Synthesis, Photooxygenation, And Characterization Of New Angular Furoquinolinone Derivatives, A New Furocoumarin Bioisoster

Synthesis of angular furoquinolinone derivatives with a new skeleton structure was accomplished via Williamson reaction of hydroxyquinolinones with alpha-haloketones, such as 3-chloro-2-butanone and phenacyl bromide, followed by treatment with polyphosphoric acid (PPA). The synthesized angular furoquinolinones were photooxygenated in chloroform or dimethyl formamide and in the presence of tetraphenylporphyrin (TPP) as a singlet oxygen sensitizer (O-1(2)). The photooxygenation reactions furnished the photocleaved product through the [2 + 2] cycloaddition reaction. All photoproducts were isolated and fully characterized by spectral analyses.