Synthesis of pyranocoumarin and furocoumarin derivatives

In this chapter, we present the synthesis of new coumarine derivatives starting from the 8-acetyl-7-hydroxy-4-methylcoumarin and subsequently by the cyclisation of 7-hydroxy-4-methyl-8-(3-aryl acrolyl)-2H-chromen-2-ones. Another series of novel coumarin-chromene compounds have been synthesized using 8-aryl-4-methyl-8,9-dihydropyrano[2,3-f]chromene-2,10-diones and the Vilsmeier Haack reagent. Further, a novel series of 8-acetyl-4-methyl-9-styryl-2H-furo [2,3-h] chromen-2-ones have been synthesized by the cyclisation of 7-hydroxy-4-methyl-8-(3-aryl acrolyl)-2H-chromen-2-ones and chloroacetone. Other new series of 4-methyl-8-phenyl-pyrano[2,3-f] chromen-2,10-diones have been synthesized from 7-hydroxy-4-methyl-8-(3-aryl acrolyl)-2H-chromen-2-ones by using DMSO/I₂ as oxidation media. And one more new series of hybrid compounds, substituted 4-chloro-8-methyl-2-phenyl-1,5-dioxa-2H-phenanthren-6-one, have been synthesized from substituted (E)-1-(7-hydroxy-4-methyl-8-coumarinyl)-3-phenyl-2-propen-1-ones by employing the Vilsmeier-Haack reaction, by conventional and microwave-assisted method.