Design, synthesis, and fungicidal activities of novel ethylenediamine bridged thiazole derivatives containing oxime ether or oxime ester moieties

Abstract

To study the influence of changing the piperidine ring on the fungicidal activity, at the same time based on the successful experience of opening the oxazoline ring, a series of novel ethylenediamine bridged thiazole derivatives containing oxime ether and oxime ester moieties were designed, synthesized, and first evaluated for their fungicidal activities against phytophthora capsaicae in vitro. The bioassays results showed that the target compounds possessed moderate fungicidal activities against phytophtho‐ra capsaicae. Compound 28b showed 53.6% fungicidal activity at 50 μg/ml. Oxime ether and oxime ester derivatives showed the similar level of activities. However, the activities of these compounds were lower than that of oxathiapiprolin, suggesting the piperidine ring was essential to maintain the fungicidal activities of these compounds. For the oxime ether derivatives, 16b, 22a, 25b, and 28b, the substituents on ethylenediamine have certain influence on the activity. Increasing the chain length of substituents is beneficial to the fungicidal activity. Meanwhile, these compounds were tested their fungicidal activities against other 9 fungi, and these compounds showed broad spectrum fungicidal activities. Some compounds exhibited more than 70% fungicial activities against specific fungi.

Advances in the green synthesis and agrichemical applications of oxathiapiprolin derivatives

“…The activities of oxime ester compounds were lower than oxime ether compounds when the two nitrogen atoms are positioned on the opposite sides. Subsequently, based on the aforementioned results, a series of novel oxathiapiprolin derivatives containing oxime ether and oxime ester moieties were synthesized, in which the piperidine ring was opened ( Tian et al, 2022 ) ( Figure 3B ). Their antifungicidal activities were evaluated and showed that the target compounds possessed moderate fungicidal activities against Phytophthora capsici , and the activities of these compounds were lower than that of oxathiapiprolin, suggesting that the piperidine ring was crucial for the fungicidal activities of these compounds.…”

Discovery of Novel Oxathiapiprolin Derivatives as Potent Fungicide Candidates

“…cubensis, and P. infestans in vivo however, its activity decreased after further opening of the piperidine ring (compound 11 ) . Replacing the pyrazole group was a feasible and efficient strategy for modifying the structure of the X-ray-coated plasmid of OXA.…”