Synthesis and Photooxygenation of Linear and Angular Furocoumarin Derivatives as a Hydroxyl Radical Source: Psoralen, Pseudopsoralen, Isopseudopsoralen, and Allopsoralen

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 (1 O 2). The photooxygenation reactions