Synthesis and biological activities of novel 1,2,4-triazole thiones and bis(1,2,4-triazole thiones) containing phenylpyrazole and piperazine moieties

Abstract

Abstract A series of novel 1,2,4-triazole thione and bis(1,2,4-triazole thione) derivatives containing phenylpyrazole and substituted piperazine moieties have been conveniently synthesized via Mannich reaction using various 1,2,4-triazole thiols, substituted piperazines, and formaldehyde at room temperature in short time. Their structures were confirmed by IR, 1 H NMR, 13 C NMR and elemental analysis. The preliminary bioassays for 27 new title compounds have shown that some of them possess certain herbicidal activities against Echinochloa crusgalli at 100 μg/mL concentration. Some of the compounds exhibited significant in vitro fungicidal activities, especially against Cercospora arachidicola and Rhizoctonia cerealis at the concentration of 50 μg/mL, and were comparable with that of control Triadimefon. Meanwhile, IXp held the control efficacy of 60% against Puccinia sorghi Schw. at 200 μg/mL concentration in the in vivo test. The SAR analysis has indicated that compounds with two CF 3 groups both on triazole and pyrazole rings are more effective than compounds with one CF 3 group or two CH 3 groups according to their fungicidal activity data. On the whole, compounds VIIIg , IXi , IXo and IXp could be used as novel lead structures for the design and discovery of new fungicides.