Latest ArticlesHerein, we adopt a simple supramolecular strategy to effectively control the tautomerism of ureidopyrimidinone (UPy) moiety and ultimately realize the complete arrangement of enol configuration. The obtained UPy derivatives containing self-complementary quadruple hydrogen bonding interactions can spontaneously self-assemble towards the formation of well-controlled, self-organized supramolecular nanostructure morphologies in both chloroform and water. The resulting aggregates had been fully characterized by various spectroscopy (absorption, emission) and microscopy (TEM, SEM and AFM) studies. It is anticipated that this study can provide an exact and excellent monomeric unit for controllable and precise supramolecular polymerization. The results achieved here also demonstrate the utility and feasibility of multiple hydrogen bonds to direct the self-assembly of small-molecule building blocks in aqueous media, which provides a strategy for the construction of well-defined and stable supramolecular architectures with chemical functionalities and physical properties as advanced materials for biological applications.
Traditional synthesis of sulfonylureas largely depends on nucleophilic addition of arylsulfonamides to pre-synthesized isocyanates. Now we report a new access to alkylsulfonylureas with good yields and broad substrate scope. With the insertion of commercialized chlorosulfonyl isocyanate under photoredox catalysis, alkylsulfonylureas are synthesized in one-pot from the corresponding anilines and silyl enolates. A reaction mechanism is proposed showing the transformation undergoes a radical process, and the practicality of this methodology is proven via application to bioactive molecules. Additionally, the anti-cancer and anti-virus screening of these compounds is evaluated.
A new method for the preparation of fluoroalkylthioethers including trifluoromethylthioether and difluoromethylthioether by iridium(Ⅰ)-catalyzed deoxgenation of fluoroalkylsulfoxides with dimethyl diazomalonate was developed. In the reaction system, dimethyl diazomalonate was used as reducing reagent and the corresponding fluoroalkylthioethers were produced through oxygen atom transfer from fluoroalkylsulfoxides to diazomalonate. The protocol featuring effective oxygen atom transfer, mild reaction conditions and good functional groups tolerance offers an alternative strategy for the synthesis of fluoroalkylthioethers.
A palladium-catalyzed formal [2 + 2 + 1] cyclization of 1-alkynyl-8-iodonaphthalene with double isocyanides is developed herein. The transformation worked well to produce a series of 7H-acenaphtho[1,2-b]pyrrole with a broad reaction scope. Isocyanides play a dual role in the reaction. One is a C1 building block, and another is used as C1N1 component. In the process, the [2 + 2 + 1] cyclization involves imidoylation, regioselective addition of imidoylpalladium species into alkyne, double imidoylation, and another addition of the resulting imidoylpalladium species into imine bonds.
In this study, a method was developed to form C(sp3)–C(sp2) bonds via copper catalyst-promoted cross coupling of 2-methylquinoline and in-situ-activated 3-haloisoquinoline under mild conditions. The multi-component tandem reaction was used to construct new C–N, C=O and C–C bonds in one pot via sequential functionalization of the N1, C3 and C1 positions of 3-haloisoquinoline. This method can be used to efficiently access 1,2-disubstituted isoquinolinones by the three-component reaction of 3-halogen isoquinoline, alkyl halide, and 2-methylquinoline.
An efficient and catalytic protocol for highly stereoselective construction of β-mannopyranosylation has been developed. Glycosylation of 2,6-lactone-bridged mannopyranosyl ortho-hexynylbenzoate with various acceptors proceeded smoothly in the presence of 5% Hg(Ⅱ) at room temperature, resulting in the corresponding β-mannosides in high yield and exclusive β-stereoselectivity.
We construct MUC1 vaccines using β-cyclodextrin grafted chitosan (CS-g-CD) as carrier via host-guest interaction. These vaccines based on non-covalent assembling can provoke robust immune responses, including high level of specific antibodies and cytokines. The induced antibodies can specifically recognize tumor cells and mediate cytotoxicity against tumor cells. These results indicate that CS-g-CD with strong immunostimulatory activities can be a straightforward platform for peptide-based vaccine construction.
A visible-light-mediated reaction of indole derivatives employing arylsulfonyl chlorides as sulfonyl surrogates has been developed, which proceeds via the sequence of reduction of sulfonyl chloride, sulfonylation, and intramolecular cyclization. This mild protocol transforms a diverse array of indole tethered alkenes and simple sulfonyl chlorides into highly valuable functionalized tetrahydrocarbazoles in good yields. This reaction is also suitable for gram-scale synthesis, which provides an efficient and green access to multi-substituted tetrahydrocarbazoles.
The low-cost CuBr-promoted domino Biginelli reaction among readily available ketones, salicylaldehyde derivatives and 3-amino-1, 2, 4-triazole was studied under solvothermal conditions, giving the novel bridged polyheterocycles bearing two or three stereocenters depending on the starting ketones. This multicomponent reaction proceeded with high diastereoselectivity (dr > 20:1) based on a combined 1H NMR, crystallographic and supercritical fluid chromatographic (SFC) analysis of the product. Time-dependent high-resolution mass spectrometry (HRMS) was performed to track the reaction process, and several key intermediates were identified, leading to the drawing of a plausible reaction mechanism. Density functional theory (DFT) calculation was supplemented, and two reaction pathways were differentiated. Moreover, in vitro antitumor activity was evaluated using HeLa and HepG2 cell lines, and two of these polyheterocycles demonstrated promising activities against HepG2 cells with EC50 down to 10 µmol/L. Additionally, ESI-MS/MS studies on all the polyheterocycles suggest a common fragmentation pathway (loss of one molecule of amino-triazole) they shared, providing the first-hand fragmentation rules for future rapid structural identification of them. The multicomponent domino reaction presented here may offer prospects for future design of more efficient strategies to access medicinally important bridged polyheterocycles.
Highly selective binding of structurally similar substrates is common for biomolecular recognition, but is often challenging to realize in synthetic hosts. Herein, we report highly selective binding of methyl viologen over other analogues by an endo-functionalized naphthobox. X-ray single crystal structure and Density Functional Theory (DFT) calculations revealed that the endo-functionalized groups in the cavity of the naphthobox is important for the high binding selectivity through the formation of multiple C–H…N, C–H…π, and π…π interactions with methyl viologen.