A simple approach to C3-ethoxycarbonylmethylation of thiophenes/furans with diethyl bromomalonate.

A mild and efficient visible-light-induced radical method was developed to produce C3-malonated five-membered heterocycles using 2-substituted thiophenes/furans and diethyl bromomalonate as the starting materials. Various 2-substituted (benzo)thiophenes/furans were suitable for the C3-ethoxycarbonylmethylation. The free radical mechanism was proposed based on the results of control experiments, cyclic voltammetry experiments and luminescence quenching experiments. We suggested that the heteroleptic halogen-bridged iridium(III) dimers might play an important role in this system.

A visible-light-induced photocatalyst-free approach for C-3 dicarbonyl coumarin production.

A mild and efficient visible-light-induced synthesis of C-3 dicarbonyl coumarins from 3-arylacetylene coumarins without a photocatalyst was reported. This iodide-mediated method exhibited broad substrate scope and good functional group tolerance, and a series of C-3 dicarbonyl coumarins were obtained in moderate to excellent yields. Based on the control experimental results, it was found that the visible-light-induced oxidation might be via both radical and ionic processes. Moreover, some synthesized compounds displayed high sensitivity to hydrogen peroxide (H2O2) with a low detection limit (DL, down to 0.149 µM).

"One-Pot" Synthesis of γ-Pyrones from Aromatic Ketones/Heteroarenes and Carboxylic Acids.

Despite the various attractive properties of γ-pyrones, there are still some deficiencies in their synthetic approaches such as lower atom economy, multistep processes, and prefunctionalization of the reagents. In this work, an efficient and simple (CF3CO)2O/CF3SO3H-mediated "one-pot" approach was realized to produce γ-pyrones by applying aromatic ketones/heteroarenes and carboxylic acids as the starting materials. The target products were isolated in moderate to excellent yields. The reaction mechanism was studied by density functional theory calculational methods. The results of experimental and theoretical investigations not only helped us explain the reason of high selectivity formation of ß-diketones but also proved that 1,3,5-ketones might be important intermediates for the cyclization to afford γ-pyrones.

Pyrazoles: 'one-pot' synthesis from arenes and carboxylic acids.

A rapid and efficient method for 'one-pot' synthesis of pyrazoles from (hetero)arenes and carboxylic acids via successive formation of ketones and ß-diketones followed by heterocyclization with hydrazine has been developed. The utility of the RCOOH/TfOH/TFAA acylation system for intermediate production of ketones and 1,3-diketones is a key feature of this approach. The preliminary evaluation of the anticancer activity of the synthesized pyrazoles is performed.

A visible-light-induced "on-off" one-pot synthesis of 3-arylacetylene coumarins with AIE properties.

A mild and simple one-pot stepwise method to synthesize 3-arylacetylene coumarins from alkynoates was demonstrated. This catalytic system involves photosensitizer-free photocatalysis and thermocatalysis processes. A series of alkynoates and phenylacetylenes were well tolerated in the optimized multi-catalytic system. The corresponding 3-arylacetylene coumarins were obtained in moderate to excellent yields. The results of the studies of their optical properties showed that the aromatic ring at the C4-position of coumarins is unfavorable for improving the molecular fluorescence quantum yield in solution. Based on the spectral studies and X-ray single crystal diffraction analysis, it was found that AIE activities may exist in some of the 3-arylvinyl-4-aryl-coumarins in their solid state. We expect that these molecules may have potential optical applications.

An efficient light on-off one-pot method for the synthesis of 3-styryl coumarins from aryl alkynoates.

An efficient one-pot stepwise method to synthesize 3-styryl-4-arylcoumarins from simple alkynoates is demonstrated. On the basis of the control experiments, a possible mechanism involving light-driven radical cyclization and Pd-catalysed cross-coupling processes for this synthesis method is proposed. The results of X-ray analysis and spectroscopy experiments prove that the substituent effect has a significant influence on the absorption and emission properties of the synthesized 3-styryl coumarins.

