Functionalized 3-(benzofuran-2-yl)-5-(4-methoxyphenyl)-4,5-dihydro-1H-pyrazole scaffolds: A new class of antimicrobials and antioxidants

A new class of functionalized 3-(benzofuran-2-yl)-5-(4-methoxyphenyl)-4,5-dihydro-1H-pyrazole scaffolds (4a–q) was synthesized by a four step reaction in good yields. Initially, o-alkyl derivative of salicyaldehyde (1) readily furnished corresponding 2-acetyl benzofuran (2) on treatment with potassium tert-butoxide (t-BuOK) in the presence of molecular sieves. Further, Claisen–Schmidt condensation reaction with 4-methoxy benzaldehyde and hydrazine hydrate followed by coupling of benzoyl chlorides afforded target compounds (4a–q). Representative of the synthesized compounds was characterized by IR, ¹H NMR, ¹³C NMR, mass, elemental analysis and evaluated for antimicrobial and antioxidant activities. The results gathered are allowed to conclude that, all newly synthesized analogues exhibit a certain degree of antimicrobial and antioxidant activities. Among the analogues, compounds (4h) and (4j) showed an excellent antimicrobial activity in the well plate method. Meanwhile, compounds (4e–f), (4l) and (4p) showed good antioxidant activity, whereas compound (4g) and (4q) displayed dominant antioxidant efficacy compared to standard butylated hydroxy anisole (BHA).