Dual-targeting multifunctional hyaluronic acid ligand-capped gold nanorods with enhanced endo-lysosomal escape ability for synergetic photodynamic-photothermal therapy of cancer.

Au nanorods (AuNRs) have attracted considerable interest as drug delivery systems because of their enhanced cell internalization and stronger drug-loading ability. In addition, the incorporation of photodynamic therapy (PDT) and photothermal therapy (PTT) into one nanosystem presents great promise to defect multiple drawbacks in cancer therapy. Herein, we fabricated a multifunctional and dual-targeting nanoplatform based on hyaluronic acid-grafted-(mPEG/triethylenetetramine-conjugated-lipoic acid/tetra(4-carboxyphenyl)porphyrin/folic acid) polymer ligand capped AuNRs (AuNRs@HA-g-(mPEG/Teta-co-(LA/TCPP/FA)) for combined photodynamic-photothermal therapy of cancer. The prepared nanoparticles displayed high TCPP loading capacity and excellent stability in different biological media. Furthermore, AuNRs@HA-g-(mPEG/Teta-co-(LA/TCPP/FA)) not only could produce a localized hyperthermia to conduct PTT, but also generate cytotoxic singlet oxygen (1 O2 ) to perform PDT under laser irradiation. Confocal imaging results disclosed that this nanoparticle endowing the specific function of polymeric ligand could enhance cellular uptake, accelerate endo/lysosomal escape, as well as produce higher reactive oxygen species. Importantly, this combination therapy strategy could also induce higher anticancer potential than PDT or PTT only against MCF-7 tumor cells in vitro. Therefore, this work presented an AuNRs-based therapeutic nanoplatform with great potential in dual-targeting and photo-induced combination therapy of cancer.

Design, synthesis and insecticidal evaluation of aryloxy dihalopropene derivatives.

Plutella xylostella (P. xylostella) is a highly migratory, cosmopolitan species and one of the most important pest of cruciferous crops worldwide. Pyridalyl as a novel class of insecticides has good efficacy against P. xylostella. On the basis of the commercial insecticide pyridalyl, a series of new aryloxy dihalopropene derivatives were designed and synthesized by using Intermediate Derivatization Methods. Their chemical structures were confirmed by (1)H NMR, high-resolution mass spectrum (HRMS), and single-crystal X-ray diffraction analysis. The insecticidal activities of the new compounds against P. xylostella were evaluated. The results of bioassays indicated that most of the compounds showed moderate to high activities at the tested concentration, especially compounds 10e and 10g displayed more than 75% insecticidal activity against P. xylostella at 6.25mg/L, while pyridalyl showed 50% insecticidal activity at the same concentration. The field trials result of the insecticidal activities showed that compound 10e as a 10% emulsifiable concentrate (EC) was effective in the control of P. xylostella at 75-150g a.i./ha, and the mortality of P. xylostella for treatment with compound 10e at 75g a.i./ha was equivalent to pyridalyl at 105g a.i./ha.

Design, synthesis and structure-activity relationship of novel diphenylamine derivatives.

Diphenylamine derivatives have been reported with good fungicidal, insecticidal, acaricidal, rodenticidal and/or herbicidal activities. To find new lead compound of this kind, a series of novel diphenylamine derivatives were designed and synthesized by the approach of Intermediate Derivatization Methods. All compounds were identified by (1)H NMR and elemental analysis. Bioassays demonstrated that some compounds substituted at 2,4,6-positions or 2,4,5-positions of phenyl ring B exhibited excellent fungicidal activities. The optimal compounds P30 and P33 showed 80% and 85% control respectively against cucumber downy mildew at 12.5mgL(-1), both 100% control against rice blast at 0.3mgL(-1) and both 100% control against cucumber gray mold at 0.9mgL(-1). The relationship between structure and fungicidal activities was discussed as well.

Discovery of pyridine-based agrochemicals by using Intermediate Derivatization Methods.

