Synthesis of polycyclic oxa-coumarins, potential antitumour agents and a short and convenient synthesis of naphthopyranoquinolines from naphthopyran chloroaldehydes.
A new chromenoquinoline-based fluorescent offâonthiol probe 2 is reported. In aqueous buffer solutions at physiological pH, the probe exhibited 223-fold enhancement in fluorescence intensity by a Michael addition of cysteine to the maleimide appended to a chromenoquinoline. Cell permeability and live cell imaging of thiols are also demonstrated.