Green synthesis of novel pyrazoline carbothioamides: A potent antimicrobial and antioxidant agents

Oxidative-stress induces inflammatory diseases caused by drug-resistant microbial stains are on the increase necessitating the invention of novel small-molecules for intervention therapy. In search of new small molecules of potent antioxidant properties, the current study was undertaken to synthesize pyrazoles and study their radical scavenging abilities. An efficient and accessible green protocol for the synthesis of thiophene-pyrazole hybrids through the 3 + 2 annulation, the reaction of chalcones 3(a-k) with thiosemicarbazide hydrochloride 4 in freshly prepared aqueous citrus extract medium produced the thiophene tethered pyrazoline carbothioamides 5(a-k) in good yields. Structure proofs of new pyrazoles provided by spectroscopic studies and elemental analysis. Furthermore, preliminary assessment of the antimicrobial, DPPH, and hydroxyl radical scavenging activities of the compounds shows that, compounds 5c and 5k have excellent antimicrobial activities, and 5a, 5b, 5c, 5d, 5g, and 5k exhibited excellent DPPH, and hydroxyl radical scavenging abilities