Facile Synthesis and in Vitro Cytotoxic Evaluation of Novel Thiadiazole,Pyrazole, and Dithiole-Androstane Derivatives

In the aim of identifying new steroidal cytotoxic agents with potential antiproliferative activity against hepatoma cell lines (Hep-G₂), we synthesized modified steroids containing the thiadiazole, pyrazole, or dithiole moiety. Epiandrosterone 1 reacted with carbon disulfide and sodium hydride to furnish α-oxoketene dithio-disodium salt 2. Treatment of 2 with the hydrazonoyl halides 5a–d produced the thiadiazole anellated androstanone 7a–d, respectively. The reaction of 1 with hydrazine hydrate produced the hydrazide adduct 8, which cyclized upon reflux in acetic acid to form the condensed pyrazoloandrostanone derivative 9. Interaction of 8 with carbon disulfide and sodium hydride formed the disodium salt 10, which reacted with ethylchloroacetate to furnish the final adduct, dithioloandrostane derivative, 13. Compounds 7a, 7d, 9, and 13 were examined for their cytotoxicity against a panel of hepatoma cell lines (Hep-G₂) using MTT assay. The results provide that, at incubation time 72 h, in DMSO, compound 7d (50 μ mol/mL) showed the most significant cytotoxic effect at P < 0.05. The higher dose (100 μ mol/mL) of compound 7d, at 48 h incubation, reversed the effect causing resistance and the growth rate return to the control level.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Zirconium complexes to overcome oxygen inhibition in free‐radical photopolymerization of acrylates: Kinetic,mechanism, and depth profiling

The photopolymerization process of acrylate coatings initiated by visible light (λ > 380 nm) and performed in air was studied in the presence of zirconium complexes. Depth profiling experiments were performed using confocal Raman microscopy showing that the conversion, which is low at the surface of the sample, increases with increasing depth and reaches a full conversion close to the substrate. RT‐FTIR spectroscopy corroborates Raman results in evidencing the efficiency of some zirconium compounds to reduce oxygen inhibition. Finally, laser flash photolysis experiments revealed that the beneficial effect in air is attributable to the reaction of the zirconium complex on the peroxyl radicals formed from the reaction of oxygen with radicals. Therefore, the oxygen present in the medium is depleted, allowing a better efficiency of the photopolymerization process. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

On the route to mimic natural movements: synthesis and photophysical properties of a molecular arachnoid

The synthesis, photoswitchability and NIR emitting properties of a novel π-extended pyrene derivative, peripherally decorated with four azobenzenyl-ethynyl legs, are reported.     

Niclosamide Is Active In Vitro against Mycetoma Pathogens

Redox-active drugs are the mainstay of parasite chemotherapy. To assess their repurposing potential for eumycetoma, we have tested a set of nitroheterocycles and peroxides in vitro against two isolates of Madurella mycetomatis, the main causative agent of eumycetoma in Sudan. All the tested compounds were inactive except for niclosamide, which had minimal inhibitory concentrations of around 1 µg/mL. Further tests with niclosamide and niclosamide ethanolamine demonstrated in vitro activity not only against M. mycetomatis but also against Actinomadura spp., causative agents of actinomycetoma, with minimal inhibitory concentrations below 1 µg/mL. The experimental compound MMV665807, a related salicylanilide without a nitro group, was as active as niclosamide, indicating that the antimycetomal action of niclosamide is independent of its redox chemistry (which is in agreement with the complete lack of activity in all other nitroheterocyclic drugs tested). Based on these results, we propose to further evaluate the salicylanilides, niclosamide in particular, as drug repurposing candidates for mycetoma.     

Study of the critical current density and the thermodynamic critical field in deuterated κ-(BEDT-TTF)2Cu[N(CN)2]Br organic superconductor

ABSTRACT

We have studied the reversible and irreversible part of the hysteresis loops as a function of slow cooling rate through the order–disorder transformation near 80?K for the deuterated (κ-D₈-Br) κ-(BEDT-TTF)₂Cu[N(CN)₂]Br organic superconductor. We estimated the critical current density J_C and the thermodynamic critical field H_C from the magnetic hysteresis loops. Temperature dependence of the critical current density derived from the irreversible part using Bean’s model. The thermodynamic critical field H_C has been obtained from the reversible part of the hysteresis loops.     

Phenanthrenoids from Juncus acutus L., new natural lipopolysaccharide-inducible nitric oxide synthase inhibitors

The novel natural product juncutol (1), 1,4,7-trimethyl-8,9-dihydro-4H-cyclopenta[def]phenanthrene-2,6-diol, along with the three related metabolites juncusol (2), dehydrojuncusol (3), and 6-hydroxymethyl-1-methyl-5-vinyl-9,10-dihydrophenanthrene-2-ol (4), were isolated from the rhizomes of Juncus acutus L. (Juncaceae) growing in Egypt. The structural identity of 1 was determined on the basis of spectroscopic analyses, including 2D NMR spectroscopy. The inhibitory effect of these natural products on the expression of inducible nitric oxide synthase (iNOS) in lipopolysaccharide-stimulated RAW264.7 macrophage cells was determined for the first time. The unprecedented symmetrical compound juncutol (1) was found to be the most potent inhibitor against the induction of the proinflammatory iNOS protein.     

