[Trapping array-based preparative two-dimensional liquid chromatography for the purification of four components in tobacco leaves].

Two-dimensional liquid chromatography (2D-LC) has gained increased attention because of its high peak capacity for separating complex samples. However, preparative 2D-LC aimed at isolating compounds is significantly different compared with one-dimensional liquid chromatography (1D-LC) in terms of method development and system configuration; thus, it is less developed than its analytical counterpart. The use of 2D-LC in large-scale product preparation has rarely been reported. Hence, a preparative 2D-LC system was developed in this study. The system was composed of one set of preparative LC modules as a separation system, with a dilution pump, switch valves, and trap column array as the interface, to enable the simultaneous isolation of several compounds. Tobacco was used as a sample, and the developed system was applied to isolate nicotine, chlorogenic acid, rutin, and solanesol. The chromatographic conditions were developed by investigating the trapping efficiency of different types of trap column packings, and chromatographic behaviors under different overload conditions. The four compounds were isolated in one 2D-LC run with high purity. The developed system features low cost because it employs medium-pressure isolation, excellent automation owing to its use of an online column switch, high stability, and capability for large-scale production. The isolation of chemicals from tobacco leaves as pharmaceutical raw materials could aid in the development of the tobacco industry and promote the local agricultural economy.

Controllable Soil Degradation Rate of 5-Substituted Sulfonylurea Herbicides as Novel AHAS Inhibitors.

Chlorsulfuron has been applied in wheat fields as a recognized herbicide worldwide, yet it was officially banned in China since 2014 for its soil persistence problem. On the basis of our previous research that 5-dimethylamino distinctively accelerated degradation rate in soils, a modified amino moiety (Ia-c) and monosubstituted amino group (Id-e) were introduced onto the fifth position of the benzene ring in sulfonylurea structures, as well as heterocyclic amino substituents (If-g) to seek a suitable soil degradation rate during such an in situ crop rotation system. Referring to the biological data and ScAHAS inhibition and ScAHAS docking results, they turned out to be AHAS inhibitors with high potent herbicidal activities. The various influence on soil degradation rate along with crop safety indicated that different substituents on the fifth position have exerted an apparent impact. Their united study of structure-activity-safety-degradation relationship has great potential to provide valuable information for further development of eco-friendly agrochemicals.

One-pot synthesis, structure and structure-activity relationship of novel bioactive diphenyl/diethyl (3-bromo-1-(3-chloropyridin-2-yl)-1H-pyrazol-5-yl)(arylamino)methylphosphonates.

BACKGROUND: N-Pyridylpyrazole derivatives have received continuous attention in agrochemical research during the last decade owing to their remarkable insecticidal or fungicidal potentials. To look for novel heterocyclic agrochemicals for increasing production of agriculture, a series of novel α-aminophosphonate derivatives containing N-pyridylpyrazole moiety were synthesized. RESULTS: The structures of the title compounds were confirmed via melting point, IR, 1 H NMR, 13 C NMR, 31 P NMR, HRMS and elemental analysis. The single crystal structure of diethyl (3-bromo-1-(3-chloropyridin-2-yl)-1H-pyrazol-5-yl)(2,6-dimethylphenylamino)methylphosphonate (compound 12b) was first reported. Moreover, the bioassays displayed that the title compounds exhibited modest or weak insecticidal activities against oriental armyworm at 200 µg mL-1 . The first investigation on the fungicidal potential of chlorantraniliprole showed no significant activities towards the six tested fungi found in this study, however, most of the title compounds displayed apparent in vitro fungicidal activity against some plant fungi, in particular excellent activities towards Physalospora piricola. Compounds 11a and 11b had EC50 values of 18.8 and 17.4 µg mL-1 , respectively, which were comparable with that of fungicide control triadimefon (EC50  = 24.7 µg mL-1 ) against Physalospora piricola. In addition, some compounds exhibited modest in vivo control efficacy at 0.5 mg mL-1 towards Sclerotinia sclerotiorum (11b: 30.1(±1.8)%), Rhizoctonia cerealis (11a: 20.4(±2.1)%; 11b: 30.2(±2.2)%), and Erysiphe graminis (11a: 30.3(±1.8)%; 12d: 40.2(±0.9)%). CONCLUSION: Compounds 11a, 11b and 12d could be promising new lead structures for the development and discovery of novel fungicides towards Physalospora piricola and Erysiphe graminis. The structure-activity relationship (SAR) analysis provided useful guidance and new understanding for the design of novel pyridylpyrazole-containing agrochemicals. © 2019 Society of Chemical Industry.

