Synthesis and Antiproliferative Activity of Cyano and Amidino Substituted 2-Phenylbenzothiazoles

Series of cyano, dicyano, amidino, and diamidino substituted 2-phenylbenzothiazoles were prepared. Mono- and dicyano substituted benzothiazoles were obtained by condensation of appropriate substituted benzaldehydes with 2-aminothiophenol or 4-amino-3-mercaptobenzonitrile. The appropriate amidines or diamidines were prepared by Pinner reaction. The compounds were tested against breast, prostate, and lung cancer cell lines in a 72 h cytotoxicity assay. Many of the compounds had at 10 μM activity equivalent to 2-(4-aminophenyl)benzothiazole, while four compounds had significantly better activity, particularly in the breast cancer model.     

Biological Studies of Some 2,4-Dichloro-5-fluorophenyl Containing Triazolothiadiazoles

Summary. A series of dichlorofluorophenyl containing triazolothiadiazoles were obtained by cyclocondensation of triazole with substituted benzoic, aryloxyacetic, and anilinoacetic acids using POCl₃ as cyclizing agent. The structures of the newly synthesized compounds were characterized and confirmed by IR, ¹H NMR, mass spectra, and elemental analysis. Selected compounds were screened for their antitubercular activity against Mycobacterium tuberculosis. The compound bearing 2,4-dichloro-5-fluorophenyl moiety at position 3, and 6 of the triazolothiadiazole showed excellent activity in vitro primary screening. Compounds with 3-chloro-4-fluorophenyl and 4-fluorophenoxymethyl moieties at position 6 of the triazolothiadiazole showed very good analgesic activity. Triazolothiadiazole with 4-chlorophenyl, 4-fluoro-3-phenoxyphenyl, and 2,4-dichloro-5-fluorophenyl moieties showed excellent antimicrobial activity against the tested strains at 6.25 μg cm⁻³ concentrations.     

Oxygen evolution on Ru1 − x Ni x O2 − y nanocrystalline electrodes

Nanocrystalline Ru_1 − x Ni _x O_2 − y with 0.02 < x < 0.30 were prepared by a sol–gel approach at temperatures between 300 and 600 °C. XRD patterns of the prepared materials indicate a single-phase character conforming to a tetragonal syngony. All prepared materials are sufficiently stable in acid media and show activity towards oxygen evolution. The activity towards oxygen evolution reaction of the materials with constant chemical composition decreases with increasing particle size. The increasing Ni content enhances the electrocatalytic activity in a stepwise manner with abrupt changes for materials containing approximately 5% or 15% of the cationic sites substituted by Ni.     

Synthesis and Reactivity of Stannyloligosilanes IV [1]: From Hydrido Substituted Stannasilanes Towards Stannasiloxanes

Summary.  Hydrido substituted stannasilanes of the type or (Z = H, Me, Ph; R, R′ = alkyl, Ph) are accessible by reaction of either alkali metal stannides (MSn(Z)R ₂; M = Li, Na) with halogen substituted silanes (; X = F, Cl) or chlorostannanes (R ₂SnCl₂, Ph₃SnCl) and fluorosilanes in the presence of magnesium. Stannasilanes with halogen substituents at the silicon as well as the tin atom are formed by treatment of the hydrido substituted stannasilanes with CHCl₃ or CCl₄. The hydrido substituted stannasilanes decompose in contact with air to distannanes and siloxanes or to the linear ( ^t Bu₂Sn(–O– ^t Bu₂Si–OH)₂) and cyclic ((– ^t Bu₂Sn–O– ⁱ Pr₂Si–O–)₂) stannasiloxanes. Received November 29, 2001. Accepted (revised) January 16, 2002     

Solvothermal Syntheses,Crystal Structures,and Properties of New [Mn(<Emphasis Type="BoldItalic">dien</Emphasis>)<Subscript>2</Subscript>]<Superscript>2+</Superscript> Complexes

