Synthesis and herbicidal activities of novel 3-(substituted benzyloxy or phenoxy)-6-methyl-4-(3-trifluoromethylphenyl)pyridazine derivatives.

Background: 4-(3-Trifluoromethylphenyl)pyridazine represents a new series of compounds with bleaching and herbicidal activities.

Results: A total of 43 novel 3-(substituted benzyloxy or phenoxy)-6-methyl-4-(3-trifluoromethylphenyl)pyridazine derivatives were synthesised, and their bleaching and herbicidal activities were evaluated through Spirodela polyrrhiza and greenhouse tests. Some compounds exhibited excellent herbicidal activities, even at a dose of 7.

A sensitive and highly selective fluorescent sensor for In(3+).

A simple neutral fluorescent sensor based on pyrazolo[1,5-a]pyrimidine exhibited a unique selectivity for indium(iii) ion (In(3+)) over various other metal ions with dramatic fluorescence response in acetonitrile.

Novel protoporphyrinogen oxidase inhibitors: 3H-pyrazolo[3,4-d][1,2,3]triazin-4-one derivatives.

A series of 3 H-pyrazolo[3,4-d][1,2,3]triazin-4-one derivatives were synthesized as candidate herbicides by diazotization of different 5(3)-amino- N-phenyl-1 H-pyrazole-4-carboxamide derivatives prepared by the reaction of substituted 5(3)-amino-pyrazole-4-carbonyl chloride with a substituted aniline. Their structures were identified by (1)H NMR and elemental analyses. The isomers D and E were isolated, and their structures were identified by two-dimensional NMR analyses (heteronuclear single quantum coherence and heteronuclear multiple-bond correlation) and single-crystal X-ray diffraction analysis.

Synthesis and herbicidal activities of novel 3-N-substituted amino-6-methyl-4-(3-trifluoromethylphenyl)pyridazine derivatives.

4-(3-Trifluoromethylphenyl)pyridazine is a new series of compounds with bleaching and herbicidal activities. Starting from ethyl 2-(3-trifluoromethylphenyl)acetate, an important intermediate 7 was synthesized in five steps with a moderate total yield of 51.5% in a safe and practical way.

Methyl 3-(4-{6-methyl-4-[3-(trifluoro-meth-yl)phen-yl]pyridazin-3-yl-oxy}phen-yl)propanoate.

In the title compound, C(22)H(19)F(3)N(2)O(3), the benzene rings of the trifluoro-methyl-phenyl and benzoyl-phenyl groups form dihedral angles of 41.89 (10) and 67.44 (10)°, respectively, with the pyridazine ring.

6-Methyl-2-p-tolyl-4-[3-(trifluoro-meth-yl)phen-yl]pyridazin-3(2H)-one.

In the title mol-ecule, C(19)H(15)F(3)N(2)O, the benzene rings of the tolyl and trifluoro-methyl-phenyl groups form dihedral angles of 64.1 (2) and 38.5 (2)°, respectively, with the pyridazine ring.

4-[3-(Trifluoro-meth-yl)phen-yl]-5,6,7,8-tetra-hydro-cinnolin-3(2H)-one.

The title compound, C(15)H(13)F(3)N(2)O, contains one benzene ring, one cyclo-hexane ring and a pyridazine ring. The dihedral angle formed by the pyridazine ring with the benzene ring is 61.5 (2)°.

Efficient construction of pyrazolo[1,5-a]pyrimidine scaffold and its exploration as a new heterocyclic fluorescent platform.

An efficient, fast and facile pyrazolo[1,5-a]pyrimidine synthetic protocol has been established by the condensation of aminopyrazoles with 1,3-dicarbonyl components in AcOH/H(2)SO(4) system. The pyrazolo[1,5-a]pyrimidine sulfides were selectively oxidized to the sulfones via a temperature-controlled stepwise oxidative fashion. The correlation between the substitution patterns of these pyrazolo[1,5-a]pyrimidines and their fluorescent spectroscopic properties were further examined, which provided the fundamentals for their potential applications in the development of new fluorescent probes.

A facile synthesis of novel herbicidal 1-phenyl-piperazine-2,6-diones.

Novel 1-phenyl-piperazine-2,6-diones were prepared by a new facile synthetic route using methyl N-substituted iminomonoacetate as starting material. The structures of these compounds were established by (1)H-NMR, (13)C-NMR and GC/MS. 2-(4-Chloro-5-cyclo-pentyl-oxy-2-fluorophenyl)-tetrahydro-2H-pyrido-[1,2-a]-pyrazine-1,3-(4H,6H)-dione displayed the greatest herbicidal activity.

The synthesis and herbicidal activity of 1-alkyl-3-(alpha-hydroxy-substituted benzylidene)pyrrolidine-2,4-diones.

In the search for better herbicides a series of 1-alkyl-3-(alpha-hydroxy-(un)substituted benzylidene)pyrrolidine-2,4-diones were prepared and their structure-activity relationships studied. All their structures have been confirmed by (1)H-NMR and elemental analysis. The preliminary bioassay results indicated that some of them have high herbicidal activity against annual dicotyledonous and monocotyledonous plants.

