Jia-Yu Xue

Synthesis and biological evaluation of novel luteolin derivatives as antibacterial agents

A series of luteolin derivatives 2-20 were prepared, 3-20 of which were first reported. The chemical structures of these compounds were confirmed by means of 1H NMR, ESI-MS and elemental analyses. The compounds were assayed for antibacterial (Bacillus subtilis, Staphylococcus aureus, Pseudomonas fluorescens and Escherichia coli) activities by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl trtrazolium bromide) method. Among the compounds tested, most of them displayed significant activity against the tested strains, and 2-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-5-hydroxy-7-(2-(3-morpholinopropylamino)ethoxy)-4H-chromen-4-one (17) showed the most favorable antibacterial activity in vitro with MICs of 1.562, 3.125, 3.125, and 6.25 microg/mL against B. subtilis, S. aureus, P. fluorescens and E. coli, respectively. Structure-activity relationships (SAR) were also discussed based on the obtained experimental data.

Synthesis, Characterization, and Antibacterial and Cytotoxic Study of Metal Complexes with Schiff Base Ligands

The synthesis of 16 metal complexes from four Schiff bases prepared from 5-chloro-2-hydroxybenzaldehyde and primary amines has been described. The synthesized Schiff base ligands and their complexes were characterized by elemental analyses, spectroscopic (UV, IR, 1H and 13C NMR, electrospray ionization-mass spectrometry) methods, and magnetic and conductance measurements. Furthermore, complexes 1a, 1b, 3d, 4a, and 4d were characterized by X-ray diffraction analysis. After the structural characterization, all the compounds were tested in vitro for their antibacterial (Bacillus subtilis, Escherichia coli, Pseudomonas fluorescens, and Staphylococcus aureus) activities. The cytotoxic activities of the synthesized compounds were evaluated in vitro against human chronic myeloid leukaemia cells (K562) and a human nasopharyngeal epidermoid tumour cell line. The results indicated that most of the complexes showed good cytotoxic activity against human cancer cell lines but weak cytotoxic activity against a human normal cell line (L02). Among the compounds tested, the cobalt complexes 1a, 2a, 3a, and 4a showed the most favourable antibacterial and cytotoxic activities.

Novel 2,4,5-trisubstituted oxazole derivatives: synthesis and antiproliferative activity.

Microwave irradiation promotes the rapid O,N-acylation-cyclodehydration cascade reaction of oximes and acid chloride. Twenty novel 2,4,5-trisubstituted oxazole derivatives containing heterocycle moiety were synthesized and evaluated for their antiproliferative activity. The twenty compounds are all first reported and their structures were established by elemental analysis, (1)H NMR and (13)C NMR spectra. The bioassay tests showed that compounds 2-(2-(2-fluorophenyl)-4-(2,3,4-trimethoxyphenyl)oxazol-5-ylthio)benzo[d]thiazole (6af), 2-(2-(pyridin-3-yl)-4-(2,3,4-trimethoxyphenyl)oxazol-5-ylthio)pyrimidine (6bg) and 2-(2-(2-fluorophenyl)-4-(2,3,4-trimethoxyphenyl)oxazol-5-ylthio)-5-methyl-1,3,4-thiadiazole (6cf) displayed good antiproliferative activity in vitro, which were comparable to the positive control (5-fluorouracil).

Enamines as novel antibacterials and their structure-activity relationships.

Twenty-six enamines were synthesized to screen for the antimicrobial activity. Out of the compounds, 22 were reported for the first time. Their chemical structures including E/Z-configurations were clearly determined by 1H NMR, ESI mass spectra and elemental analyses, coupled with three selected single-crystal structures. In general, these synthetic compounds were shown to be more effective to inhibit growth of bacteria than fungi. The most active compound, (E)-ethyl 3-(4-hydroxyphenylamino)-2-(4-chlorophenyl)acrylate (1b), showed considerable antibacterial activities against Staphylococcus aureus ATCC 6538 with MIC of 0.5 microg/mL and against Pseudomonas fluorescens ATCC 13525 with MIC of 1.5 microg/mL, which was superior to the positive controls penicillin and kanamycin, respectively. Structure-activity relationship analysis revealed: as for A-ring, the compounds substituted at 3,5-positions were more active than 2,4-position-substituted derivatives, and halo-substituted analogs at 2-position had essentially same activities as the 4-position-substituted derivatives. Increase of steric hindrance around the nitrogen atom led to an inactive compound.

