Fused-Fluoran Leuco Dyes with Large Color-Change Derived from Two-Step Equilibrium: iso-Aminobenzopyranoxanthenes
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- 作者：Yoshinao Shirasaki ; Yuta Okamoto ; Atsuya Muranaka ; Shinichiro Kamino ; Daisuke Sawada ; Daisuke Hashizume ; Masanobu Uchiyama
- 刊名：Journal of Organic Chemistry
- 出版年：2016
- 出版时间：December 2, 2016
- 年：2016
- 卷：81
- 期：23
- 页码：12046-12051
- 全文大小：411K
- ISSN：1520-6904
文摘
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.