Synthesis, biological evaluation and SAR analysis of novel poly-heterocyclic compounds containing pyridylpyrazole group.

BACKGROUND: In recent years, pyridylpyrazole derivatives, such as pyridylpyrazole-containing anthranilic diamide have attracted much attention by virtue of their useful insecticidal properties and unique action mode. Moreover, some pyridylpyrazole-containing compounds have also been found to possess significant fungicidal activities. With the aim of discovering new bioactive agrochemicals for crop protection, a series of poly-heterocyclic compounds containing pyridylpyrazole and aziridine, or ß-lactam, or thiazolinone moieties were synthesized. RESULTS: A series of pyridylpyrazole-containing poly-heterocyclic compounds were obtained, and confirmed through IR, 1 H NMR, 13 C NMR, HRMS and elemental analysis. The crystalline structure of 4-(3-bromo-1-(3-chloropyridin-2-yl)-1H-pyrazol-5-yl)-3-chloro-1-mesitylazetidin-2-one (compound 13f) was determined to further illustrate a trans- configuration of the ß-lactam motif. In addition, bioassays showed that most of these new compounds exhibited modest insecticidal activity towards Mythimna separate Walker at 200 µg mL-1 . Some of the compounds displayed excellent fungicidal activity towards some plant fungi, including Cercospora arachidicola (13j: EC50 = 14.5 µg mL-1 ), Physalospora piricola (12d and 13d: EC50 = 10.5 and 9.70 µg mL-1 ), Alternaria solani Sorauer (13j: EC50 = 7.29 µg mL-1 ), Puccinia sorghi Schw. (13d: control efficacy 99.0 ± 2.1% at 200 µg mL-1 ) and Erysiphe graminis (14d: control efficacy 95.0 ± 1.4% at 200 µg mL-1 ). CONCLUSION: Compounds 12b-12e, 13a, 13d, 13f, 13j, 13 k and 14d could be considered potential fungicidal lead compounds to do further structural optimization. The structure-activity relationship analysis in this study brings some new understanding to the biological activities of N-pyridylpyrazole-containing compounds, and provides important information for the research and development of novel agricultural fungicides with poly-heterocyclic structures. © 2017 Society of Chemical Industry.

Synthesis, biological activities and SAR studies of new 3-substitutedphenyl-4-substitutedbenzylideneamino-1,2,4-triazole Mannich bases and bis-Mannich bases as ketol-acid reductoisomerase inhibitors.

A series of new 3-substitutedphenyl-4-substitutedbenzylideneamino-1,2,4-triazole Mannich bases and bis-Mannich bases were synthesized through Mannich reaction with high yields. Their structures were confirmed by means of IR, 1H NMR, 13C NMR and elemental analysis. The preliminary bioassay indicated that compounds 7g, 7h and 7l exhibited potent in vitro inhibitory activities against ketol-acid reductoisomerase (KARI) with Ki value of (0.38 ±â€¯0.25), (6.59 ±â€¯2.75) and (8.46 ±â€¯3.99) µmol/L, respectively, and were comparable with IpOHA. They could be new KARI inhibitors for follow-up research. Some of the title compounds also exhibited obvious herbicidal activities against Echinochloa crusgalli and remarkable in vitro fungicidal activities against Physalospora piricola and Rhizoctonia cerealis. The SAR of the compounds were analyzed, in which the molecular docking revealed the binding mode of 7g with the KARI, and the 3D-QSAR results provided useful information for guiding further optimization of this kind of structures to discover new fungicidal agents towards Rhizoctonia cerealis.

Research on Controllable Degradation of Novel Sulfonylurea Herbicides in Acidic and Alkaline Soils.

The degradation issue of sulfonylurea (SU) has become one of the biggest challenges that hamper the development and application of this class of herbicides, especially in the alkaline soils of northern China. On the basis of the previous discovery that some substituents on the fifth position of the benzene ring in Chlorsulfuron could hasten its degradation rate, apparently in acidic soil, this work on Metsulfuron-methyl showed more convincing results. Two novel compounds (I-1 and I-2) were designed and synthesized, and they still retained potent herbicidal activity in tests against both dicotyledons and monocotyledons. The half-lives of degradation (DT50) assay revealed that I-1 showed an accelerated degradation rate in acidic soil (pH 5.59). Moreover, we delighted to find that the degradation rate of I-1 was 9-10-fold faster than that of Metsulfuron-methyl and Chlorsulfuron when in alkaline soil (pH 8.46), which has more practical value. This research suggests that a modified structure that has potent herbicidal activity as well as accelerated degradation rate could be realized and this approach may provide a way to improve the residue problem of SUs in farmlands with alkaline soil.

