Synthesis And Bioactivity Study Of Nitrogen-and Sulfur-containing Heterocompounds With Pyridine Ring

One hundred and thirty-five novel target compounds were synthesized and confirmed by 'H NMR, IR and HRMS. Their bioactivities were also determined.On the basis of the principle of bioisosterism and combination of active groups, sixteen novel 2-oxazolidinethione derivatives containing pyridine ring were designed and synthesized from (substituted)pyridine carboxylic acid via Grignard reaction, oximation, Neber rearrangement, reduction, cyclization, addition reaction, and so on. Some compounds exhibite good herbicidal activities against tested weeds. The aerial part and root inhibitory activity of compound I-f against Eclipta prostrasta reach 90% at 100 mg/L. The result of qualitative structure-activity relationship shows that the combination of appropriate steric property and proper lipophilicity is necessary for herbicidal activity.According to the principle of combination of active group, twenty-eight piperazine derivatives containing pyridinemethyl/thiazolemethyl were designed and synthesized from 2-chloro-5-(chloromethyl)pyridine or 2-chloro-5-(chloromethyl)thiazole via N-alkylation and addition reaction. Some compounds show weak herbicidal activity and insecticidal activity against bean alphid but good insecticidal activity against wiggler, among which compound IIB-f exhibited 100% mortality against wiggler at 50 mg/L.Four series of novel 2-phenyl-iminothiazolidine derivatives were prepared via N-alkylation, addition and cyclization, and so on from 2-chloro-5-(chloromethyl)pyridine, 2-chloro-5-(chloromethyl)thiazole, pyridine-3-carboxyaldehyde and pyridine-2-carboxyaldehyde, respectively. Some compounds exhibit good fungicidal and insecticidal activity. Especially, 3-pyridinemethyl-2-(substituted)phenyliminothiazolidine derivatives IIIC show high herbicidal activity. The results of quantitative structure-activity relationship show that the electronic parameter is the main factor toaffect the herbicidal activities.Two series of novel bis-2-phenyliminothiazolidine derivatives with different linkers were prepared from 2-phenyliminothiazolidine via N-alkylation with 2,6-bis-(chloromethyl)-pyridine and addition reaction with m-xylylenediisothiocyanate, respectively. Some compounds IVA show selectively herbicidal activity against Triticum aestivum. The results of structure-activity relationship show that appropriately decreasing the length and rigidity of linker and introducing halogen into phenyl benefit to bioactivity.