Zhao-Hui Sun

Microwave Assistant One Pot Synthesis, Crystal Structure, Antifungal Activities and 3D-QSAR of Novel 1,2,4-Triazolo[4,3-a]pyridines

A series of novel 1,2,4‐triazolo[4,3‐a]pyridines were synthesized, and their structures were characterized by 1H NMR, MS, elemental analysis, and single‐crystal X‐ray diffraction analysis. The antifungal activities were evaluated. The antifungal activity results indicated that the compound 2b, 2g, 2p, and 2i exhibited good activities. The activity of compound 2b, 2g, 2p, and 2i can compare with the commercial pesticide. The 3D‐QSAR model was developed using CoMFA method. Both the steric and electronic field distributions of CoMFA are in good agreement in this work and will be very helpful in designing a new set of analogues.

Facile and efficient synthesis and herbicidal activity determination of novel 1,2,4-triazolo[4,3-a]pyridin-3(2H)-one derivatives via microwave irradiation

A series of novel 1,2,4-triazolo[4,3-a]pyridin-3(2H)-one derivatives were synthesized and identified by (1)H NMR, single crystal X-ray diffraction, elemental analysis or HRMS, and their herbicidal activities were determined at different concentrations. It was found that some of the title compounds possess high herbicidal activity. Furthermore, DFT calculation was used to study the SAR.

Synthesis and insecticidal activity of novel pyrimidine derivatives containing urea pharmacophore against Aedes aegypti.

BACKGROUND Aedes aegypti is a major mosquito vector for the transmission of serious diseases, especially dengue and yellow fever. More than 1 billion people in developing countries are at risk. The widespread and continual use of pesticides can lead to resistant mosquitoes. In order to maintain mosquito control gains, it is critical to develop and evaluate novel bioactive molecules that differ in mode of action from currently used products. RESULTS A series of novel pyrimidine derivatives were designed and synthesized. Their structures were elucidated by proton nuclear magnetic resonance spectroscopy and high-resolution mass spectrometry. The biological activities of these compounds were tested against Ae. aegypti. Many of them exhibited insecticidal activity against adult and larval mosquitoes. Compound 4d displayed relatively good activity to reach 70% mortality at 2 µg mL-1 . Furthermore, density functional theory calculations were established to study the structure-activity relationship of these novel compounds. CONCLUSION A practical synthetic route for pyrimidine derivatives is presented. This study suggests that these pyrimidine derivatives exhibit some activity against the yellow fever mosquito and, with further structure modification, could be novel lead compounds for the development of insecticides against mosquitoes.

Microwave Assistant Synthesis, Antifungal Activity and DFT Theoretical Study of Some Novel 1,2,4-Triazole Derivatives Containing Pyridine Moiety

In order to investigate the biological activity of novel 1,2,4-triazole compounds, seventeen novel 1,2,4-triazole derivatives containing pyridine moiety were synthesized under microwave assistant condition by multi-step reactions. The structures were characterized by 1H NMR, MS and elemental analyses. The target compounds were evaluated for their fungicidal activities against Stemphylium lycopersici (Enjoji) Yamamoto, Fusarium oxysporum. sp. cucumebrium, and Botrytis cinerea in vivo, and the results indicated that some of the title compounds displayed excellent fungicidal activities. Theoretical calculation of the title compound was carried out with B3LYP/6-31G (d,p). The full geometry optimization was carried out using 6-31G (d,p) basis set, and the frontier orbital energy, atomic net charges were discussed, and the structure-activity relationship was also studied.

Design, Synthesis, DFT Study and Antifungal Activity of Pyrazolecarboxamide Derivatives

A series of novel pyrazole amide derivatives were designed and synthesized by multi-step reactions from phenylhydrazine and ethyl 3-oxobutanoate as starting materials, and their structures were characterized by NMR, MS and elemental analysis. The antifungal activity of the title compounds was determined. The results indicated that some of title compounds exhibited moderate antifungal activity. Furthermore, DFT calculations were used to study the structure-activity relationships (SAR).

