Synthesis and study of N,N‐disubstituted 4‐[(4‐aminophenyl)diazenyl]benzylidene‐4′‐alkylanilines

A series of N,N‐disubstituted‐4‐[(4‐aminophenyl)diazenyl]benzylidene‐4′‐alkylanilines (azo dyes) were synthesized from the reaction of the corresponding benzaldehyde with alkylanilines. These azo dyes exhibit nematic and SmC phases on heating. Their order parameter, photo‐stability and miscibility were studied by investigation of a representative sample.     

Palladacyclic complexes bearing CNN-type ligands as catalysts in the Heck reaction

Preparations of novel unsymmetrical, tridentate nitrogen ligand precursors, PhN=C(CMe2)(NPh)C=N(CH2)2NMe2(1) and PhN=C(CMe2)(NPh)C=N(CH2)Py (2), are described. Treatment of 1 with 1 molar equiv. (COD)PdCl2 in the presence of NEt3 or with 1 molar equiv. Pd(OAc)2 affords orthometallated palladium(II) complexes, [PhN=C(CMe2)(N-eta1-Ph)C=N(CH2)2NMe2]PdX (X=Cl (3); X=OAc (4)), respectively. Compound can be yielded via the reaction of with an excess of LiCl in methanol. Treatment of with 1 molar equiv. of (COD)PdCl2, Pd(OAc)2 or Pd(TFA)2 affords orthometallated palladium(II) complexes, [PhN=C(CMe2)(N-eta1-Ph)C=NCH2Py]PdX (X=Cl (5); X=OAc (6); X=TFA (7)), respectively. The crystal and molecular structures are reported for compounds 2, 3, 5 and 6. The application of these novel palladacyclic complexes to the Heck reaction with aryl halide substrates was examined.     

Synthesis and antiproliferative evaluation of 2,3-diarylquinoline derivatives

A number of 2,3-diarylquinoline derivatives were synthesized and evaluated for antiproliferative activities against the growth of six cancer cell lines including human hepatocellular carcinoma (Hep G2 and Hep 3B), non-small cell lung cancer (A549 and H1299), and breast cancer (MCF-7 and MDA-MB-231) cell lines. The preliminary results indicated that 6-fluoro-2,3-bis{4-[2-(piperidin-1-yl)ethoxy]phenyl}quinoline (16b) was one of the most active compounds against the growth of Hep 3B, H1299, and MDA-MB-231 with a GI(50) value of 0.71, 1.46, and 0.72 μM respectively which was more active than tamoxifen. Further investigations have shown that 16b induced cell cycle arrest at G2/M phase followed by DNA fragmentation via an increase in the protein expression of Bad, Bax and decrease in Bcl-2, and PARP which consequently cause cell death.     

Fine Substituent Effects in Sandwich Complexes: A Threshold Ionization Study of Monosubstituted Chromium Bisarene Compounds

Mass‐analyzed threshold ionization spectra of jet‐cooled [(η⁶‐PhMe)(η⁶‐PhH)Cr] and [(η⁶‐Ph₂)(η⁶‐PhH)Cr] reveal with unprecedented accuracy the effects of methyl and phenyl groups on the electronic structure of bis(η⁶‐benzene)chromium. These “pure” substituent effects allow quantitative experimental determination of the ionization energy changes caused by the mutual substituent influence in bisarene systems. Two types of such influence have been revealed for the first time in bis(η⁶‐toluene)chromium.     

Vibrations and theoretical calculations of p-methylanisole in the first electronically excited S1 and ionic ground D0 states

One-color (1C), two-color (2C) resonant two-photon ionization (R2PI), and mass analyzed threshold ionization (MATI) methods have been applied to study the S(1)<--S(0) transition and threshold ionization of p-methylanisole. The excitation energy of the S(1)<--S(0) transition is determined to be 35,401+/-2 cm(-1), the adiabatic ionization energy of this molecule is measured to be 63,965+/-15 and 63,972+/-5 cm(-1) by the 2C-R2PI and MATI methods. Most of the observed R2PI and MATI bands result from the in-plane ring vibrations. The frequencies of vibrations 9b, 1 and 7a are measured to be 393, 800 and 1168 cm(-1) in the S(1) state, and 412, 811 and 1220 cm(-1) in the D(0) state, respectively. This indicates the molecular structure in the D(0) state is more rigid than that in the S(1) state.     

Geiparvarin Analogues: Synthesis and Anticancer Evaluation of α-Methylidene-γ-butyrolactone-Bearing Coumarins

To determine some of the structural features of geiparvarin that account for its cytostatic activity in vitro, certain geiparvarin analogues modified in the furan-3(2H)-one moiety and the alkenyloxy substituent were synthesized and tested against the growth of 60 human cancer cell lines derived from nine cancer-cell types. These compounds demonstrated a strong growth-inhibitory activity against leukemia cell lines but were relatively inactive against non-small-cell lung cancers and CNS cancers. Comparison of the mean log GI₅₀ values of γ-[(E)-1-methylprop-1-enyl]-α-methylidene-γ-butyrolactones 7 – 9 revealed that 7-[(E)-3-(2,3,4,5-tetrahydro-4-methylidene-5-oxofuran-2-yl)but-2-enyloxy]-2H- 1-benzopyran-2-one ( 8 ; −5.47) was more active than its 6-substituted counterpart 7 (−5.21) and its 3-chloro-4-methyl derivative 9 (−5.31) and had a potency similar to that of geiparvarin (log GI₅₀=−5.41). These results indicated that the furan-3(2H)-one moiety of geiparvarin could be replaced by an α-methylidene-γ-butyrolactone unit without losing the anticancer potency, and that the best substitution site at the coumarin moiety was C(7). The alkenyloxy substituent of 8 was also replaced by a methoxy substituent. Among these α-methylidene-γ-butyrolactones, 7-[(2,3,4,5-tetrahydro-4-methylidene-5-oxo-2-phenylfuran-2-yl)methoxy]-2H-1-benzopyran-2-one ( 11 ) was the most potent with a mean log GI₅₀ value of −5.83 and a range value of 132 (10^2.12).     

Simultaneous determination of thymidylate and thymidine diphosphate by capillary electrophoresis as a rapid monitoring tool for thymidine kinase and thymidylate kinase activities

A simple and rapid capillary electrophoretic method was developed for the simultaneous determination of thymidylate (TMP) and thymidine 5'-diphosphate (TDP) in enzyme assays without using radioactive-labeled substrates. Prior to electrophoretic separation, addition of acetonitrile and sodium chloride to the assay solution and brief centrifugation are recommended for the purpose of sample cleanup and sample stacking. The separation of micromolar TMP and TDP from millimolar adenosine 5'-triphosphate (ATP) was performed at 25 degrees C using sodium tetraborate as the background electrolyte. Under the optimal condition, a good separation with high efficiency was achieved in 6 min. Several parameters affecting the separation were studied, including the pH of electrolyte, the applied voltage, and acetonitrile-salt sample stacking. The fronting of the ATP peak resulting from the interference of magnesium ion in the enzyme assay buffer was suppressed by the addition of sodium ethylenediaminetetraacetate to the sample solution. Using deoxyadenylate as an internal standard, the linear range of the method was 5-200 microM, and the concentration limits of detection of TMP and TDP were 2.6 and 3.8 microM, respectively. Application of the proposed method for simultaneous determination of TMP and TDP in enzyme assays was demonstrated by the activity assays of thymidine kinase and thymidylate kinase from white spot syndrome virus. This is a sensitive, nonradioactive method for thymidine kinase and thymidylate kinase assays.