Tris(hydroxymethyl)aminomethane (THAM): A recyclable and biodegradable organobase catalyst for green synthesis of 2-amino-4H-chromenes in an aqueous ethanol media

We developed a green method to create 2-amino-4H-chromenes in an environmentally-friendly and efficient way. The process uses a domino Knoevenagel-Michael cyclocondensation reaction. Tris(hydroxymethyl)aminomethane (THAM) a recyclable and biodegradable organobase catalyst is used in an aqueous ethanol media, and the reaction is done at room temperature. Several criteria for sustainable and green chemistry are met by the current protocol's many benefits, which include being energy-efficient; reusable, affordable, and readily available precursor substances; operational simplicity; a suitable and quick procedure; high yields; green solvent; direct work-up without column chromatographic separation; and high atom-economy. In addition, the sustainable THAM stayed stable and could be used five times without reducing the catalytic activity, making it great for solving environmental issues and meeting industry needs.