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ABSTRACT: 4-(3-Trifluoromethylphenyl)pyridazine represents a new series of compounds with bleaching and herbicidal activities.
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 7.5 g ha(-1).
The results showed that a substituted phenoxy group at the 3-position of the pyridazine ring and the electron-withdrawing group at the para-position on the benzene ring were essential for high herbicidal activity.
Pest Management Science 11/2011; 68(2):276-84. · 2.25 Impact Factor
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ABSTRACT: 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.
Organic & Biomolecular Chemistry 08/2010; 8(15):3394-7. · 3.70 Impact Factor
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Journal of Heterocyclic Chemistry 06/2009; 46(4):584 - 590. · 1.22 Impact Factor
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ABSTRACT: A series of novel 6,7,8,9-tetrahydro-2-(2-aryloxypyrimidin-4-yl)-2H-[1,2,4]triazolo[4,3-a]azepin-3(5H)-ones were designed and efficiently synthesized. Their structures were determined by IR, 13C and 1H NMR, mass spectroscopy, and elemental analysis. These compounds were screened for herbicidal activities against rape and barnyard grass. Compounds 5a-5f and 5m exhibited moderate herbicidal activity against rape. In addition, the synthesis of the intermediate 1-(azepan-2-ylidene)-2-(2-chloropyrimidin-4-yl)-hydrazine (3) was studied and the reason for the low yield in the initial procedure is discussed as well.
Journal of Heterocyclic Chemistry 03/2009; 43(5):1275 - 1280. · 1.22 Impact Factor
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ABSTRACT: A series of novel sulfone-containing pyrazolo[1,5-a]pyrimidines (2-3) and pyrazolo[5,1-d][1,2,3,5]tetra-zine-4(3H)-ones (5a-5k) were designed and efficiently synthesized, some of which have been identified as being potential rape inhibitors. These results widen the structural diversity of rape inhibitors and confirm the perspectives of further investigations in this area. Moreover, a plausible reaction mechanism is outlined.
Journal of Heterocyclic Chemistry 03/2009; 42(4):609 - 613. · 1.22 Impact Factor
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Hua-bin Li,
You-quan Zhu,
Xiao-wei Song,
Fang-zhong Hu,
Bin Liu,
Yong-hong Li,
Zi-xia Niu,
Pei Liu,
Zhi-hong Wang,
Hai-bin Song,
Xiao-mao Zou, Hua-zheng Yang
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ABSTRACT: 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. The bioassay results showed that some of the title compounds exhibited both excellent herbicidal activity at a dose of 93.75 g/ha and strong inhibition against protoporphyrinogen oxidase activity in vitro. The structure-activity relationship showed that D16 possessed the highest activities both in vivo and in vitro when the N-substituted group of the pyrazole ring was allyl and the N-substituted group of benzooxazinone was propargyl.
Journal of Agricultural and Food Chemistry 10/2008; 56(20):9535-42. · 2.82 Impact Factor
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ABSTRACT: 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. Twenty-six novel 3-N-substituted amino-6-methyl-4-(3-trifluoromethylphenyl)pyridazine derivatives were synthesized and evaluated through a Spirodela polyrrhiza test and greenhouse test. Some compounds can completely inhibit Chl at 1 microg/mL and exhibit equal or higher herbicidal activities with the commercial bleaching herbicide diflufenican against dicotyledonous plants at a rate of 75 g/ha.
Journal of Agricultural and Food Chemistry 08/2008; 56(15):6567-72. · 2.82 Impact Factor
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ABSTRACT: 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. Red-shifts were easily achieved by the incorporation of unsaturated groups at the 5- and 7-positions, which suggested an approach for synthesizing long wavelength pyrazolo[1,5-a]pyrimidine dyes. The fluorescent spectroscopic properties were found to be sensitive to the hydroxy-containing and carbonyl-containing media such as alcohol and acetone, which helps to confirm the promising perspectives of further investigations in this area.
Journal of Fluorescence 04/2008; 18(2):357-63. · 2.11 Impact Factor
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ABSTRACT: 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. The methyl-propanoate group is nearly coplanar with the attached benzene ring [dihedral angle = 3.9 (2)°]. The trifluoro-methyl group is disordered over two positions; the site-occupancy factors are ca 0.64 and 0.36. In the crystal structure, inversion-related mol-ecules are linked through C-H⋯O hydrogen bonds and C-H⋯π inter-actions.
Acta Crystallographica Section E Structure Reports Online 01/2008; 64(Pt 6):o1044. · 0.35 Impact Factor
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ABSTRACT: 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)°. The crystal structure is stabilized by two inter-molecular hydrogen bonds (N-H⋯O and C-H⋯F). The cyclohexane ring adopts a screw-boat conformation. The CF(3) group is disordered over two positions; the site occupancy factors are ca 0.6 and 0.4.