Regioselective phosphinylation of coumarins under green LED irradiation and its mechanism.

The regioselective synthesis of 3-phosphinylated coumarins in moderate to excellent yields was developed via an EY/BPO-mediated cross-dehydrogenative coupling (CDC) reaction under green LED irradiation. The results of control experiments showed that the active intermediate, a P-centered radical, might be obtained through energy transfer and electron transfer processes.

Modulatory Functionalization of Gold Nanorods Using Supramolecular Assemblies.

Supramolecular-assembly-mediated functionalization of gold nanorods (GNRs) has been developed by reversible phase transfer between water and oils, which offers a facile method for fabricating robust GNRs with surface-charge tunability. In this regard, trimethylammonium (TMA) GNRs were initially prepared from conventional cetyltrimethylammonium bromide (CTAB) GNRs by means of a ligand-exchange reaction in the presence of an excess amount of TMA ligands. To further expand their functionality and potential applications, electrostatic assemblies of positively charged TMA-GNRs with negatively charged oleate ions were prepared. These assemblies (OA-GNRs) can undergo facile phase transfer from water to hexane. Interestingly, the reversible electrostatic assembly between the TMA and OA ions fabricated onto GNRs can be easily disrupted by treatment with HCl, which removes the OA ions from the GNRs to re-form the TMA-GNRs, which can be made soluble in aqueous media again. In addition, OA-GNRs can be further used for the synthesis of negatively charged GNRs such as 11-mercaptoundecanoic acid (MUA) GNRs, which are hard to prepare directly from CTAB-GNRs. This versatile method for phase transfer and functionalization on GNRs is expected to broaden the scope of their applications in sensing, biomedical imaging, photothermal therapies, and drug delivery systems.

Method for Direct Synthesis of α-Cyanomethyl-ß-dicarbonyl Compounds with Acetonitrile and 1,3-Dicarbonyls.

A novel and efficient method for the synthesis of α-cyanomethyl-ß-dicarbonyls in moderate to excellent yields is developed by using inactive CH3CN and simple 1,3-dicarbonyls. A radical mechanism is proposed under the ESI-MS (electrospray ionization mass spectrometry) analysis results of control experiments.

G-749, a novel FLT3 kinase inhibitor, can overcome drug resistance for the treatment of acute myeloid leukemia.

Aberrant activations of Fms-like tyrosine receptor kinase (FLT) 3 are implicated in the pathogenesis of 20% to 30% of patients with acute myeloid leukemia (AML). G-749 is a novel FLT3 inhibitor that showed potent and sustained inhibition of the FLT3 wild type and mutants including FLT3-ITD, FLT3-D835Y, FLT3-ITD/N676D, and FLT3-ITD/F691L in cellular assays. G-749 retained its inhibitory potency in various drug-resistance milieus such as patient plasma, FLT3 ligand surge, and stromal protection. Furthermore, it displayed potent antileukemic activity in bone marrow blasts from AML patients regardless of FLT3 mutation status, including those with little or only minor responses to AC220 or PKC412. Oral administration of G-749 yielded complete tumor regression and increased life span in animal models. Thus, G-749 appears to be a promising next-generation drug candidate for the treatment of relapsed and refractory AML patients with various FLT3-ITD/FLT3-TKD mutants and further shows the ability to overcome drug resistance.

High-efficiency blue phosphorescent organic light-emitting diodes using a carbazole and carboline-based host material.

A novel bipolar host 9-(4-(9H-pyrido[2,3-b]indol-9-yl)phenyl)-9H-3,9'-bicarbazole (pBCb2Cz) was prepared for high efficiency blue phosphorescent organic light-emitting diodes (PhOLEDs), a high triplet energy (ET) material, employing electron-deficient α-carboline. pBCb2Cz (ET = 2.93 eV) was effective as a host material for FIrpic- and FCNIrpic-based blue PhOLEDs, and highest quantum efficiencies of 23.0 and 16.2%, respectively, were achieved.

