New synthesis of two tridentate bipyrazolic compounds and their cytotoxic activity tumor cell lines

Two new tripodal compounds - 4-{bis[(3,5-dimethyl-1H-pyrazole-1-yl)methyl]amino}butane-1-ol (1); ethyl 1-[((2-hydroxyethyl){[3-(ethoxycarbonyl)-5-methyl-1H-pyrazole-1-yl]methyl} amino)methyl]-5-methyl-1H-pyrazole-3-carboxylate (2) were reported. The evaluation of the cytotoxic properties in vitro of these ligands, was examined on two tumor cell lines - P815 (mastocytome murine) and Hep (carcinoma of human larynx). The concentration required to induce 50% of lysis (IC(50)) was more pronounced against P815 cell line (IC(50): 39.42 microg mL(-1) for the compound 1 and 97.74 microg mL(-1) for the compound 2) than the Hep cell line (IC(50): 83.49 microg mL(-1) for compound 1 and 185.30 microg mL(-1) for compound 2). Statistical analysis shows that the compound 1 is two to three folds more cytotoxic than the compound 2 (p < 0.05). Interestingly, the cytotoxic activity depends strongly on both the substituents linked to the aminic nitrogen and pyrazolic rings.     

Local electronic structure of olivine phases of LixFePO4

Changes in the local electronic structure at atoms around Li sites in the olivine phase of LiFePO4 were studied during delithiation. Electron energy loss spectrometry was used for measuring shifts and intensities of the near-edge structure at the K-edge of O and at the L-edges of P and Fe. Electronic structure calculations were performed on these materials with a plane-wave pseudopotential code and with an atomic multiplet code with crystal fields. It is found that both Fe and O atoms accommodate some of the charge around the Li+ ion, evidently in a hybridized Fe-O state. The O 2p levels appear to be fully occupied at the composition LiFePO4. With delithiation, however, these states are partially emptied, suggestive of a more covalent bonding to the oxygen atom in FePO4 as compared to LiFePO4. The same behavior is found for the white lines at the Fe L2,3-edges, which also undergo a shift in energy upon delithiation. A charge transfer of up to 0.48 electrons is found at the Fe atoms, as determined from white line intensity variations after delithiation, while the remaining charge is compensated by O atoms. No changes are evident at the P L2,3-edges.     

One pot Pd(OAc)2-catalysed 2,5-diarylation of imidazoles derivatives

The regioselective 2- or 5-arylation of imidazole derivatives with aryl halides using palladium catalysts has been described in recent years; whereas the arylation at both C2 and C5 carbons of imidazoles in high yields has not been performed. We found conditions allowing the access to these 2,5-diarylimidazoles via a one pot reaction. The choice of the base was found to be crucial to obtain these products in high yields. Using CsOAc as the base, DMA as the solvent and only 2 mol % of the phosphine-free Pd(OAc)₂ the catalyst, the target 2,5-diarylated imidazoles were obtained in moderate to good yields with a wide variety of aryl bromides. Substituents such as fluoro, trifluoromethyl, formyl, acetyl, propionyl, ester, nitro or nitrile on the aryl bromide were tolerated. Sterically congested aryl bromides or heteroaryl bromides can also be employed. Surprisingly the nature of the substituent at position 1 on the imidazole derivative exhibits a huge influence on the reaction.     

Study of mechanism retention of nonvolatile alkylphosphonic acids on unmodified selected polymer-based ion exchanger columns

The retention of alkylphosphonic acids (MPA, EPA, PPA, and BPA) and inorganic anions (Cl⁻, NO₃⁻, and SO₄²⁻) were studied on two anion exchangers, e.g., Dionex IonPac AS4A-SC (250 ± 4 mm I.D.) and Satisfaction P 4000-SAX (50 ± 4.6 mm I.D.) under isocratic elution conditions with evaporative light scattering detector. The plots of retention factors, k, of organic anions vs. the reciprocal of eluent ion concentration show good linearity. The major retention mechanisms are interpreted as ion exchange and some others interactions. The C effect of organic modifier added to the aqueous buffered mobile phase is also investigated.     

Sono-Transition-Metal Catalysis of One-Pot Three-Step Synthesis of Glycosyl-1,2,3-triazoles

As a continuation of our studies directed at the development of straightforward and sustainable methodologies, we describe herein an original example of a combined effect of ultrasonic activation and iron–copper dual catalysis that allows an efficient and ecofriendly one-pot, three-step route to a new series of nucleoside-substituted triazoles. The reactions were carried out under both conventional and ultrasonic irradiation conditions.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.     

Are the hyperharmonics integral? A partial answer via the small intervals containing primes

In a recent work, the authors have used Bertrand's postulate to give a partial answer to the conjecture of Mez? which says that the hyperharmonic numbers – iterations of partial sums of harmonic numbers – are not integers. In this Note, using small intervals containing prime numbers, we prove that a great class of hyperharmonic numbers are not integers.     

Synthesis and antitumor activity of puupehedione and related compounds

The first enantiospecific synthesis of bioactive marine puupehedione (2) and related compounds from (−)-sclareol (11) is reported. The antitumor activity of these compounds was assayed and compared with that of the natural products.     

Extraction behaviour of amino acid esters by functionalised calix[4]arenes

Calixarenes 2–4, 6 and 7 in the cone conformation variously substituted by acid or amido functions, glycolic chains and hydroxyl groups were synthesised. They have been used in extraction of native amino acid and amino acid esters.