Synthesis and characterization of chromogenic fluoran compounds containing 4-keto-quinazolinone moieties

Chromogenic fluoran compounds containing 4-ketoquinazolinone were synthesized by reacting 2-(4-diethylamino-2-hydroxybenzoyl)benzoic acid with various substituted 4-ketoquinazolinones in the presence of sulfuric acid. The 4-ketoquinazolinones were obtained by reacting various substituted benzoxazin-4-ones with 4-aminophenol or 2-nitro-p-anisidine. All the synthesized derivatives were identified by conventional methods, such as melting points, elemental analysis, IR, H-1-NMR, and UV-visible spectroscopy in organic solvent and 95% acetic acid. All the fluoran compounds develop colour on contact with acidic or electron-accepting compounds.