Green Chemical Synthesis and Analgesic Activity of Fluorinated Thiazolidinone, Pyrazolidinone, and Dioxanedione Derivatives

Facile lemon juice catalyzed green and efficient synthesis of a series of new classes of 5-(fluorinatedbenzylidene)-2-thioxo-1,3-thiazolidin-4-ones (3a–e), 5-methyl-4-(fluorinatedbenzylidene)-2-phenylpyrazolidin-3-ones (5a–e), and 2,2-dimethyl-5-(fluorinatedbenzylidene)-1,3-dioxane-4,6-diones (7a–e) by the reaction of fluorinated aromatic aldehydes with active methylene compounds is reported. Lemon juice is natural acid catalyst which is readily available, cheap, nontoxic, and ecofriendly. This method is experimentally simple, clean, high yielding, green, and with reduced reaction times. The product is purified by simple filtration followed by washing with water and drying process. Some of the synthesized compounds have been evaluated “in vivo” for their analgesic activity and all the synthesized compounds are characterized by IR, 1H NMR, 13C NMR, 19F NMR, and mass spectral studies.