A facile synthesis of the sex pheromone of Grapholitha molesta

The sex pheromone of Grapholitha molesta, (Z/E)-8-dodecylen-1-ol acetate, was easily synthesized in an overall yield of 41.5% with 1,8-octanediol as starting material via mono-esterification, PCC oxidation, and Witting reactions. The Z/E ratio is 83:17. Configuration transformation of Z/E 83:17 compound with sodium nitrite and nitric acid resulted in the production of a compound with Z/E 24:76. The products were confirmed by IR, ¹H NMR, and MS spectral data.     

Copper sulfide nanoparticle-decorated graphene as a catalytic amplification platform for electrochemical detection of alkaline phosphatase activity

Copper sulfide nanoparticle-decorated graphene sheet (CuS/GR) was successfully synthesized and used as a signal amplification platform for electrochemical detection of alkaline phosphatase activity. First, CuS/GR was prepared through a microwave-assisted hydrothermal approach. The CuS/GR nanocomposites exhibited excellent electrocatalytic activity toward the oxidation of ALP hydrolyzed products such as 1-naphthol, which produced a current response. Thus, a catalytic amplification platform based on CuS/GR nanocomposite for electrochemical detection of ALP activity was designed using 1-naphthyl phosphate as a model substrate. The current response increased linearly with ALP concentration from 0.1 to 100 U L⁻¹ with a detection limit of 0.02 U L⁻¹. The assay was applied to estimate ALP activity in human serum samples with satisfactory results. This strategy may find widespread and promising applications in other sensing systems that involves ALP.     

Non-enzymatic sensing of uric acid using a carbon nanotube ionic-liquid paste electrode modified with poly(β-cyclodextrin)

We describe a nonenzymatic electrochemical sensor for uric acid. It is based on a carbon nanotube ionic-liquid paste electrode modified with poly(β-cyclodextrin) that was prepared in-situ by electropolymerization. The functionalized multi-walled carbon nanotubes and the surface morphology of the modified electrodes were characterized by transmission electronic microscopy and scanning electron microscopy. The electrochemical response of uric acid was studied by cyclic voltammetry and linear sweep voltammetry. The effects of scan rate, pH value, electropolymerization cycles and accumulation time were also studied. Under optimized experimental conditions and at a working voltage of 500 mV vs. Ag/AgCl (3 M KCl), response to uric acid is linear in the 0.6 to 400 μΜ and in the 0.4 to 1 mΜ concentration ranges, and the detection limit is 0.3 μΜ (at an S/N of 3). The electrode was successfully applied to the detection of uric acid in (spiked) human urine samples.

SEM images of (a) carbon ionic liquid electrode (CILE) (b) MWNT-CILE (c) β-CD/CILE (d) β-CD/ MWNT-CILE. The surfaces of carbon ionic liquid electrode (CILE) (a) and MWNT-CILE (b) were homogenous and no separated carbon layers can be observed; After β- cyclodextrin (CD) was modified on CILE and MWNT-CILE, the surfaces of β-CD modified electrodes (c and d) exhibited loose and porous morphologies.

     

Design,synthesis and structure-activity relationship of 4,5-dihydropyrrolo[3,4-c]pyrazol-6(1H)-ones as potent p53-MDM2 inhibitors

In the past decade, the p53-MDM2 protein-protein interaction by small molecules has been confirmed as a successful strategy for cancer therapy. In our previous work, pyrrolo[3,4-c]pyrazol-6(1H)-ones were found to be potent p53-MDM2 inhibitors. Further optimization and structure-activity relationship studies were described in the present work. The result revealed that benzyl group on position N1 of imidazole and bromine on C4-phenyl of pyrrolidone showed higher inhibitory activities. In vitro antiproliferative assay demonstrated the potent p53-MDM2 inhibitor 5c with 4-fold selectivity for U2 OS and Saos-2 cells. These data indicated that 4,5-dihydropyrrolo[3,4-c]pyrazol-6(1H)-one moiety is a valuable scaffold for further development of p53-MDM2 inhibitors.     

Photoinduced hydrogen evolution with bisviologen-linked ruthenium(II) complexes and hydrogenase

Bisviologen-linked ruthenium(II) complexes with different methylene chain length between ruthenium complex and viologen, Ru(bpy)₂(dcbpy)C_mV_AC_nV_B(m=2, n=3; m=3, n=4), were synthesized and characterized. From luminescence spectra, the photoexcited state of Ru(bpy)₂(dcbpy) moiety is oxidatively quenched by the bound viologen, and an intramolecular electron transfer occurs. Luminescence lifetime measurements show that the electron transfers from the photoexcited state of ruthenium(II) complex moiety to the bound bisviologen more rapidly than that of monoviologen-linked ruthenium(II) complexes. Ru(bpy)₂(dcbpy)C_mV_AC_nV_B were applied to the photoinduced hydrogen evolution in the system containing nicotinamide-adenine dinucleotide phosphate (reduced form, NADPH), Ru(bpy)₂(dcbpy)C_mV_AC_nV_B and hydrogenase under steady state irradiation. In the case of Ru(bpy)₂(dcbpy)C₃V_AC₄V_B, the efficient photoinduced hydrogen evolution was observed.