Ghulam Qadeer

Synthesis, herbicidal, fungicidal and insecticidal evaluation of 3-(dichlorophenyl)- isocoumarins and (±)-3-(dichlorophenyl)-3,4-dihydroisocoumarins

This is the first report showing that 3-(dichlorophenyl)isocoumarins and (±)-3,4-dihydroisocoumarins are plant and plant fungus growth inhibitors. 3-Dichlorophenylisocoumarins were synthesized by condensation of homophthalic acid with dichlorobenzoyl chlorides. The alkaline hydrolysis of these isocoumarins afforded keto acids. Racemic 3-(Dichlorophenyl)-3,4-dihydroisocoumarins were obtained by reduction of keto acids to racemic hydroxy acids, followed by cyclodehydration using acetic anhydride. The herbicidal, fungicidal and insecticidal activities of the synthesized compounds have been evaluated. Some of the synthesized compounds show excellent herbicidal and fungicidal activities but none of the synthesized compounds presented any insecticidal effects on the test insects. The findings of this study suggest that isocoumarins and related compounds may serve as lead compounds towards the design of bioactive herbicides and fungicides.

4-(3-Methoxy-phen-yl)-3-[2-(4-methoxy-phen-yl)eth-yl]-1H-1,2,4-triazol-5(4H)-one.

The asymmetric unit of the title compound, C18H19N3O3, contains two crystallographically independent but similar molecules. The triazole ring is oriented with respect to the benzene rings to form dihedral angles of 57.96 (6) and 7.01 (6)° in one molecule, and 64.37 (5) and 10.73 (5)° in the other. The two independent molecules are linked into a dimer by intermolecular N—H⋯O hydrogen bonds.

1-(3-Chloro­benz­yl)-5-iodo­indoline-2,3-dione

In the title compound, C15H9ClINO2, which possesses anticonvulsant activity, the iodoindoline ring system is essentially planar (maximum deviation 1.245 Å) and is oriented with respect to the 3-chlorobenzyl ring at a dihedral angle of 76.59 (3)°. In the crystal, there is a π–π contact between iodoindoline ring systems [centroid–centroid distance = 3.8188 (4) Å].

4-(4-Methoxyphenyl)-3-[2-(2-methoxyphenyl)ethyl]-1H-1,2,4-triazol-5(4H)-one

The title compound, C18H19N3O3, is a biologically active triazole derivative. The five-membered ring is oriented with respect to the six-membered rings at dihedral angles of 51.59 (4) and 61.37 (4)°. The crystal structure is stabilized by intermolecular N—H⋯O hydrogen-bond interactions between centrosymmetrically related molecules [the dihedral angle between the benzene rings is 47.44 (5)°].

3-(3-Fluoro-benz-yl)isochroman-1-one.

In the molecule of the title compound, C16H13FO2, the aromatic rings are oriented at a dihedral angle of 74.46 (4)°. The heterocyclic ring adopts a twisted conformation. In the crystal structure, there is a weak C—H⋯π interaction.

1-(2,6-Dichloro­phen­yl)indolin-2-one

In the molecule of the title compound, C14H9Cl2NO, the planar indole ring system [with a maximum deviation of 0.020 (2) Å for the N atom] is oriented at a dihedral angle of 72.17 (3)° with respect to the phenyl ring. In the crystal structure, weak intermolecular C—H⋯O hydrogen bonds link the molecules. A weak C—H⋯π interaction may further stabilize the structure.

Methyl 2,5-dichloro-benzoate.

In the molecule of the title compound, C8H6Cl2O2, the benzene ring is oriented with respect to the planar ester group at a dihedral angle of 39.22 (3)°.

5-(2-Methoxy-benz-yl)-4-(2-methoxy-phen-yl)-4H-1,2,4-triazol-3-ol.

In the molecule of the title compound, C17H17N3O3, the triazole ring is oriented at dihedral angles of 88.09 (3) and 83.72 (3)° with respect to the 2-methoxybenzyl and 2-methoxyphenyl rings, respectively. The dihedral angle between the 2-methoxybenzyl and 2-methoxyphenyl rings is 52.95 (3)°. In the crystal structure, intermolecular N—H⋯O hydrogen bonds link the molecules into centrosymmetric dimers. There is a π–π contact between the 2-methoxyphenyl rings [centroid–centroid distance = 3.811 (3) Å].

3-(4-Methoxybenzoyl)propionic acid

In the crystal of the title compound, C11H12O4, inversion dimers arise from pairs of intermolecular O—H⋯O hydrogen bonds and C—H⋯O bonds further consolidate the packing. There is also a C—H⋯π contact between the benzene ring and the methylene group.

Ethyl 2-({5-[2-(benzoyl­amino)phen­yl]-1,3,4-oxadiazol-2-yl}sulfan­yl)acetate

In the title compound, C19H17O3N4S, a substituted oxadiazole derivative and an important biologically active compound, electron delocalization in the oxadiazole ring is reflected in the C—N bond lengths.