Formal [4+2] Reaction between 1,3‐Diynes and Pyrroles: Gold(I)‐Catalyzed Indole Synthesis by Double Hydroarylation

Indole synthesis by a gold(I)‐catalyzed intermolecular formal [4+2] reaction between 1,3‐diynes and pyrroles has been developed. This reaction involves the hydroarylation of 1,3‐diynes with pyrroles followed by an intramolecular hydroarylation to give the 4,7‐disubstituted indoles. This reaction can also be applied to the synthesis of carbazoles when indoles are used as the nucleophiles instead of pyrroles.     

The Complexity of Collective Decision

This paper is about the dynamics of collective decision when an individual adapts his rational decision to the others'. We consider an organization of heterogeneous agents, in which each agent faces the binary decision problem. The standard way of modeling a collective decision is to assume everyone has the same value or payoff structure. This paper considers collective decision of agents with heterogeneous payoffs. We obtain and classify rational decision rules of heterogeneous agents into a few categories depending on their idiosyncratic payoff structure. We also obtain the micro–macro dynamics that relate the aggregate collective decision with the underlying individual decisions. We investigate the roles of particular types of agents such as hardcore, conformists, and nonconformists. We show that agents' rational behavior combined with the others produce stable orders, and sometimes complex cyclic behavior.     

Synthesis of (+)-laurencin via ring expansion of a C-glycoside derivative

Laurencin was efficiently synthesized from a C-glycoside derivative based on ring expansion of the oxane part of the starting compound into an eight-membered cyclic ether via a ring-cleavage/ring-closing olefin metathesis process, stereoselective introduction of a bromo group at C4, and convergent construction of the side-chain part using a lithiated enyne unit.     

Phase Equilibrium in the System Ln-M-O: III. Ln=Gd at 1100°C

Phase equilibrium in the system Gd-Mn-O has been established at 1100°C while varying the partial pressure of oxygen between 0 and 13.00 in −log (P_O2/atm), and a phase diagram at 1100°C is presented as a Gd₂O₃-MnO-MnO₂ system. Under the experimental conditions, Gd₂O₃, MnO, Mn₃O₄, GdMnO₃, and GdMn₂O₅ phases are present at 1100°C, but Gd₂MnO₄, Mn₂O₃, and MnO₂ are not stable in the system. The substantial difference from the previously studied La-Mn-O and Nd-Mn-O systems lies in the fact that the LnMn₂O₅-type phase is stable under the present experimental conditions. A wide range of nonstoichiometry has been found in the GdMnO₃ phase coexisting with Gd₂O₃. X in GdMnO_3+X ranges from −0.03 at log P_O2=−9.47 to 0.05 at log P_O2=0. Nonstoichiometry is represented by an equation, N_O/N_GdMnO3=3.00×10⁻⁴(log P_O2)³+5.80×10⁻³(log P_O2)²+3.52×10⁻²(log P_O2)+0.0464, and the activities of components in solid solution are calculated from the equation. Similar to the case of LaMnO₃, GdMnO₃ seems to vary in composition between the Gd₂O₃-rich and Gd₂O₃-poor sides. Lattice constants of GdMnO₃ produced under different oxygen partial pressures and those of GdMn₂O₅ prepared in air were determined, along with spacings and relative intensities of GdMn₂O₅. Standard Gibbs energies of reactions shown in the system were calculated and compared with previously reported values.     

Efficient and convenient heterogeneous palladium-catalyzed regioselective deuteration at the benzylic position

The Pd/C-catalyzed efficient and regioselective hydrogen-deuterium (H-D) exchange reaction on the benzylic site proceeded in D2O in the presence of a small amount of H2 gas. The use of the Pd/C-ethylenediamine complex [Pd/C(en)] as a catalyst instead of Pd/C led to the efficient deuterium incorporation into the benzylic site of O-benzyl protective groups without hydrogenolysis. These H-D exchange reactions provide a post synthetic and D(2)-gas-free deuterium-labeling method on a wide variety of benzylic sites using D2O as the deuterium source and heterogeneous Pd/C or Pd/C(en) as a reusable heterogeneous palladium catalyst under mild and neutral conditions.     

Simple column‐switching HPLC method for determining levels of the antifungal agent micafungin in human plasma and application to patient samples

Micafungin is an echinocandin antifungal agent that is important for treating candidiasis in emergency and intensive care medicine; however, current methods for measuring micafungin plasma levels are lengthy and complicated. We report a simple quantitative method using column‐switching high‐performance liquid chromatography (HPLC) for determining micafungin in human plasma samples. Human plasma was directly injected into a column‐switching HPLC system with a MAYI‐ODS pre‐column to remove the plasma matrix. The calibration curve for micafungin showed good linearity in the range 0.1–10 µg/mL in human plasma. The mean relative standard deviation value of the intra‐day and inter‐day precision was less than 7.3%. More than 450 successive, accurate measurements were made before the system had to be washed with ammonium acetate solution. The therapeutic micafungin level in patients' plasma was successfully measured using this method. Because the pretreatment is simple and reproducible, our method can be used for routine therapeutic monitoring. Copyright © 2012 John Wiley & Sons, Ltd.     

Palladium-catalyzed distannylation of ortho-quinodimethanes

An exo-diene moiety of various ortho-quinodimethanes, regardless of its transient character, was inserted into a Sn-Sn sigma-bond of hexabutyldistannane in the presence of a palladium catalyst, giving alpha,alpha'-bis(tributylstannyl)-o-xylenes straightforwardly.     

Cu2+ -mediated assembly of the minor groove binders on the DNA template with sequence selectivity

The ligands (Bpy-H, 5) have been designed to connect the Hoechst33258 skeleton for DNA binding and 2,2'-bipyridine for Cu(2+) complexation. It has been revealed that the new Hoechst ligand long Bpy-H (5L) having a long linker exhibits Cu(2+)-mediated assembly on the DNA template having two A(3)T(3) sites in a selective manner depending on the length of the linker of the ligand as well as on the distance between the two A(3)T(3) sites of DNA. [reaction: see text]