Process for the manufacture of color formers of indoles and anhydrides of aromatic or heteroaromatic, vicinal dicarboxylic acids, new color formers of these classes of substance and their use

摘要

A process for the manufacture of color formers comprising reaction of 2 moles of an indole in the presence of a condensation agent with about 1 mole of an anhydride of the formula <IMAGE> wherein A is the residue of a benzene or naphthalene or of a heterocyclic ring, the new color formers obtained by reacting 2 moles of an indole with a halogen- or nitro-substituted phthalic anhydride, or the anhydride of a vicinal naphthalene pyridine or quinoline dicarboxylic acid, the new 3,3-bis-(indol-3-yl)-phthalides substituted at the nitrogen atom with aralkyl or alkyl with 6 to 18 carbon atoms or alkenyl radicals with 3 to 18 carbon atoms or substituted alkyl or alkylene groups with 1 to 18 and 3 to 18 carbon atoms respectively and pressure sensitive recording paper containing at least one of the new color formers.