摘要 |
Compounds of the formula <IMAGE> wherein R1 is hydrogen, chlorine, phenyl, dialkylamino of 2-4 carbon atoms or alkyl or alkoxy each of up to 18 carbon atoms; R2 is hydrogen, chlorine, bromine or alkyl or alkoxy each of up to 4 carbon atoms; R3 and R4, which can be the same or different, each is hydrogen or alkyl of up to 6 carbon atoms; R5 is hydrogen or alkyl or alkanoyl each of up to 4 carbon atoms; and R6 is hydrogen or methyl, with the proviso that not all of R1 to R6 simultaneously are hydrogen, are effective photosensitizers, especially for photopolymerization of unsaturated compounds and for hardening of printing dyes. |