Cassia obtusifolia MetE as a Cytosolic Target for Potassium Isolespedezate,a Leaf‐Opening Factor of Cassia plants: Target Exploration by a Compact Molecular‐Probe Strategy

Affinity chromatography by using ligand‐immobilized bead technology is generally the first choice for target exploration of a bioactive ligand. However, when a ligand has comparatively low affinity against its target, serious difficulties will be raised in affinity‐based target detection. We report here that the use of compact molecular probes (CMP) will be advantageous in such cases; it enables the retention of moderate affinity between the ligand and its target in contrast to immobilizing the ligand on affinity beads that will cause a serious drop in affinity to preclude target detection. In the CMP strategy, a CMP containing an azide handle is used for an initial affinity‐based labeling of target, and subsequent tagging by CuAAC with a large FLAG tag will give a tagged target protein. By using the CMP strategy, we succeeded in the identification of Cassia obtusifolia MetE as a cytosolic target protein of potassium isolespedezate ( 1 ), a moderately bioactive ligand.     

Ruthenium-catalyzed cyclization/transfer hydrogenation of 1,6-diynes: unprecedented mode of alcohol activation via metallacyclopentatriene

The first transfer-hydrogenative cyclization of 1,6-diynes that leads to exocyclic dienes was developed using a ruthenium catalyst and MeOH as a H(2) surrogate.     

Photoinduced isothermal phase transitions of liquid-crystalline macrocyclic azobenzenes

Liquid-crystalline macrocyclic compounds, tethered by two or three azobenzenes bearing alkoxy side chains, exhibit isothermal phase transitions from liquid-crystal to isotropic as well as from crystal to isotropic phases upon light irradiation due to the drastic conformational change of their macrocyclic backbone.     

Platinadithiolene-conjugated pyrylium salt with strong intramolecular donor-acceptor interaction

Protonation of a new platinum complex, Pt(1-pdtAq)((t)Bu(2)bpy), where 1-pdtAq is 1-(phenyldithiolenethynyl)anthraquinone, afforded a cyclized structure, [Pt(1-pdtPyl)((t)Bu(2)bpy)](+), with a unique electronic structure due to intense intramolecular charge transfer.     

A reversal phenomenon of enantioface selectivity by the cooperative operation of two chiral catalysts

The reversal phenomenon of enantioface selectivity in the asymmetric addition of diisopropylzinc to aldehydes was observed by mixing two chiral β-amino alcohol catalysts. The opposite enantiomeric product was formed on using a mixture of two chiral catalysts that possess individual enantioselectivity.     

Silane Coupling Agent Modifies the Mechanical Properties of a Chitosan Microfiber

Chitosan microfibers are widely used in medical applications because they have favorable inherent properties. However, their mechanical properties require further improvement. In the present study, a trimethoxysilane aldehyde (TMSA) crosslinking agent was added to chitosan microfibers to improve their tensile strength. The chitosan microfibers were prepared using a coagulation method. The tensile strength of the chitosan microfibers was improved by crosslinking them with TMSA, even when only a small amount was used (less than 1%). TMSA did not change the orientation of the chitosan molecules. Furthermore, aldehyde derived from TMSA did not remain, and siloxane units were formed in the microfibers.     

Chemoenzymatic Posttranslational Modification Reactions for the Synthesis of Ψ[CH2NH]‐Containing Peptides

The Ψ[CH₂NH] reduced amide bond is a peptide isostere widely used in the development of bioactive pseudopeptides. Reported here is a method of chemoenzymatic posttranslational modification for the synthesis of Ψ[CH₂NH]‐containing peptides converted from ribosomally expressed peptides. The posttranslational conversion composed of an enzymatic cyclodehydration and facile two‐step chemical reduction achieves deoxygenation of a specific amide bond present in a nonprotected peptide in water. This method generates the Ψ[CH₂NH] bond in peptides and is applicable to various peptide sequences, potentially enabling the preparation of a library of Ψ[CH₂NH]‐containing peptides.     

Chemoenzymatic Posttranslational Modification Reactions for the Synthesis of Ψ[CH2NH]-Containing Peptides

The Ψ[CH₂NH] reduced amide bond is a peptide isostere widely used in the development of bioactive pseudopeptides. Reported here is a method of chemoenzymatic posttranslational modification for the synthesis of Ψ[CH₂NH]-containing peptides converted from ribosomally expressed peptides. The posttranslational conversion composed of an enzymatic cyclodehydration and facile two-step chemical reduction achieves deoxygenation of a specific amide bond present in a nonprotected peptide in water. This method generates the Ψ[CH₂NH] bond in peptides and is applicable to various peptide sequences, potentially enabling the preparation of a library of Ψ[CH₂NH]-containing peptides.     

Toward Efficient Synthesis of Chiral Zeolites: A Rational Strategy for Fluoride-Free Synthesis of STW-Type Zeolite

The STW-type zeolite is attractive for developing novel enantioselective syntheses/separation of chiral compounds because it is the only chiral zeolitic microporous material whose enantioenriched synthesis has been achieved. In addition to the conventional industries in which zeolites are used, STW should have diverse industrial applications in the pharmaceutical and food industries. However, the toxic and caustic fluoride required for synthesizing STW severely hinders its commercialization by mass production. Herein, we report the first example of fluoride-free STW synthesis, in which the two roles of fluoride—formation of a zeolitic framework rich in tetravalent T-atoms and promotion of double 4-membered ring unit formation—were substituted by dry gel conversion and Ge addition, respectively. The STW obtained was highly crystalline, with a similar micropore volume and thermal stability as those of original fluoride-based STW. Our approach is promising not only for the fluoride-free synthesis of enantiomeric STW but also for general fluoride-free syntheses.