Synthesis of one-pot pyrazolo[4′,3′:5,6]pyrano[2,3-<i>c</i>]phenazin-15-yl) methanone derivatives <i>via</i> a multi-component using Fe₃O₄@TiO₂-SO₃H as a recoverable magnetic catalyst under microwave irradiation

A new one-pot method for the synthesis four-component of pyrazolo[4′,3′:5,6]pyrano[2,3-c]phenazin-15-yl)methanone derivatives has been developed in the presence of nano Fe₃O₄@TiO₂-SO₃H catalysts (heterogeneous acid) under microwave conditions and in a solvent-free environment at 180 W. One of the benefits of using this catalyst was its re-use in subsequent stages of its reaction without much loss in its activity, which was carried out by an external magnet and recovered. The catalyst was synthesized and characterized by XRD, EDX, TEM, FESEM, TGA-DTA, BET, VSM and AFM. The productivity of the products obtained from this protocol (MAOS) is significantly high and the shorter reaction time in the synthesis process over the reflux method. These results showed advantages for synthesis, such as mild reaction conditions, no use of toxic catalysts in the laboratory, solvent-free environment, low energy consumption and Economically Affordable.