Efficient Method for the Synthesis of Tectorigenin

Abstract Tectorigenin, isolated from the rhizomes of Belamcanda chinensis, shows a wide variety of biological activities. The interest in its biological activities has been matched by a corresponding interest in its synthesis. We herein reported a convenient synthesis of tectorigenin in good yield. The starting material, 2,4,6‐trihydroxyanisole, gave the intermediate 2,4,4′,6‐tetrahydroxy‐3‐methoxydeoxybenzoin by a Hoesch reaction with 4‐hydroxyphenylacetonitrile. The intermediate was then reacted with methanesulfonyl chloride to produce a mixture of tectorigenin and Ψ‐tectorigenin. Purification of tectorigenin was unnecessary at this stage as Ψ‐tectorigenin in the mixture was isomerized to tectorigenin by refluxing in n‐BuOH in the presence of K2CO3.

Synthesis of Resveratrol Analogues, and Evaluation of Their Cytotoxic and Xanthine Oxidase Inhibitory Activities

Thirteen resveratrol (=5‐[(E)‐2‐(4‐hydroxyphenyl)ethenyl]benzene‐1,3‐diol) analogues with a CHO group have been prepared by partial synthesis from resveratrol. The synthesized compounds have been evaluated for their cytotoxic activity against a human nasopharyngeal epidermoid tumor cell line KB, as well as for their xanthine oxidase inhibitory activity. Compounds 2, 3, and 6a showed the most significant cytotoxic activities against the cell line KB, and compound 2 also exhibited strong xanthine oxidase inhibitory activity.

Synthesis of α-Aminoalkyl Phosphonate Derivatives of Resveratrol as Potential Antitumour Agents

Several α-aminoalkyl phosphonate derivatives of resveratrol were first prepared by partial synthesis from resveratrol. Antitumour activities of the synthesized compounds were determined against a human nasopharyngeal epidermoid tumour cell line KB and a human normal cell line L02 in vitro. The results indicated that these compounds showed good cytotoxic activity against KB but weak cytotoxic activity against L02. Compounds 5c and 5d showed significant cytotoxic activity against KB, with median inhibition concentration (IC50) values of 0.4 μM and 0.9 μM, respectively. On the basis of the biological results, the structure–activity relationship is discussed concisely. The potent antitumour activities shown by 5c and 5d make these resveratrol phosphonate derivatives of great interest for further investigations.

Synthesis and Structure–Activity Relationship Analysis of Enamines as Potential Antibacterial Agents

Twenty-four new enamines [(Z)-4–15 and (E)-4–15] were synthesized for the first time. Their chemical structures were determined by means of 1H NMR spectroscopy, electrospray ionization-mass spectrometry, and elemental analysis. All of the compounds were assayed for antibacterial (Bacillus subtilis ATCC 6633, Escherichia coli ATCC 35218, Pseudomonas fluorescens ATCC 13525, and Staphylococcus aureus ATCC 6538) and antifungal (Aspergillus niger ATCC 16404, Candida albicans ATCC 10231, and Trichophyton rubrum ATCC 10218) activities by the 3-(4,5-dimethyl thiazole-2yl)-2,5-diphenyl tetrazolium bromide (MTT) method. Four compounds, (E)-ethyl 3-(4-fluorophenylamino)-2-(3-methoxyphenyl)acrylate ((E)-6), (E)-ethyl 3-(4-chlorophenylamino)-2-(3-methoxyphenyl)acrylate ((E)-9), (E)-ethyl 3-(4-bromophenylamino)-2-(3-methoxyphenyl)acrylate ((E)-12), and (E)-ethyl 3-(2,4-dibromophenylamino)-2-(3-methoxyphenyl)acrylate ((E)-13) showed considerable antibacterial activity against Pseudomonas fluorescens with minimum inhibitory concentrations of 12.5, 12.5, 3.12, and 6.25 μg mL–1, respectively. Structure–activity relationship analyses revealed that, in general, an (E)-isomer exhibited higher antibacterial activity than the corresponding (Z)-isomer.

(5,5,7,12,12,14-Hexamethyl-1,4,8,11-tetra­azacyclo­tetra­decane-1,8-diacetato)nickel(II) tetra­hydrate

# 2005 International Union of Crystallography Printed in Great Britain – all rights reserved The Ni atom in the title compound, [Ni(C20H38N4O4)] 4H2O, is chelated by four N atoms of the macrocycle and also covalently bonded to two carboxylate groups, in a cis-N4O2Ni octahedral environment. The mononuclear complex interacts with the solvent water molecules to form a three-dimensional network structure.