BMC Med Genomics
November 2024
Background: Ischemic stroke (IS) is a commonly seen cerebrovascular disease which seriously endangers the health of middle age and old people. However, its etiology and pathogenesis have not yet fully comprehended. miR-30 gene is a novel gene which may be involved in IS.
View Article and Find Full Text PDFAdvancements in flexible electronic technology, especially the progress in foldable displays and under-display cameras (UDC), have created an urgent demand for high-performance colorless polyimide (CPI). However, current CPIs lack sufficient heat resistance for substrate applications. In this work, four kinds of rigid spirobifluorene diamines are designed, and the corresponding polyimides are prepared by their condensation with 5,5'-(perfluoropropane-2,2-diyl) bis(isobenzofuran-1,3-dione) (6FDA) or 9,9-bis(3,4-dicarboxyphenyl) fluorene dianhydride (BPAF).
View Article and Find Full Text PDFAn asymmetric intramolecular spiro-amination to high steric hindering -C-H bond of 1,3-dicarbonyl via nitrene transfer using inactive aryl azides has been carried out by developing a novel Cp*Ir(III)-SPDO (spiro-pyrrolidine oxazoline) catalyst, thereby enabling the first successful construction of structurally rigid spiro-quaternary indolinone cores with moderate to high yields and excellent enantioselectivities. DFT computations support the presence of double bridging H-F bonds between [SbF] and both the ligand and substrate, which favors the plane-differentiation of the enol π-bond for nitrenoid attacking. These findings open up numerous opportunities for the development of new asymmetric nitrene transfer systems.
View Article and Find Full Text PDFA protocol for the electrooxidative [3+2] annulation to generate indolo[2,3-]indoles in an undivided cell is reported. It exhibits good yields with excellent regioselectivities and tolerates various functional groups without external chemical oxidants. Cyclic voltammetry and density functional theory calculations indicate that the [3+2] annulation is initiated by the simultaneous anodic oxidation of indole and aniline derivatives, and the step to determine the rate relies on the combination of radical cations.
View Article and Find Full Text PDFBridged chiral biaryls are axially chiral compounds with a medium-sized ring connecting the two arenes. Compared with plentiful methods for the enantioselective synthesis of biaryl compounds, synthetic approaches for this subclass of bridged atropisomers are limited. Here we show an atroposelective synthesis of 1,3-diaxial bridged eight-membered terphenyl atropisomers through an Co/SPDO (spirocyclic pyrrolidine oxazoline)-catalyzed aerobic oxidative coupling/desymmetrization reaction of prochiral phenols.
View Article and Find Full Text PDFA novel ion exchange strategy has been developed to enable the asymmetric construction of axially chiral sulfone-containing styrenes. This approach provides a practical synthesis pathway for various axially chiral sulfone-containing styrenes with good yields, exceptional enantioselectivities, and nearly complete E/Z selectivities. Additionally, the reaction mechanism is elucidated in detail through density functional theory (DFT) calculations.
View Article and Find Full Text PDFAliphatic allylic amines are common in natural products and pharmaceuticals. The oxidative intermolecular amination of C(sp)-H bonds represents one of the most straightforward strategies to construct these motifs. However, the utilization of widely internal alkenes with amines in this transformation remains a synthetic challenge due to the inefficient coordination of metals to internal alkenes and excessive coordination with aliphatic and aromatic amines, resulting in decreasing the reactivity of the catalyst.
View Article and Find Full Text PDFAn efficient palladium-catalyzed enantioselective direct -alkylation of indoles using a novel type of axially chiral styrene-phosphine ligand was developed. This reaction demonstrated good functional group compatibility and a wide range scope of substrates in mild conditions. Moreover, the DFT calculations expounded the coordination mode of the metal catalyst and the axially chiral styrene-phosphine ligand in the enantioselectivity control.
View Article and Find Full Text PDFThe short-chain dehydrogenase/reductase (SDR) superfamily members acyl-ACP reductases FabG and FabI are indispensable core enzymatic modules and catalytic orientation controllers in type-II fatty acid biosynthesis. Herein, we report their distinct substrate allosteric recognition and enantioselective reduction mechanisms. FabG achieves allosteric regulation of ACP and NADPH through ACP binding across two adjacent FabG monomers, while FabI follows an irreversible compulsory order of substrate binding in that NADH binding must precede that of ACP on a discrete FabI monomer.
View Article and Find Full Text PDFAn axially chiral styrene-based organocatalyst, featuring a combination of axially chiral styrene-based structure and a pyrrole ring, has been designed and synthesized. This catalyst demonstrates remarkable capabilities in producing a wide range of densely substituted spirooxindoles that feature an alkyne-substituted quaternary stereogenic center. These spirooxindoles are generated through mild cascade Michael/cyclization reactions, resulting in high conversion rates and exceptional enantioselectivity.
View Article and Find Full Text PDFHerein, we describe a stereoselective sulfa-Michael/aldol cyclization reaction promoted by a rationally designed novel axially chiral styrene-based organocatalyst. A variety of highly substituted tetrahydrothiophenes featuring an alkyne-substituted quaternary stereogenic center are obtained in good yields, excellent stereoselectivities, and exclusive selectivities. This process tolerates a broad range of alkynyl-substituted acrylamides under mind conditions.
