Selective,one-pot synthesis of 2,3,6-trisubstituted pyridine and 2-cyclohexen-1-one derivatives from bicyclic ketals

Boron difluoromethanesulfonate, prepared from 5 equivalents of trimethylsilyl methanesulfonate and 1 equivalent of boron trifluoride etherate, has proved to be an active Lewis acid catalyst for the one-pot transformation reaction of bicyclic ketals in the 6,8-dioxabicyclo[3.2.1]octane series to 2,3,6-trisubstituted pyridine or 2-cyclohexen-1-one selectively, depending on conditions. A 1,5-diketone was the reaction intermediate for both products. Pyridine was formed selectively by using a nitrile as a solvent or a reagent, but cyclohexenone was prepared in methylene chloride instead of a nitrile.     

Dually Electroactive Disulfide‐Confined Aryldiazonium Salt Used as a Linker Molecule for Preparing Immunosensor Platforms

A new electroactive disulfide‐confined aryl diazonium (DSAD) salt was synthesized and used as a linker for biomolecules immobilization to prepare two kinds of immunoassay platforms. DSAD was electrodeposited on ITO electrode surfaces by cyclic voltammetry. Disulfide group of DSAD attached on the surfaces were electrochemically oxidized into thiosulfinate or thiosulfonate groups. For the first work, a detection of rabbit antigen was performed on ITO microelectrodes array by spatially‐selective approach. In the second work, DSAD was deposited on electrochemically reduced graphene oxide‐modified ITO surfaces, which were used as a platform for electrochemical sandwich immunoassay for detecting mouse antigen.     

Analyses of the TCR repertoire of MHC class II-restricted innate CD4+ T cells

Analysis of the T-cell receptor (TCR) repertoire of innate CD4⁺ T cells selected by major histocompatibility complex (MHC) class II-dependent thymocyte–thymocyte (T-T) interaction (T-T CD4⁺ T cells) is essential for predicting the characteristics of the antigens that bind to these T cells and for distinguishing T-T CD4⁺ T cells from other types of innate T cells. Using the TCR^mini Tg mouse model, we show that the repertoire of TCRα chains in T-T CD4⁺ T cells was extremely diverse, in contrast to the repertoires previously described for other types of innate T cells. The TCRα chain sequences significantly overlapped between T-T CD4⁺ T cells and conventional CD4⁺ T cells in the thymus and spleen. However, the diversity of the TCRα repertoire of T-T CD4⁺ T cells seemed to be restricted compared with that of conventional CD4⁺ T cells. Interestingly, the frequency of the parental OT-II TCRα chains was significantly reduced in the process of T-T interaction. This diverse and shifted repertoire in T-T CD4⁺ T cells has biological relevance in terms of defense against diverse pathogens and a possible regulatory role during peripheral T-T interaction.     

Diversity‐Oriented Approach for Chemical Biology

Synthetic molecules that modulate and probe biological events are critical tools in chemical biology. Utilizing combinatorial and diversity‐oriented synthetic strategies, access to large numbers of small molecules is becoming more and more feasible, and research groups in this field can take advantage of the power of chemical diversity. Since the majority of early studies were focused on the discovery of compounds that perturb protein functions, diversity‐based approaches are often considered as therapeutic lead discovery tactics. However, the diversity‐oriented approach can also be applied to advance distinct aims, such as target protein identification, or the development of imaging probes and sensors. This review provides a personal perspective of the chemical‐diversity‐based approach and how this principle can be adapted to various chemical biology studies.     

Gold Nanorod–Photosensitizer Complex Obtained by Layer‐by‐Layer Method for Photodynamic/Photothermal Therapy In Vitro

Gold nanorod (GNR)–photosensitizer (PS) complex was prepared using anionic PS (sodium salt of purpurin‐18) and cationic poly(allylamine hydrochloride) by layer‐by‐layer method, and was characterized by transmission electron microscopy, UV‐vis spectroscopy, and zeta potential. The GNR–PS complex is a promising agent for synergistic (photothermal and photodynamic) therapy (PTT/PDT), in which PTT generates heat as well as operates the PS release which maximize the following PDT activity. The combined dual therapy, PTT followed by PDT, exhibits a significantly higher photocytotoxicity result based on synergistic effect of hyperthermia from PTT as well as singlet oxygen photogeneration from PDT.     

