Synthesis, Structure and Biological Activities of Novel 2‐(Trifluoromethyl)‐ 6‐arylimidazo[2,1‐ b ][1,3,4]‐thiadiazole (bis‐)Mannich Base Derivatives Containing Substitutedpiperazine Moiety

A convenient and practicable method for the synthesis of the novel 2‐(trifluoromethyl)‐6‐arylimidazo[2,1‐ b ][1,3,4]‐thiadiazole (bis‐)Mannich base derivatives containing various substitutedpiperazine motif has been developed based on the fused‐heterocycle intermediate. The new structures were identified through melting points, 1 H NMR, 13 C NMR, 19 F NMR, elemental analysis (or HRMS) and X‐ray single‐crystal diffraction. The pesticidal bioassays showed that some of compounds exhibited good fungicidal activities against Cercospora arachidicola , Physalospora piricola and Rhizoctonia cereali at 50 mg/L; some of them displayed favourable insecticidal activities against oriental armyworm ( Mythimna separata Walker) at 200 mg/L, particularly, Vk and Vm with mortality rate of 75% and 80% respectively, could be considered as new insecticidal lead compounds for further structural optimization.