Green Synthesis of Isoxazole Derivatives by a One-Pot Multicomponent Reaction and Their Antiviral Activity Evaluation

Abstract

A series of 4-substituted isoxazole derivatives were synthesized by a one-pot multicomponent reaction between aromatic aldehydes, ethyl acetoacetate, and hydroxylamine hydrochloride, with sulfonated rice straw ash (RSA-SO₃H) used as an acid catalyst. The synthesized compounds were characterized using IR and ¹H and ¹³C NMR spectroscopy and mass spectrometry. The antiviral activities of these derivatives were evaluated in vivo on Kufri Jyoti potato plants against the mechanically transmitted ssRNA Potato Virus Y (PVY), employing protective, simultaneous, and curative treatment approaches. Among the synthesized compounds, (4-(4-diethylamino)benzylidene)-3-methylisoxazol-5(4H)-one exhibited a significant antiviral activity, particularly in the protective treatment at a concentration of 250 µg/mL.