Systemic activity of simeconazole and its derivatives in plants

Abstract

The systemic activity of simeconazole (RS-2-(4-fluorophenyl)-1-(1H-1,2,4-triazol-1-yl)-3-trimethylsilylpropan-2-ol) and a number of its derivatives in plants has been investigated to establish which portion of the structure of the molecule contributes to this outstanding activity. The results revealed that the hydroxyl group of the simeconazole moiety is essential for vapour-phase activity and translocation from roots of the compound. They showed that the presence of a fluorine atom in the structure was not indispensable for vapour-phase activity or translocation from roots, although the fluorine atom contributed to these systemic movements. In addition, it was found that the fungicidal activity of simeconazole against Rhizoctonia solani Kühn and Blumeria graminis DC fsp hordei Marchal is potentiated by the fluorine atom, since the activity of a compound which lacked fluorine in the 4-position of the phenyl ring was inferior to that of simeconazole. A compound in which the silicon atom of simeconazole was replaced by a carbon atom showed lower antifungal activity than simeconazole, while phytotoxicity was caused in rice plants by soil drench of the compound. Therefore, the silicon atom of simeconazole may contribute to its selectivity between fungi and plants.

1-Acetonyl-4-(2,5-dimethyl-4H-1,2,4-triazol-4-yl)-3-(2-thienylmethyl)-1H-1,2,4-triazol-5(4H)-one

“…For related literature, see: Chai et al (2003); Er-Rahimini & Mornet (1992); Ichikawa et al (2001); Jenkins et al (1989); Kim et al (2003); Nakib et al (1994); Sancak et al (2005); Tsuda et al (2004); Ueda (2003); Zhu et al (2000); Ç oruh et al (2003).…”

“…In a continuing search for pharmacologically active, 1,2,4-triazol and 1,2,4-triazol-5-one compounds, it has been found that most azole fungicides have been developed for diseases of cereal crops; examples include fluconazole (Ichikawa et al, 2001), ravuconazole (Ueda, 2003) and posaconazole . Moreover, 1,2,4-triazole derivatives have broad-spectrum biological effects, such as insecticidal (Tsuda et al, 2004), herbicidal (Chai et al, 2003), anticonvulsant (Er-Rahimini & Mornet, 1992), antitumor (Nakib et al, 1994) and plant growth regulatory activities (Jenkins et al, 1989).…”

4-(2-Pyridylmethyleneamino)-3-(2-thienylmethyl)-1H-1,2,4-triazol-5(4H)-one

“…Triazole ring systems are typical planar 6-electron partially aromatic systems, and 1,2,4-triazole and its derivatives are used as starting materials for the synthesis of many heterocycles (Desenko, 1995). Recently, much attention has been focused on 1,2,4-triazole derivatives for their broadspectrum activities, such as fungicidal, insecticidal, herbicidal, anticonvulsant, antitumour and plant growth regulatory activities (Jenkins et al, 1989;Er-Rahimini & Mornet, 1992;Nakib et al, 1994;Chai et al, 2003;Tsuda et al, 2004).…”

4,4′-Butane-1,4-diylbis[3-ethyl-1H-1,2,4-triazol-5(4H)-one] and 4-hydroxy-3-n-propyl-1H-1,2,4-triazol-5(4H)-one

“…Recently, much attention has been focused on 1,2,4-triazole derivatives for their broad-spectrum fungicidal, insecticidal, herbicidal, anticonvulsant, antitumour and plant growth regulatory activities (Tsuda & Itoh, 2004;Chai et al, 2003;Er-Rahimini & Mornet, 1992;Nakib et al, 1994;Jenkins et al, 1989). Disubstituted 1,2,4-triazole derivatives have also been reported to show antituberculotic activities (I Â kizler et al, 1998).…”