Hua-Zheng Yang

1-Benzyl-3-(α-hydroxy­benzyl­idene)­pyrrolidine-2,4-dione

The title compound, C18H15NO3, is a potent new herbicide containing the pyrrolidine-2,4-dione ring system. In the crystalline state, the molecular skeleton contains one enol hydrogen-bonded moiety, formed from benzoyl Czdbnd;O isomerization.

3-(α-Hydro­xy-2-methoxy­lbenzyl­idene)-1-iso­propyl­pyrrolidine-2,4-dione

The title compound, C15H17NO4, is a potent new herbicide containing the pyrrolidine-2,4-dione ring system. In the crystalline state, the molecular skeleton contains one enol grouping, which is intramolecularly hydrogen bonded to a neighboring keto O atom.

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 1H-NMR, 13C-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.

2-Chloro-4-(3,5-di­methyl-1H-pyrazol-1-yl)­pyrimidine

In the crystal structure of the title compound, C9H9ClN4, there are non-classical intramolecular C—H⋯N hydrogen bonds and intermolecular C—H⋯π interactions.

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 80.78 (11)/89.75 (11), 89.13 (9) and 87.52 (13) degrees , respectively. The distances between the farthest two atoms, viz. O...F in the two molecules of (I), and Cl...F in (II) and (III), are 11.763 (7)/11.953 (6), 10.734 (10) and 10.889 (9) A, respectively. In all three crystal structures, the molecules are linked to generate sheets of molecules via C-H...O interactions.

4‐(4‐tert‐Butyl­phen­oxy)‐2‐chloro­pyrimidine

In the title compound, C14H15ClN2O, the benzene and pyrimidine rings are nearly perpendicular, the dihedral angle between them being 84.7 (2)°.

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...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.

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 50.96 (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.