Design, synthesis, and quantitative structure-activity relationship study of herbicidal analogues of pyrazolo[5,1-d][1,2,3,5]tetrazin-4(3H)ones.

A series of pyrazolo[5,1-d][1,2,3,5]tetrazin-4(3H)one derivatives were designed, synthesized, and evaluated for their herbicidal activities where some of these compounds provided >80% control of Brassica campestris at 10 microg/mL. Quantitative structure-activity relationship studies were performed on these compounds using physicochemical parameters (electronic, Verloop, or hydrophobic) as independent parameters and herbicidal activity as a dependent parameter, where herbicidal activity correlated best (r > 0.8) with physicochemical parameters in this set of molecules.

tert-Butyl 4-({[(E)-1,3-dimethyl-5-phen-oxy-pyrazol-4-yl]meth-yl}amino-oxymeth-yl)benzoate.

The title compound, C(24)H(27)N(3)O(4), also known as fenpyroximate, is a commercial acaricide. The benzene ring of the phen-oxy group is approximately perpendicular to the pyrazole ring with a dihedral angle of 84.37 (11)°.

A quantitative structure-activity relationship study of herbicidal analogues of alpha-hydroxy-substituted 3-benzylidenepyrrolidene-2,4-diones.

A series of pyrrolidine-2,4-dione and piperidine-2,4-dione derivatives were prepared and evaluated for their herbicidal activities where some of these compounds exhibited good bioactivity against Echinochloa crus-galli in comparison with sulcotrione. Quantitative structure-activity relationship studies were performed on these compounds using physicochemical parameters (hydrophobic, electronic, and Taft) as independent parameters and herbicidal activity as a dependent parameter, where herbicidal activity correlated best (r > 0.8) with hydrophobic (pi(o) + pi(p)), steric (Es), STERIMOL (B4), indicator (H(M)), van der Waals volume (V), and electronic parameter (sigma(m) + sigma(p)) in this set of molecules; the optimum van der Waals volume for R(2) is about 41.

Synthesis and herbicidal activity of novel alpha,alpha,alpha-trifluoro-m-tolyl pyridazinone derivatives.

A series of novel alpha,alpha,alpha-trifluoro-m-tolyl pyridazinone derivatives was synthesised. Herbicidal activities of the two intermediate compounds and 15 pyridazinone derivatives were evaluated through barnyardgrass and rape cup tests and Spirodela polyrrhiza (L.) Schleiden tests.

Ethyl 5-amino-3-(4,6-dimethylpyrimidin-2-ylamino)-1-methyl-1H-pyrazole-4-carboxylate and ethyl 5-amino-3-(4,6-dimethylpyrimidin-2-ylamino)-1-(2-nitrophenylsulfonyl)-1H-pyrazole-4-carboxylate.

The molecular structures of ethyl 5-amino-3-(4,6-dimethylpyrimidin-2-ylamino)-1-methyl-1H-pyrazole-4-carboxylate, C13H18N6O2, (I), and ethyl 5-amino-3-(4,6-dimethylpyrimidin-2-ylamino)-1-(2-nitrophenylsulfonyl)-1H-pyrazole-4-carboxylate, C18H19N7O6S, (II), have been determined. There are two intramolecular N-H..

Three trifluoromethyl-substituted protoporphyrinogen IX oxidase inhibitors.

The structures of methyl 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoate, C15H9ClF3N3O5, (I), methyl 2-chloro-5-[3-methyl-2,6-dioxo-4-(trifluoromethyl)-1,2,3,6-tetrahydropyrimidin-1-yl]benzoate, C14H10ClF3N2O4, (II), and 2-[4-chloro-2-fluoro-5-(prop-2-ynyloxy)phenyl]-4-(trifluoromethyl)piperidine-2,6-dione, C15H10ClF4NO3, (III), are similar in their dihedral angles and in the distances between the farthest two atoms. There are two independent molecules in the structure of (I). The dihedral angles between the two aromatic rings in each molecule in (I), between the benzene and tetrahydropyrimidine rings in (II), and between the benzene ring and the five-atom planar portion of the piperidine-2,6-dione ring in (III) are 80.

Two isomeric 2-[4-chloro-2-fluoro-5-(prop-2-ynyloxy)phenyl]hexahydroisoindole-1,3-dione compounds.

The molecular structures of 2-[4-chloro-2-fluoro-5-(prop-2-ynyloxy)phenyl]-1,3,4,5,6,7-hexahydroisoindole-1,3-dione, C17H13ClFNO3, (I), and the isomeric compound 2-[4-chloro-2-fluoro-5-(prop-2-ynyloxy)phenyl]-cis-1,3,3a,4,7,7a-hexahydroisoindole-1,3-dione, (II), are, as anticipated, significantly different in their conformations and in the distances between the farthest two atoms. The six-membered ring of the 1,3,4,5,6,7-hexahydroisoindole-1,3-dione moiety in (I) adopts a half-chair conformation. The dihedral angle between the five-membered dione ring of (I) and the benzene ring is 50.