Design, Synthesis, and Fungicidal Evaluation of Novel Pyrazole-furan and Pyrazole-pyrrole Carboxamide as Succinate Dehydrogenase Inhibitors.

The identification of novel succinate dehydrogenase (SDH) inhibitors represents one of the most attractive directions in the field of fungicide research and development. During our continuous efforts to pursue inhibitors belonging to this class, some structurally novel pyrazole-furan carboxamide and pyrazole-pyrrole carboxamide derivatives have been discovered via the introduction of scaffold hopping and bioisosterism to compound 1, a remarkably potent lead obtained by pharmacophore-based virtual screening. As a result of the evaluation against three destructive fungi, including Sclerotinia sclerotiorum, Rhizoctonia solani, and Pyricularia grisea, a majority of them displayed potent fungicidal activities.

Discovery of Novel Succinate Dehydrogenase Inhibitors by the Integration of in Silico Library Design and Pharmacophore Mapping.

Succinate dehydrogenase (SDH) has been demonstrated as a promising target for fungicide discovery. Crystal structure data have indicated that the carboxyl "core" of current SDH inhibitors contributed largely to their binding affinity. Thus, identifying novel carboxyl "core" SDH inhibitors would remarkably improve the biological potency of current SDHI fungicides.

Synthesis, antifungal activity, and QSAR study of novel trichodermin derivatives.

In an attempt to discover more potential antifungal agents, in this study, 21 novel trichodermin derivatives containing conjugated oxime ester (5a-5u) were designed and synthesized and were screened for in vitro antifungal activity. The bioassay tests showed that some of them exhibited good inhibitory activity against the tested pathogenic fungi. Compound 5a exhibited better activity against Pyricularia oryzae and Sclerotonia sclerotiorum than trichodermin, and compound 5j showed particular activity against P.

Synthesis and biological evaluation of novel trichodermin derivatives as antifungal agents.

To discover more potential antifungal agents, 17 novel trichodermin derivatives were designed and synthesized by modification of 3 and 4a. The structures of all the synthesized compounds were confirmed by (1)H NMR, ESI-MS and HRMS. Their antifungal activities against Ustilaginoidea oryzae and Pyricularia oryzae were evaluated.

3-(2,5-Di-methyl-phen-yl)-8-meth-oxy-2-oxo-1-aza-spiro-[4.5]dec-3-en-4-yl 3-(2-bromo-4-fluoro-phen-yl)acrylate.

In the title compound, C27H27BrFNO4, which is an inhibitor of acetyl-CoA carboxyl-ase, the cyclo-hexane ring displays a chair comformation with the spiro-C and meth-oxy-bearing C atoms deviating by 0.681 (7) and -0.655 (1) Å, resppectively, from the mean plane formed by the other four C atoms of the spiro-C6 ring.

Structure, bioactivity and implications for environmental remediation of complexes comprising the fungicide hexaconazole bound to copper.

Background: In agricultural areas excessive amounts of toxic heavy metals are a growing threat to the environment and human health. Measures should be taken to minimise the risk of adverse health effects. Hence, we investigated the possibilities of hexaconazole (a commercial fungicidal) as a dual-function ligand that has heavy metal ions chelating and fungicidal activities.

(1'S,4'S)-5-(2,5-Dimethyl-phen-yl)-4'-meth-oxy-6-oxa-3-aza-spiro-[bicyclo-[3.1.0]hexane-2,1'-cyclo-hexa-n]-4-one.

In the title compound, C18H23NO3, the cyclo-hexane ring has a chair conformation. The oxirane plane (OCC) makes a dihedral angle of 76.15 (13)° with that of the pyrrolidine ring to which it is fused.

Metabolism-based synthesis, biological evaluation and structure-activity relationship analysis of spirotetramat analogues as potential lipid biosynthesis inhibitors.

Background: In previous studies, scientists found that, when spirotetramat was introduced into plants or animals, it was mainly metabolised at positions C-4 and C-8. That is to say, these two functional positions potentially played an important role in spirotetramat's bioactivities. In order to develop novel insecticides or miticides, the present authors designed and synthesised 35 spirotetramat analogues based on metabolite structures.

8-{[(E)-3-(2-Chloro-phen-yl)acrylo-yloxy]imino}-12,13-ep-oxy-trichethec-9-en-4-yl (E)-3-(2-chloro-phen-yl)acrylate.

In the title compound, C(33)H(31)Cl(2)NO(6), the five-membered ring displays an envelope conformation, whereas the two six-membered rings both exhibit a chair conformation. As for the seven-membered ring, the dihedral angle between the mean planes formed by the four C atoms of the envelope unit and the three C and one O atoms of the six-membered chair is 69.08 (4)°, and these two mean planes are nearly perpendicular to the ep-oxy ring, making dihedral angles of 87.

3-tert-Butyl-2-oxo-1-oxaspiro-[4.5]dec-3-en-4-yl 4-chloro-benzoate.

The title tetronic acid derivative, C(20)H(23)ClO(4), which is a spiro-diclofen analogue, has two crystallographically independent mol-ecules in the asymmetric unit (Z' = 2). The cyclo-hexane rings in the respective mol-ecules A and B adopt chair conformations [four C atoms are planar with mean deviations of 0.013 (2) and 0.

Synthesis and bioactivity evaluation of novel spiromesifen derivatives.

Background: The development of environmentally friendly and novel structural pesticides is now an area of intense research in the agriculture field. Spirocyclic tetronic acids such as spiromesifen are typical compounds of this kind. In order to discover novel compounds with improved and broader-spectrum insecticidal activities, a series of spiromesifen derivatives were synthesised and bioassayed.