Summary.  The two new compounds Mn(dien)₂[MoS₄] (1) and Mn(dien)₂[Mo₂O₂S₆] (2) (dien = diethylenetriamine) were prepared under solvothermal conditions. Both compounds were obtained as phase-pure products. The structures consist of new [Mn(dien)₂]²⁺ cations and isolated tetrahedral [MoS₄]²⁻ (1) or [Mo₂O₂S₆]²⁻ (2) anions. Between the anions and the cations, hydrogen bonding is observed. Compound 1 crystallizes in the tetragonal space group I (a = 10.219(2), c = 9.259(2) ?, Z = 2), whereas 2 crystallizes in the monoclinic space group P2₁/c (a = 8.703(2), b = 18.390(4), c = 14.603(3) ?, β = 103.18(3)°, Z = 4). The thermal behaviour of the thiomolybdates was investigated using difference thermoanalysis (DTA) and thermogravimetry (TG). Both compounds decompose under argon with a single endothermic signal in the DTA curve (peak maximum: 252 (1) and 242°C (2)). Received November 5, 2001. Accepted December 27, 2001     

Synthesis,antiinflammatory and antimicrobial activities of some 2,4-dichloro-5-fluorophenyl substituted arylidenetriazolothiazolidinones

A series of 2,4-dichloro-5-fluorophenyl substituted arylidenetriazolothiazolidinones were obtained by one-pot reaction of 3-(2,4-dichloro-5-fluorophenyl)-4H-1,2,4-triazole-5-thiol with substituted benzaldehydes and monochloroacetic acid in the presence of acetic anhydride, acetic acid, and sodium acetate. The structures of the newly synthesized compounds were characterized and confirmed by IR, ¹H NMR, mass spectra, and elemental analysis. Compounds bearing the 4-methylthiophenyl, 3,4-methylenedioxyphenyl, and 2,3,5-trichlorophenyl moiety showed excellent antiinflammatory activity. The antimicrobial screening studies revealed that compounds with 4-anisyl, 4-methylthiophenyl, 3,4-methylenedioxyphenyl, and 2,3,5-trichlorophenyl at position 5 of the arylidenetriazolothiazolidinone moiety showed excellent activity against all tested strains at 6.25 μg cm⁻³ concentrations. Correspondence: Mari Sithambaram Karthikeyan, Department of Chemistry, Mangalore University, Mangalagangothri 574199, Karnataka, India.     

Synthesis and Photophysical Properties of 3,6-Diphenyl-9-hexyl-9<Emphasis Type="Italic">H</Emphasis>-carbazole Derivatives Bearing Electron Withdrawing Groups

Summary. 3,6-Diphenyl-9-hexyl-9H-carbazole derivatives bearing electron withdrawing groups, such as the formyl or the nitro-group in 4-positions of the phenyl substituents, were prepared and characterized. Their photophysical properties were evaluated and compared with those of the unsubstituted counterpart 3,6-diphenyl-9-hexyl-9H-carbazole. The electron withdrawing groups bearing compounds exhibited considerable red shifts of the absorption and the emission maxima. While 3,6-di(4-nitrophenyl)-9-hexyl-9H-carbazole emitted in the orange region of the visible spectrum with its emission maximum peaking at 585 nm, 3,6-di(4-formylphenyl)-9-hexyl-9H-carbazole gave a pure blue emission with a luminescence quantum yield of 95% peaking at 450 nm. Observed features were explained using quantum mechanical calculations and organic light emitting diodes using the formylphenyl substituted compound as emissive layer were built demonstrating the practical applicability of this class of compounds.     

