Development of new quinoline-based photo-labile groups for photo-regulation of bioactive molecules

A series of quinoline-based photo-removable protecting (caging) groups were synthesized for the development of new chemical tools to photo-regulate bioactive molecules in living cells and tissues with improved properties. Compared with the recently developed 8-bromo-7-hydroxyquinolinyl (BHQ) chromophore, change of the bromine substituent to a pyridine group led to a new photo-labile group (3′-PyHQ) with an increased water solubility, a lower self-fluorescence, and a higher photolysis efficiency. It was proposed that the replacement of a halogen group by a pyridine-like heterocycle may provide a general strategy to improve the existing photo-caging groups.