Synthesis and Herbicidal Activities of 3-(Substituted phenyl)isoxazole Derivatives

Several novel 3-(substituted phenyl)isoxazole derivatives were prepared from phenyl butan-1,3-dione. Their structures were confirmed by 1H NMR, IR, and CIMS. Preliminary bioassay showed that some of them exhibited good activities toward various weeds.

Synthesis and Herbicidal Activities of N'-(substituted pyrimidin-2-yl)-N-Substituted Phenoxyacetyl Thiourea Derivatives

Fifteen N'-(substituted pyrimidin-2-y1)-N-substituted phenoxyacetyl thioureas were synthesized and tested for biological activities. All of them are new compounds and their structures were confirmed by IR. IHNMR. MS and elemental analysis. Some of the target compounds showed excellent inhibitory activities against root and stalk of dicotyledon plant (such as radish). and selective on monoctyledon plant (such as rice).

Synthesis and herbicidal activities of pyridyl sulfonylureas:More convenient preparation process of phenyl pyrimidylcarbamates

Four 4-monosubstituted pyrimidine pyridyl sulfonylureas were synthesized from pyridinesulfonamide and phenyl pyrimidylcarbamate and screened for herbicidal activities. We also reported a convenient preparation process of phenyl pyrimidylcarbamates from pyrimidineamine and phenyl chloroformate.

Herbicidal Activities of Eupatorium adenophorum Extracts by 3 Extraction Methods

[ Objective ] The paper was to screen the better extraction method for herbicidal active substances of Eupatorium adenophorum. [ Method ] Three com- mon extraction methods, Soxhlet extraction, ultrasonic extraction and conventional extraction method, were used to prepare E. adenophorum extracts, and the herblcidal activity of E. adenophorum extracts extracted by 3 methods was studied by seed germination method. [ Result] The extraction rate of Soxhlet extraction was the highest of （22.54 ± 0.48 ）%, and the herbicidal activities of E. adenophorum extracted by Soxhlet extraction was relatively stronger. [ Conclusion] Soxhlet extraction was the better extraction method for herbicidal active substances of E. adenophorum.

Antimicrobial,herbicidal and antifeedant activities of mansonone E from the heartwoods of Mansonia gagei Drumm

In vitro biological activities including anti-phytopathogenic fungi, antibacterial, antifeedant and herbicidal activities of the extracts from the heartwoods of Mansonia gagei Drumm. were evaluated. The dichloromethane （DCM） extract displayed antifungal activity against four plant pathogenic fungi （Altemaria porri, Colletotrichum gloeosporioides, Fusarium oxysporum and Phytophthora parasitica） higher than the methanolic （MeOH） extract. The separation of the DCM extract using bioassay guided antifungal activity against P. parasiUca led to the isolation of mansorins A, B, and C, mansonones C, E, G and H. Among isolated compounds, mansonone E displayed the highest antifungal activity against P. parasitica, followed by mansonone C, mansorin B and mansonone G. This potent compound revealed the same minimum inhibitory concentrations （MIC） of 31 μg mL-1 against C. gloeosporioides and P. parasitica, and minimum fungicidal concentration （MFC） of 31 and 125 μg mL-1, respectively. Moreover, mansonone E exhibited highly significant antibacterial activity against both Xanthomonas oryzae pv. oryzae （Xoo） and X. oryzae pv. oryzicola （Xoc） with MIC and minimum bactericidal concentration （MBC） as 7.8 and 〉500μg mL-1, respectively. This compound furthermore could inhibit the feed of Spodoptera litura with 45.9% antifeedant and significantly herbicidal activity reduced the shoot and root growth of Brassica chinensis, Oryza sativa, Mimosa pigra and Echinochlooa crus-galli. Mansonone E has potential as a new natural pesticide for agricultural plant pathogen management.

Synthesis, Crystal Structure, and Herbicidal Activities of 2-Cyanoacrylates Containing 1,3,4-Thiadiazole Moieties

Three series of novel 2-cyanoacrylates 7a--7f, 9a-9f, 10a--10f containing 1,3,4-thiadiazole ring moieties were synthesized as herbicidal inhibitors of photosystem II （PS II） electron transportation. Their structures were clearly verified by lH NMR, 13C NMR, elemental analysis （or HRMS analysis） and single-crystal X-ray diffraction analysis. Bioassay showed that a suitable group at the 3-position of acrylates was essential for high herbicidal activ- ity. In particular, compound 7e showed the best herbicidal activities and gave 100% inhibitory activity against rape and amaranth pigweed at a dose of 1.5 kg/ha. Introduction of substituent with higher polarity such as sulfinyl or sulfonyl to the 5-position of 1,3,4-thiadiazole decreased herbicidal activities.

