Latest ArticlesDue to the heterogeneity of tumors, single phototherapy cannot completely ablate tumors and inhibit tumor metastasis. To overcome these, we formulated targeted and multifunctional polymersomes ABC@ICG-IMQ-LHRH (AIRL) that encapsulated Toll-like receptor (TLR) 7/8 agonist imiquimod (IMQ) and photosensitizer indocyanine green (ICG) in the hydrophobic layer as well as bubble-generator NH4HCO3 in the hydrophilic cavity to inhibit the growth of primary and distant tumors, and prevent tumor metastasis through synergistic photoimmunotherapy. The AIRL polymersomes exhibited uniform and stable size, and high drug encapsulation efficiency, acid/reduction/laser responsiveness, excellent photothermal conversion efficiency, effective reactive oxygen species generation, high tumor accumulation. AIRL could be effectively internalized by dendritic cells (DCs), achieve lysosome escape and enhance DCs maturation. The synergistic photoimmunotherapy via AIRL polymersomes remarkably promoted the differentiation and activation of T cells, elevated strong systemic immune response to eradicate primary tumors and inhibit the growth of distant tumors. Simultaneously, the endurable immunological memory prevented tumor metastasis, which provided a promising nanoplatform for the combination therapy of cancer.
Cr(Ⅵ), one of the most hazardous metal pollutants, poses significant threats to the environment and human health. Herein, a novel MoS2 composite (MoS2/PVP/PAM) modified by polyvinylpyrrolidone (PVP) and polyacrylamide (PAM) was synthesized to enhance the removal of Cr(Ⅵ). Characterization analysis including SEM, XRD, FTIR, and XPS indicated that PVP and PAM could increase the interlayer spacing and the dispersibility of MoS2, and introduce pyrrolic N and amino functional groups. The batch experiments showed that MoS2/PVP/PAM represented excellent Cr(Ⅵ) removal performance over a wide pH range, and exhibited a significantly higher maximum Cr(Ⅵ) adsorption capacity (274.73mg/g, at pH 3.0, and 298K) than pure MoS2. The adsorption of Cr(Ⅵ) followed Langmuir and pseudo-second-order kinetic model, which was a homogeneous monolayer chemisorption process. MoS2/PVP/PAM showed stable removal of Cr(Ⅵ) in the presence of humic acid (HA), interfering cations and anions at different concentrations. Moreover, it had excellent selectivity for Cr(Ⅵ) (Kd value of 1.69× 107mL/g) when coexisting with a variety of competing ions. Multiple characterization revealed that Cr(Ⅵ) was reduced to low toxicity Cr(Ⅲ) by Mo4+ and S2−, and then chelated on the surface of the adsorbent by pyrrolic N. This research expanded the design concept for MoS2 composites by demonstrating the potential of MoS2/PVP/PAM as a promising material for selective elimination of Cr(Ⅵ) in water.
Ynones are important skeletons in bioactive molecules and valuable building blocks for organic synthesis, thus great efforts have been devoted to their preparation. While, introducing prochiral substrates to construct ynones bearing a chiral framework is unrealized to date. Herein, we reported the first example of Pd/SOP-catalyzed asymmetric carbonylative alkynylation via a non-classical carbonylative Sonogashira-type approach (acyl-Pd(Ⅱ) species generated from nucleophiles). By using cyclic diaryliodonium salts as prochiral substrates, various axial chiral ynones with good functional group tolerance (39 examples), satisfied yields (71%-96%) and excellent enantioselectivities (generally 94%-99% ee) were produced. Synthesis of bioactive compounds, scale-up experiment and useful transformations were also conducted to demonstrate the utility of this process.
The classification of π-/σ-aromaticity depends on the electrons with the dominating contributions. Traditionally, π- and σ-aromaticity are used to describe the unsaturated and saturated systems, respectively. Thus, it is rarely reported that π-aromaticity is dominated in a saturated system. Here we demonstrate that π-aromaticity could be dominating in several fully saturated four-membered rings (4MRs), supported by various aromaticity indices including ΔBL, NICS, EDDB, MCI, and AdNDP. The origin of such π-aromaticity in saturated rings could be attributed to an introduction of two additional electrons into the π-type LUMO of the parent neutral species. Our findings represent a novel approach to achieve π-aromaticity into a fully saturated system which has traditionally been dominated by σ-aromaticity.
Macrocycle confinement induced guest near-infrared (NIR) luminescence was research hotspot currently. Here in, we reported a cucurbit[7]uril (CB[7]) confined 3,7-bis((E)-2-(pyridin-4-yl)vinyl)-10-H-phenothiazine bridged bis(4-(4-bromophenyl)pyridine) (G), which not only boosted its NIR luminescence but also realized detection of HClO/ClO− in living cells and lysosome imaging. Fluorescence spectroscopy experiments were performed to calculate the detection ability of probe G to HClO/ClO− up to 147 nmol/L. As compared with G, supramolecular probe G⊂CB[7] formed after encapsulated by CB[7], the detection ability towards HClO/ClO− was improved to 24 nmol/L which was ascribe to the macrocycle CB[7] confinement increasing the fluorescence intensity to 103 folds. Accompanying the excitation wavelength changing, the fluorescence red-shifted to 820 nm when excited by 570 nm light, which was used to NIR lysosome imaging. Meanwhile, the supramolecular assembly G⊂CB[7] was also successfully used to highly sense to exogenous HClO/ClO− in RAW 264.7 cells and live animal.
A novel asymmetric [4 + 2] cycloaddition of 2-methylidenetrimethylene carbonate with pyrrolidone-derived enones has been achieved to produce the functionalized tetrahydropyran-fused spirocyclic scaffolds via palladium-catalysis. An array of enantioenriched spiro-pyrrolidine-2,3-diones bearing adjacent quaternary and tertiary stereocenters are obtained in high yields with excellent enantioselectivities (up to 96% yield and 99% ee). The further transformation of the product has been accomplished for the construction of medical interesting β2,2-amino acids and β-lactams. Preliminary mechanistic research was well conducted.
Dicarboxylic acids have a wide range of applications in the polymer industry to construct valuable materials. Photocatalysis has recently emerged as an efficient and sustainable strategy to generate dicarboxylic acids. However, photocatalytic dicarboxylation with CO2 is mainly limited to unsaturated bonds, and the dicarboxylation of C–C single bonds still remains a challenge. Herein, we report a photocatalytic dicarboxylation of C–C single bonds in strained rings with CO2 units via consecutive photo-induced electron transfer (ConPET). It is also the first photocatalytic reductive ring-opening reaction of cyclobutanes. Notably, this transition-metal-free protocol exhibits good functional group tolerance, broad substrate scope, facile scalability, and easy product derivatizations. Moreover, diacids can easily be derivatized to main-chain liquid crystalline polyesters.
We report the unprecedent Pd(I) catalyzed ring-opening arylation of cyclopropyl-α-aminoamides. This protocol allows facile access to biologically important α-ketoamide-containing oligopeptides and even more challenging peptide-natural product conjugates. Site selectivity was achieved by introduction of special unnatural amino acids, which also meets the requisite of bioorthogonal chemistry. Mechanism investigations reveals a distinct domino radical ring-opening process through Pd(I) catalysis.
The H-bond promoted electrochemical [2 + 2 + 1] annulation of benzo[d]isothiazole 1,1-dioxides, N-arylglycines and paraformaldehyde for the synthesis of various benzo[d]imidazo[1,5-b]isothiazole 5,5-dioxide derivatives under redox mediator, catalyst and electrolyte-free conditions was developed.
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