Synthesis and biological activities of novel 5-substituted-1,3,4-oxadiazole Mannich bases and bis-Mannich bases as ketol-acid reductoisomerase inhibitors.

A series of novel 5-substituted-1,3,4-oxadiazole Mannich bases and bis-Mannich bases have been conveniently synthesized in good yields. Their structures were characterized by IR, (1)H NMR, (13)C NMR and elemental analysis. The preliminary bioassay results indicated that some of the compounds showed promising in vitro fungicidal activities towards several test plant fungi; some of them exhibited significant herbicidal activities against Brassica campestris and excellent in vitro inhibitory activities against rice ketol-acid reductoisomerase (KARI). Among 14 novel compounds, 8c, 8d and 8m showed potent KARI inhibitory activities with Ki value of (0.96±0.42), (3.86±0.49) and (3.10±0.71) µmol/L, respectively, and were comparable with IpOHA. These compounds could be novel KARI inhibitors for further investigation. The density functional theory (DFT) calculations and molecular docking were carried out to study the structure-activity relationship (SAR) of the active inhibitors in this Letter.

Syntheses, biological activities and SAR studies of novel carboxamide compounds containing piperazine and arylsulfonyl moieties.

A series of novel carboxamide compounds 19a-19j, 20a-20j and 22a-22d containing piperazine and arylsulfonyl moieties have been synthesized. The bioassay results showed that some compounds exhibited favorable herbicidal activities against dicotyledonous plants and many of them possessed excellent antifungal activities. Among 24 novel compounds, some showed superiority over the commercial fungicides Chlorothalonil, Dimethomorph, Thiophanate-methyl, Iprodione, and Zhongshengmycin at 500 mg/L concentration. Some compounds also exhibited high KARI inhibitory activity at 100 µg/mL concentration and could be used as new KARI lead inhibitors for further studies. Moreover, SAR of these new compounds were comprehensively investigated using different computational methods in which 3D-QSAR model obtained provided useful information for further structural optimization for the discovery of new fungicides. The results of this research will contribute to explore comprehensive biological activities of piperazine-containing compounds in different areas of chemistry.

Synthesis, insecticidal activities, and SAR studies of novel pyridylpyrazole acid derivatives based on amide bridge modification of anthranilic diamide insecticides.

Anthranilic diamides are one of the most important classes of modern agricultural insecticides. To discover new structure-modified compounds with high activity, series of novel carbonyl thioureas, carbonyl ureas, oxadiazoles, carbonyl thiophosphorylureas, oxadiazole-containing amides, and thiazoline-containing amides were designed through the modification of the amide bridge based on the structure of chlorantraniliprole and were synthesized, and bioassays were carried out. The compounds were characterized and confirmed by melting point, IR, (1)H NMR, and elemental analyses or HRMS. Preliminary bioassays indicated that some compounds exhibited significant insecticidal activities against oriental armyworm, diamondback moth, beet armyworm, corn borer, and mosquito. Among them, trifluoroethoxyl-containing carbonyl thiourea 20a showed best larvicidal activity against oriental armyworm, with LC50 and LC95 values of 0.1812 and 0.7767 mg/L, respectively. Meanwhile, 20c and 20e showed 86 and 57% death rates against diamondback moth at 0.005 mg/L, and the LC50 values of the two compounds were 0.0017 and 0.0023 mg/L, respectively, which were lower than that of the control chlorantraniliprole. The relationship between structure and insecticidal activity was discussed, and the HF calculation results indicated that the carbonyl thiourea moiety plays an important role in the insecticidal activity. The present work demonstrated that the trifluoroethoxyl-containing carbonyl thioureas can be used as lead compounds for further development of novel insecticides.

Development of 35 microsatellite markers from heat stress transcription factors in Populus simonii (Salicaceae).

PREMISE OF THE STUDY: Microsatellite markers within regulators of heat stress transcription factors were identified in the Populus trichocarpa genome, and then developed for P. simonii to investigate the genetic diversity of germplasm resources and to further identify favorable alleles significantly associated with stress-resistant traits. METHODS AND RESULTS: Thirty-five novel microsatellite markers were identified from genes controlling heat stress transcription factors in P. simonii using a Sanger sequencing protocol. Polymorphisms in 48 individuals from 16 populations of P. simonii revealed that the number of alleles per locus ranged from two to nine with an average of 4.6; the observed heterozygosity and expected heterozygosity per locus varied from 0.143 to 0.857 and from 0.257 to 0.948, respectively. CONCLUSIONS: The new polymorphic markers developed during this study will facilitate the construction of genetic linkage maps and will aid in marker-assisted breeding of a new germplasm with desirable abiotic stress resistance in Populus species.