Synthesis, antiinflammatory and antimicrobial activities of some 2,4-dichloro-5-fluorophenyl substituted arylidenetriazolothiazolidinones

A series of 2,4-dichloro-5-fluorophenyl substituted arylidenetriazolothiazolidinones were obtained by one-pot reaction of 3-(2,4-dichloro-5-fluorophenyl)-4H-1,2,4-triazole-5-thiol with substituted benzaldehydes and monochloroacetic acid in the presence of acetic anhydride, acetic acid, and sodium acetate. The structures of the newly synthesized compounds were characterized and confirmed by IR, ¹H NMR, mass spectra, and elemental analysis. Compounds bearing the 4-methylthiophenyl, 3,4-methylenedioxyphenyl, and 2,3,5-trichlorophenyl moiety showed excellent antiinflammatory activity. The antimicrobial screening studies revealed that compounds with 4-anisyl, 4-methylthiophenyl, 3,4-methylenedioxyphenyl, and 2,3,5-trichlorophenyl at position 5 of the arylidenetriazolothiazolidinone moiety showed excellent activity against all tested strains at 6.25 μg cm⁻³ concentrations.     

Synthesis, Characterization, and Evaluation of Antimicrobial Activity of Some 1,2,4-Triazole Derivatives Bearing an Antipyryl Moiety

Summary.  Some novel 4-[[2-[[5-(2-furanyl)-4-alkyl/aryl-4H-1,2,4-triazol-3-yl]thio]-acetyl/propionyl]-amino]-1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazoles were synthesized and evaluated for in vitro antibacterial activity against Staphylococcus aureus ATCC 29213, Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC 25922, and Enterococcus faecalis ATCC 29212 and antifungal activity against Candida albicans ATCC 10231, Candida parapsilosis ATCC 22019, Candida krusei ATCC 6258, Candida parapsilosis, Trichophyton mentagrophytes var. erinacei NCPF 375, Microsporum gypseum NCPF 580, and Trichophyton rubrum using the microbroth dilution method. All of the compounds were found to be ineffective against the above bacteria within the applied MIC ranges. On the other hand, they were effective against fungi to different degrees. Three compounds showed high activity against C. parapsilosis and T. mentagrophytes var. erinacei NCPF 375 (MIC = 8 μg cm⁻³). The in vitro antimycobacterial activity of the new compounds was also investigated against Mycobacterium tuberculosis H₃₇RV (ATCC 27294) in BACTEC 12B medium using a broth microdilution assay, the Microplate Alamar Blue Assay (MABA). Compounds exhibiting fluorescence were tested in the BACTEC 460 radiometric system. The most active compound was found with 66% inhibition at >6.25 μg cm⁻³. Corresponding author. E-mail: nurayulusoy@yahoo.com Received July 24, 2002; accepted August 26, 2002     

A Selective Conversion of Benzylic Alcohols to the Corresponding Carbonyl Compounds by Means of an Ag(III) Complex

Summary.  Carbonyl compounds of the type XPhCOR (R = H, Me, Ph; X = H, Me, Cl, Br) are prepared in high yields by reaction of the corresponding benzylic alcohols XPhCHOHR with KNa₄ [Ag(HIO₆)₂]×12H₂O in alkaline solution. This method allows the selective oxidation of benzylic alcohols in compounds containing other types of alcoholic functional groups. Received January 18, 2000. Accepted (revised) February 23, 2000     

Design,Synthesis, and Anticancer Activity of New Oxadiazolyl‐Linked and Thiazolyl‐Linked Benzimidazole Arylidines,Thioglycoside, and Acyclic Analogs

2‐[(4‐Thiazolylmethyl)thio]‐1H‐benzimidazole 3 was prepared and was allowed to react with ethyl chloroactate then with hydrazine hydrate to afford the hydrazide derivative 5 , which was then reacted with aromatic aldehydes to afford the corresponding arylidine derivatives 6 – 9 . Heterocyclization of the latter hydrazones with acetic anhydride afforded the substituted 1,3,4‐oxadiazoline derivatives 10 – 13 . In addition, new ((thiazolyl)imidazolyl) oxadiazole thioglycoside and acyclic‐C nucleoside analog were prepared via heterocylization of the hydrazide 5 then glycosylation with α‐acetobromoglucose or condensation with D‐xylose, respectively. All the new compounds were structurally characterized. The anticancer activity of some of the newly synthesized compounds was studied against human breast cancer cells (MCF‐7). The results of the anticancer activity showed that compounds 8 , 11 , 12 , 17 , and 18 revealed high activities superior to Doxorubicin; however, the other derivatives showed moderate to low inhibition activities against human breast cancer cells. Docking studies into CDK2 enzyme were investigated, which supported the anticancer activity results.     

