Chemical Research in Chinese Universities

Trans-2,3-dihydrofuran derivatives 3 or 4 substituted with a sulfonyl group were prepared with high chemoselectivity and good yields by [1+4]-addition reaction of α,β-unsaturated ketones 1 with arsonium bromide 2 in CH2Cl2 in the presence of potassium carbonate at room temperature. The structures of the products were characterized by IR, MS, 1H NMR, elemental analysis and single crystal X-ray diffraction analysis. A mechanism for the formation of products was also proposed.

Structures and nonlinear optical(NLO) properties of eleven new Li n -P m (n=1–5) species were investigated in detail with the help of ab initio computation, in which one to the maximum five Li atoms are doped over the polycyclic π-conjugated pentacene. These Li-doped pentacene systems exhibit large adsorption energies(ca. 107.0–141.3 kJ/mol) and considerable first hyperpolarizabilities(even up to 4.1×104 a.u.), where the number of Li atoms, the doping site, and the distance between the neighboring Li atoms have important impacts on the β 0 value. In the doped pentacene systems with less Li atoms(one or two), the improvement of β 0 value can be attributed to the simple transfer of the charge from Li atom to pentacene. Differently, doped more Li atoms(three to five) can cause not only charge transfer but also excess electron, and this cooperation can endow the doped systems with the much larger first hyperpolarizabilities. These fascinating findings are advantageous for the design of new NLO materials based on the intriguing polycyclic π-conjugated systems.

The effect of magnetic nanoparticles(mNPs) on the devitrification crystallization of typical vitrification solution Vs55 was systematically explored by differential scanning calorimetry(DSC) and cryomicroscope system. The results show that, (i) the mNPs coated by both carboxylic acid(CA) and polyethylene glycol(PEG) had little effect on the glass transition temperature(Tg) of Vs55, but had significant effect on the devitrification transition temperature(Td) and devitrification enthalpy $({H_{{T_{\rm{d}}}}})$ , (ii) in the range of the devitrification area(−85— −60 °C), the MNPs coated by CA can significantly accelerate the devitrification of Vs55 as the isothermal temperatures and the cooling rates increased, and the ice growth rate was 0.37 μm/s at the isothermal temperature of −85 °C, and was about 2.19 μm/s at −75 °C. Also, the ice growth rates rose from 1.72 μm/s to 3.54 μm/s when the cooling rates were increased from 2 °C/min to 100 °C/min(at the isothermal temperature of −75 °C), (iii) magnetic nanoparticles coated by both PEG and CA could promote the devitrification of Vs55, for instance, without any crystal growth inside Vs55 at the isothermal temperature of −80 °C, but 1.04 and 2.31 μm/s for adding magnetic nanoparticles coated by CA and PEG, respectively. Compared with the samples coated by CA, PEG promoted the devitrification of Vs55 in a much more positive way, and the ice growth rates were 0.62 and 6.25 μm/s at the isothermal temperatures of −85 and −75 °C, respectively. These results indicate that the surface coating of MNPs could significantly affect the recrystallization of Vs55, and further work should be conducted in the future research.

In this paper, the evaluation on the biological activity of an array of P-stereogenic diaryphosphinamides as novel inhibitors of malignant melanoma was presented. Among 20 derivatives being screened, several of them displayed high inhibition rate up to 90% against the B16 melanoma cells at 100 μg/mL. Moreover, one of them displayed high inhibition activity with IC50 value of 5.8 μg/mL. In contrast, a comparative assay showed that all the compounds were almost inactive or showed only very weak inhibition ability against an array of cell lines including HL7702, Bel7402, HT1080, A549 and McF7 cells. The results suggested that the P-stereogenic diarylphosphinamides may serve as a class of novel lead molecules for further development of new inhibitors for selective inhibition of melanoma.

A series of 50%CuO-25%ZnO-25%Al(Zr) oxide catalysts was synthesized by a reverse co-precipitation method and characterized by XRD, N2 adsorption-desorption, H2-TPR, H2-TPD and CO2-TPD, and used as catalyst for CO2 hydrogenation to methanol under mild conditions(200―260 °C and 1―3 MPa). Consequently, H2-TPR ex-hibited that the dispersed CuO species increased with the zirconium content, while the H2-TPD showed that small amount of zirconia can increase the H2 desorption amount. As a result, Cat-2 and Cat-3 exhibited an enhanced H2-spillover effect, the most H2 desorption amount, which showed an optimum activity of about 7% methanol yield.