Abstract
Synthesis of linear and angular furocoumarins with new skeleton structure of potential photobiological feature interest was carried out through Williamson reaction of hydroxycoumarins with 3-chloro-2-butanone followed by cyclization with polyphosphoric acid or by heating in a strongly alkaline solution. The photooxygenation reactions of synthesized furocoumarins were performed in chloroform and in the presence of tetraphenylporphyrin as singlet oxygen sensitizer (O-1(2)). The photooxygenation reactions afforded the photocleaved product through [2+2] cycloaddition and the photooxygenated products through ene reaction and [4+2] cycloaddition. The photoproducts were isolated and fully characterized by spectral analyses.