Synthesis of New Metal-Free and Metal-Containing Phthalocyanines with Tertiaryor Quaternary Aminoethyl Substituents

Summary.  A novel phthalodinitrile derivative carrying dimethylaminoethylsulfanyl groups at positions 4 and 5 was synthesized from 2-dimethylaminoethanethiol hydrochloride and 1,2-dichloro-4,5-dicyanobenzene. Its cyclotetramerization in the presence of 2-dimethylamino-ethanol or metal salts (CoCl₂, Zn(OAc)₂) gave metal-free or metal-containing phthalocyanines (M = Co or Zn). These phthalocyanines were converted into water soluble quaternized products by reaction with methyl iodide. The new compounds were characterized by elemental analysis, IR, NMR, and electronic spectra.     

Solvothermal Syntheses, Crystal Structures, and Properties of New [Mn( dien )2]2+ Complexes

 The two new compounds Mn(dien)₂[MoS₄] (1) and Mn(dien)₂[Mo₂O₂S₆] (2) (dien = diethylenetriamine) were prepared under solvothermal conditions. Both compounds were obtained as phase-pure products. The structures consist of new [Mn(dien)₂]²⁺ cations and isolated tetrahedral [MoS₄]²⁻ (1) or [Mo₂O₂S₆]²⁻ (2) anions. Between the anions and the cations, hydrogen bonding is observed. Compound 1 crystallizes in the tetragonal space group I (a = 10.219(2), c = 9.259(2) ?, Z = 2), whereas 2 crystallizes in the monoclinic space group P2₁/c (a = 8.703(2), b = 18.390(4), c = 14.603(3) ?, β = 103.18(3)°, Z = 4). The thermal behaviour of the thiomolybdates was investigated using difference thermoanalysis (DTA) and thermogravimetry (TG). Both compounds decompose under argon with a single endothermic signal in the DTA curve (peak maximum: 252 (1) and 242°C (2)).     

New 6-(4-Bromophenyl)-imidazo[2,1-b]thiazole Derivatives: Synthesis and Antimicrobial Activity

Summary.  New 4-alkyl/aryl-1-((6-(4-bromophenyl)-imidazo[2,1-b]thiazol-3-yl)-acetyl)-3-thiosemicarbazides and 3-alkyl/aryl-2-(((6-(4-bromophenyl)-imidazo[2,1-b]thiazol-3-yl)-acetyl)-hydrazono)-4-thiazolidinones were synthesized from 6-(4-bromophenyl)-imidazo[2,1-b]thiazole-3-acetic acid hydrazide. Their structures were elucidated by elemental analyses and spectroscopic data. All compounds were tested for antibacterial and antifungal activities. The antimicrobial activities of the compounds were assessed by the microbroth dilution technique. The compounds were also evaluated for antituberculosis activity against Mycobacterium tuberculosis H₃₇Rv (ATCC 27294); they exhibited varying degrees of inhibition in the in vitro primary screening at 6.25 μg · cm⁻³. The most active compound was 3-(4-nitrophenyl)-2-(((6-(4-bromophenyl)-imidazo[2,1-b]thiazol-3-yl)-acetyl)-hydrazono)-4-thiazolidinone. Corresponding author. E-mail: nurayulusoy@yahoo.com Received December 10, 2001. Accepted (revised) March 1, 2002     

Synthesis and Photophysical Properties of 3,6-Diphenyl-9-hexyl-9H-carbazole Derivatives Bearing Electron Withdrawing Groups

