Synthesis and acid-base properties of bifunctional compounds based on 2-styrylquinoline and 6-hydroxynaphthalene-2-carboxylic acid

Abstract

The reaction of 6-hydroxynaphthalene-2-carboxylic acid with 2-{(E)-2-[4-(ω-bromoalkoxy)phenyl]-ethenyl}quinolines gave ω-{4-[(E)-2-(quinolin-2-yl)ethenyl]phenoxy}alkyl 6-hydroxynaphthalene-2-carboxylates possessing both photoacid and photobase properties. The acidities of the naphthol fragment in the ground (pK a ) and singlet excited states (pK a *) of 3-{4-[(E)-2-(quinolin-2-yl)ethenyl]phenoxy}propyl 6-hydroxynaphthalene-2-carboxylate are pK a 9.0 and pK a * 2.4, and of the quinoline fragment, pK a 4.6, pK a * 12.6, respectively.