Synthesis and insecticidal activities of novel anthranilic diamides containing acylthiourea and acylurea.

Two series of anthranilic diamides containing acylthiourea and acylurea linkers were designed and synthesized, with changed length and flexibility of the linkers to compare to known anthranilic diamide insecticides. In total, 26 novel compounds were synthesized, and all compounds were characterized by (1)H nuclear magnetic resonance and high-resolution mass spectrometry. Their insecticidal activities against oriental armyworm (Mythimna separata), mosquito larvae (Culex pipiens pallens), and diamondback moth (Plutella xylostella) were evaluated. The larvicidal activities against oriental armyworm indicated that the introduction of acylthiourea into some structures could retain their insecticidal activity; 8 of the 15 compounds (13a-13e, 14a-14e, and 15a-15e) exhibited 100% larvicidal activity at 10 mg/L. However, the introduction of acylurea decreased the insecticidal activity; only 3 of the 11 compounds (17a-17k) exhibited 100% larvicidal activity at 200 mg/L. The whole-cell patch-clamp technique indicated that compound 13b and chlorantraniliprole exhibited similar effects on the voltage-gated calcium channel. The calcium-imaging technique was also applied to investigate the effects of compounds 13b and 15a on the intracellular calcium ion concentration ([Ca(2+)](i)), which indicated that they released stored calcium ions from endoplasmic reticulum. Experimental results denoted that several new compounds are potential activators of the insect ryanodine receptor (RyR).

Synthesis, structure, and biological activity of novel (oxdi/tri)azoles derivatives containing 1,2,3-thiadiazole or methyl moiety.

To develop novel inhibitors of ketol-acid reductoisomerase, a series of (oxdi/tri)azoles derivatives was synthesized and characterized by (1)H  NMR, MS, elemental analyses, and crystallography. According to the biological activities of these compounds obtained both in vivo and in vitro, compound 4-cyclopropyl-3-((4-fluorobenzyl)thio)-5-methyl-4H-1,2,4-triazole showed excellent KARI inhibitory activity (100% at 100 µg mL (-1)  in vitro). In addition, most of the title compounds exhibited good herbicidal activity against Brassica campestris in vivo.

The structure-activity relationship in herbicidal monosubstituted sulfonylureas.

BACKGROUND: The herbicide sulfonylurea (SU) belongs to one of the most important class of herbicides worldwide. It is well known for its ecofriendly, extreme low toxicity towards mammals and ultralow dosage application. The original inventor, G Levitt, set out structure-activity relationship (SAR) guidelines for SU structural design to attain superhigh bioactivity. A new approach to SU molecular design has been developed. RESULTS: After the analysis of scores of SU products by X-ray diffraction methodology and after greenhouse herbicidal screening of 900 novel SU structures synthesised in the authors' laboratory, it was found that several SU structures containing a monosubstituted pyrimidine moiety retain excellent herbicidal characteristics, which has led to partial revision of the Levitt guidelines. CONCLUSIONS: Among the novel SU molecules, monosulfuron and monosulfuron-ester have been developed into two new herbicides that have been officially approved for field application and applied in millet and wheat fields in China. A systematic structural study of the new substrate-target complex and the relative mode of action in comparison with conventional SU has been carried out. A new mode of action has been postulated.

Synthesis, structure and biological activity of novel 1,2,4-triazole mannich bases containing a substituted benzylpiperazine moiety.

A series of novel Mannich bases with trifluoromethyl-1,2,4-triazole and substituted benzylpiperazine moieties were synthesized. Their structures were confirmed by IR, (1) H NMR and elemental analysis. The single crystal structure of compound 4r was also determined. The preliminary bioassays showed that most of the lead compounds had low herbicidal activity against Brassica campestris, Echinochloa crusgalli, and KARI enzyme. However, most of them exhibited significant fungicidal activity at the dosage of 50 µg/mL toward five test fungi. Among the 18 novel compounds, several showed superiority over the commercial fungicide Triadimefon against Cercospora arachidicola and Fusarium oxysporum f. sp. cucumerinum during this study. Meanwhile, some compounds displayed plant growth regulatory activity at the dosage of 10 µg/mL.

Synthesis and antifungal activities of new pyrazole derivatives via 1,3-dipolar cycloaddition reaction.

