Synthesis of quinazolinone-1,3,4-oxadiazole conjugates and studies of their antibacterial and antioxidant activity

Daina Zicane, Zenta Tetere, In

Abstract

Quinazolinone - 1,3,4-oxadiazole conjugates were obtained from the mixed hydrazides of (hetero)aromatic carboxylic acids and 3-[4-oxoquinazolin-3(4H)-yl]propanoic acid. The latter was synthesized from isatoic anhydride, β-alanine and formic acid. Antimicrobial and antioxidant activities of the synthesized compounds were studied. Although the newly obtained compounds did not demonstrate significant antimicrobial activity, several substances containing hydrazide moiety in the side chain at C-3 showed promising antiradical activity. Several of the observed antiradical activities against frequently used standards of free radicals 2,2-diphenyl-1-picrylhidrazyl and galvinoxyl were comparable with those of well known antioxidant butylated hydroxytoluene. Interestingly, transformation of hydrazides into oxadiazoles caused dramatic loss of antiradical activity. The obtained mixed hydrazides represent an unexplored class of antioxidants, in which the hydrazide moiety is crucial for the antiradical activity.