摘要 |
A chromenoindole compound of the formula <IMAGE> (1) wherein R1 and R2 independently of one another represent hydrogen, alkyl which has at most 12 carbon atoms and is unsubstituted or substituted by halogen, hydroxyl, cyano or lower alkoxy; cycloalkyl, phenyl, benzyl, or phenyl or benzyl which are substituted by halogen, lower alkyl or lower alkoxy, or R1 and R2, together with the nitrogen atom which links them, represent a 5-membered or 6-membered heterocyclic radical, Q is hydrogen, lower alkyl, phenyl, benzyl or the groups of the formulae (1a) or (1b) <IMAGE> X and X' each represent hydrogen, halogen, lower alkyl or lower alkoxy, Y represents hydrogen, alkyl of 1 to 12 carbon atoms, phenyl or benzyl and the rings A and B independently of one another are unsubstituted or substituted by halogen, nitro, lower alkyl, lower alkoxy, phenoxy, amino or amino substituted by lower alkyl, phenyl or benzyl; these compounds are particularly useful as colour formers which give intense red to blue colour shades of excellent light fastness when they are brought into contact with an electron acceptor. |