Cobalt-Promoted Photoredox 1,2-Amidoamination of Alkenes with -Sulfonamidopyridin-1-ium Salts and Free Amines.

A cobalt-promoted photoredox 1,2-amidoamination of alkenes with -sulfonamidopyridin-1-ium salts and free amines for the synthesis of unsymmetrical vicinal diamines has been developed. The reaction handles -(sulfonamido)pyridin-1-ium salts as the sulfonamidyl radical precursors and free amines as the nucleophilic terminating reagents to enable the formation of two new C(sp)-N bonds in a single reaction step and offers a route to selectively producing unsymmetrical vicinal diamines with an exquisite selectivity and a good compatibility of functional groups.

Photo-controllable binding and release of HPO using an azobenzene based smart macrocycle.

Herein, we describe the design and synthesis of an unusual azobenzene-bearing macrocycle , whose isomer was found able to 100% transform into its configuration under photoirradiation, for selectively recognizing HPO with reversibly photo-controllable binding and release properties.

Co-Catalyzed Dual C5/C8-H Bond Functionalization of Imidazo[1,2]pyrazines with Disulfides and Grignard Reagents.

An efficient difunctionalization at C5/C8 of imidazo[1,2]pyrazines has been developed using disulfides and Grignard reagents under cheap cobalt catalysis. This one-pot, two-step, three-component transformation is performed under mild conditions; various Grignard reagents (aryl and alkyl) and disulfides are tolerated. Mechanistic studies and control experiments demonstrate this reaction proceeded via an anionic intermediate.

[Study on the application of a new type of vertebral plate nail guide].

Objective: To explore safety and accuracy of novel C laminar staple guide through in vitro experiments.

Methods: From January 2018 to June 2018, 40 patients who underwent three-dimensional CT of cervical spine were selected, including 21 males and 19 females, heighted from 165 to 180 cm with an average of (172.9±9.

Dual Palladium/Copper-Catalyzed -Selective Intermolecular Allenylsilylation of Terminal Alkynes: Entry to ()-Silyl Enallenes.

A palladium-/copper-cocatalyzed three-component -allenylsilylation of terminal alkynes with propargyl acetates and PhMeSiBpin is described, which is driven by the regioselective allenylation of the alkyne with propargyl acetates and then silylation. This method allows the simultaneous incorporation of an allene and silicon across the C≡C bond and provides a highly chemo-, regio-, and stereoselective alkyne difunctionalization route to the synthesis of valuable ()-silyl enallenes. The utility of this method is highlighted by late-stage derivatization of bioactive compounds.

Synthesis and anti-proliferative activities of 5,6,7-trimethoxyflavones and their derivatives.

A series of 5,6,7-trimethoxyflavones and their derivatives , , and , including the natural products 5,6,7-trimethoxy-4'-hydroxyflavone (), 5,6,7,3',4' -pentamethoxyflavone (sinensetin, ), 5,6,7-trimethoxy-3',4'-methyl enedioxy flavone (), 5,6,7,3'-tetramethoxy-4,5'-methylenedioxyflavone (), 5,6,7, 3',4',5'-hextamethoxyflavone (), 5-hydroxy-3,4,2',3',4'-pentamethoxy chal-cone (), 5,4'-dihydroxy-6,7-dimethoxy flavone (cirsimaritin, ) and 5-hydroxy-6,7,3', 4'-tetramethoxyflavone (5-demethylsinensetin, ), 3,5,6,7,3',4'-hexamethoxyflavone (3-methoxysinensetin, ) and 5'-hydroxy-3,6,7,3',4'-pentamethoxyflavone () were synthesized. Their anti-proliferative activity in vitro was evaluated against a panel of four human cancer cell lines (Aspc-1, HCT-116, HepG-2 and SUN-5) by the CTG assay. The results showed that most of the synthetic compounds exhibited moderate to high anti-proliferative activities.

External-oxidant-free amino-benzoyloxylation of unactivated alkenes of unsaturated ketoximes with O-benzoylhydroxylamines.

A new copper-catalyzed two-component amino-benzoyloxylation of unactivated alkenes of unsaturated ketoximes with O-benzoylhydroxylamines as the benzoyloxy sources is developed. Chemoselectivity of this method toward amino-benzoyloxylation or oxy-benzoyloxylation of alkenyl ketoximes relies on the position of the tethered olefins, and provides an external-oxidant-free alkene difunctionalization route that directly utilizes O-benzoylhydroxylamines as the benzoyloxy radical precursors and internal oxidants for the divergent synthesis of cyclic nitrones and isoxazolines.

A lattice topology optimization of cervical interbody fusion cage and finite element comparison with ZK60 and Ti-6Al-4V cages.

