Synthesis and Electronic Spectra of Some Monoazo Disperse Dyes Derived from N-Methylindoline

Several monoazo dyes suitable for transfer printing have been prepared from N-methylindoline and compared with the corresponding derivatives of N-methyl-1,2,3,4-tetrahydroquinoline (kairoline). The presence of a five-membered terminal ring system leads to diminished pi-interaction and results in modest hypsochromic and hypochromic shifts of the visible absorption band, relative to the analogous kairoline derivatives, together with some deterioration in lightfastness properties on synthetic-polymer fibres