Synthesis and Electronic Spectra of Some Disperse Dyes Derived from 9-Phenylazo-1-ketojulolidine

Several monoazo dyes have been prepared from 1-ketojulolidine and compared with their julolidine counterparts. The presence of a carbonyl group in the terminal bridging system leads to improved light fastness properties on synthetic-polymer fibres, but also to an essentially constant hypsochromic shift (70 nm) of the first absorption band. The azojulolidine dyes exhibit a marked negative halochromism. Unlike the parent julolidine dyes, the ketojulolidine disperse dyes are not suitable for transfer printing