Design, Synthesis and Herbicidal Activities of Tetrahydroisoindoline-1,3-dione Derivatives Containing Alkoxycarbonyl Substituted 2-Benzoxazolinone

Several different alkoxycarbonyl-substituted 2-benzoxazolinone moieties have been incorporated into a tetrahy- droisoindoline-1,3-dione scaffold to provide 25 compounds （1a-lu and 2a-2d）. The structures of these compounds were confirmed by 1H and 13C NMR, HRMS and X-ray single-crystal diffraction. Some of these compounds （1g, 1h, 1j, 1k） exhibited excellent herbicidal activities against Abutilon theophrasti, Amaranthus retroflexus and Eehinochloa crus-galli at a rate of 375 g AI·ha^-1. Among them, compounds lh and 1j displayed the best post-emergence herbicidal effect against Abutilon theophrasti with ED50 values of 1.8 and 5.3 g AI·ha^-1, respectively, which are superior to that of the commercial acifluorfen （44.3 g AI·ha^-1）. Field trials demonstrated that compound lh exhibited similar herbicidal activity to a high concentration atrazine, and found to be safer for maize than atrazine. The results of this study therefore show that compound lh could potentially be used as a post-emergence herbicide for maize fields.

Synthesis and Herbicidal Activities of 2-Methylpropan-2-aminium O-Methyl 1-（Substituted Phenoxyacetoxy）alkylphosphonates

A series of 2-methylpropan-2-aminium O-methyl 1-（substituted phenoxyacetoxy）alkylphosphonates （5a-5o） was selectively synthesized by reacting the corresponding O,O-dimethyl l-（substituted phenoxyacetoxy）-alkylphosphonates with an excess of 2-methylpropan-2-amine.The results of preliminary bioassays show that the title compounds exhibit moderate to good herbicidal activities against Brassica napus and Echinochloa crusgalli.Furthermore,compounds 5a-5j,which show much higher activities than compounds 5k-5o,were selected to further evaluate their post-emergence herbicidal activity at a dosage of 150 g/ha（l ha=10000 m2）.Especially,2-methylpropan-2-aminium O-methyl 1-[2-（4-chloro-2-methylphenoxy）acetoxy]butylphosphonate（5h） shows 100％ inhibitory effect on the growth of Brassica juncea and Amaranthus retroflexus,which is comparable with the commercial herbicide 2,4-dichlorophenoxy acetic acid（2,4-D）.

Synthesis and Herbicidal Activities of Novel Uracil Derivatives Containing Pyrimidinyl Moiety

In order to find novel protoporphyrinogen oxidase inhibitors with high efficacy, broad-spectrum activity, and safety to crops, nine title compounds（4a-4i） were designed and synthesized by introducing pyrimidine moiety into the uracil skeleton with commercially herbicide butafenacil as the lead compound. Their structures were con- firmed by 1H NMR, IR, mass spectroscopy and elemental analysis. The bioassay results indicate that most of com- pounds 4 tested exhibit good to excellent herbicidal activities against B. campestris, A. retroflexus, E. crusgalli and D. sanguinalis in pre-emergence treatment at a dose of 1.5 kg/ha（1 ha=10^4 m^2）, for example, compound 4i showed 100% inhibition against the four plants tested in pre-emergence treatment at a dose of 1.5 kg/ha. So, this type of skeleton can be used as a valuable lead compound for the further development of a pre-emergent herbicide.

Synthesis and Herbicidal Activities of Potassium Methyl 1-（Substituted Phenoxyacetoxy）alkylphosphonate

A series of potassium methyl 1-（substituted phenoxyacetoxy）alkylphosphonates（9a--9o） was designed and synthesized. The results of preliminary bioassays indicate that most of the title compounds possess excellent pre-emergence and post-emergence herbicidal activities against Brassica napus, Amaranthus mangostanus, Medicago sativa, Echinochloa crusgalli, and Digitaria sanguinalis at a dosage of 1500 g/ha（1 ha=10000 m2）. Especially, potas- sium methyl 1-（2,4-dichlorophenoxyacetoxy）-l-（4-methylphenyl）methylphosphonate（9g） and potassium methyl 1-（2,4-dichlorophenoxyacetoxy）-l-（furan-2-yl）methylphosphonate（9j） show the best herbicidal activity against five tested weeds with more than 85% inhibitory rate in Dre-emergence.