Design, synthesis, and biological activities of milbemycin analogues.

Milbemycins have received considerable interest in agricultural chemistry due to a special action mode, extremely high activity against arachnoide pests, low toxicity to mammals, and environmentally benign characteristics. Two series of novel milbemycin analogues (4Ia-6IIc) containing alkyl and aryl groups at the 4'- and 13-positions were designed and synthesized by five schemes. These analogues were identified by (1)H NMR, (13)C NMR, and elemental analysis (or HRMS).

Trichodermin (12,13-ep-oxy-trichethec-9-en-4β-yl 4-fluoro-benzoate).

IN THE TITLE TRICHODERMIN COMPOUND (SYSTEMATIC NAME: 12,13-ep-oxy-trichothec-9-en-4β-yl 4-fluoro-benzoate), C(22)H(25)FO(4), the five-membered ring displays an envelope conformation, whereas the two six-membered rings show the different conformations, viz. chair and half-chair. As for the seven-membered ring, the dihedral angle between the mean planes formed by the four C atoms of the envelope unit and the three C and one O atoms of the six-membered chair is 68.

4-Hydr-oxy-3-mesityl-1-oxaspiro-[4.4]non-3-en-2-one.

In the title compound, C(17)H(20)O(3), the five-membered cyclo-pentyl ring displays an envelope conformation, with the atom at the flap position 0.538 (3) Å out of the mean plane formed by the other four atoms. The dihedral angle between the benzene and furan rings is 63.

Dihalogenated trichodermin (4β-acet-oxy-9,10-dibromo-12,13-epoxy-tri-chothec).

In the title dihalogenated trichodermin mol-ecule, C(17)H(24)Br(2)O(4) (systematic name: 9,10-dibromo-12,13-epoxy-trichothec-9-en-4β-yl acetate), the five-membered ring displays an envelope conformation, whereas the two six-membered rings show the same conformation, viz. chair. As for the seven-membered ring, the dihedral angle between the mean planes formed by the four C atoms of the envelope unit and the three C and one O atoms of the six-membered chair is 69.

3-(2,4-Dichloro-phen-yl)-2-oxo-1-oxaspiro-[4.5]dec-3-en-4-yl acetate.

In the title compound, C(17)H(16)Cl(2)O(4), the cyclo-hexyl ring displays a chair conformation [the four C atoms are planar with a mean deviation of 0.001 (2) Å and the two C atoms at the flap positions deviate by 0.625 (2) and -0.

3-(2,4-Dichloro-phen-yl)-2-oxo-1-oxa-spiro-[4.5]dec-3-en-4-yl 4-chloro-benzoate.

In the title spiro-diclofen derivative, C(22)H(17)Cl(3)O(4), the cyclo-hexane ring adopts a chair conformation [four C atoms are planar with a mean deviation of 0.018 Å and the two C atoms at the flap positions deviate by 0.613 (4) and -0.

Trichodermol (4α-hydr-oxy-12,13-epoxy-trichothec-9-ene).

In the title compound, C(15)H(22)O(3), the five-membered ring displays an envelope conformation, whereas the two six-membered rings show different conformations, viz. chair and half-chair. In the crystal, mol-ecules are linked through inter-molecular O-H⋯O hydrogen bonds, forming chains running along the b axis.

2-(4-Chloro-phen-yl)-3-methyl-N-(5-methyl-thia-zol-2-yl)butanamide.

In the title compound, C(15)H(17)ClN(2)OS, the thia-zole ring, which is essentially planar with a maximum deviation of 0.044 (3) Å, makes a dihedral angle of 54.76 (8)° with the benzene ring.

3-Mesityl-2-oxo-1-oxaspiro-[4.4]non-3-en-4-yl 2-(4-chloro-phen-yl)-3-methyl-butyrate.

In the title compound, C(28)H(31)ClO(4), the five-membered cyclo-pentyl ring displays an envelope conformation with the atom at the flap position 0.519 (3) Å out of the mean plane formed by the other four atoms. The furan ring makes dihedral angles of 72.

Hapten design and indirect competitive immunoassay for parathion determination: correlation with molecular modeling and principal component analysis.

A novel procedure for parathion hapten design is described. The optimal antigen for parathion was selected after molecular modeling studies of six types of potentially immunizing haptens with the aim to identify the best mimicking target analyte. Heterologous competitive indirect enzyme-linked immunosorbent assay (ELISA) was developed after screening a battery of competitors as coating antigens.

Hapten synthesis for enzyme-linked immunoassay of the insecticide triazophos.

Two haptens of the insecticide triazophos (O,O-diethyl O-[1-phenyl-1H-1,2,4-triazol-3-yl] phosphorothioate) were synthesized by introducing appropriate spacers in the O-ethyl site of the analyte molecular structure. First, thiophosphoryl chloride (PSCl(3)) reacts with methanol at low temperature to give O-ethyl dichlorothiophosphate. After reacting with 1-phenyl-3H-1,2,4-triazol, the O-ethyl dichlorothiophosphate was transformed into the intermediate O-ethyl O-(1-phenyl-1H-1,2,4-triazol-3-yl) chlorothiophosphate.

[RAPD analysis on different varieties of Rehmannia glutinosa].

Objective: To provide molecular evidences for its breeding by studying the genetic relationship among varieties of Rehmannia glutinosa.

Method: Nineteen varieties were detected by Randomly Amplified Polymorphic DNA(RAPD) markers.

Result: The 20 selected primers produced 163 bands, among which 114(69.