Guest-induced self-assembly of a macrocyclic boronic ester containing diarylethene units: enhancement of photoresponsivity

Guest-induced self-assembly of a macrocyclic boronic ester containing photochromic diarylethene units is realized and this macrocycle showed high quantum yield of photoisomerization due to favourable conformational constraint.     

Visualization of dynamic change in contraction-induced lipid composition in mouse skeletal muscle by matrix-assisted laser desorption/ionization imaging mass spectrometry

Lipids in skeletal muscle play a fundamental role both in normal muscle metabolism and in disease states. Skeletal muscle lipid accumulation is associated with several chronic metabolic disorders, including obesity, insulin resistance, and type 2 diabetes. However, it is poorly understood whether the lipid composition of skeletal muscle changes by contraction, due to the complexity of lipid molecular species. In this study, we used matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS) to investigate changes in skeletal muscle lipid composition induced by contraction. We successfully observed the reduction of diacylglycerol and triacylglycerol, which are generally associated with muscle contraction. Interestingly, we found the accumulation of some saturated and mono-unsaturated fatty acids and poly-unsaturated fatty acids containing phosphatidylcholine in contracted muscles. Moreover, the distributions of several types of lipid were changed by contraction. Our results show that changes in the lipid amount, lipid composition, and energy metabolic activity can be evaluated in each local spot of cells and tissues at the same time using MALDI-IMS. In conclusion, MALDI-IMS is a powerful tool for studying lipid changes associated with contractions.     

Phase retrieval using an aperture-array filter under partially coherent illumination

Recently we have proposed a deterministic phase retrieval method using an aperture-array filter to reconstruct a complex-valued object from a single diffraction intensity pattern. We describe here the effect of quasi-monochromatic partially coherent illumination on the object reconstruction by the phase retrieval method, and then present the method of eliminating the effect of the partially coherent illumination from the diffraction intensity pattern via a simple Fourier deconvolution operation provided that the complex degree of spatial coherence of the illuminating beam is known. The usefulness of this method is shown in computer-simulated examples of the object reconstructions under Gaussian Schell-model partially coherent illumination.     

Rhodium‐Catalyzed C−H Activation Enabled by an Indium Metalloligand

Rhodium complexes with an indium metalloligand were successfully synthesized by utilizing a pyridine‐tethered cyclopentadienyl ligand as a support for an In?Rh bond. The indium metalloligand dramatically changes the electronic and redox properties of the rhodium metal, thereby enabling catalysis of sp²C?H bond activation.     

New sensitive derivatization of hydroxysteroids for high-performance liquid chromatography with fluorescence detection

New highly sensitive and moderately reactive derivatization reagents for hydroxysteroids have been developed. Two derivatization reagents, 1-anthroyl nitrile and 9-anthroyl nitrile, were readily prepared from the corresponding anthracenecarboxylic acid in two steps. The hydroxysteroid was condensed with the anthroyl nitrile in the presence of triethylamine under mild conditions. The resulting ester showed a single peak of the theoretical shap on the chromatogram and provided excellent sensitivity. The detection limit of the C-21 ester formed from cortisol was 10 pg in normal-phase chromatorgraphy.     

Regeneration of NADH and ketone hydrogenation by hydrogen with the combination of hydrogenase and alcohol dehydrogenase

Applied Biochemistry and Biotechnology - The regeneration of nicotinamide-adenine dinucleotide (reduced form, NADH) by the reaction of NAD with hydrogen gas was carried out in the presence of the...     

A facile method for the synthesis of polycyclic indole derivatives: the generation and reaction of tungsten-containing azomethine ylides

Treatment of N-(o-alkynylphenyl)imine derivatives with W(CO)(5)(L) induces the 5-endo-mode of cyclization of the imine nitrogen onto the electrophilically activated alkyne moiety to afford a novel reactive species, a metal-containing azomethine ylide. [3 + 2] cycloaddition of this ylide species with various electron-rich alkenes proceeds smoothly to give unstable carbene complexes, which in turn undergo 1,2-hydrogen-, alkyl-, and aryl-migration to afford in good yield 6-5-5 tricyclic indole skeletons having an alkyl or an aryl substituent at the 3-position of the indole nucleus.     

Synthetic control leading to chiral compounds

A highly diastereoselective cross aldol reaction is developed using divalent tin enolates formed from stannous trifluoromethanesulfonate and carbonyl compounds. The reaction is extended to a highly enantioselective cross aldol reaction employing chiral diamines derived from (S)-proline as ligands.     

Rhenium(I)‐Catalyzed Generation of α,β‐Unsaturated Carbene Complex Intermediates from Propargyl Ethers for the Preparation of Cycloheptadiene Derivatives

The rhenium(I)‐catalyzed generation of α,β‐unsaturated carbene complex intermediates from easily available propargyl ethers was achieved for the concise construction of cycloheptadiene derivatives through the formal [4+3] cycloaddition reaction with siloxydienes.