Ketohydrazone dyes derived from 4-morpholino-2-naphthol and ortho-substituted anilines: Further examination of the hyperchromism induced by the 4-morpholino-2-naphthol moiety

A series of ketohydrazone dyes has been synthesised from 4-morpholino-2-naphthol and ortho -substituted anilines by conventional diazotisation coupling chemistry. Whilst the new, dull orange-red, exhibit only a minor variation absorption maxima across range substituents, they are hyperchromic relative to Sudan 1 their none analogue. Protonation selected dye examples results in bathochromic shift afford vibrant purple-coloured protonated species. • new have synthesised. The orange shades with narrow maxima. more intense colouring (hyperchromic) non-ortho substituted λ max .