Pyridine-based compounds have been playing a crucial role as agrochemicals or pesticides including fungicides, insecticides/acaricides and herbicides, etc. Since most of the agrochemicals listed in the Pesticide Manual were discovered through screening programs that relied on trial-and-error testing and new agrochemical discovery is not benefiting as much from the in silico new chemical compound identification/discovery techniques used in pharmaceutical research, it has become more important to find new methods to enhance the efficiency of discovering novel lead compounds in the agrochemical field to shorten the time of research phases in order to meet changing market requirements. In this review, we selected 18 representative known agrochemicals containing a pyridine moiety and extrapolate their discovery from the perspective of Intermediate Derivatization Methods in the hope that this approach will have greater appeal to researchers engaged in the discovery of agrochemicals and/or pharmaceuticals.

Synthesis and evaluation of substituted 3-(pyridin-2-yl)benzenesulfonamide derivatives as potent herbicidal agents.

In an attempt to obtain novel candidate compound for weed control, a series of newly substituted 3-(pyridin-2-yl)benzenesulfonamide derivatives 2 were designed and synthesized using compound II7 as a lead compound by Intermediate Derivatization Methods and their herbicidal activities were evaluated. The herbicidal activity assay in greenhouse tests showed several compounds (2g, 2i, 2j, 2k, 2l, 2m, 2n and 2o) exhibited significant herbicidal activity for controlling velvet leaf (Abutilon theophrasti medic.) and youth-and-old age (Zinnia elegans jacq.) at 37.5ga.i./ha. In particular, 2h was found to be the most potential candidate herbicide and was proved higher activity than the lead compound II7. The result of the weed controlling spectrum test showed that 2h could effectively control dayflower (Commelina tuberosa), bur beggarticks (Bidens tripartita linn.), youth-and-old age, cassia tora (Cassiaobtusifolia L.), velvet leaf, purslane (Portulaca oleracea) and false daisy (Eclipta prostrata L.). In addition, the mixture of compound 2h and propanil could produce a synergistic effect and enhance herbicidal activity. The result of the herbicidal activity assay in field test demonstrated that 2h could effectively control dayflower and nightshade (Disambiguation) with long-lasting persistence. The present work indicates that 2h may be a novel compound candidate as a potential herbicide.

Feasibility Study on Quantitative Analysis of Sulfide Concentration and pH of Marine Sediment Pore Water via Raman Spectroscopy.

Marine sediment pore water is one of the important objects in the study of global environmental change, marine geology and biogeochemistry. Anoxic pore water in highly reducing deep-sea sediments commonly contains a large amount of dissolved sulfide (H2S and HS-). The sulfide species within sediment pore water are significant not only because the importance of themselves, but also because they exist as a function of pH which is another key parameter in pore water study. As degassing and chemical equilibrium altering are both inevitable, concentrations of sulfide species and pH value of marine sediment pore water acquired with traditional non-in situ technologies are of great uncertainty, and cannot represent the real geochemistry information. However, the recent deployment of an in situ laser Raman pore water sampler allows us to observe spectral sulfide signals of marine sediments in situ and in real time, which provide us a new technique to solve this problem. Sulfide species in water have a relatively strong Raman signal, which often appears in the form of a characteristic overlapping peak between 2 550 - 2 620 cm(-1) and can be decomposed into HS- at 2 572 cm(-1) and H2S at 2 592 cm(-1). In the present paper, quantitative analysis of H2S and HS- with Raman spectroscopy is proved practicable and the accuracy is good. The pH of pore water is an important influencing factor of the diagenetic processes. As H2S and HS- are conjugate acid-base pairs, sulfide species within pore water exist as a function of pH and their concentration ratio depend on pH. This relationship is also shown in the Raman spectrum. To formulate the pore water pH calculation, sulfide solutions with pH range from 6.11 to 13.05 were prepared and their Raman spectra were observed. It is verified that the morphology of overlapping peaks change regularly with pH values. This phenomenon provides us the possibility of measuring the pH of pore water in situ via Raman spectroscopy. Based on peaks decomposition and correlativity analysis, we propose here a novel in situ pH measuring method for sediment pore water containing sulfide. This method can be used to measure the pH of pore water when the overlapping peak of sulfide is resolvable. The application scope of this pH measuring method in this study is 6.11 - 8.32, which covers almost all pH value of marine sediment pore water already known. The study provides additional technical reference for obtaining high-fidelity information of marine sediment pore water.

CD44-mediated tumor homing of hyaluronic acid nanogels for hypoxia-activated photodynamic therapy against tumor.

