Publications by authors named "Hongjun Ren"

Background: Treadmill training, including body weight-supported treadmill training (BWSTT), is widely used in stroke rehabilitation. However, its efficacy in improving walking outcomes may vary depending on patients' baseline functional status.

Objective: This study aims to systematically evaluate effectiveness of treadmill training on walking speed and endurance in stroke survivors and to assess influence of baseline dependency and use of BWSTT.

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We report a Pd-catalyzed decarboxylative Negishi coupling reaction for efficient biaryl synthesis from various zinc aryl carboxylates, including polyfluorobenzoates and heteroaryl carboxylates, using DMF as the solvent. This mild reaction exhibits a broad substrate scope and enables late-stage functionalization of bioactive molecules. Mechanistic studies show that DMF-assisted zinc catalyzes decarboxylation of polyfluorinated aryl carboxylates to generate arylzinc reagents in situ, which then undergo Negishi coupling catalyzed by palladium with arylthianthrenium salts to form biaryl compounds.

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Objectives: Blood cell-free DNA (cfDNA) can be a new reliable tool for detecting epidermal growth factor receptor () mutations in non-small cell lung cancer (NSCLC) patients. However, the currently reported cfDNA assays have a limited role in detecting drug-resistant mutations due to their deficiencies in sensitivity, stability, or mutation detection rate.

Methods: We developed an -derived flap endonuclease ( FEN)-based DNA-enhanced amplification system of mutated cfDNA by designing a pair of hairpin probes to anneal with wild-type cfDNA to form two 5'-flaps, allowing for the specific cleavage of wild-type cfDNA by FEN.

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The thiazole-2-imine derivatives with interesting pharmacological activities have attracted significant attention. However, previously reported synthesis strategies usually suffered from some drawbacks, such as the use of metals/additive and harsh reaction conditions. Herein, we developed a metal- and photoinitiator-free photocatalytic strategy for the synthesis of various selenium-substituted thiazole-2-imine derivatives for the first time.

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Introduction: Tilapia produces a large number of by-products during processing, which contain potentially flavorful peptides.

Methods: The application of PyRx software enabled batch molecular docking andscreening of 16 potential salty peptides from 189 peptides identified in the enzymaticdigestion of tilapia by-products.

Results: According to sensory analysis, all 16 peptides werepredominantly salty with a threshold of 0.

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We developed a Pd-catalyzed decarboxylative cross-coupling of zinc polyfluorobenzoates, which were used as precursors for producing zinc reagents in situ, with aryl bromides and nonaflates, providing a mild and efficient pathway for the synthesis of polyfluorinated biaryls. This protocol exhibits a broad substrate scope and excellent functional tolerance. Moreover, the versatility of this approach was demonstrated by the straightforward late-stage modification of drugs, biologically active molecules, and pesticides, indicating its potential significance in drug discovery.

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Photoinduced decarbonylative C-C bond formation with readily accessible aldehydes as alkyl sources is described. This protocol provides a sustainable alternative for the effective construction of diverse valuable 4-alkylated sulfonyl ketimines under metal- and photosensitizer-free conditions. Significantly, in this reaction, air serves as the green oxidant, and cyclic sulfamidate imines play a dual role of substrate and photocatalyst, thus affording a concise reaction system for C-H alkylation of cyclic sulfamidate imines.

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Objective: Our previous study reveals that proprotein convertase subtilisin/kexin type 9 (PCSK9) is positively related to inflammatory markers, T helper (Th)-17 cells, and treatment response in ankylosing spondylitis (AS) patients. Subsequently, this study aimed to explore the effect of PCSK9 on Th cell differentiation and its potential molecular mechanism in AS.

Methods: Serum PCSK9 was determined by enzyme-linked immunosorbent assay in 20 AS patients and 20 healthy controls (HCs).

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The mutation or function loss of tumour suppressor p53 plays an important role in abnormal cell proliferation and cancer generation. Murine Double Minute 2 (MDM2) is one of the key negative regulators of p53. p53 reactivation by inhibiting MDM2-p53 interaction represents a promising therapeutic option in cancer treatment.

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Electrochemical oxidation of alkene difunctionalization with simultaneous construction of C-Se and C-S bonds is reported. The products of β-selenylethyl dithiocarbamates are obtained with CS, amines, alkenes, and diphenyl diselenides in the absence of any oxidant or metal. Furthermore, the transformation is compatible with various groups.

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The transition-metal-free direct cross-coupling between polyfluoroarenes and benzyl chlorides is reported. In this strategy, a variety of polyfluoro di-, tri- and tetra-arylmethanes was efficiently prepared with good to excellent yields in the presence of Mg turnings via a one-pot procedure. Significantly, this method provides a general approach for the synthesis of polyfluorinated polyarylmethanes.

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A green and efficient approach for the difunctionalization of ynamides by merging the electrochemical and organoselenium-catalyzed processes is described. This strategy features mild reaction conditions, broad functional group tolerance and high atom-economy, and requires no external chemical oxidant. Hence, we provide a sustainable alternative for the synthesis of polysubstituted oxazoles.

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Objective: Proprotein convertase subtilisin/kexin type 9 (PCSK9) participates in the autoimmune disease pathology by regulating T helper (Th) cell differentiation, NF-κB pathway, toll-like receptor 4, etc. This study intended to investigate the association of serum PCSK9 with disease activity, Th cells, and treatment response in ankylosing spondylitis (AS) patients.

