An Efficient, Eco-Friendly Synthesis of Pyran Annulated Indole Analogs under Conventional Heating and Microwave Irradiation, and Their Anticancer and Antioxidant Activity

Abstract

A rapid, facile, green, eco-friendly, cost effective, and efficient method for the synthesis of pyran annulated indole analogs via one-pot, three components reaction is developed. According to the developed method 2,5-disubstituted-1H-indol-3-carboxaldehyde, malononitrile and various phenols react under MW assisted solvent-free conditions. These compounds can be also prepared under a conventional method that is characterized by some disadvantages in comparison with the above approach. Structures of products are confirmed by FT-IR, ¹H and ¹³C NMR, and mass spectral data. The in vitro antioxidant and cytotoxic activities of the products are evaluated against three tumor cell lines and discussed in terms of structure―activity analysis. Among the screened compounds 3d, 4a, 4b, 5a, and 5b exhibit excellent antioxidant activity. Compounds 4b, 5a, and 5b demonstrate strong cytotoxic activity.