Hong-Wu He

Prenylated xanthones from the bark of Garcinia xanthochymus and their 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities.

Garcinia xanthochymus has been widely used in traditional Chinese medicine for expelling worms and removing food toxins. Bioassay-guided fractionation of an EtOAc-soluble extract of G. xanthochymus stem bark led to the isolation of six new xanthones. Their structures were elucidated by spectroscopic methods, especially 2D-NMR techniques. Free-radical-scavenging activities of the isolated compounds were elucidated through DPPH method. Most of the isolated compounds showed considerable free radical scavenging activity on DPPH assay. Compound 1 exhibited effective antioxidant scavenging activity against DPPH radical with an IC50 value of 19.64 μM, and compound 6 showed the lowest activity among all the tested molecules, with an IC50 value of 66.88 μM. These findings support the notion that the plant genus Garcinia is a good source of bioactive compounds.

3-(4-Methoxy­phenoxy)-2-phenyl-3H-1-benzofuro[3,2-d]pyrimidin-1-one

Pyrimidine derivatives are attracting increasing attention in the synthetic chemistry community because of the important role played by such systems in many natural products, antibiotics and drugs (Ding et al., 2004). In recent years, we have been engaged in the preparation of derivatives of heterocycles using the aza-Wittig reaction. In this paper, we present the X-ray crystallographic analysis of the title compound, (I).

[2-(Phenyl­diazen­yl)pyrrolato]bis(2-pyridylphen­yl)iridium(III)

In the title compound, [Ir(C10H8N3)(C11H8N)2], the Ir center is octahedrally coordinated by the three chelating ligands, with two cyclometalated 2-pyridylphenyl ligands [Ir—N = 2.049 (5) and 2.030 (5) Å; Ir—C = 2.016 (6) and 2.012 (6) Å] and a bidentate 2-(phenyldiazenyl)pyrrolate ligand [Ir—N = 2.204 (5) and 2.079 (5) Å]. The Ir—N(diazenyl) bond is longer than the Ir—N(pyrrolate) bond. The structure is stabilized by aromatic π–π stacking, the shortest parallel distance between ring centroids being 3.426 (8) Å..

(S)-2-[(2,4-Dichloro­phen­yl)(hy­droxy)meth­yl]-5,5-dimethyl-1,3,2-dioxa­phosphinane 2-oxide

In the title molecule, C12H15Cl2O4P, the cyclic dioxaphosphinane ring adopts a chair conformation. In the crystal, intermolecular O—H⋯O hydrogen bonds link the molecules into chains propagating along the b axis.

N,N′-Bis[4-(trifluoro­meth­yl)phen­yl]pyridine-2,6-dicarboxamide

In the title molecule, C21H13F6N3O2, the pyridine ring forms dihedral angles of 1.7 (1) and 5.2 (1)° with the two benzene rings. In the crystal structure, intermolecular N—H⋯O hydrogen bonds and π⋯π interactions [centroid–centroid distance of 3.628 (3) Å between aromatic rings] link molecules into stacks along the c axis. The two trifluoromethyl groups are each rotationally disordered between two orientations, with occupancy ratios of 0.58 (1):0.42 (1) and 0.55 (1):0.45 (1).

(E)-Methyl 3-{3-[(4-bromo­phen­oxy)­methyl]phen­yl}acrylate

In the molecule of the title compound, C17H15BrO3, the rings make a dihedral angle of 75.54 (17)°. In the crystal structure, intermolecular C—H⋯O hydrogen bonds link the molecules into centrosymmetric dimers, and the π-stacked dimers interact with neighbouring dimers via C—H⋯π stacking interactions.

2-[(4-Chloro-phen-yl)(hy-droxy)meth-yl]-5,5-dimethyl-1,3,2-dioxaphosphinan-2-one.

In the title compound, C12H16ClO4P, the phosphonate ring adopts a chair conformation. In the crystal, intermolecular O—H⋯O hydrogen bonds link the molecules into chains propagating along the b axis.

(S)-2-[1-(4-Bromo-phen-yl)-1-hy-droxy-ethyl]-5,5-dimethyl-1,3,2-dioxaphos-phinane 2-oxide.

In the crystal structure of the title molecule, C13H18BrO4P, the phosphonate ring adopts a chair conformation. Molecules are linked by an O—H⋯O hydrogen bond [O⋯O = 2.780 (3) Å] to form chains parallel to the c axis. Two C—H⋯O interactions help to stabilize the crystal structure.

(Dimeth-oxy-phosphor-yl)(furan-2-yl)methyl 2-(2,4-dichloro-phen-oxy)acetate.

In the title compound, C15H15Cl2O7P, the benzene and furan rings form a dihedral angle of 73.54 (1)°. In the crystal, weak intermolecular C—H⋯O hydrogen bonds link the molecules into layers parallel to (100).

6-(4-Fluoro­pheneth­yl)-7-imino-3-phenyl-2,3,6,7-tetra­hydro-1,3-thia­zolo[4,5-d]pyrimidine-2-thione

In the title compound, C19H15FN4S2, the mean plane of the thiazolopyrimidine makes a dihedral angle of 77.6 (1)° with the attached phenyl ring. The crystal packing is stabilized by intermolecular C—H⋯N hydrogen bonds and weak C—H—π stacking interactions.