一种简洁的(+)-新黄皮酰胺的全合成

从化合物5出发,首先通过C-3位羟基的转位反应制得(+)-新黄皮酰胺(1)的前体化合物4,然后经过酮羰基的还原反应合成得到(+)-新黄皮酰胺(1).提供了一种简洁的(+)-新黄皮酰胺的全合成路线.考察了化合物5中C-3位羟基的转位反应的实验条件.     

An “off–on” fluorescence probe for chromium(III) ion determination in aqueous solution

An “off–on” rhodamine-based fluorescence probe for the selective signaling of Cr(III) has been designed by exploiting the guest-induced structure transform mechanism. This system shows a sharp Cr(III)-selective fluorescence enhancement response in 100% aqueous system under physiological pH value and possesses high selectivity against the background of environmentally and biologically relevant metal ions including Cr(VI), Al(III), Fe(III), Cd(II), Co(II), Cu(II), Ni(II), Zn(II), Mg(II), Ba(II), Pb(II), Na(I), and K(I). Under optimum conditions, the fluorescence intensity enhancement of this system is linearly proportional to Cr(III) concentration from 5.0 × 10⁻⁸ to 7.0 × 10⁻⁶ mol L⁻¹ with a detection limit of 1.6 × 10⁻⁸ mol L⁻¹.     

Partial Oxidation of Ethane to Syngas over Supported Metal Catalysts

The reaction performance for C₂H₆-O₂ to syngas over different supported metal catalysts was investigated in a flow-reactor. The activated behavior of ethane is different from that of methane over the supported nickel catalysts. Although there may exist a gas phase reaction at high temperatures, over a Ni (or Rh)/-Al₂O₃ catalyst, the partial oxidation of ethane to syngas is a heterogeneous process, while over a Pt (or Pd)/-Al₂O₃ catalyst, it may be a homo-heterogeneous process. The Ni/-Al₂O₃ and Rh/-Al₂O₃ catalysts are suitable for partial oxidation of ethane to syngas at high temperatures.     

Development and applications of fluorescent indicators for Mg2+ and Zn2+

In a study of the spectroscopic behavior of two Schiff base derivatives, salicylaldehyde salicylhydrazone (1) and salicylaldehyde benzoylhydrazone (2), Schiff base 1 has high selectivity for Zn(2+) ion not only in abiotic systems but also in living cells. The ion selectivity of 1 for Zn(2+) can be switched for Mg(2+) by swapping the solvent from ethanol-water to DMF (N,N-dimethylformamide)-water mixtures. Imine 2 is a good fluorescent probe for Zn(2+) in ethanol-water media. Many other ions tested, such as Li(+), Na(+), Al(3+), K(+), Ca(2+), Cr(3+), Mn(2+), Fe(3+), Co(2+), Ni(2+), Cu(2+), Ag(+), Cd(2+), Sn(2+), Ba(2+), Hg(2+), and Pb(2+), failed to induce any spectral change in various solvents. The selectivity mechanism of 1 and 2 for metal ions is based on a combinational effect of proton transfer (ESPT), C═N isomerization, and chelation-enhanced fluorescence (CHEF). The coordination modes of the complexes were investigated.     

Study on Glucose Biofuel Cells Using an Electrochemical Noise Device

An electrochemical noise (ECN) device was utilized for the first time to study and characterize a glucose/O₂ membraneless biofuel cell (BFC) and a monopolar glucose BFC. In the glucose/O₂ membraneless BFC, ferrocene (Fc) and glucose oxidase (GOD) were immobilized on a multiwalled carbon nanotubes (MWCNTs)/Au electrode with a gelatin film at the anode; and laccase (Lac) and an electron mediator, 2,2′‐azinobis (3‐ethylbenzothiazoline‐6‐sulfonate) diammonium salt (ABTS), were immobilized on a MWCNTs/Au electrode with polypyrrole at the cathode. This BFC was performed in a stirred acetate buffer solution (pH 5.0) containing 40 mmol/L glucose in air, with a maximum power density of 8 μW/cm², an open‐circuit cell voltage of 0.29 V, and a short‐circuit current density of 85 μA/cm², respectively. The cell current at the load of 100 kΩ retained 78.9% of the initial value after continuous discharging for 15 h in a stirred acetate buffer solution (pH 5.0) containing 40 mmol/L glucose in air. The performance decrease of the BFC resulted mainly from the leakage of the ABTS mediator immobilized at the cathode, as revealed by the two‐channel quartz crystal microbalance technique. In addition, a monopolar glucose BFC was performed with the same anode as that in the glucose/O₂ membraneless BFC in a stirred phosphate buffer solution (pH 7.0) containing 40 mmol/L glucose, and a carbon cathode in Nafion‐membrane‐isolated acidic KMnO₄, with a maximum power density of 115 μW/cm², an open‐circuit cell voltage of 1.24 V, and a short‐circuit current density of 202 μA/cm², respectively, which are superior to those of the glucose/O₂ membraneless BFC. A modification of the anode with MWCNTs for the monopolar glucose BFC increased the maximum power density by a factor of 1.8. The ECN device is highly recommended as a convenient, real‐time and sensitive technique for BFC studies.     

基于α-溴代酮的催化不对称合成3,3-螺环丙基吲哚酮和乙烯基环丙烷

在甲基化奎尼丁(20mol%)的催化下,分别实现了α-溴代酮与3-(取代亚甲基)吲哚酮和缺电子1,3-二烯的高度非对映选择性和对映选择性的环丙烷化反应,以46%~99%收率、高达98%ee和20∶1 dr生成相应的3,3-螺环丙基吲哚酮和乙烯基环丙烷.通过催化的氮叶立德策略,成功发展了一种用于上述手性化合物的简便合成方法.     

Crystal structures of the complexes of rare earth picrates with N, N, N'''', N''''-tetraphenyl-3, 6-dioxaoctanediamide

The complexes of rare earth picrate with N,N,N',N'-tetraphenyl-3,6-dioxaoctanediamide(TDD),Eu(picc(TDD)] 2CH3CN and [ Y(pic)3(TDD)],have been synthesized.The crystal structures reveal that TDD at is as n tetradentate ligand,forming a ring-like coordination structure with its oxygen atoms together with one oxygen atom of the bidentate pterate In the Eu(Ⅲ) complex,the europium ion with a larger ionic radius lies out of the ring,while in the Y(Ⅲ) complex,the yttrium ion with a smaller ionic radius enters the cavity of the ligand.The structures of the complexes are greatly affected by the ionic radii due to participation of the picrates in coordination.     

碳苷研究(Ⅵ)——1-芳基-D-吡喃葡萄糖碳苷的快原子轰击质谱

快原子轰击质谱(FAB-MS)是近几年发展起来的一种质谱新技术^[1],特别适于极性大、不易挥发和对热不稳定的化合物,已用于多肽^[2]、核酸^[3]及苷^[4]的结构测定。