3,6-Diphenyl-9-hexyl-9H-carbazole derivatives bearing electron withdrawing groups, such as the formyl or the nitro-group in 4-positions of the phenyl substituents, were prepared and characterized. Their photophysical properties were evaluated and compared with those of the unsubstituted counterpart 3,6-diphenyl-9-hexyl-9H-carbazole. The electron withdrawing groups bearing compounds exhibited considerable red shifts of the absorption and the emission maxima. While 3,6-di(4-nitrophenyl)-9-hexyl-9H-carbazole emitted in the orange region of the visible spectrum with its emission maximum peaking at 585 nm, 3,6-di(4-formylphenyl)-9-hexyl-9H-carbazole gave a pure blue emission with a luminescence quantum yield of 95% peaking at 450 nm. Observed features were explained using quantum mechanical calculations and organic light emitting diodes using the formylphenyl substituted compound as emissive layer were built demonstrating the practical applicability of this class of compounds.     

Synthesis,Spectral Characterization,and In Vitro Biological Evaluation of Some Novel Isoquinolinone‐based Heterocycles as Potential Antitumor Agents

A series of new N‐substituted isoquinolin‐1,3‐dione derivatives were prepared, starting from reaction of (Z)‐4‐((E)‐3‐phenylallylidene)isochromane‐1,3‐dione 4 with different nitrogen nucleophiles. The assigned structures of the prepared compounds were elucidated by spectral methods (IR, ¹H NMR, ¹³C NMR, and mass spectroscopy). Some of the newly prepared compounds were tested in vitro against a panel of three human tumor cell lines, namely, hepatocellular carcinoma (liver) HepG2, colon cancer HCT‐116, and mammary gland breast MCF‐7. Also, they were tested as antioxidants. Some of the tested compounds showed very strong cytotoxic activity with respect to the standard.     

Enzyme-linked immunosorbent assays for the sensitive analysis of 2,4-dinitroaniline and 2,6-dinitroaniline in water and soil

The development and characterization of one rat monoclonal antibody (mAb) for 2,4-dinitroaniline and of two rat mAbs for 2,6-dinitroaniline are described. With the immunization of rats with 2,4,6-trinitrophenyl-glycylglycine–keyhole limpet hemocyanine (KLH) conjugate one mAb (PK 5H6) has been developed and formatted into a competitive enzyme-linked immunosorbent assay (ELISA). This assay no. 1 is very sensitive for 2,4-dinitroaniline with a test midpoint of 0.24 ± 0.06 μg L⁻¹ (n = 19) in 40 mM phosphate-buffered saline (PBS). A second hapten, 3-(4-amino-2,6-dinitrophenyl)propionic acid, which was also conjugated to KLH and used for the immunization of rats, led to two sensitive ELISAs for 2,6-dinitroaniline in 40 mM PBS with test midpoints of 0.61 ± 0.08 μg L⁻¹ (n = 15; mAb DNT4 3C6; assay no. 2) and 0.94 ± 0.29 μg L⁻¹ (n = 17; mAb DNT4 1A7, assay no. 3). Selectivities of all mAbs were checked with more than 20 compounds, including nitroaromatic compounds, 2,6-dinitroaniline pesticides, and other substituted derivatives of aniline. As very noticeable cross-reactivities, all mAbs recognize 2-chloro-4,6-dinitroaniline, 4-chloro-2,6-dinitroaniline and 2-bromo-4,6-dinitroaniline, the last of these being a major metabolite of the azo dye Disperse Blue 79. As first demonstrations of applications, two ELISAs (assays no. 1 and 2) were used for the analysis of 2,4- or 2,6-dinitroaniline in spiked water and soil samples. Recovery data were determined and the majority of these data were in the range of 90–120%. These assays can contribute to a very cost-effective and environmentally friendly immunochemical surveillance monitoring of environmental samples for contaminations with these compounds. To the best of the authors’ knowledge, these are the first antibodies described for 2,4-dinitroaniline and for 2,6-dinitroaniline.     