Synthesis, Structure and Biological Activities of 2-Methylthio-3-cyano-7-(4-methoxyphenyl)-pyrazolo[1,5-a]pyrimidine

The crystal structure of 2-methylthio-3-cyano-7-（4-methoxyphenyl）-pyrazolo[1,5- a]-pyrimidine （C15H12N4OS, Mr = 296.35） has been determined by single-crystal X-ray diffraction analysis. The crystal belongs to monoclinic, space group P21/c with a = 9.200（3）, b = 15.570（5）, c = 11.125（4） A,β= 114.273（6）°, V= 1452.7（8） A^3, Z= 4, De= 1.355 g/cm^3, μ= 0.227 mm^-1, F（000） = 616, R = 0.0499 and wR = 0.0949 for 2947 unique reflections with 1633 observed ones （I 〉 2σ（I））. The results show that all ring atoms in the pyrazolopyrimidine moiety are almost coplanar with a strong tensile force, which might be an important active site. The preliminary biological test shows that the title compound has moderate herbicidal activities.

The Herbicidal Activity of Mutant Isolates from Botrytis cinerea

Fifteen mutant isolates were obtained by ultraviolet mutation from parent isolate Botrytis cinerea BC-4. Among them three mutant isolates, BC4-1, BC4-2, and BC4-15, showed strong herbicidal activity. BC4-1 showed maximum herbicidal activity for inhibition of germination and growth of Digitaria sanguinalis L. and Arnaranthus retroflexus L. The results also showed that herbicidal activity was influenced by differing pH of PD media, with pH value of 4.0 being the optimum. The crude toxin was extracted using chloroform, petroleum ether, and ethyl acetate, respectively, and the ethyl acetate extracts showed the strongest inhibitory activity on the germination and growth of D. sanguinalis L. and A. retroflexus L. Using HPLC, one fraction with an absorption peak at 271 nm was separated from the crude toxin. This fraction could strongly inhibit the growth of D. sanguinalis L. at a concentration of 100 mg L^-1 and could completely inhibit the seed germination of D. sanguinalis L. and A. retroflexus L. at a concentration of 50 mg L^-1 .

Antifungal,Insecticidal and Herbicidal Properties of Volatile Components from Paenibacillus polymyxa Strain BMP-11

The volatiles produced by Paenibacillus polymyxa strain BMP-11 which was isolated from the rhizosphere soil of cucumber in a greenhouse were analyzed by SPME-GC-MS.Based on the preliminary test,three kinds of purchased commercial products 1-octen-3-ol,benzothiazole and citronellol were chosen to give further assessment of their bioactivity.Antifungal bioassays in sealed dishes revealed that those three compounds strongly inhibited the mycelia growth of the eight pathogens at a low treatment dosage and induced the mycelial morphological abnormalities.During the experiment,we even found that citronellol completely prevented the pigment production of the tested fungus,Fusarium oxysporum,however,1-octen-3-ol and benzothiazole had slight effect.The germination was inhibited to different degrees when spores of Botrytis cinerea exposed to these compounds for 24 h in water agar plate.Furthermore,fumigation results showed that 1-octen-3-ol and benzothiazole had strong toxicity against Tribolium castaneum,LC50 was 16.76 and 3.50 mg L-1,respectively.The fumigation activity was also found similar to the positive control,1,3-dichloropropene （LC50 =10.13 mg L-1）.Results of herbicidal assays showed that tested compounds had inhibitory effects on the seed germination and seedling growth of Amaranthus retroflexus,Echinochloa crusgalli and Chenopodium album.Findings of the present study suggested that the antifungal,insecticidal and herbicidal properties of the components were contained in volatiles.These agents or even their derivatives may have a potential to be used as fungicide,insecticide as well as herbicide.

Synthesis and Herbicidal Activity of Novel Sulfonylureas Containing Thiadiazol Moiety

Thirteen novel sulfonylureas containing thiadiazole moiety were synthesized in a two-step reaction. Their structures were determined using IR, ^1H NMR, HRFTMS, and elemental analysis. Herbicidal activities of these compounds were determined in the green house bio-assay. The results show that four compounds among them exhibit some activity toward four tested herbs.

Synthesis and Herbicidal Activity of Novel 5-Substituted Benzenesulfonylureas

Sulfonylurea herbicides have been widely used because of their low application rates, good crop sdeetivities and low mammalian toxicities. However, some sulfonylureas might persist unfavourably in the environment with residual problems. In order to look for ecologically safer and environmentally benign sulfonylureas, and on keeping the pyrimidine ring being monosubstitated, 15 novd C5-monosubstituted benzenesulfonylurea compounds were synthesized. The structures of all the compounds synthesized were confirmed by demental analysis and ^1H NMR. Preliminary herbicidal activities of these new sulfonylurea compounds were determined by ALS screening （ in vitro） and pot bioassay experiments（ in vivo）. The herbicidal results show that some novel sulfonylureas are comparable to commercial Foramsulfuron and Monosulfuron.

