Palladium-catalysed amination of bromofluorans and an investigation of their thermochromic behaviour

The palladium-catalysed amination of readily accessible bromofluorans and bromobenzo[a]fluorans has been accomplished with a series of anilines and morpholine. The resulting aminofluorans generated intense black shades upon formulation in methyl stearate containing bisphenol A. The route provides an alternative approach to various amino substituted fluorans without the need of a series of individual diphenylamine intermediates.

► Synthesis of novel bromofluorans and bromobenzo[a]fluorans.
► Palladium-catalysed amination of bromofluorans and bromobenzo[a]fluorans.
► Alternative route to black developing colour formers from common readily accessible starting materials.