Background: In current clinical practice, the most commonly used fusion cage materials are titanium (Ti) alloys. However, titanium alloys are non-degradable and may cause stress shielding. ZK60 is a bio-absorbable implant that can effectively avoid long-term complications, such as stress shielding effects, implant displacement, and foreign body reactions.

Pedicle Screw Insertion: Is O-Arm-Based Navigation Superior to the Conventional Freehand Technique? A Systematic Review and Meta-Analysis.

Background: Although O-arm-based navigation (ON) has been considered a better choice than the conventional freehand (FH) technique for spine surgery, clinical evidence showing the accuracy of ON compared with the FH technique is limited. The purpose of this study was to evaluate the accuracy of pedicle screw insertion under ON compared with the FH technique.

Methods: The Cochrane Library, Ovid, Web of Science, PubMed, Embase, and CNKI online databases were searched up to January 2020.

Brønsted Acid-Catalyzed Asymmetric Friedel-Crafts Alkylation of Indoles with Benzothiazole-Bearing Trifluoromethyl Ketone Hydrates.

An efficient Brønsted acid-catalyzed asymmetric Friedel-Crafts alkylation of indoles with benzothiazole-bearing trifluoromethyl ketone hydrates as electrophiles has been developed. The mild organocatalytic reactions proceeded well with low catalyst loading to afford a range of enantioenriched α-trifluoromethyl tertiary alcohols containing both benzothiazole and indole rings with excellent yields and enantioselectivities.

Dicarbonylative benzannulation of 3-acetoxy-1,4-enynes with CO and silylboranes by Pd and Cu cooperative catalysis: one-step access to 3-hydroxyarylacylsilanes.

A new, general Pd/Cu-cocatalysed dicarbonylative benzannulation of 3-acetoxy-1,4-enynes with CO and silylboranes is described. The method utilizes CO as both a one-carbon (C1) unit and an external addition functional reagent to achieve an unprecedented dicarbonylative benzannulation process, and represents a facile, efficient route to 3-hydroxyarylacylsilanes. Mechanistically, the silyl-Cu intermediate formed from CuF2 and silylboranes, and silyl-Pd intermediate generated by transmetallation are two key factors for successfully targeting the reaction and selectivity.

A novel mitochondria-targeted near-infrared (NIR) probe for detection of viscosity changes in living cell, zebra fishes and living mice.

Viscosity is a key factor that determines the diffusion-controlled processes in biological systems. The matrix of mitochondria contains various enzymes and other proteins with high density, and the diffusion of which are severely restricted by the cristae, making it the most crowded place in the cells. Herein, we reported a new near-infrared probe NV-1 with increased Stokes shift for monitoring viscosity changes in mitochondria.

Visible-Light Induction/Brønsted Acid Catalysis in Relay for the Enantioselective Synthesis of Tetrahydroquinolines.

An efficient method merging Brønsted acid catalysis with visible-light induction for the highly enantioselective synthesis of tetrahydroquinolines has been developed. This mild process directly transforms 2-aminoenones into 2-substituted tetrahydroquinolines with excellent enantioselectivities through a relay visible-light-induced cyclization/chiral phosphoric acid-catalyzed transfer hydrogenation reaction.

Annulation Cascades of N-Allyl- N-((2-bromoaryl)ethynyl)amides Involving C-H Functionalization.

An annulation cascades of N-allyl- N-((2-bromoaryl)ethynyl)amides with terminal alkynes or 1,3-dicarbonyls involving C-H functionalization for producing 2,3-functionalized indoles has been first developed by means of Cu catalysis. The method is enabled by the formation of the ketenimine intermediates to deliver 2,3-disubstituted indoles through a sequence of aza-Claisen rearrangement, C-H functionalization, Ullmann C-N coupling, and cyclization.

A novel mitochondria-targeted rhodamine analogue for the detection of viscosity changes in living cells, zebra fish and living mice.

Monitoring the intracellular viscosity changes is crucial for better understanding diffusion-controlled cellular processes. Herein, we synthesized a novel phenyl-substituted imidazole-fused rhodamine analogue RV-1 with a long absorption wavelength at 573 nm and a large Stokes shift of about 82 nm for monitoring the changes in cellular viscosity. The new probe RV-1 showed a very strong fluorescence emission at around 655 nm, with a 48.

Synthesis and antiproliferative activities of thioxoflavonoids on three human cancer cells.

Two series of fifteen novel thioxoflavonoids and were synthesized from corresponding flavonoids and by reacting with Lawesson's reagent, respectively. Their antiproliferative activities were evaluated on a panel of three human cancer cell lines (Hela, HCC1954 and SK-OV-3) using cell counting kit-8 (CCK-8) assay. The results showed that most of the target compounds exhibited moderate to good antiproliferative activities against the three human cancer cell lines.

