Photoreorganization of 2-methyl-3-(prop-2-ynyloxy)-4H-chromen-4-ones: Synthesis of 4-methylcoumarin Derivatives

The coumarin derivatives have the anabolic, antioxidant, hepatoprotective, anticoagulant, HIV-proteases’ inhibitory, CNS depressant, hypnotics, sedative, diuretic, analgesic and antitubercular activities. In the present study, the synthesis of some 4-methylcoumarin derivatives in appreciably good yields has been achieved by the photo-irradiation of th e 2-methyl-3-(prop-2-ynyloxy)-4H-chromen-4-ones with pyrex filtered UV-light from 125W Hg lamp. The reaction is unprecedented and proceeded under mild and eco-friendly conditions within 60 minutes and may become an important tool for obtaining the 4-methylcoumarin derivatives. Keywords: Chromenones, coumarins, photo-irradiation, Norrish type-1 reaction, ring-opening /cyclization, γ-H abstraction.