Fluorescence Properties of 6-Methoxy-4-p-toluenesulfonyl-carbostyrils and 6-Methoxy-4-p-toluenesulfonyloxy-carbostyrils

The research on fluorescent carbostyrils of the general type I has been going on in our work group for several years. In the course of these investigations we found that carbostyrils of type II having a 4-p-toluenesulfonyl group in position 4 - formed as not isolated intermediates in many cases during our investigations of strongly fluorescent 4-cyano-carbostyrils - showed surprisingly strong fluorescence: they exhibit long-wave absorption and fluorescence properties, and high quantum yields. These findings prompted us to investigate the synthesis and luminescence properties of 4-p-toluenesulfonyl-carbostyrils of type II dependent on the nature of substituents in position 3. In this contribution new types of the acceptor group in position 4 such as toluenesulfonyl and toluenesulfonyloxy groups are investigated, which were in earlier investigations applied as intermediates for e.g. strong fluorescent cyano-carbostyrils. Observations during the reaction sequences revealed that they have already similar strong fluorescence properties as the desired target molecules.