Huibin Yang

Synthesis and Herbicidal Activity of Diphenyl Ether Derivatives Containing Unsaturated Carboxylates

A series of novel diphenyl ether derivatives containing unsaturated carboxylates were designed and synthesized. Their structures were identified by (1)H nuclear magnetic resonance and elemental analyses. The bioassays indicated that the compounds 5b and 5c exhibited good herbicidal activities against velvetleaf at a concentration of 30-40 g/hm(2). The relationship between structure and herbicidal activity was also discussed. Among unsaturated carboxylates group, butenoate is the most promising one. Amonst them, 4-ethoxy-4-oxobutenyl 5-(2-chloro-4-(trifluoromethyl)phenoxy)-2-nitrobenzoate 5b was identified as the most promising candidate due to its high protoporphyrinogen IX oxidase inhibition effect (pI(50) = 6.64) and good herbicidal activity against broadleaf weeds with selectivity to soybean and low toxicity to mammals.

Ethyl 3-bromo-1-(3-chloro-2-pyrid­yl)-4,5-dihydro-1H-pyrazole-5-carboxyl­ate

The title compound, C11H11BrClN3O2, contains two molecules in the asymmetric unit in which the dihedral angles between the pyrazole and pyridine rings are 30.0 (2) and 22.3 (2)°.

(E)-2-[(4-Chloro-1,3-dimethyl-1H-pyrazol-5-yl)methyl-eneamino]benzamide.

In the title compound, C13H13ClN4O, the dihedral angle between the aromatic rings is 33.47 (9)° and an intramolecular N—H⋯N hydrogen bond generates an S(6) ring. In the crystal, inversion dimers linked by pairs of N—H⋯O hydrogen bonds occur, resulting in R 2 2(8) loops.

N-[4-Chloro-2-methyl-6-(N-methyl­car­bam­oyl)phen­yl]-1-(3-chloro-2-pyrid­yl)-3-trifluoro­meth­yl-1H-pyrazole-5-carboxamide

In the title compound, C19H14Cl2F3N5O2, which shows insecticidal activity, the dihedral angle between the pyrazole and pyridine rings is 68.15 (16)°. In the crystal structure, the molecules are linked by N—H⋯O and C—H⋯O hydrogen bonds and an intramolecular N—H⋯O interaction also occurs. The F atoms of the –CF3 group are disordered over two sets of sites in a 0.800 (8):0.200 (8) ratio.