Acta Crystallographica Section E Structure Reports Online 01/2008; 64(Pt 2):o464. · 0.35 Impact Factor
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ABSTRACT: 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. The CF(3) group is disordered over two orientations, with site-occupancy factors of ca 0.56 and 0.44.
Acta Crystallographica Section E Structure Reports Online 01/2008; 64(Pt 4):o675. · 0.35 Impact Factor
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ABSTRACT: A series of 2-(3-(trifluoromethyl)-5-(alkoxy)-1H-pyrazol-1-yl)-4-aryloxypyrimidine derivatives were designed and synthesized. The structures of all the title compounds were confirmed by 1H NMR and elementary analysis. These compounds were screened for herbicidal activity against rape and barnyard grass. Compound B13 exhibited moderate herbicidal activity.
Journal of Heterocyclic Chemistry 06/2007; 44(4):967 - 971. · 1.22 Impact Factor
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ABSTRACT: 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. The herbicidal activity against B. campestris was mainly affected by the molar refractivity (MR) for R1, Taft (Eso) for R2 or R6, Verloop (Lm) for R3 or R5, and electronic parameters (Hammett's constants) for R4. The optimal MR for herbicidal activity is 0.95. The herbicidal activity against Echinochloa crus-galli was mainly related with the substituents' hydrophobic parameter. The optimal pi parameters for R1 and R4 for herbicidal activity are 0.72 and 0.68, respectively. In general, these compounds showed greater herbicidal activity toward B. campestris than E. crus-galli.
Journal of Agricultural and Food Chemistry 03/2007; 55(4):1364-9. · 2.82 Impact Factor
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ABSTRACT: 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)°. The dihedral angle between the phen-oxy and the benzoate benzene rings is 48.83 (8)°.
Acta Crystallographica Section E Structure Reports Online 01/2007; 64(Pt 1):o192. · 0.35 Impact Factor
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ABSTRACT: 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 41.8 A3; when B4 is equal to 3, the target molecule possessed the lowest herbicidal activity.
Journal of Agricultural and Food Chemistry 09/2006; 54(19):7200-5. · 2.82 Impact Factor
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ABSTRACT: 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. Selected compounds were also evaluated under greenhouse conditions. Bleaching activities were observed at 10 microg ml(-1) and some compounds exhibited herbicidal activities at a rate of 300 g ha(-1). The relationship between crystal structures and herbicidal activities is discussed through a comparison of two compounds (5a and 5f).
Pest Management Science 07/2006; 62(6):522-30. · 2.25 Impact Factor
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ABSTRACT: A series of novel ,,-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. Selected compounds were also evaluated under greenhouse conditions. Bleaching activities were observed at 10 µg ml−1 and some compounds exhibited herbicidal activities at a rate of 300 g ha−1. The relationship between crystal structures and herbicidal activities is discussed through a comparison of two compounds (5a and 5f). Copyright © 2006 Society of Chemical Industry
Pest Management Science 04/2006; 62(6):522 - 530. · 2.25 Impact Factor
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ABSTRACT: A series of 2-cyano-3-methylthio-3-substituted methylaminoacrylates were synthesized as herbicidal inhibitors of photosystem II (PSII) electron transport, in order to estimate the effect of fluorine atom, pyridyl group, chirality and ester chain on activity. The important intermediate 2-fluoro-5-aminomethylpyridine was synthesized with high yield. The bioassay results showed that most of title compounds had high herbicidal activity in postemergence treatment. The introduction of an -methyl into the 3-substituted methylamino could improve the activity notably. The replacement of hydrogen by chlorine or fluorine group and phenyl by pyridyl group showed different effects, and at the same time, the ester chain affected the activity too.
Chinese Journal of Chemistry 03/2006; 24(4):521 - 526. · 0.75 Impact Factor
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ABSTRACT: 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...O bonds and one intermolecular N-H...O hydrogen bond in (I). The rings formed by the N-H...O hydrogen bonds are almost planar. In (II), three intramolecular N-H...O hydrogen bonds exist.
Acta Crystallographica Section C Crystal Structure Communications 06/2005; 61(Pt 5):o281-3. · 0.52 Impact Factor
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ABSTRACT: 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 50.96 (7) degrees . The six-membered ring of the cis-1,3,3a,4,7,7a-hexahydroisoindole-1,3-dione moiety in (II) adopts a boat conformation. The dihedral angle in (II) between the five-membered dione ring and the benzene ring is 61.03 (13) degrees . In the crystal structures, the molecules are linked by C-H...O hydrogen bonds and weak pi-pi interactions. Compound (I) is a much more potent herbicide than (II). The Cl...H distances between the farthest two atoms in (I) and (II) are 11.37 and 9.97 A, respectively.
Acta Crystallographica Section C Crystal Structure Communications 03/2005; 61(Pt 2):o114-7. · 0.52 Impact Factor
