Synthesis, anti-oomycete activity, and SAR studies of paeonol derivatives.

Three series of sulfonate derivatives of paeonol were synthesized and screened in vitro for their anti-oomycete activity against P. capsici, respectively. Among all the compounds, 4m displayed the best promising and pronounced anti-oomycete activity against P. capsici than zoxamide, with the EC50 values of 24.51 and 26.87 mg/L, respectively. The results show that acetyl and 4-OCH3 are two necessary groups. The existence of these two sites is closely related to the anti-oomycete activity. Relatively speaking, hydroxyl group is well tolerated, and the results showed that after modification of hydroxyl group with sulfonyl, the anti-oomycete activity was significantly increased. [Formula: see text].

Reinvestigation of the Substitutions Reaction of Stereogenic Phosphoryl Compounds: Stereochemistry, Mechanism, and Applications.

Nucleophilic substitutions at P centers are of high importance in biological processes and asymmetric synthesis. However, detailed studies on this topic are rare. P-Stereogenic compounds containing P-Cl, P-O, and P-S bonds were diastereoselectively prepared and then used to study the substitution of Cl, O, and S at phosphorus centers with organometallic reagents. It was proposed that with alkynyl metallic reagents an SN2-like mechanism (route A1) and a Berry pseudorotation (BPR) of pentacoordinated phosphorus intermediates (route B1) were involved and afforded P-inverted and P-retained products, respectively. The P-inverted conversion of a P-Cl functionality to a P-C functionality can be controlled by either the temperature or the order of addition of the starting materials. The introduction of a P-Cl bond using an alkyl metallic reagent proceeded through routes A2 and A2'. At higher temperatures, P-inverted products were predominantly afforded via SN2-like route A2. At lower temperatures, bis-substituted products were formed via route A2' and cleavage of the P-O bond. The P-S bonds were accompanied by the epimerization of the starting materials, triggered by the alkylthio anion, via route C. The epimerization can be suppressed by the use of a poorly soluble magnesium alkylthiolate, and the P-retained compounds will be formed as the major products via route B3 and BPR of the intermediates.

Variable mechanism of nucleophilic substitution of P-stereogenic phosphoryl chloride with alkynyl metallic reagents.

The variable mechanism for substitution of P-stereogenic phosphoryl chloride with alkynyl metallic reagents, which depends on temperature, stoichiometry of starting materials, and the structure of the nucleophilic reagent, is assumed as either SN2-like or Berry pseudorotation of pentacoordinated phosphorus intermediates, affording inversion and retention products, respectively. The formation of the inversion product can be controlled to occur predominantly to afford (RP)-alkynylphosphinates.

Addition of optically pure H-phosphinate to ketones: selectivity, stereochemistry and mechanism.

Aromatic methyl ketones and cyclic asymmetric ketones underwent hydrophosphorylation with P-stereogenic H-P species in the presence of potassium carbonate to produce P,C-stereogenic tertiary α-hydroxyl phosphinates in excellent yields with up to 99 : 1 dr. The diastereoselectivity was induced by a reversible conversion of less stable stereomer of product to that of a more stable one via an equilibrium, which was confirmed by aldehyde/ketone exchanging reaction. Toward the exchange, aliphatic or aldehyde carbonyl were more active than aromatic or ketone carbonyls, respectively. The stability difference between the two diastereomers was controlled by the sizes of substituents linking to phosphorus or α-carbon.

(R(P),R(P))-Bis[(3-menthyloxy)(phenyl)-phosphino-yl] disulfide.

The molecule of the title compound, C(32)H(48)O(4)P(2)S(2), has 2 symmetry, the mid-point of the S-S bond being located on a twofold rotation axis. The two tetra-hedral P units are linked by a S-S bond with a P-S-S-P torsion angle is 131.19 (6)°. The dihedral angle between two phenyl rings is 12.66 (13)°. The cyclo-hexane ring of the menthoxyl group displays a chair conformation. Weak inter-molecular C-H⋯O hydrogen bonding is present in the crystal structure.

[Effect of imatinib at different concentrations on rat C6 glioma cell apoptosis and cell cycle].

OBJECTIVE: To investigate the effect of imatinib on rat C6 glioma cell apoptosis and cell cycle. METHODS: MTT assay was used to determine the OD value of C6 glioma cells following treatment with imatinib at different concentrations (0.156, 10 and 15 micromo/L) for 24, 48 and 72 h. The cell apoptosis was assayed by Hochest/PI staining and the cell cycle changes were analyzed by flow cytometry. RESULTS: Imatinib treatment resulted in increased number of apoptotic cells in a time- and dose-dependent manner. A 72-h treatment of the cells with imatinib at 10 and 15 micromo/L caused increased cell percentage in G(0)/G(1) phase to (68.53-/+0.83)% and (70.41-/+0.62)%, (P<0.01), decreased the percentage of G(2) phase cells to (14.48-/+0.12)% and (13.84-/+2.86)% (P<0.01), and decreased the percentage of S phase cells to (16.98-/+0.72)% and (15.78-/+2.28)%, respectively (P<0.01). CONCLUSION: Imatinib can induce apoptosis and affect the distribution of the cell cycle of C6 cells in vitro.

