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

Abstract 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,1H NMR,13C NMR,19F NMR, elemental analysis (or HRMS) and X‐ray single‐crystal diffraction. The pesticidal bioassays showed that some of compounds exhibited good fungicidal activities againstCercospora arachidicola,Physalospora piricolaandRhizoctonia cerealiat 50 mg/L; some of them displayed favourable insecticidal activities against oriental armyworm (Mythimna separataWalker) at 200 mg/L, particularly,VkandVmwith mortality rate of 75% and 80% respectively, could be considered as new insecticidal lead compounds for further structural optimization.