Studies in the Synthesis of Coumarino-a-pyrones and Furocoumarins. Part IX: Synthesis of 2-Methyl-4-oxo-4H-furo (3,2-c) benzopyrans

4-Allyloxycoumarin derivatives (II), when subjected to Claisen rearrangement gave 2-methyl-2,3- dihydro-4-oxo-4H-furo(3,2-c)benzopyran derivatives (III). These on dehydrogenation with palladised charcoal (10%) afforded the corresponding 2-methyl-4-oxo-4H(3,2-c)benzopyran derivatives (IV)