Novel Synthesis,Crystal Structure and Herbicidal Activity of(3R,4R)-4,7,7-Trimethyl-6-oxabicyclo[3.2.1]octane-3,4-diol

The title compound, （3R,4R）-4,7,7-trimethyl-6-oxabicyclo[3.2.1]octane-3,4-diol （Cl0HlsO3）, has been synthesized by using one-step catalytic synthetic method from a-pinene and structurally characterized by means of IR, JH-NMR, J3C-NMR, HRMS and single-crystal X-ray diffraction. The crystal belongs to the monoclinic system, space group P21/n with a = 7.277（4）, b = 18.177（11）, c = 7.939（5） A, β = 91.122（8）°, Z = 4, V = 1049.9（11） A, Dc = 1.178 g/cm3, Mr = 186.24, λ（MoKa） = 0.71073 A, μ = 0.09 mm^-1, F（000） = 408, R = 0.051 and wR = 0.144. The title complex molecules contained two hydroxyls and are connected through hydrogen bonds to generate a two-dimensional network. Especially, the preliminary herbicidal activity results show that the title compound exhibits herbicidal activity against rape （Brassica campestris） and barnyard grass （Echinochloa crusgalli）.

Synthesis and Biological Activities of α-Amino Acylamines Derivatives Containing Furan and Pyridine Ring

In order to find better herbicidal activity and fungicidal activity of a-amino acid derivatives, we introduced furan rings and pyridyl groups to seven different a-amino acids to form a series of 14 novel a-amino acylamines derivatives via dicyclohexylcarbodiimide/4-dimethylaminopyridine（DCC/DMAP） coupling method. The structures of all the compounds prepared were confirmed by IR, LC/MS, IH NMR, and elemental analysis. The herbicidal and fungicidal results show that some compounds containing glycine and valine substrate have good activities.

Crystal Structure and Biological Activities of N-(5-(4-Chloro-2-(trifluoromethyl)phenyl)furan-2-carbonyl)-N'-(4,6-dimethylpyrimidin-2-yl)thiourea

The new title compound N-（5-（4-chloro-2-（trifluoromethyl）phenyl）furan-2-carbon-yl）- N＇-（4,6-dimethylpyrimidin-2-yl）thiourea （C19H14C1F3N4O2S） has been synthesized, and its crystal structure and biological behaviors were studied. The title compound crystallizes in the monoclinic system, space group P21/c with a = 7.932（5）, b = 33.46（2）, c = 7.556（5） A, β = 98.058（9）°, V = 1986（2） A^3 Mr = 454.85, Z = 4, Dc = 1.521 g/cm^3, μ = 0.349 mm^-1 and F（000） = 928. The structure was solved by direct methods and refined to R = 0.0724 and wR= 0.1429 for 3494 observed reflections （I 〉 2σ（I））. Intermolecular hydrogen bonds along the b axis together with the continuous π-π interactions construct the three-dimensional architecture of the title compound. The preliminary biological tests show definite herbicidalactivity for the title compound.

Synthesis and Herbicidal Activity of Novel Sulfonylurea Derivatives

Sulfonylurea herbicides have been applied worldwide in agriculture. Some sulfonylurea residues might exist in soil longer than that people expected. However, flupyrsulfuron-methyl-sodium which was firstly reported as a new 5-substituted sulfonylurea herbicide has less than one month residual life. Therefore, 5-substituted benzenesulfonylureas are potential molecules to regulate its residual situation. In order to develop new sulfonylurea derivatives, the substituent on the critical 5-posotion of the benzene ring was optimized. On the basis of our former work on sulfonylureas which contains a characteristic mono-substituted pyrimidine moiety, twenty-six new sulfonylurea deriva- tives were synthesized and their structures were confirmed by 1H NMR, 31p NMR and elemental analysis. The greenhouse bioassay tests show that some title compounds exhibit potent herbicidal activity.

Syntheses, Crystal Structures, and Biological Activities of Two 5-Pyrimidinyl-1,2,4-oxadiazoles

Two 5-pyrimidinyl-1,2,4-oxadiazoles were synthesized through two different routes and their structures were characterized by single-crystal X-ray diffraction, NMR and MS. Compound 3, 5-（2-chloro-4-methyl-6-phenylpyrimidin-5-yl）-3-phenyl-1,2,4-oxadiazole, crystallizes in orthorhombic, space group Pbca with a = 19.1575（11）, b = 8.2115（5）, c = 21.2035（12）A, V = 3335.6（3）A3 and Z = 4. Compound 6, 5-（2,6-dichloropyrimidin-4-yl）-3-phenyl-1,2,4-oxadiazole, crystallizes in monoclinic space group Pn with a = 8.4275（13）, b = 5.4088（8）, c = 13.493（2）A, β = 99.768（3）°, V = 4658.6（6）A3 and Z = 8. Preliminary bioassay indicated that the two title compounds had good herbicidal activities.