Bioassay-Guided Isolation and Structure Elucidation of Fungicidal and Herbicidal Compounds from Ambrosia salsola (Asteraceae)

The discovery of potent natural and ecofriendly pesticides is one of the focuses of the agrochemical industry, and plant species are a source of many potentially active compounds. We describe the bioassay-guided isolation of antifungal and phytotoxic compounds from the ethyl acetate extract of Ambrosia salsola twigs and leaves. With this methodology, we isolated and identified twelve compounds (four chalcones, six flavonols and two pseudoguaianolide sesquiterpene lactones). Three new chalcones were elucidated as (S)-beta-Hydroxy-2,3,4,6\u27-tetrahydroxy-5-methoxydihydrochalcone (salsolol A), (S)-beta-Hydroxy-2\u27,4,4\u27,6\u27-tetrahydroxy-3-methoxydihydrochalcone (salsolol B), and (R)-alpha, (R)-beta-Dihydroxy-2,3,4,4,6\u27-pentahydroxydihydrochalcone (salsolol C) together with nine known compounds: balanochalcone, six quercetin derivatives, confertin, and neoambrosin. Chemical structures were determined based on comprehensive direct analysis in real time-high resolution mass spectrometry (HR-DART-MS), as well as 1D and 2D NMR experiments: Cosy Double Quantum Filter (DQFCOSY), Heteronuclear Multiple Quantum Coherence (HMQC) and Heteronuclear Multiple Bond Coherence (HMBC), and the absolute configurations of the chalcones were confirmed by CD spectra analysis. Crystal structure of confertin was determined by X-ray diffraction. The phytotoxicity of purified compounds was evaluated, and neoambrosim was active against Agrostis stolonifera at 1 mM, while confertin was active against both, Lactuca sativa and A. stolonifera at 1 mM and 100 mu M, respectively. Confertin and salsolol A and B had IC50 values of 261, 275, and 251 mu M, respectively, against Lemna pausicotata (duckweed). The antifungal activity was also tested against Colletotrichum fragariae Brooks using a thin layer chromatography bioautography assay. Both confertin and neoambrosin were antifungal at 100 mu M, with a higher confertin activity than that of neoambrosin at this concentration

(3aR,6aR)-1-Phenyl-5-[(R)-1-phenyl­ethyl]-3-[4-(trifluoro­meth­yl)phen­yl]-1,6a-dihydro­pyrrolo[3,4-c]pyrazole-4,6(3aH,5H)-dione

In the title mol­ecule, C26H20F3N3O2, the two central five-membered rings form a dihedral angle of 62.94 (8)°. The absolute configuration was determined by analysis of Bijvoet pairs based on resonant scattering of light atoms, yielding a Hooft parameter y = −0.05 (11). Notable intra- and inter­molecular contacts include C—H⋯O and C—H⋯π(arene) hydrogen bonds

A cycloaddition product of a chiral maleimide: 4-{(3aS*,6aS*)-4,6-dioxo-1-phenyl-5-[(1R)-1-phenyl­ethyl]-1,3a,4,5,6,6a-hexa­hydro­pyrrolo[3,4-c]pyrazol-3-yl}phenyl acetate

In the title mol­ecule, C27H23N3O4, the two central five-membered rings form a dihedral angle of 63.66 (4)°. The absolute configuration was determined by analysis of Bijvoet pairs based on resonant scattering of light atoms, yielding a Hooft parameter y = −0.10 (7)

2,4-Dichloro­phenyl 4-bromo­benzene­sulfonate

In the title mol­ecule, C12H7BrCl2O3S, the dihedral angle between the two benzene rings is 55.18 (5)°. The notable inter­molecular contacts include C—H⋯O and π–π inter­actions [centroid–centroid distances = 4.037 (1) and 3.349 (1) Å]

4-Nitro­phenyl 4-bromo­benzene­sulfonate

In the title mol­ecule, C12H8BrNO5S, the dihedral angle between the two benzene rings is 30.02 (7)°. The crystal structure is stabilized by weak C—H⋯O inter­actions

Simultaneous Enhancement of Near-Infrared Emission and Dye Photodegradation in a Racemic Aspartic Acid Compound via Metal-Ion Modification

Changing functionalities of materials using simple methods is an active area of research, as it is green and lowers the developing cost of new products for the enterprises. A new small molecule racemic N,N-dimethyl aspartic acid has been prepared. Its structure is determined by single-crystal X-ray diffraction. It is characterized by FTIR, XPS, 1 H NMR, and mass spectroscopy. Its near-infrared luminescence can be enhanced by the combination of metal ions, including Dy3+, Gd3+, Nd3+, Er3+, Sr3+, Y3+, Zn2+, Zr4+, Ho3+, Yb3+, La3+, Pr6+/Pr3+, and Sm3+ ions. An optical chemistry mechanism upon interaction between the sensitizer and activator is proposed. Furthermore, the association of Ca2+, Sr2+, or Zr4+ ions to the molecule enhanced its photodegradation for dyes under white-light irradiation. Specifically, rhodamine 6G can be degraded by the Ca2+-modified molecule; rhodamine B, rhodamine 6G, and fluorescein sodium salt can be degraded by the Sr2+- or Zr4+-modified molecule. This surprising development opens a way in simultaneously increasing NIR luminescence and the ability of dye photodegradation for the investigated molecule

11β,13-Dihydro­lactucin-8-O-acetate hemihydrate

The title structure (systematic name: 9-hydroxy­methyl-3,6-di­methyl-3-methyl­ene-2,7-dioxo-3,3a,4,5,9a,9b-hexa­hydro­azu­leno[4,5-b]furan-4-yl acetate hemihydrate), C17H20O6·0.5H2O, from Lactuca floridana, has two independent sesquiterpene lactone mol­ecules in the asymmetric unit. Both have their seven-membered rings in the chair conformation. In the crystal, the OH groups and the water mol­ecule form classical O—H⋯O hydrogen bonds with O⋯O distances in the range 2.6750 (17)–2.8160 (18) Å

Chlorido(1-cyclo­pentyl­idene-4-ethyl­thio­semicarbazidato-κ2 N 1,S)diphenyl­tin(IV)

The Sn atom in the title compound, [Sn(C6H5)2(C8H14N3S)Cl], is penta­coordinated with a trigonal-bipyramidal coordination geometry. The 1-cyclo­pentyl­idene-4-ethyl­thio­semicarbazidate (cpetsc) ligand coordinates through the S atom and the N atom bonds to the cyclo­pentyl group, forming a five-membered ring with the Sn center. The chloride ligand and the coordinated N atom are in axial positions. In the crystal structure, inter­molecular N—H⋯Cl hydrogen bonds form chains along [101]