A series of cycloadducts--pyrazoles via 1,3-dipolar cycloaddition reactions of generated nitrilimines with N-(4-chloro-2-fluorophenyl)maleimide were described. The novel compounds synthesized were characterized by (1)H NMR, MS, and elemental analysis. The fungicidal tests showed that most of the title compounds exhibit significant fungicidal activities against Corynespora cassiicola.

Synthesis and biological activity of some novel trifluoromethyl-substituted 1,2,4-triazole and bis(1,2,4-triazole) Mannich bases containing piperazine rings.

A series of trifluoromethyl-substituted 1,2,4-triazole Mannich base 6 and bis(1,2,4-triazole) Mannich base 7 containing pyrimidinylpiperazine rings via the Mannich reaction were synthesized and characterized by infrared (IR), (1)H nuclear magnetic resonance (NMR), and elemental analysis. The fungicidal tests indicated that most of compounds 6 and 7 possessed excellent fungicidal activity. Among 19 novel compounds, some showed superiority over commercial fungicides Dimethomorph, Thiophanate-methyl, Iprodione, and Zhongshengmycin. Some compounds also exhibited favorable herbicidal activity in the preliminary studies. On the basis of the comparative molecular field analysis (CoMFA), five novel compounds were subsequently synthesized, their activities were estimated fairly accurately, and compounds 6-A1 and 7-A2 displayed good fungicidal activity against Pseudoperonospora cubensis (96.9 and 84.9%) as 6h and 7c, respectively.

The effects of Stichopus japonicus acid mucopolysaccharide on the apoptosis of the human hepatocellular carcinoma cell line HepG2.

In this study, the effects of Stichopus japonicus acid mucopolysaccharide (SJAMP) on the apoptosis of the human hepatocellular carcinoma cell line HepG2 were examined. The underlying mechanism was investigated by determining the effect of SJAMP on the expression of Bcl-2 and nm23-H1 genes in HepG2 cells. In vitro cultured HepG2 cells were treated with different concentrations of SJAMP. The dimethylthiazol (MTT) assay was used to determine the inhibition of cell proliferation. Expression of Bcl-2 and nm23-H1 genes was determined by Western blot analysis. The results showed that SJAMP inhibited the proliferation of HepG2 cells in a time- and dose-dependent manner, SJAMP induced apoptosis in HepG2 cells, and SJAMP decreased the expression of Bcl-2 and increased the expression of nm23-H1. We conclude that SJAMP inhibits the proliferation of HepG2 cells by inducing apoptosis. These results provide a theoretical basis for the utilization of SJAMP as a potential antitumor component for the treatment of hepatocellular carcinoma.

High throughput receptor-based virtual screening under ZINC database, synthesis, and biological evaluation of ketol-acid reductoisomerase inhibitors.

Ketol-acid reductoisomerase (KARI; EC 1.1.1.86) catalyzes the second common step in branched-chain amino acid biosynthesis. This enzyme is an important target for drug design. Based on the crystal structure of ketol-acid reductoisomerase/N-hydroxy-N-isopropyloxamate (IpOHA) complex, we have carried out high throughput receptor-based virtual screening of the ZINC/drug like database (2 000 000 compounds) to look for novel inhibitors of KARI for the first time. Some novel compounds were found to inhibit rice KARI in vitro among 15 procured compounds. This method can provide useful information for further design and discovery of KARI inhibitors.

Synthesis of some N, n'-diacylhydrazine derivatives with radical-scavenging and antifungal activity.

A series of N,N'-diacylhydrazines were prepared and their structures were confirmed by 1H NMR, MS and FTICR-MS. They were tested radical-scavenging activity in vitro. The preliminary bioassays of title compounds showed that two compounds had excellent radical-scavenging activity comparable with vitamin C, while the activity is highly relative to the substituents. Surprisingly, several compounds also exhibit favorable fungicidal activities. To further explore the comprehensive structure-activity relationships about the fungicidal activity, a three-dimensional quantitative structure-activity relationship analysis using the method of comparative molecular field analysis was performed.

Synthesis, antifungal activities and 3D-QSAR study of N-(5-substituted-1,3,4-thiadiazol-2-yl)cyclopropanecarboxamides.

A series of cyclopropanecarboxamide were prepared and tested for antifungal activity in vivo. The preliminary bioassays indicated that some compounds are comparable to the commercial fungicides. To further explore the comprehensive structure-activity relationship on the basis of fungicidal activity data, comparative molecular field analysis (CoMFA) was performed, and a statistically reliable model with good predictive power (r(2)=0.8, q(2)=0.516) was achieved. Based on the CoMFA, compound 7p was designed and synthesized, which was found to display a good antifungal activity (79.38%) as 7g and 7h.