Platinum-catalyzed highly selective thiocarbonylation of acetylenes with thiols and carbon monoxide

A novel carbonylative addition of thiols (RSH) to terminal acetylenes (R′-CCH) takes place successfully in the presence of platinum catalysts under the pressure of carbon monoxide, providing α,β-unsaturated thioesters (R′-C(C(O)SR)CH₂) in good yields regioselectively. This ‘hydrothiocarbonylation’ reaction of acetylenes may include the formation of the platinum sulfide complex as key species.     

Synthesis of 2-acylindole-3-acetic acids: a novel base-mediated indole synthesis

An efficient and expedient synthetic route to 2-acylindole-3-acetic acids is described. This work first demonstrates a one-pot room-temperature indole ring construction via the in situ generation of indoline intermediate.     

Novel oxidation of toluenes catalyzed by reusable vanadyl(IV) sulfate under mild conditions with molecular oxygen

Efficient oxidation system using reusable vanadyl(IV) sulfate catalyst was established. Toluenes were easily oxidized under molecular oxygen (0.1 MPa) at 100 °C catalyzed by vanadyl(IV) sulfate to afford the corresponding benzoic acids in excellent yields. The recovered catalyst could be reused without loss of activity.     

Modification of a Small β‐Barrel Protein,To Give Pseudo‐Amyloid Structures,Inhibits Amyloid β‐Peptide Aggregation

Aggregation of amyloid β‐peptide (Aβ) is closely related to the pathogenesis of Alzheimer’s disease (AD). Although much effort has been devoted to the construction of molecules that inhibit the aggregation of Aβ1‐42, high doses are needed for the inhibition of Aβ aggregation in many cases. Previously, we reported that designed green fluorescent protein (GFP) analogues that gives pseudo‐Aβ β‐sheet structures can work as an aggregation inhibitor against Aβ. To further test this design strategy, we constructed protein analogues that mimic Aβ β‐sheet structures of amyloids by using insulin‐like growth factor 2 receptor domain 11 (IGF2R‐d11) as a scaffold. A designed protein, named IG11KK, which has a parallel configuration of Aβ‐like β sheets, can bind more preferentially to oligomeric Aβ1‐42 than the monomer. Moreover, IG11KK suppressed the aggregation of Aβ1‐42 efficiently, even though lower concentrations of IG11KK than Aβ were used. The aggregation kinetics of Aβ in the presence of the designed proteins revealed that IG11KK can work as an inhibitor not only for the early to middle stages, but also in the latter stage of Aβ aggregation owing to its favorable binding to oligomeric structures of Aβ. The design strategy using β‐barrel proteins such as IGF2R‐d11 and GFP is useful in generating excellent inhibitors of protein misfolding and amyloid formation.     

Thorium and americium solubilities in cement pore water containing superplasticiser compared with thermodynamic calculations

The solubility of thorium and americium in pore water squeezed from a cement paste was investigated by a batch method from oversaturation. The cement paste was prepared by mixing ordinary Portland cement with deionised water; in some cases the deionised water contained a polycarboxylic acid–base type superplasticiser. Following solidification, pore water was squeezed from the cement paste and collected for use in the solubility experiments. The aim of these was to investigate whether there was any effect of superplasticiser on the solubility of thorium and americium in the squeezed cement pore waters. The obtained solubility values in the two squeezed pore waters (with and without superplasticiser present) were similar. Thermodynamic calculations were performed with the thermodynamic database developed by Japan Atomic Energy Agency and compared with the experimental data to verify their applicability. These results showed that the superplasticiser used in the present study after mixing with the cement paste did not have a significant effect on solubility of thorium and americium, and the thermodynamic calculations were applicable in the present system. Size distribution of colloidal species of thorium and americium was also investigated.     

Magnetic moment of short lived β-emitter 24mAl

The magnetic moment of short lived β-emitter ^24mAl (426 keV, I ^π ?=?1^?+?, T _1/2?=?131 ms) has been measured by means of β-NMR technique, for the first time. From the β-NMR spectrum, the magnetic moment was determined as $\left| {\upmu}\left( ^{\rm 24m}{\rm Al} \right) \right|=\left( {2.99\pm 0.09} \right){\upmu}_{\rm N}$ . Combined with the known magnetic moment of the mirror partner ^24mNa, the expectation value of <?S _z?> is obtained to be (0.08 ± 0.12). These values are reproduced well by the shell model calculation.     

Electromagnetic moments of the beta-emitting nucleus 16N

The nuclear magnetic dipole moment mu and electric quadrupole moment Q of the beta-emitting 16N(Ipi = 2(-), T(1/2) = 7.13 s) nucleus have been determined for the first time by detecting its beta-NMR in a MgO crystal and beta-NQR (nuclear quadrupole resonance) in a TiO (2) crystal to be /mu/ = (1.9859+/-0.0011) mu(N) and /Q/ = (17.9+/-1.7) mb, respectively. Although the prediction of mu given by the Hartree-Fock calculation agrees well with the experiment, an abnormally small effective charge for neutrons is required to account for the experimental Q.     

One-step synthesis of (1-iodovinyl) arenes from trimethylsilyl ethynylarene through iodotrimethylsilane-mediated hydroiodation

One-step access to (1-iodovinyl) arenes from trimethylsilyl ethynylarenes is described. The method is superior to a conventional multi-step approach, and is enhanced by the Sonogashira reaction that provides ready access to a variety of trimethylsilyl ethynylarenes.     

Peptide design based on an antibody complementarity-determining region (CDR): construction of porphyrin-binding peptides and their affinity maturation by a combinatorial method

We have utilized sequence information from an antiheme monoclonal antibody to develop novel porphyrin-binding peptides. Several peptides which have an intramolecular disulfide bond in different positions and different chain lengths were prepared. The affinities of peptides for meso-tetrakis(4-carboxyphenyl)porphyrin were increased by an appropriate conformational restraint using a disulfide bond. Detailed studies with a representative 12-peptide, 12C4, whose length was reduced from 20 residues of the complementarity-determining region (CDR), indicated that both the hydrophobic and electrostatic interactions were essential factors in the peptide-porphyrin binding. Moreover, two-dimensional 1H NMR spectroscopy revealed the conformation of the peptide and the critical residues for the porphyrin-binding. According to the obtained results, a further minimized 9-peptide, 9L, was successfully redesigned with a sequence capable of forming a beta-turn instead of a disulfide bond. Furthermore, affinity maturation studies of 9L were performed by using a combinatorial approach such as the spot-synthesis method. Peptides with an improved affinity for porphyrins were prepared by systematic amino acid replacement. Thus, the design of peptides targeted to porphyrins was demonstrated by the combination of antibody information and the rationally designed combinatorial method.