Considering the highly important biological and medicinal properties of naphthofurans, the synthesis of these heterocycles has attracted the interest of medicinal and organic chemists. This review aims to describe the different strategies developed so far for the synthesis of naphthofurans and their applications and the literature reports for the period of 2000 to early 2020. After a brief introduction of the types of naphthofurans and their biological activities, the different synthetic approaches such as chemical and photochemical, methods are described and organized on the basis of the catalysts and the other reagents employed in the syntheses. Some of the reactions have been applied successfully to the synthesis of biologically important compounds.

Introduction: 2-Amino-7-hydroxy-4-phenyl-4H-chromene-3-carbonitrile (4) was synthesized through three-component reaction in ethanol/piperidine solution. Methods: Synthesis of several new 4H-chromenes (5-14) has been achieved involving various reactions. The structure of these new compounds was confirmed using IR, 1H NMR and 13C NMR, as well as MS spectroscopy. Results and Conclusion: All newly substituted chromene derivatives display potential analgesic and anticonvulsant activities. The structure activity relationship study revealed that 2-amino-4-phenyl-3-(1H-tetrazol-5-yl)-4H-chromen-7-ol (13) was more beneficial than 8-hydroxy-2-methyl-5-phenyl-3,5-dihydro-4H-chromeno[2,3-d]pyrimidin-4-one (11), 8-hydroxy-2,5-diphenyl-3,5-dihydro-4H-chromeno[2,3-d]pyrimidin-4-one (12), and 8-hydroxy-5-phenyl-3,5-dihydro-4H-chromeno[2,3-d]pyrimidin-4-one (14) for analgesic and anti-inflammatory activities.