| abstract |
Naphtholactam trimethine dyes of the formula in the R¹, R², R³ and R⁴ are the same or different and are each independently C₁-C₂₂-alkyl, which is optionally substituted and / or interrupted by one or more oxygen atoms, one or more imino groups or one or more C₁-C₄-alkylimino groups, if appropriate are substituted C₅-C₇-cycloalkyl or optionally substituted phenyl and the rings A, B, C and D are optionally substituted and / or benzo-fused, and optical recording medium containing the new dyes. |