Biflavones and Furanone Glucosides from Zabelia tyaihyonii

Two new biflavones, (aR)‐3′‐methoxycupressuflavone ( 1 ) and (aR)‐3′,3′′′‐dimethoxycupressuflavone ( 2 ), and two new furanone glucosides, zabeliosides A and B ( 3 and 4 , resp.), along with two known biflavones, cupressuflavone ( 5 ) and amentoflavone ( 6 ), were isolated from the leaves of Zabelia tyaihyonii. The structures of the new compounds were elucidated by 1D‐ and 2D‐NMR, HR‐ESI‐MS, and circular dichroism.     

Morphology-Directed Selective Production of Ethylene or Ethane from CO2 on a Cu Mesopore Electrode

The electrocatalytic conversion of CO₂ to value-added hydrocarbons is receiving significant attention as a promising way to close the broken carbon-cycle. While most metal catalysts produce C₁ species, such as carbon monoxide and formate, the production of various hydrocarbons and alcohols comprising more than two carbons has been achieved using copper (Cu)-based catalysts only. Methods for producing specific C₂ reduction outcomes with high selectivity, however, are not available thus far. Herein, the morphological effect of a Cu mesopore electrode on the selective production of C₂ products, ethylene or ethane, is presented. Cu mesopore electrodes with precisely controlled pore widths and depths were prepared by using a thermal deposition process on anodized aluminum oxide. With this simple synthesis method, we demonstrated that C₂ chemical selectivity can be tuned by systematically altering the morphology. Supported by computational simulations, we proved that nanomorphology can change the local pH and, additionally, retention time of key intermediates by confining the chemicals inside the pores.     

Two New C‐seco Limonoids from the Fruit of Melia azedarach

A phytochemical investigation of the fruits of Melia azedarach led to the isolation of two new C‐seco‐nimbolinin‐type limonoids, 3α‐acetoxy‐1α,7α‐dihydroxy‐12α‐methoxynimbolinin ( 1 ) and 3α‐acetoxy‐1α,12α‐dihydroxy‐7α‐(2‐methylprop‐2‐enoyl)nimbolinin ( 2 ), together with eleven known compounds, 3 – 13 . Their structures were elucidated on the basis of extensive spectroscopic analysis, including ¹H‐ and ¹³C‐NMR, HMQC, HMBC, NOESY, and HR‐FAB‐MS.     

TiO2–SiO2 in PEG: A Highly Efficient Green Catalytic System for One‐Pot Synthesis of Benzo[a]xanthen‐11‐ones

Polyethylene glycol was found to be an inexpensive non‐toxic and effective medium for the one‐pot synthesis of benzo[a]xanthen‐11‐ones in the presence of TiO₂–SiO₂ as the catalyst in good to excellent yield. The salient features of this protocol are the simplicity of the procedure, the ready accessibility of the catalyst, its cost effectiveness, and reusable catalyst in relatively short reaction times.     

BF3·SiO2-catalyzed one-pot synthesis of α-aminophosphonates in ionic liquid and neat conditions

α-Aminophosphonates were synthesized in a simple and efficient method from the three-component condensation reaction of 5-amino 2,2-difluoro-1,3-benzodioxole, aromatic aldehydes, and diethyl phosphite by silica-supported boron trifluoride (BF₃·SiO₂) in ionic liquid ([bmim][HCl]) under solvent-free conditions at room temperature in good to excellent yields and short reaction times. The catalyst can be recovered and reused for several times without any significant loss of activity. It was observed that a homogeneous reaction medium proved beneficial for the yield of the reaction.