Design, synthesis and fungicidal activity of 3,4-dichloroisothiazolocoumarin-containing strobilurins

Abstract

Twenty-one novel 3,4-dichloroisothiazolocoumarin-containing strobilurins were rationally designed and synthesized. Preliminary bioassay showed that compounds 7c, 7h and 7l exhibited over 80% inhibitory rate against Sclerotinia sclerotiorum at 50 μg/mL, 7c exhibited good activity against S. sclerotiorum with median effective concentration (EC 50 ) of 4.08 μg/mL, while the positive control coumoxystrobin showed EC 50 of 1.00 μg/mL. In addition, 7d showed better fungicidal activity with a lower EC 50 value of 7.65 μg/mL against Botrytis cinerea than that of positive control trifloxystrobin with its EC 50 value of 21.96 μg/mL. This study indicated that 3,4-dichloroisothiazolocoumarin-containing strobilurin was a promising fungicide lead deserved for further study.

Syntheses, reactivity, and biological applications of coumarins

“…A series of 21 novel 3,4-dichloroisothiazolocoumarin-containing strobilurins were rationally designed and synthesized by Fan and co-workers ( Lv et al, 2022 ). Derivative 189 exhibited good antifungal activity against Sclerotinia sclerotiorum with a EC 50 of 4.08 µM, (coumoxystrobin was used as reference, EC 50 = 1.0 µM) ( Figure 2B ).…”

Comprehensive Overview of β-Methoxyacrylate Derivatives as Cytochrome bc1 Inhibitors for Novel Pesticide Discovery

“…The lead compound 40a exhibited remarkable in vitro fungicidal activity against S. sclerotiorum (EC 50 = 4.08 μg/mL), close to that of control coumoxystrobin (EC 50 = 1.00 μg/mL). Another lead compound 40b showed good in vitro fungicidal activity against B. cinerea with EC 50 value of 17.65 μg/mL, slightly better than that of trifloxystrobin (EC 50 = 21.96 μg/mL) …”

“…Another lead compound 40b showed good in vitro fungicidal activity against B. cinerea with EC 50 value of 17.65 μg/mL, slightly better than that of trifloxystrobin (EC 50 = 21.96 μg/ mL). 65 These results demonstrated that coumarin could serve as a promising side chain for novel β-methoxyacrylate pesticide discovery and natural products could be an important source of side chains.…”

Design, Synthesis and Fungicidal Activity of Ester Derivatives of 4-(3,4-Dichloroisothiazole) 7-Hydroxy Coumarin

“…Agrochemicals are important strategical materials for crop protection and food safety production [ 1 , 2 ]. However, the unreasonable and unscientific use of some pesticides has also resulted in a series of risks [ 3 , 4 ], including increasing pest resistance [ 5 ], toxicity against non-target organisms and potential environmental pollution [ 6 ].…”

“…Although compounds 1a and 1b displayed favorable in vitro activity, their in vivo performance was suboptimal [ 1 ]. Subsequently, a series of 3,4-dichloroisothiazolocoumarin-containing strobilurins were developed and found to have poor solubility [ 2 ]. To continue the exploration of fungicidal leads and improve the physicochemical properties of a weak acidic moiety of 7-hydroxy group on the coumarins, the esterification of 7-hydroxy coumarins was carried out ( Figure 2 ), the in vitro and in vivo fungicidal activity of the target compounds were simultaneously evaluated, and notably, compounds 2ai and 2ar were found to show good activity.…”