His6-OPH enzyme-based bio-hybrid material for organophosphate detection

In this work, we report on the development of a bio-sensing film for the detection of organophosphorous compounds using sol–gel technology. A novel sol–gel immobilization method employing tetraethoxysilane/3-glycidoxypropyltrimethoxysilane/water hybrid material was developed and used to immobilize the hexahistidine-tagged organophosphorous hydrolase enzyme (His₆-OPH). Bio-sensing layers with encapsulated His₆-OPH of various structures (water/silane, precursor ratios) have been prepared. The optimal (P = 5:1, R = 188) bio-sensing layers retained 90% of the initial enzyme activity. Furthermore, the bio-sensing layer prepared by this method was able to maintain its activity at or above 80% of its initial activity for 2 weeks. The bio-hybrid film also showed excellent reusability and improved activity at neutral pH in comparison to the same enzyme in solution.     

Phosphated Alumina Catalysts: Surface Properties and Reactivity towards 2-PrOH Decomposition

Summary. The influence of the type of precursor, the phosphate content, as well as the source of phosphate ions on the surface texture, acidity, and catalytic activity of phosphated aluminas has been described. Phosphated alumina catalysts were prepared by impregnating two different precursors with two different sources of phosphate in different loading levels w = 3, 6, and 10% PO₄ ³⁻. The characterisation of the catalyst was performed using X-ray powder diffraction (XRD), thermal analysis (TG), and nitrogen adsorption–desorption methods at 77 K. The surface acidity of the catalysts has been studied by FT-IR spectroscopy of adsorbed pyridine at different temperatures. Moreover, the activity in the catalytic decomposition of isopropanol (2-PrOH) has been investigated at 520 K. Investigation of the surface properties shows that the addition of phosphate ions does not change the crystal phase (γ-phase) and the samples prepared from gel and phosphoric acid have the highest surface area. An FT-IR study of pyridine adsorption shows both Lewis and Br?nsted acid sites on the surface of the samples prepared from gel, while only Lewis acid sites are detected on the samples prepared from crystalline oxide. The catalytic activity by 2-PrOH conversion shows that the conversion of 2-PrOH as well as the selectivity towards propene formation increases from w = 3 to 6% followed by a decline for w = 10%. Moreover, the strongest activity was detected in case of phosphated alumina gel with w = 6% which gives 97.3% propene and 96.1% conversion of 2-PrOH.     

Crystal Structure of infin; 2[Cu2I2(μ-4-4′-bipyridine)] and Investigations on the Thermal Decomposition of CuX-4,4′-bipyridine Coordination Polymers

Summary.  The inorganic-organic coordination polymer _infin; ²[Cu₂I₂(μ-4-4′-bipyridine)] was prepared by the reaction of Cu(I)I and 4,4^′-bipyridine in acetonitrile. Its structure consists of staircase-like CuX double chains which are connected to sheets by the 4,4^′-bipyridine ligands. The thermal decomposition of the corresponding 1:1 copper(I) halide-4,4^′-bipyridine compounds _infin; ²[CuX(μ-4-4′-bipyridine)] (X = Cl, Br, I) was investigated using simultaneous difference thermal analysis and thermogravimetry (DTA-TG), thermomicroscopy, and temperature resolved X-ray powder diffraction in air or argon. Upon heating _infin; ²[CuX(μ-4-4′-bipyridine)], several changes in sample mass are observed which correspond to a stepwise loss of the organic ligands. Temperature-resolved X-ray powder diffraction proves that _infin; ²[CuX(μ-4-4′-bipyridine)] transforms to _infin; ²[Cu₂ X ₂(μ-4-4′-bipyridine)] during the decomposition; the latter looses the remaining ligands when heated further, forming the corresponding copper(I)halides. When the experiments were performed under an argon atmosphere, the 2:1 coordination polymers were obtained as phase-pure compounds. Received March 1, 2001. Accepted April 11, 2001