Publication statusPublished - Dec 2 2016


ASJC Scopus subject areas

  • Organic Chemistry

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