Bis(ammonium) tris­(hexa­aqua­magnesium) tetra­kis(hydrogen phosphite)

The structure of the title compound, (NH₄)₂[Mg(H₂O)₆]₃(HPO₃)₄, consists of [Mg(H₂O)₆]²⁺ and (NH₄)⁺ cations and (HPO₃)²⁻ anions held together by an intricate network of hydrogen bonds involving all H atoms except for one linked directly to a P atom. The Mg²⁺ cations are octa­hedrally coordinated by six water mol­ecules. One of the Mg atoms is located on a site with 2/m symmetry, whereas the other Mg atom and the P and N atoms occupy sites with m symmetry.     

Antitumor,cytotoxic, and antioxidant evaluation of six heterocyclic compounds containing different heterocycle moieties

Heterocyclic compounds with different heterocycle moieties, namely benzoxazinone, benzimidazole, quinazolinone, and benzofuranone heterocyclic rings, were synthesized, characterized, and evaluated for their anticancer activity against human hepatocellular carcinoma cell line (HepG2) using sulforhodamine B (SRB) and dimethylthiazol-diphenyltetrazolium bromide (MTT) assays. Also, their cytotoxic activities were tested against human epithelioid carcinoma (Hela) cell line in comparison with normal cell, amniotic epithelial (WISH) cell line, as an in vitro toxicity estimation model. The results showed clearly that 2-(2-benzyl-4-oxoquinazolin-3(4H)-yl)acetohydrazide 4 is the most potent antioxidant and anticancer agents. Although, 3-amino-2-benzylquinazolin-4(3H)-one 5 is less potent anticancer agent against Hela but it is more safe against normal cell (WISH).     

From molecular to macroscopic engineering: shaping hydrogen-bonded organic nanomaterials

The self‐assembly and self‐organization behavior of chromophoric acetylenic scaffolds bearing 2,6‐bis(acetylamino)pyridine ( 1 , 2 ) or uracyl‐type ( 3 – 9 ) terminal groups has been investigated by photophysical and microscopic methods. Systematic absorption and luminescence studies show that 1 and 2 , thanks to a combination of solvophilic/solvophobic forces and π–π stacking interactions, undergo self‐organization in apolar solvents (i.e., cyclohexane) and form spherical nanoparticles, as evidenced by wide‐field optical microscopy, TEM, and AFM analysis. For the longer molecular module, 2 , a more uniform size distribution is found (80–200 nm) compared to 1 (20–1000 nm). Temperature scans in the range 283–353 K show that the self‐organized nanoparticles are reversibly formed and destroyed, being stable at lower temperatures. Molecular modules 1 and 2 were then thoroughly mixed with the complementary triply hydrogen‐bonding units 3 – 9 . Depending on the specific geometrical structure of 3 – 9 , different nanostructures are evidenced by microscopic investigations. Combination of modules 1 or 2 with 3 , which bears only one terminal uracyl unit, leads to the formation of vesicular structures; instead, when 1 is combined with bis‐uracyl derivative 4 or 5 , a structural evolution from nanoparticles to nanowires is observed. The length of the wires obtained by mixing 1 and 4 or 1 and 5 can be controlled by addition of 3 , which prompts transformation of the wires into shorter rods. The replacement of linear system 5 with the related angular modules 6 and 7 enables formation of helical nanostructures, unambiguously evidenced by AFM. Finally, thermally induced self‐assembly was studied in parallel with modules 8 and 9 , in which the uracyl recognition sites are protected with tert‐butyloxycarbonyl (BOC) groups. This strategy allows further control of the self‐assembly/self‐organization process by temperature, since the BOC group is completely removed on heating. Microscopy studies show that the BOC‐protected ditopic modules 8 self‐assemble and self‐organize with 1 into ordered linear nanostructures, whereas BOC‐protected tritopic system 9 gives rise to extended domains of circular nano‐objects in combination with 1 .     

Structural and nanomechanical properties of porous silicon: Cheap substrate for CMOS process industry

The surface topology of porous silicon (PSi) is a relevant parameter that decides the compatibility of such substrate with CMOS process. Using standard resistivity (1–10 Ω·cm) of Si substrate to fabricate PSi-S is a low cost solution for the industry. In this paper, through an atomic force microscopy (AFM) analysis, the root mean square (RMS) roughness, the power spectral density and the correlation length were determined for different PSi layers. Furthermore, the measured hardness, Young's modulus, and stress have been made for different thicknesses of PSi: 5, 10, 50, and 200 μm. The obtained results demonstrated that very interesting properties have been achieved with the 50 μm-thick PSi-S layer with a maximum porosity around 65%, a surface roughness less than 1 nm and a hardness value of (~1 GPa). The realized results encourage the utilization the PSi-based substrate into the industry process and thus the development of a Systems-on-Chip (SoC).