Discovery of novel pyridine carboxamides with antifungal activity as potential succinate dehydrogenase inhibitors.

Fifteen novel pyridine carboxamide derivatives bearing a diarylamine-modified scaffold were designed, synthesized, and their antifungal activity was evaluated. Preliminary bioassay results showed that some of the synthesized compounds exhibited moderate to good in vitro antifungal activity. Further, compound 6-chloro-N-(2-(phenylamino)phenyl)nicotinamide (3f) displayed good in vivo antifungal activity against Botrytis cinerea. The enzymatic test on B. cinerea succinate dehydrogenase (SDH) showed that the inhibitory activity possessed by compound 3f equally matches that of thifluzamide. Molecular docking results demonstrated that compound 3f could commendably dock with the active site of SDH via stable hydrogen bonds and hydrophobic interactions, suggesting the possible binding modes of the title compounds with SDH. The results above revealed that the target compounds would be the leading fungicide compound for further investigation.

Anti-proliferative activity and structure-activity relationship of honokiol derivatives.

As a known natural product with anti-tumor activity, honokiol has been widely researched and structural modified. Lots of honokiol derivatives have been found to possess good anti-proliferative activity and showed great potential in cancer therapy, but the SAR (structure-activity relationship) was still confused. Here in, the SAR were comprehensively researched by summary of reported derivatives and synthesis of novel derivatives. Amongst novel derivatives, the promising compounds A6 and A10 exhibited potent and selective anti-proliferative activities against K562 cell line with the IC50 values of 5.04 and 7.08 µM respectively. The SAR was discussed around honokiol and 79 derivatives by the means of CoMFA and theoretical calculation, which provided useful suggestion for further structural optimization of honokiol derivatives.

Design, synthesis and fungicidal activity evaluation of novel pyrimidinamine derivatives containing phenyl-thiazole/oxazole moiety.

Diflumetorim is a member of pyrimidinamine fungicides that possess excellent antifungal activities. Nevertheless, as reported that the activity of diflumetorim to corn rust (Puccinia sorghi) was not ideal (EC50 = 53.26 mg/L). Herein, a series of novel pyrimidinamine derivatives containing phenyl-thiazole/oxazole moiety were designed based on our previous study and the structural characteristics of diflumetorim, synthesized and bioassayed to discover novel fungicides with excellent antifungal activities. Among these compounds, T18 gave the optimal fungicidal activity, which respectively offers control effects with EC50 values of 0.93 mg/L against P. sorghi and 1.24 mg/L against E. graminis, significantly superior to commercial fungicides diflumetorim, tebuconazole, and flusilazole. Cell cytotoxicity results suggested that compound T18 has lower toxicities than diflumetorim. Furthermore, DFT calculation indicated that the phenyl-thiazole/oxazole moiety plays an unarguable role in the improvement of activity, which will contribute to designing and developing more potent compounds in the future.

Novel aryloxyphenoxypropionate derivates containing benzofuran moiety: Design, synthesis, herbicidal activity, docking study and theoretical calculation.

A series of novel aryloxyphenoxypropionate (APP) herbicides containing benzofuran moiety were designed, synthesized and tested for herbicidal activity. The bioassay results indicated that most of target compounds possessed moderate to good herbicidal activity against monocotyledonous weeds. Compounds 5a-5d and 6a-6d showed 100% control efficiency against crabgrass (Digitaria sanguinalis) and barnyard grass (Echinochloa crus-galli) in both pre-emergence and post-emergence treatments at the dosage of 1500 g a.i. ha-1. Compound 6c was the most promising, with herbicidal activity better than clodinafop-propargyl. Molecular docking for compound 6c and its hydrolysis acid 1c were performed. ACCase activities of some compounds were also tested. Theoretical calculations for corresponding hydrolysis products 1a-1ewere carried out. Based on the results of molecular docking, enzyme activity test and theoretical calculation, the potential mechanism for herbicidal activity of these compounds was evaluated.

Design, synthesis, DFT study and antifungal activity of the derivatives of pyrazolecarboxamide containing thiazole or oxazole ring.

Pyrazolecarboxamide fungicides are one of the most important classes of agricultural fungicides, which belong to succinodehydrogenase inhibitors (SDHIS). To discover new pyrazolecarboxamide analogues with broad spectrum and high activity, a class of new compounds of pyrazole carboxamide derivatives containing thiazole or oxazole ring were designed by scaffold hopping and bioisosterism, and 36 pyrazole carboxamide derivatives with antifungal activity were synthesized. Those compounds were evaluated against five phytopathogenic fungi, Gibberella zeae, Phytophythora capsici, Sclerotonia sclerotiorum, Erysiphe graminis and Puccinia sorghi. The results indicated that most of the compounds displayed good fungicidal activities, especially against E. graminis. Theoretical calculations were carried out at the B3LYP/6-31G (d, p) level and the full geometry optimization was carried out using the 6-31G (d, p) basis set, and the frontier orbital energy, atomic net charges, molecular docking were discussed, and the structure-activity relationships were also studied.

Semi-synthesis, structural modification and biological evaluation of 5-arylbenzofuran neolignans.

5-Arylbenzofuran neolignans, a newfound class of natural products, were reported to possess several kinds of pharmacological activities. To solve the lack of natural sources and promote the research of 5-arylbenzofuran neolignans in all fields, an available semi-synthesis methodology of 5-arylbenzofuran neolignans was developed, and a detailed structural modification was conducted. In the meantime, a one-pot process of Waker-type cyclization and Wacker-type oxidation was developed. To explore the potential of 5-arylbenzofuran neolignans as bioactive substances, 5-arylbenzofuran neolignans and their derivatives were evaluated for their cytotoxicity. As a result, a preliminary structure-activity relationship was obtained. Most derivatives revealed low cytotoxic effects suggesting that they were relatively safer than the natural 5-arylbenzofuran neolignan. Several derivatives showed high cytotoxicities which were found to be closely associated with apoptosis-inducing. The selectivity assay for cytotoxicity showed tumor cells were more sensitive to the promising compounds than normal cells.