In this study, unique hypoxia-activated hyaluronic acid nanogels (HANGs) were reported for CD44-targeted delivery of photosensitizers (chlorin e6, Ce6) for diagnostic imaging and photodynamic therapy (PDT) of cancers. Through the use of a hypoxia-responsive cross-linker (AZO-CDI), the HANGs were prepared by chemically cross-linking primary amine groups-functionalized hyaluronic acid (HA). Under normoxic condition, fluorescence of Ce6 conjugated on the HANGs was highly quenched, and level of reactive oxygen species (ROS) generated from the HANGs was rather low after laser irradiation. However, under hypoxic condition, the HANGs underwent rapid disassociation, and fluorescence of Ce6 conjugated on the HANGs was recovered, triggering high-level singlet oxygen generation after laser irradiation. Due to the presence of HA, the HANGs showed much higher cellular uptake by CD44-positive cancer cells (A549 cells) than that by CD44-negative cancer cells (HepG2 cells). In addition, the HANGs could generate higher level of ROS in A549 cells because of improved cancer cell uptake. This excellent tumor-targeting and singlet oxygen-generating ability of the HANGs was favorable to hypoxia-activated PDT of CD44-positive cancers with significant inhibition of tumor growth within the whole treatment period. Taken together, the HANGs are safe and effective tools in treating CD44-positive cancers.

[Raman spectroscopic investigation of hydrogen storage in nitrogen gas hydrates].

Recently, hydrogen storage using clathrate hydrate as a medium has become a hotspot of hydrogen storage research In the present paper, the laser Raman spectroscopy was used to study the hydrogen storage in nitrogen hydrate. The synthetic nitrogen hydrate was reacted with hydrogen gas under relatively mild conditions (e.g., 15 MPa, -18 degrees C). The Raman spectra of the reaction products show that the hydrogen molecules have enclathrated the cavities of the nitrogen hydrate, with multiple hydrogen cage occupancies in the clathrate cavities. The reaction time is an important factor affecting the hydrogen storage in nitrogen hydrate. The experimental results suggest that nitrogen hydrates are expected to be an effective media for hydrogen storage.

[In situ Raman spectroscopic observation of micro-processes of methane hydrate formation and dissociation].

Micro laser Raman spectroscopic technique was used for in situ observation of the micro-processes of methane hydrate formed and decomposed in a high pressure transparent capillary. The changes in clathrate structure of methane hydrate were investigated during these processes. The results show that, during hydrate formation, the Raman peak (2 917 cm(-1)) of methane gas gradually splits into two peaks (2 905 and 2 915 cm(-1)) representing large and small cages, respectively, suggesting that the dissolved methane molecules go into two different chemical environments. In the meantime, the hydrogen bonds interaction is strengthened because water is changing from liquid to solid state gradually. As a result, the O-H stretching vibrations of water shift to lower wavenumber. During the decomposition process of methane hydrates, the Raman peaks of the methane molecules both in the large and small cages gradually clear up, and finally turn into a single peak of methane gas. The experimental results show that laser Raman spectroscopy can accurately demonstrate some relevant information of hydrate crystal structure changes during the formation and dissociation processes of methane hydrate.

[Determination of hydration number of methane hydrates using micro-laser Raman spectroscopy].

Methane hydrates are clathrate compounds that are formed by methane molecules and water molecules under low temperature and high pressure conditions. It was found that methane hydrates exist widely in sea-shelf floor and permafrost, and are considered as a potential energy resource. In the crystal lattice of clathrate hydrate, the water molecules form both large cages (5(12)6(2)) and small cages (5(12)) under the interaction of the hydrogen-hydrogen bond. In this paper, the authors designed a set of experimental apparatus for methane hydrates formation. Based on this equipment, the authors synthesized a series of methane hydrates in various systems in laboratory, including SDS solution (3% Wt) and methane, powdered ice and methane, and powdered ice and methane and natural sand with various sizes (i. e. 250-350, 180-250, 125-180 and 63-90 microm), under different temperature and pressure. The authors also designed a small device which was proved to be convenient for Raman determination of the methane hydrates. Raman spectroscopy was used to analyze the methane hydrates and to measure the structural parameters such as hydration numbers and cage occupancies. The results show that the methane hydrate samples are all in structure I type, and hydration numbers and cage occupancies are almost independent of the sediment sizes. In the three systems, the large cages of methane hydrate samples are nearly full occupied, with the occupancy ratios larger than 97%, whereas the small cages between 80% and 86%. The hydration numbers of these methane hydrate samples are between 6.05 and 6.15.

