Application of Sustainable Natural Bioresources in Agriculture: Iodine-Mediated Oxidative Cyclization for Metal-Free One-Pot Synthesis of N-Phenylpyrazole Sarisan Analogues as Insecticidal Agents

Abstract

In view of potential agricultural activity of sarisan (isolated from many plants or easily synthesized from sesamol, another biorenewable natural product) analogues, many research studies on the application of these biorenewable and abundant natural resources have been proceeded. A series of novel sarisan analogues containing N-phenylpyrazole were synthesized and evaluated for their insecticidal activity against a crop-threatening insect pest, Mythimna separata Walker. Meanwhile, an iodine-mediated oxidative intramolecular C–N bond formation methodology has been established for the one-pot synthesis of these N-phenylpyrazole-containing sarisan analogues. This practical one-pot methodology is metal-free and requires no separation of the less stable intermediate hydrazones. In addition, it was found that compounds 8l–r exhibited more promising insecticidal activity with the final mortality rates (FMRs) >62.1%, when compared with the positive control toosendanin. Especially, compound 8r with 2-fluoro-4-bromophenyl showed the most potent insecticidal activity, the FMR of which was 79.3%. On the basis of this, some interesting results of structure–activity relationships were also discussed.

Natural Product‐Based Fungicides Discovery: Design, Synthesis and Antifungal Activities of Some Sarisan Analogs Containing 1,3,4‐Oxadiazole Moieties

“…[8,9] 1,3,4-Oxadiazole is an important class of N-heterocyclic compounds with a wide range of biological activities including antimicrobial, anticancer, antiviral, insecticidal and antifungal activities. [10 -13] As a part of our ongoing research aimed at the discovery and development of natural product-based compounds with potent bioactivities, [14][15][16][17] herein, in this article we have prepared a series of sarisan analogs containing 1,3,4oxadiazole moieties and evaluated for their antifungal activities. 1 These authors contributed equally to this work.…”

Design, Synthesis, and Biological Evaluation of Novel Osthole-Based Isoxazoline Derivatives as Insecticide Candidates

“…This feature indicates that these osthole derivatives have slow-acting insecticidal effects, similar to those of Nphenylpyrazole sarisan analogues that we previously reported. 27 Among all the title osthole derivatives B1−21, B2, B7, B9, B11, B12, B14, and B21 exhibited more potent GI activity than other derivatives. The CMRs of B2, B7, B9, B11, B12, B14, and B21 at 30 days were all greater than 89%, which were much better than that of toosendanin (53.6% ± 3.3).…”

Development of Novel (+)-Nootkatone Thioethers Containing 1,3,4-Oxadiazole/Thiadiazole Moieties as Insecticide Candidates against Three Species of Insect Pests

“…This phenomenon was in line with the results of some previous reports. 33,40 As depicted in Table 1, the precursor (+)-nootkatone itself displayed moderate GI activity. To our delight, after the introduction of 1,3,4-oxadiazoles or 1,3,4-thiadiazoles on the C-13 position of (+)-nootkatone, most title derivatives exhibited more potent GI activities than the precursor (+)-nootkatone, and some of these derivatives even displayed stronger GI activity than toosendanin.…”