Primary aminomethyl derivatives of kaempferol: hydrogen bond-assisted synthesis, anticancer activity and spectral properties.

A series of primary aminomethyl derivatives of kaempferol were synthesized by a combination strategy involving two steps of the Mannich reaction and S2 nucleophilic substitution. The structures of the products show that the preferential aminomethylations are in the position C-6 or C-8 of the A-ring of kaempferol, especially the latter. Interestingly, the experimental data indicate that the intermolecular hydrogen bonding plays a key role in the formation of primary aminomethyl products of kaempferol.

Synthesis and antiproliferative activities of aminoalkylated polymethoxyflavonoid derivatives.

A series of novel aminoalkylated polymethoxyflavonoid derivatives 3-11 was synthesised from 5-hydroxy-3,7,3',4'-tetramethoxyflavonoid (1) through extending alkoxy chain at the 5-position, and introducing amine hydrogen bond receptor at the end of the side chain. Their antiproliferative activities were evaluated in vitro on a panel of three human cancer cell lines (Hela, HCC1954 and SK-OV-3). The results showed that all the target compounds exhibited antiproliferative activities against investigated cancer cells with IC values of 9.

Manganese-Catalyzed Intermolecular Oxidative Annulation of Alkynes with γ-Vinyl Aldehydes: An Entry to Bridged Carbocyclic Systems.

Manganese-catalyzed intermolecular oxidative annulation of alkynes with γ-vinyl aldehydes involving acylation and alkylation is described, thus providing a scenario for the divergent synthesis of bridged carbocyclic systems. By means of this manganese-catalyzed alkyne dicarbofunctionalization strategy, three chemical bonds, including two C-C bonds and one C-H bond, are formed via an aldehyde C(sp)-H oxidative functionalization/[4 + 2] annulation/protonation cascade.

A Carbazole-Fused-RhodamineProbe for Detection of HOCl in Living Cells.

A novel fluorescent probe CR-ClO for detection of HOCl based on a carbazole fused rhodamine was designed and synthesized. The probe utilized a HOCl-promoted oxidation reaction, which lead to the ring opening of the compound with a strong enhancement of the fluorescent emission at about 587 nm.The new probe CR-ClO has excellent selectivity and high sensitivity to ClO,whose detection limit to ClO is 1.

Discovery of potent and selective acetylcholinesterase (AChE) inhibitors: acacetin 7-O-methyl ether Mannich base derivatives synthesised from easy access natural product naringin.

Naringin, as a component universal existing in the peel of some fruits or medicinal plants, was usually selected as the material to synthesise bioactive derivates since it was easy to gain with low cost. In present investigation, eight new acacetin-7-O-methyl ether Mannich base derivatives (1-8) were synthesised from naringin. The bioactivity evaluation revealed that most of them exhibited moderate or potent acetylcholinesterase (AChE) inhibitory activity.

Synthesis and Antiproliferative Activity of Thioxoflavones Mannich Base Derivatives.

Two series of 12 novel thioxoflavones Mannich base derivatives 5a-f and 6a-f were synthesized via Mannich reaction of 4',7-dimethoxy-5-hydroxyflavothione (3) or 3',4',7-trimethoxy-5-hydroxyflavothione (4) with appropriate aliphatic amines or alicyclic amines and formaldehyde. Thioxoflavones 3 and 4 were prepared from 4',7-dimethoxy-5-hydroxyflavone (1) and 3',4',7-trimethoxy-5-hydroxyflavone (2) with Lawesson's reagent, respectively. Their antiproliferative activities in vitro were evaluated on a panel of three human cell lines (HeLa, HCC1954, and SK-OV-3) by CCK-8 assay.

A Ratiometric and near-Infrared Fluorescent Probe for Imaging Cu in Living Cells and Animals.

We have rationally constructed a novel ratiometric and near-infrared Cu fluorescent probe based on a tricarbocyanine chromophore. The new probe NIR-Cu showed a ratiometric fluorescent response to Cu with a large emission wavelength shift (up to 142 nm) in the far-red to near-infrared region. The probe also displayed a large variation in the fluorescence ratio (I/I) to Cu species with high sensitivity and selectivity.

Synthesis of Icaritin and β-anhydroicaritin Mannich Base Derivatives and Their Cytotoxic Activities on Three Human Cancer Cell Lines.

Background: Prenyl flavonoid icaritin (1) and β-anhydroicaritin (2) are two natural products with important biological and pharmacological effects. such as antiosteoporosis, estrogen regulation and antitumor properties.

Objective: The present study investigates the synthesis and cytotoxic activities on three Human cancer cell lines (Hela, HCC1954 and SK-OV-3) of icaritin and β-anhydroicaritin Mannich base derivatives in vitro models.