Quantitative structure-activity relationship (QSAR) directed the discovery of 3-(pyridin-2-yl)benzenesulfonamide derivatives as novel herbicidal agents.

BACKGROUND: Agrochemicals have been crucial to the production of food, and the need for the development of novel agrochemicals continues unceasing owing to the loss of existing produces via the growth of resistance and the desire for products with more propitious environmental and toxicological patterns. RESULTS: The results of both CoMFA and CoMSIA models indicated that biological activity can effectively be improved through the structural optimisation and molecular design of these synthetic compounds from the aspects of steric, electrostatic, hydrophobic, hydrogen bond donor and acceptor fields. Data of postemergence herbicidal activity in the greenhouse explained that most new 3-(pyridin-2-yl)benzenesulfonamide derivatives (4c-4 t) could control highly effectively against barnyardgrass, foxtail, vetleaf, and youth and old age (herbicidal activity ≥90%); for example, compounds 4q-4 t exhibit excellent biological activity equivalent/superior to commercial saflufenacil/sulcotrione at the low concentration of 37.5 g a.i./ha, and in particular, the herbicidal activity of compound 4 t for four experimental plant species is found to be notably greater than saflufenacil (3.75 g a.i./ha). Meanwhile, compound 4 t also has good crop selectivity for weed control in maize. CONCLUSION: The novel compounds such as 4 t have remarkable biological activity after the structural optimisation utilising the constructed 3D-QSAR models, i.e. such QSAR models have great accuracy. © 2017 Society of Chemical Industry.

Synthesis and fungicidal evaluation of novel chalcone-based strobilurin analogues.

Strobilurin derivatives have become one of the most important classes of agricultural fungicide due to a novel action mode, wide fungicidal spectrum, lower toxicity toward mammalian cells, and environmentally benign characteristics. To discover new strobilurin analogues with high activity against resistant pathogens, a series of new chalcone-based strobilurin derivatives are designed and synthesized by integrating a chalcone scaffold with a strobilurin pharmacophore. The preliminary bioassay showed that some of the chalcone analogues exhibited good in vivo fungicidal activities against Pseudoperoniospora cubensis and Sphaerotheca fuliginea at the dosage of 200 microg mL(-1). Two compounds, (E)-methyl 2-[2-({3-[(E)-3-(2-chlorophenyl)acryloyl]phenoxy}methyl)phenyl]-3-methoxyacrylate (1e) and (E)-methyl 2-[2-({3-[(E)-3-(3-bromophenyl)acryloyl]phenoxy}methyl)phenyl]-3-methoxyacrylate (1l), were found to display higher fungicidal activities against P. cubensis (EC90=118.52 microg mL(-1) for 1e and EC90=113.64 microg mL(-1) for 1l) than Kresoxim-methyl (EC90=154.92 microg mL(-1)) and were identified as the most promising candidates for further study. The present work demonstrated that strobilurin analogues containing chalcone as a side chain could be used as a lead structure for further developing novel fungicides. To our knowledge, this is the first report about the syntheses and fungicidal activities of chalcone-based strobilurin derivatives.

Design, synthesis, and fungicidal activities of new strobilurin derivatives.

Strobilurins are one of the most important classes of agricultural fungicides. To discover new strobilurin analogues with high activity against resistant pathogens, a series of new strobilurin derivatives bearing structurally diverse heterocycle side chains 3a-m and 4a-g were designed and synthesized via a microwave-assisted procedure. The advantages, such as good to excellent yields, shorter reaction times, mild reaction conditions, and simple purification procedures, distinguish the present synthetic protocol as a highly efficient method for the preparation of strobilurin thioether derivatives. Bioassays indicated that most of the compounds showed broad-spectrum fungicidal activity in vitro. Interestingly, as compared to the control of a commercial strobilurin fungicide, Kresoxim-methyl, compounds 3b, 3g, 4c, and 4d possessed remarkably higher in vitro fungicidal activity against six kinds of tested fungi. Exhilaratingly, compound 3g exhibited higher in vivo activity against Sphaerotheca fuliginea and Pseudoperoniospora cubensis than Kresoxim-methyl, and the in vivo fungicidal activities of compound 4d and Kresoxim-methyl against S. fuliginea and P. cubensis are at the same level. The present work demonstrated that strobilurin analogues containing benzothiazole side chains could be used as a lead structure for further developing novel fungicides.