Synthesis and bioactivities of novel 1,3,4-oxadiazole derivatives containing 1,2,3-thiadiazole moiety

GRAPHICAL ABSTRACT Abstract Some novel 1,3,4-oxadiazole derivatives containing 1,2,3-thiadiazole were synthesized under microwave-assistant condition by multi-step reactions. The structures were characterized by 1H NMR, MS, and elemental analyses. The target compounds were evaluated for their herbicidal activities against Brassica campestris and Echinochloa crusgalli, and the results indicated that some of the title compounds displayed good herbicidal activities.

Synthesis, Crystal Structure, and Biological Activity of Some Novel Sulfoxide Compounds Containing 1,2,3-Thiadiazole Moiety

GRAPHICAL ABSTRACT Abstract Some new sulfoxide compounds containing 1,2,3-thiadiazole moiety were synthesized from diethyl carbonate and hydrazine hydrate by multi-step reactions. Their structures were confirmed by NMR, MS, and elemental analysis. One of the title compounds, 5-(4-cyclopropyl-5-((3-fluorobenzyl)sulfinyl)-4H-1,2,4-triazol-3-yl)-4-methyl-1,2,3-thiadiazole (C15H14FN5OS2), was structurally determined by a single crystal X-ray diffraction study. The biological activity of the title compound was determined, and the results showed that it displays moderate biological activities.

Design, synthesis, biological activity and density function theory study of pyrazole derivatives containing 1,3,4-thiadiazole moiety

A variety of pyrazole derivatives containing 1,3,4-thiadiazole moiety were synthesized under micro-wave irradiation, and their structures were confirmed by 1H NMR and HRMS. They were evaluated for herbicidal and antifungal activities, and the results indicated that two compounds with a phenyl group (6a) and 4-tert-butylphenyl group (6n) possess good herbicidal activity for dicotyledon Brassica campestris and Raphanus sativus with the inhibition of 90% for root and 80%–90% for stalk at 100 ppm respectively. The structure-activity relationship of compounds 6a and 6n was also studied by density function theory method.

Microwave assisted synthesis, antifungal activity, DFT and SAR study of 1,2,4-triazolo[4,3-a]pyridine derivatives containing hydrazone moieties

BackgroundThe increasing prevalence of multi-drug resistant fungal infections has encouraged the search for new antifungal agents. Hydrazone derivatives always exhibited diversity activities, including antifungal, anti-inflammatory, anti-oxidation, anti-cancer activity. Regarding the heterocyclic moiety, 1,2,4-triazolo[4,3-a]pyridine derivatives also display broad activities, such as antifungal activity, anticonvulsant activity, herbicidal activity, antimicrobial activity and anticancer activity.ResultsA series of novel 1,2,4-triazolo[4,3-a]pyridine derivatives containing hydrazone moiety were designed and synthesized from 2,3-dichloropyridine, hydrazine hydrate by multi-step reactions under microwave irradiation condition, and their structures were characterized by FT IR, 1H NMR, 13C NMR, 19F NMR, MS and elemental analysis. The antifungal activities of title compounds were determined. The results indicated that some of the title compounds exhibited good antifungal activity. Furthermore, DFT calculation was carried out for studying the structure–activity relationship (SAR).ConclusionA practical synthetic route to obtain 1,2,4-triazolo[4,3-a]pyridine derivatives is presented. This study suggests that the 1,2,4-triazolo[4,3-a]pyridine derivatives exhibited good antifungal activity.

Synthesis and crystal structure of (2-chloro-4-(phenylthio)phenyl) (3-methyl-1-phenyl-5-(phenylthio)-1H-pyrazol-4-yl)methanone

Abstract(2-Chloro-4-(phenylthio)phenyl)(3-methyl-1-phenyl-5-(phenylthio)-1H-pyrazol-4-yl)methanone was obtained by accident. In order to know the structure of this product, the compound was isolated by column chromatography and recrystallized from EtOH. The compound was characterized by X-ray diffraction. The compound crystallized in the triclinic space group P-1 with a = 9.909(2) Å, b = 11.824(2) Å, c = 13.056(3) Å, α = 63.309(3)°, β = 89.964(4)°, γ = 67.727(3)°, V = 1237.7(4) Å3, Z = 2 and R = 0.0414.