Synthesis and Structure Elucidation of 2‐((1,2,3‐triazol‐4‐yl)‐1,3,4‐oxadiazol‐2‐yl)Thio)‐1‐arylethan‐1‐ones

ABSTRACT Several new 2‐(1,2,3‐triazol‐4‐yl)‐1,3,4‐oxadiazol‐2‐yl)thio)‐1‐arylethan‐1‐ones were synthesized in excellent yields using simple procedures. Reaction of 1‐(4‐fluorophenyl)‐5‐methyl‐1 H ‐1,2,3‐triazole‐4‐carbohydrazide ( 1 ) with carbon disulfide in ethanol and in the presence of potassium hydroxide at 0°C to room temperature for 6 h gave potassium 2‐(1‐(4‐fluorophenyl)‐5‐methyl‐1 H ‐1,2,3‐triazole‐4‐carbonyl)hydrazine‐1‐carbodithioate ( 2 ) as an intermediate. Subsequent in situ treatment of 2 with aqueous ethanol under reflux for 6 h, followed by neutralization with hydrochloric acid, gave 5‐(1‐(4‐fluorophenyl)‐5‐methyl‐1 H ‐1,2,3‐triazol‐4‐yl)‐1,3,4‐oxadiazole‐2‐thiol ( 3 ) in 70% yield. Reactions of thiol 3 with various phenacyl bromides 4 in ethanol in basic medium under reflux for 5 h gave the corresponding 2‐(1,2,3‐triazol‐4‐yl)‐1,3,4‐oxadiazol‐2‐yl)thio)‐1‐arylethan‐1‐ones 5a – f in 83%–88% yields. The structures of the newly synthesized heterocycles were elucidated using spectroscopic data and single‐crystal x‐ray structure determination. The intermolecular interactions in the crystal structures were explored.