NETosis-Inspired Cell Surface-Constrained Framework Nucleic Acids Traps (FNATs) for Cascaded Extracellular Recognition and Cellular Behavior Modulation.

Upon pathogenic stimulation, activated neutrophils release nuclear DNA into the extracellular environment, forming web-like DNA structures known as neutrophil extracellular traps (NETs), which capture and kill bacteria, fungi, and cancer cells. This phenomenon is commonly referred to as NETosis. Inspired by this, we introduce a cell surface-constrained web-like framework nucleic acids traps (FNATs) with programmable extracellular recognition capability and cellular behavior modulation. This approach facilitates dynamic key chemical signaling molecule recognition such as adenosine triphosphate (ATP), which is elevated in the extracellular microenvironment, and triggers FNA self-assembly. This, in turn, leads to in situ tightly interwoven FNAs formation on the cell surface, thereby inhibiting target cell migration. Furthermore, it activates a photosensitizer-capturing switch, chlorin e6 (Ce6), and induces cell self-destruction. This cascade platform provides new potential tools for visualizing dynamic extracellular activities and manipulating cellular behaviors using programmable in situ self-assembling DNA molecular devices.

Generation of Fused Seven-Membered Polycyclic Systems via Ring Expansion and Application to the Total Synthesis of Sesquiterpenoids.

Seven-membered polycyclic architectures, widely present in natural products and molecular drugs, are challenging synthetic targets. However, methods for synthesizing fused medium-sized bicyclo[m.n.0] ring systems, including the benzo-cycloheptane systems, are still urgent. Herein we describe a base-induced ring expansion as a general strategy to construct a wide range of fused seven-membered ring systems. The application of this method was demonstrated by the efficient total syntheses of two sesquiterpenoids, plecarpenene and plecarpenone, both bearing a fused bicyclo[5.3.0]decane skeleton.

Online Liquid Microextraction Coupled with HPLC-ABTS for Rapid Screening of Natural Antioxidants: Case Study of Three Different Teas.

In the present study, an online liquid extraction coupled with high-performance liquid chromatography-2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (HPLC-ABTS) system for rapid screening of antioxidants in tea samples was proposed. As an example, the tea samples were firstly extracted by online HPLC extractor with mobile phase at 70°C, then the hyphenated HPLC-ABTS was used for the chromatographic separation on a Poroshell EC C18 column by 0.3% aqueous formic acid and acetonitrile with a gradient elution at 1.5 mL·min-1, and the UV and antioxidant chromatograms with detection wavelengths at 270 nm and 750 nm were recorded, respectively. The established system integrated the processes of online HPLC sample extraction, HPLC separation and online antioxidants detection, the total analysis time of which was <20 min. The developed method was successfully applied to samples of green tea, oolong tea and black tea. As a result, 11 antioxidants were found in tea samples, including gallocatechin, epigallocatechin, catechin, chlorogenic acid, epicatechin, epigallocatechingallate, epicatechingallate, rutin, 1,4,6-trigalloylglucose, quercetin-3-glycoside and kaempferol-3-glucoside. The combined online liquid microextraction and online HPLC-ABTS method is a rapid and green approach for the quality evaluation of tea.

Visible light photoredox catalyzed deprotection of 1,3-oxathiolanes.

An efficient visible light photoredox catalyzed aerobic deprotection of 1,3-oxathiolanes using organic dye Eosin Y as a photocatalyst is disclosed. The deprotection procedure features the use of a metal-free catalyst, mild conditions, a broad range of substrate scope, and good functional group tolerance. 35 examples were tested under the standard conditions and most of them afforded the deprotected products in modest to high yields.

Di-tert-butyl peroxide-mediated atom-transfer radical addition of 2-chlorodithiane to aryl alkynes under mild conditions.

Atom transfer radical addition (ATRA) of 2-chlorodithiane onto aryl alkynes through the use of di-tert-butyl peroxide as an oxidant at room temperature directly affords a variety of synthetically valuable ß-chloro-(Z)-vinyl dithianes in good yields with high regioselectivities and without the assistance of any transition metals. It provides an operationally simple pathway to access vinyl dithianes with controlled formation of a new C(sp(2) )C bond and a C(sp(2) )Cl bond.

Asymmetric total synthesis of fusarentin 6-methyl ether and its biomimetic transformation into fusarentin 6,7-dimethyl ether, 7-O-demethylmonocerin, and (+)-monocerin.

A concise asymmetric total synthesis of a fusarentin ether (1) with sequential biomimetic transformation to its analogues fusarentin 6,7-dimethyl ether (2), 7-O-demethylmonocerin (3), and (+)-monocerin (4) has been accomplished. The cis-fused furobenzopyranones of 7-O-demethylmonocerin (3) and (+)-monocerin (4) were efficiently constructed via an intramolecular nucleophilic trapping of a quinonemethide intermediate, which was obtained by benzylic oxidation of fusarentin 6-methyl ether (1) using hypervalent iodine reagent.

Synthesis of the tetracyclic core (ABCE rings) of daphenylline.

A concise synthesis of the tetracyclic core (ABCE rings) of daphenylline has been accomplished involving a benzobicyclo[3.3.1] lactam as the key intermediate. This bridged bicyclic intermediate was efficiently constructed via a Brønsted acid promoted intramolecular Friedel-Crafts type Michael addition of a δ-benzyl α,ß-unsaturated δ-lactam.

Rapid construction of the [6-6-6-5] tetracyclic skeleton of the Daphniphyllum alkaloid daphenylline.

You can call me Al: A concise route for construction of the [6-6-6-5] tetracyclic skeleton of daphenylline, a structurally novel Daphniphyllum alkaloid, has been developed with full stereocontrol in only 8 steps from two known fragments. This approach features an intramolecular [3+2] cycloaddition of a 2-azaallyl anion with an alkene to form the cis-fused AC rings.

Asymmetric total synthesis of cladosporin and isocladosporin.

The first asymmetric total syntheses of cladosporin and isocladosporin were accomplished in 8 steps with 8% overall yield and 10 steps with 26% overall yield, respectively. The relative configuration of isocladosporin was determined via this total synthesis.

Tandem oxidative dearomatization/intramolecular Diels-Alder reaction for construction of the tricyclic core of palhinine A.

A concise construction of the 6/6/5 tricyclic core of Lycopodium alkaloid palhinine A (1) has been accomplished. The developed synthetic strategy featured a tandem oxidative dearomatization/intramolecular Diels-Alder reaction to construct C/D rings and an intramolecular 5-exo-trig radical cyclization to install the B ring of palhinine A (1). The developed approach paves the way for the total synthesis of palhinine A (1).

Au-catalyzed piperidine synthesis via tandem acyloxy migration/intramolecular [3 + 2] cycloaddition of enynyl esters.

An Au-catalyzed tandem protocol involving enynyl ester isomerization and subsequent intramolecular [3 + 2] cyclization has been developed. This strategy provides an efficient approach for the synthesis of polyfunctional piperidines, which are subunits of many bioactive molecules.

PtI2-catalyzed tandem 3,3-rearrangement/Nazarov reaction of arylpropargylic esters: synthesis of indanone derivatives.

An efficient PtI(2)-catalyzed tandem reaction of arylpropargylic esters, involving 3,3-rearrangement and Nazarov reaction, has been developed to produce 3-substituted and 3,3-disubstituted indanone derivatives. This approach provided a pathway to the synthesis of indanone skeletons in natural products.