Methods: Eighty-nine active AS patients were enrolled in this multicenter, prospective study.

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Selective C-F bond cleavage of polyfluoroarenes has attracted tremendous interest due to its promising applications in introducing fluorinated building blocks into organic molecules. However, it remains a challenge to achieve highly site-selective C-F bond cleavage because of the intrinsic inertness of the C-F bond and the difficulty in distinguishing specific C-F bonds on the aromatic ring. Herein we report an efficient nucleophilic aromatic substitution (SAr) reaction of polyfluoroarenes with Grignard reagents that employs MnFe-based bimetallic metal-organic coordination polymers (MOCPs) as recyclable and reusable heterogeneous catalysts.

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Ring opening of cycloalkanols has been employed as a commonly used strategy to prepare diverse distal functionalized ketones. However, most of these ketones obtained by this strategy belong to monofunctional ketones, while difunctional ketones with more potential application value have been rarely reported. Herein, we first reported a mild I-promoted ring-opening selenation of cyclopropanol to synthesize various distal difunctional ketones.

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Objective: To investigate the effectiveness of soft tissue balance technique by flexor pollicis longus (FPL) tendon transfer for Wassel Ⅳ-D thumb duplication in children.

Methods: A clinical data of 14 children with Wassel Ⅳ-D thumb duplication met the selection criteria between January 2017 and January 2021 was retrospectively analyzed. There were 5 boys and 9 girls with an average age of 21.

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A scalable cyanation of -difluoroalkenes to (hetero)arylacetonitrile derivatives was developed. This strategy features mild reaction conditions, excellent yields, wide substrate scope, and broad functional group tolerance. Significantly, in this reaction, aqueous ammonia offers a "N" source for the "CN" reagent and entirely avoids the use of toxic cyanating reagents or metal catalysis.

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A [3 + 2]-annulation of -difluoroalkenes and pyridinium ylides was developed employing ambient air as the sole oxidant in an open-vessel manner, affording a series of multifunctionalized 2-fluoroindolizines in moderate to good yields. In this reaction, -difluoroalkene acts as a C2 synthon and entirely avoids the competitive addition-elimination process, which provides facile access to 2-fluoroindolizines.

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An efficient cascade reaction of 2-(1-alkynyl)-2-alken-1-ones with 2-naphthols promoted by silver trifluoroacetate is disclosed, providing an expeditious access to 1,2-dihydronaphtho[2,1-]furans with moderate to good yields. This domino process involves highly regio- and diastereoselective sequential cyclization/nucleophilic addition/oxidative ring opening/oxa-Michael addition reactions to construct three new chemical bonds and one new five-membered ring. A gram-scale experiment and the preliminary results to develop an asymmetric variant are also presented to show the practicality and potential of the current reaction.

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Herein, we describe a gold(I)-catalyzed generation of nonclassical gold-containing 1,4-all-carbon dipoles from cycloisomerization/1,2-carbene transfer/ring opening cascade reactions of readily accessible allenyl ketones bearing a cyclopropyl moiety and its cyclization with tropone. This method features an unprecedented formal [8+4] high-order cycloaddition under mild conditions for delivering structurally complex 7,7,5-tricycles in generally moderate to high yields.

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Article Synopsis
  • A Mannich reaction was developed using α-amino acid-derived azlactones and isatin-derived ketimines, facilitated by a chiral bifunctional squaramide organocatalyst.
  • The reaction produced α,β-diamino acid derivatives with varying yields (40-95%), and showed moderate to excellent diastereoselectivity (3:1 to 20:1) and enantioselectivity (66-97%).
  • This method is practical for larger-scale production, allowing easy conversion of the Mannich adduct into α,β-diamino esters with simple processes.
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By choosing suitable ligand-directed gold catalysts, two types of gold-containing all-carbon 1,4-dipoles could be generated selectively from the gold(I)-catalyzed cycloisomerizations of allenyl ketones bearing a cyclopropyl moiety, which undergo [4 + 3] cycloadditions with nitrones to produce two regiomers of furan-condensed N,O-seven-membered rings in moderate to excellent yields highly selectively.

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Article Synopsis
  • A new reaction using N-heterocyclic carbenes (NHCs) has been developed, combining aliphatic aldehydes and oxindole-derived α,β-unsaturated ketimines to produce spirocyclic oxindole δ-lactams.
  • The reaction occurs under oxidative conditions and yields good results in terms of both overall yield and chiral selectivity.
  • It can be scaled up for larger productions and the resulting compounds can be modified into other valuable chemicals.
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The rapid construction of three-dimensional fused carbocycles is a key challenge in synthetic chemistry. Herein, an unprecedented and practical tandem Nazarov/oxidative umpolung 4π-ring closure of readily available 1,2-allenyl aryl ketones mediated by iron(III) chloride has been developed, furnishing a new family of indanone-fused molecular architectures in moderate to excellent yields. The indanone-containing blocks can be efficiently converted to unsymmetrical dibenzo[,]pentalenes.

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A novel and expedient method for transformation of readily available 1-isochromanones bearing a diaryl allenic moiety at the C4-position to functionalized 5 H-dibenzo[ c, g]chromen-5-ones under mild conditions is developed. This strategy is based on the dual abilities of iron(III) chloride to promote selective C-O bond cleavage/6π electrocyclization and an oxidative aromatization sequence.

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