Synthesis of pyrano isoxazoline/isoxazole annulated coumarins via intramolecular nitrile oxide cycloaddition and their cytotoxicity

Abstract

An efficient and straight forward procedure for the syntheses of isoxazoline/isoxazole fused coumarin analogues 7a–7g and 8a–8g from the corresponding 7-O-allyloxy coumarin oximes 5a–5g and 7-O-propargyloxy coumarin oximes 6a–6g is presented. High yields and simple experimental procedures are important features of this methodology. This method is useful for the construction of many biologically active fused heterocycles. The structures of synthesized compounds are established on the basis of IR, NMR, and MS data. The products were tested for in vitro cytotoxic activity against three human cancer cell lines. All tested compounds demonstrated high cytotoxic activity.