Design, synthesis and structure-activity relationship of novel oxime ether strobilurin derivatives containing substituted benzofurans.

BACKGROUND: Strobilurins are one of the most important classes of agricultural fungicides. To discover new strobilurin analogues with broad spectrum and high activity, a series of novel oxime ether strobilurin derivatives containing substituted benzofurans in the side chain were synthesised and bioassayed. RESULTS: The synthesised compounds were characterised by (1) H NMR, (13) C NMR, MS and HRMS. Bioassays demonstrated that most target compounds possessed good or excellent fungicidal activities, especially against Erysiphe graminis and Pyricularia oryzae. Furthermore, methyl 3-methoxypropenoate oxime ethers exhibited remarkably higher activities against E. graminis, Colletotrichum lagenarium and Puccinia sorghi Schw. Notably, (E,E)-methyl 3-methoxy-2-{2-[({[5-fluoro-1-(benzofuran-2-yl)ethylidene]amino}oxy)methyl]phenyl}propenoate (BSF2) and (E,E)-methyl 3-methoxy-2-{2-[({[5-chloro-1-(benzofuran-2-yl)ethylidene]amino}oxy)methyl]phenyl}propenoate (BSF3) were identified as the most promising candidates for further study. CONCLUSION: The present work demonstrates that oxime ether strobilurin derivatives containing benzofurans can be used as possible lead compounds for developing novel fungicides.

Design, synthesis, and herbicidal activity of novel substituted 3-(pyridin-2-yl)benzenesulfonamide derivatives.

A series of novel substituted 3-(pyridin-2-yl)benzenesulfonamide derivatives were designed and synthesized using 2-phenylpridines as the lead compound by intermediate derivatization methods in an attempt to obtain novel compound candidates for weed control. The herbicidal activity assay in glasshouse tests showed several compounds (II6, II7, II8, II9, II10, II11, III2, III3, III4, and III5) could efficiently control velvet leaf, youth-and-old age, barnyard grass, and foxtail at the 37.5 g/ha active substance. Especially, the activities of II6, II7, III2, and III4 were proved roughly equivalent to the saflufenacil and better than 95% sulcotrione at the same concentration. The result of the herbicidal activity assay in field tests demonstrated that II7 at 60 g/ha active substance could give the same effect as bentazon at 1440 g/ha active substance to control dayflower and nightshade, meanwhile II7 showed better activity than oxyfluorfen to control arrowhead and security to rice. The present work indicates that II7 may be a novel compound candidate for potential herbicide.

Design, synthesis and structure-activity relationship of novel insecticidal dichloro-allyloxy-phenol derivatives containing substituted pyrazol-3-ols.

BACKGROUND: Pyridalyl, consisting of dicholoro-allyoxy-phenol moiety, is a novel class of insecticide showing extraordinary activities against various lepidopterous and thysanopterous pests on cotton and vegetables. To discover further novel insecticides, a series of new dichloro-allyloxy-phenol derivatives containing substituted pyrazol-3-ol moieties were designed and synthesised via the intermediate derivatisation method. RESULTS: The target compounds were characterised by (1) H NMR, IR, MS and elemental analysis. Bioassays indicated that some of these compounds exhibited good insecticidal activities against diamondback moth (Plutella xylostella) at 6.25 mg L(-1) . The structure-activity relationship is discussed. CONCLUSION: The present work demonstrates that dichloro-allyloxy-phenol derivatives with substituted phenylpyrazole moieties can be used as lead compounds to develop further novel insecticides.

Design, synthesis, and structure-activity relationship of novel aniline derivatives of chlorothalonil.

