Synthesis and antioxidant activity of 14-Aryl-14H-dibenzo[a,j] xanthene’s and bis(3-hydroxy-5,5′-dimethyl-2-cyclohexene-1-ones) derivatives using silica-tungstosulfonic acid catalyst

The synthesis of biologically active benzoxanthene, and bis(3-hydroxy-5,5’-dimethyl-2-cyclohexene-1-ones) derivatives has been conducted under an environmentally benign method by using an efficient catalyst, silica-tungstosulphonic acid. The benefits of this catalyst include being safe for the environment, low-cost, and simple to construct. It produces good yields and high purity in a short time and facilitates easy cleansing, products are obtained by straightforward recrystallization without the need for column chromatography. The reagent retained its catalytic activity for at least five consecutive cycles of reuse. The catalyst is described by IR, XRD, and SEM-EDX, which clearly shows that sulfonation happens in silica tungstic acid. In addition, the targeted derivatives were studied for anti-oxidant properties such as DPPH, reducing power assay, and H₂O₂ scavenging activity. The synthesized products such as 3e, 5k, 5 m, 5o, and 5p showed good anti-oxidant properties. Among all of these compounds, 5p showed good activity due to the nitro substitution on the benzene ring.