Solvent-assisted directed self-assembly of spherical microdomain block copolymers to high areal density arrays.

The fabrication process for 5 Tb/in(2) bit patterns using solvent-assisted directed self-assembly is investigated. The N-methyl-2-pyrrolidone solvent vapor-annealing method was used to achieve good long-range lateral ordering of low-molecular-weight polystyrene-block-polydimethylsiloxane with a lattice spacing of 11 nm on flat Si substrates, PS modified substrates and lithographically patterned substrates, respectively.

Organic-inorganic vesicular hybrids driven by assembly of dendritic amphiphiles: site-selective encapsulation of nanoparticles.

The amphiphilic block codendrimer self-assembled into supramolecular vesicles with a bilayer membrane in both hydrophilic and hydrophobic solvents. Surface-modified quantum dots (QDs) were successfully entrapped within the wall of vesicles through a simple self-assembly process without any structural disruption.

High quantum efficiency blue phosphorescent organic light-emitting diodes using 6-position-modified benzofuro[2,3-b]pyridine derivatives.

High quantum efficiency blue phosphorescent organic light-emitting diodes were developed using 6- position modified benzofuro[2,3-b]pyridine derivatives as host materials. Two high triplet energy host materials derived from benzofuro[2,3-b]pyridine modified with carbazole or 9-phenylcarbazole were synthesized and the device performances of the host materials were investigated. A high quantum efficiency of 24.3% was achieved using the benzofuro[2,3-b]pyridine host materials due to good charge balance and energy transfer.

Hierarchical helical assembly of conjugated poly(3-hexylthiophene)-block-poly(3-triethylene glycol thiophene) diblock copolymers.

We report on the solution-state assembly of all-conjugated polythiophene diblock copolymers containing nonpolar (hexyl) and polar (triethylene glycol) side chains. The polar substituents provide a large contrast in solubility, enabling formation of stably suspended crystalline fibrils even under very poor solvent conditions for the poly(3-hexylthiophene) block. For appropriate block ratios, complexation of the triethylene glycol side chains with added potassium ions drives the formation of helical nanowires that further bundle into superhelical structures.

Self-assembly of coordination polymers into multi-stranded nanofibers with tunable chirality.

We have demonstrated that the formation of multi-stranded nanofibers with tunable chirality from coordination polymers and their hierarchical assembly into interconnected 3-D networks leading to thermoresponsive gelation.

Interconversion of planar networks and vesicles triggered by temperature.

Dumbbell-shaped amphiphiles based on an elongated rod segment can self-assemble into planar networks with in-plane hexagonally ordered pores in aqueous solution. On increasing temperature, the 2D networks change into hollow capsules passing through the closed sheets as an intermediate structure due to a LCST behavior of the oligoether dendritic exterior. The primary driving force for this interesting feature seems to originate from a consequence of the energy balance between hydrophobic interactions of anisotropic rod segments and alkyl chains, and repulsive interactions between dissimilar blocks. This dynamic structural variation triggered by external stimuli in a self-assembling system can provide a useful strategy to create smart supramolecular materials and biomimetic systems.

Synthesis of Aromatic Macrocyclic Amphiphiles and their Self-Assembling Behavior in Aqueous Solution.

A triblock amphiphilic macrocycle consisting of a macrocyclic aromatic segment, a hydrophilic oligo(ethylene oxide) branch, and a hydrophobic alkyl dendron is successfully synthesized and characterized. The resulting cyclic amphiphile is observed to self-assemble into hollow double-layered capsules in aqueous solution, as confirmed by dynamic light scattering and cryogenic transmission electron microscopy investigations. The capsules are able to encapsulate hydrophobic guest molecules through aromatic interactions with high stability.