Chlorothalonil with both low cost and low toxicity is a popularly used fungicide in the agrochemical field. The presence of nucleophilic groups on this compound allows further chemical modifications to obtain novel chlorothalonil derivatives. Fluazinam, another commercially available agent with a broad fungicidal spectrum, has a scaffold of diaryl amine structure. To mimic this backbone structure, a variety of (un)substituted phenyl amines was used as nucleophilic agents to react with chlorothalonil to obtain compounds with a diphenyl amine structure. Via an elegant design, two leads, 2,4,5-trichloro-6-(2,4-dichlorophenylamino)isophthalonitrile (7) and 2,4,5-trichloro-6-(2,4,6-trichlorophenylamino)isophthalonitrile (11), with potential fungicidal activity were discovered after a preliminary bioassay screen. These two leads were further modified to obtain final products by replacing the chlorine groups in the phenyl ring in phenyl amine with other functional groups. These functional groups with various electronic properties and spatial characteristics were considered to explore the relationship between structure and fungicidal activity. The results indicate that the electron-withdrawing group NO2 on the 4 position on the right phenyl ring plays a unique role on enhancing the fungicidal activity. The compounds were identified by proton nuclear magnetic resonance and elemental analysis. Bioassays demonstrated that some of the title compounds exhibited excellent fungicidal activities against cucumber downy mildew at 25 mg/L. Compound 20 has been shown as the optimal structure with 85% control against cucumber downy mildew at 6.25 mg/L concentration. The relationship between structure and fungicidal activity is reported. The present work demonstrates that chlorothalonil derivatives can be used as possible lead compounds for developing novel fungicides.

The discovery of SYP-10913 and SYP-11277: novel strobilurin acaricides.

BACKGROUND: As previously reported, methyl (E)-2-[2-(2-phenylamino-6-trifluoromethylpyrimidin-4-yloxymethyl)phenyl]-3-methoxyacrylate has proven to be a new lead with highly acaricidal activity. Following on from this, in an effort to discover new strobilurin analogues with improved activity, a series of substituted pyrimidines were synthesised and bioassayed. RESULTS: All compounds were characterised by (1) H NMR, IR, MS and elemental analysis. Preliminary bioassays demonstrated that some of the title compounds exhibited notable control of Tetranychus cinnabarinus (Boisd.) at 1.25 mg L(-1) . The relationship between structure and acaricidal activity is discussed. CONCLUSION: Two compounds of particular interest, 6j (SYP-10913) and 6k (SYP-11277), exhibited potent acaricidal activity. The acaricidal potencies of these analogues are higher than that of fluacrypyrim in greenhouse applications, and are comparable with those of commercial acaricides such as spirodiclofen and propargite in field trials.

Synthesis and bioactivity of novel coumarin derivatives.

A series of coumarin derivatives (6-8) containing (E)-methyl 2-(methoxyimino)-2-phenylacetate, (E)-2-(methoxyimino)-N-methyl-2-phenylacetamide and methyl methoxy(phenyl)carbamate were synthesized from substituted resorcinols (1) and substituted beta-keto esters (2) as starting material via cyclization and condensation reactions. The test results indicated that (E)-methyl 2-{2-[(3-hexyl-4-methyl-coumarin-7-yloxy)methyl]phenyl}-2-(methoxyimino)acetate (6f) was the optimal structure with good fungicidal activity against cucumber grey mold (CGM) giving 100% control at 100 mg L(-1) concentration, much higher than that of coumoxystrobin. Methyl 2-[(3,4-dimethyl-coumarin -7-yloxy)methyl]phenyl(methoxy)carbamate (8a) was another optimal structure with good fungicidal activity against wheat powdery mildew (WPM) showing 100% control at 50 mg L(-1) concentration, at the same level as that of the commercial kresoxim-methyl, and very significantly higher than that of coumoxystrobin (no control against WPM at 400 mg L(-1)).

Design, synthesis and structure-activity relationship of novel coumarin derivatives.

BACKGROUND: The lead coumarin derivative (E)-methyl 3-methoxy-2-[2-(4-methylcoumarin-7-yloxymethyl)phenyl]acrylate was discovered by using an intermediate derivatisation method. To discover new coumarin derivatives with improved activity, a series of substituted coumarins were synthesised and bioassayed. RESULTS: The compounds were identified by ¹H NMR, IR, MS and elemental analysis. Bioassays demonstrated that some of the title compounds exhibited excellent fungicidal activity against cucumber downy mildew at 25 mg L⁻¹. The relationship between structure and fungicidal activity is reported. CONCLUSION: The present work demonstrates that coumarin derivatives containing methoxyacrylate moieties can be used as possible lead compounds for developing novel fungicides.