[Qualitative fingerprint and quantitative determination of caffeic acid in compound dandelion enema].

OBJECTIVE: To establish a qualitative and quantitative reversed-phase high-performance liquid chromatography (RP-HPLC) with fingerprinting technique for quality control of compound dandelion enema. METHODS: HPLC was utilized for quality assessment of 10 batches of samples. RP-HPLC analysis was performed on a Hypersil BDS C18 column (4.6 mm x 250 mm, 5 microm) with the mixture of acetonitrile (A) and potassium phosphate solution (B) (pH3.2) as the mobile phase in gradient mode. The concentrations of solvent A were 10%, 80% and 80% at 0, 38 and 40 min, respectively. The column temperature was set at 35 degrees C, the flow rate at 0.7 ml/min and the detection wavelength at 254 nm. RESULTS: HPLC fingerprinting was established from the 10 batches, and the data showed 23 characteristic peaks in the compound dandelion enema for use as index peaks for qualitative identification. Comparison of the retention time and the on-line UV spectra of the samples with the chemical standards identified peaks 3, 4 and 8 as protocatechualdehyde, caffeic acid and ferulic acid, respectively. The contents of caffeic acid in the compound dandelion enema ranged between 63.7 and 136.8 microg/ml. CONCLUSION: High specific chromatographic fingerprinting and quantitative measurement of caffeic acid allows rigorous quality control of compound dandelion enema.

[High-performance liquid chromatography combined with mass spectrum analysis for chromatographic fingerprinting of compound dandelion enema].

OBJECTIVE: To identify the active components of compound dandelion enema, a preparation from 7 traditional Chinese herbal drugs for treatment of gynecological diseases. METHODS: Three-dimensional high-performance liquid chromatography (3D-HPLC) was employed to separate the ethyl acetate extract of compound dandelion Enema, and HPLC combined with mass spectrum (MS) analysis used for chromatographic fingerprinting. RESULT: By comparing the ionic fragments of MS and retention time of each peak, the main active components in compound dandelion enema were determined, including caffeic acid, ferulic acid and protocatechualdehyde. CONCLUSION: HPLC coupled with mass spectroscopy can be used for qualitative analysis of compound dandelion enema.

[High-performance capillary electrophoresis for determining caffeic acid content in Fujie enema and Taraxacum mongolicum Hand.-Mazz].

OBJECTIVE: To determine caffeic acid content in Fujie enema and the crude traditional Chinese herbal drug Taraxacum mongolicum Hand.-Mazz. for controlling the quality of the enema at the levels of both the crude drugs and the final product. METHODS: Caffeic acid content in both the enema and the crude drug was determined at 313 nm Using high-performance capillary electrophoresis (HPCE), under the optimized conditions achieved with a fused-silica capillary tube (75 micromx0 cm) and 20 mmol/L borate running buffer (pH=9.18) at a constant voltage of 12 kV and a sampling time of 5 s at 25 degrees Celsius. RESULTS: The calibration curve displayed good linear relationship within caffeic acid concentration range of 10 to 100 microg/ml (r=0.999 2). The regression equation was Y=1002.45X-327.87, and the average recovery was more than 95%. CONCLUSION: HPCE is simple, rapid and sensitive in separation and determination of caffeic acid in Fujie enema and the crude drug of Taraxacum mongolicum Hand.-Mazz.

[Absorption and distribution of 5-aminosalicylic acid from its chitosan capsule degraded by colon bacteria-released enzymes in rats].

OBJECTIVE: To examine the absorption and distribution of 5-aminosalicylic acid (5-ASA) in rat colon after oral administration of its chitosan capsule. METHODS: 5-ASA in chitosan capsules (4.8 mg per 3 capsules) were administered orally in rats via a polyethylene cannula under light ether anesthesia. The rats in control group were given 1 ml 5-ASA carboxymethyl cellulose suspension (4.8 mg). Blood samples were obtained from the rat hearts and the colon tissues sampled at a given interval to measure the concentration of 5-ASA by HPLC. RESULTS: The area under the curve (AUC(0-12)) in the serum samples of chitosan capsule group was 0.62 times that of the control group, while in the colon tissue, the AUC(0-12) of chitosan capsule group was as much as 3.62 times that of the control group. CONCLUSION: The chitosan capsule may be a useful carrier of 5-ASA for colon-specific delivery.