View Article and Find Full Text PDFThe first total syntheses of polycyclic diterpenes phomopsene (), methyl phomopsenonate (), and -phomopsene () have been accomplished through the unusual cascade reorganization of C-C single bonds. This approach features: (i) a synergistic Nazarov cyclization/double ring expansions in one-step, developed by authors, to rapid and stereospecific construction of the 5/5/5/5 tetraquinane scaffold bearing contiguous quaternary centers and (ii) a one-pot strategic ring expansion through Beckmann fragmentation/recombination to efficiently assemble the requisite 5/5/6/5 tetracyclic skeleton of the target molecules -. This work enables us to determine that the correct structure of -phomopsene is, in fact, the C7 epimer of the originally assigned structure.
View Article and Find Full Text PDFAn asymmetric intramolecular hydroalkylation of unactivated internal olefins with tethered cyclic ketones was realized by the cooperative catalysis of a newly designed chiral amine (SPD-NH ) and Pd complex, providing straightforward access to either bridged or fused bicyclic systems containing three stereogenic centers with excellent enantioselectivity (up to 99 % ee) and diastereoselectivity (up to >20 : 1 dr). Notably, the bicyclic products could be conveniently transformed into a diverse range of key structures frequently found in bioactive terpenes, such as Δ -protoilludene, cracroson D, and vulgarisins. The steric hindrance between the Ar group of the SPD-NH catalyst and the branched chain of the substrate, hydrogen-bonding interactions between the N-H of the enamine motif and the C=O of the directing group MQ, and the counterion of the Pd complex were identified as key factors for excellent stereoinduction in this dual catalytic process by density functional theory calculations.
View Article and Find Full Text PDFBackground: There is an increased concern that statins may have an unintended effect of elevated lipoprotein(a) [Lp(a)]. We conducted a large sample real-world study to test the association.
Methods: This retrospective cohort study was conducted using data from an integrated SuValue database, which includes 221 hospitals across China covering more than 200,000 of population with longitudinal follow-up to 10 years.
Utilization of Freon-type methanes as functional one-carbon synthons in the synthesis of various deuterated indoline alkaloids was demonstrated here. A series of halomethyl radicals were generated from electro-reductive C-X cleavage of Freon-type methanes and captured efficiently by acrylamides to provide various halogenated oxindoles radical cyclization. This reaction features good functional group tolerance, and deuterium and fluorine atoms could be introduced facilely from Freon-type methanes.
View Article and Find Full Text PDFBioinspired palladium-catalyzed intramolecular cyclization of amino acid derivatives containing a vinyl iodide moiety by C-H activation enabled rapid access to a wide range of functionalized proline derivatives with an exocyclic olefin. To demonstrate the practicality of this methodology, the functionalized prolines were used as intermediates for the synthesis of several natural products: lucentamycin A, oxotomaymycin, oxoprothracarcin, and barmumycin.
View Article and Find Full Text PDFThe cell-wall recycling process is important for bacterial survival in nutrient-limited conditions and, in certain cases, is directly involved in antibiotic resistance. In the sophisticated cell-wall recycling process in Escherichia coli, the transcriptional repressor MurR controls the expression of murP and murQ, which are involved in transporting and metabolizing N-acetylmuramic acid (MurNAc), generating N-acetylmuramic acid-6-phosphate (MurNAc-6-P) and N-acetylglucosamine-6-phosphate (GlcNAc-6-P). Here, we report that both MurNAc-6-P and GlcNAc-6-P can bind to MurR and weaken the DNA binding ability of MurR.
View Article and Find Full Text PDFMisplaced or excessive hypochlorous acid in lysosomes has a close association with lots of diseases, so monitoring hypochlorous acid in lysosomes is particularly necessary. In the present work, a novel lysosome-targetable fluorescent probe (Lyso-R-HClO) for hypochlorous acid based on a HClO-mediated cyclization reaction was developed. In the fluorescent probe, the morpholine unit and the site of a HClO-mediated cyclization reaction were, respectively, used as the lysosome-targetable group and the response group.
View Article and Find Full Text PDFHerein we disclose a highly efficient enantioselective -C-H alkylation of aniline derivatives promoted by a base/Co/indeno-pybox ligand system. This methodology leads to the efficient construction of a series of enantioenriched aniline derivatives bearing all-carbon quaternary stereocenters. In addition, several special biologically or medicinally active indoles are facilely synthesized by our Co-catalyzed asymmetry synthesis method.
View Article and Find Full Text PDFHigh brightness Si nanocrystal white light-emitting diodes (WLED) based on differentially passivated silicon nanocrystals (SiNCs) are reported. The active layer was made by mixing freestanding SiNCs with hydrogen silsesquioxane, followed by annealing at moderately high temperatures, which finally led to a continuous spectral light emission covering red, green and blue regimes. The photoluminescence quantum yield (PLQY) of the active layer was 11.
View Article and Find Full Text PDFObjective: Formaldehyde (FA) is known to induce lung injury, but the underlying molecular mechanism remains largely unclear. CDR1as is an important member of the circular RNAs (circRNAs) family and functions as miRNA sponges with gene-regulatory potential. Our earlier circRNA microarray data showed CDR1as was highly expressed in lung tissue exposed to FA.
View Article and Find Full Text PDFWe report the efficient syntheses of chiral tetrahydroindole pyrazolinones by the asymmetric [3 + 2] cascade cyclizations (indolizations) of simple aniline derivatives with pyrazolinone ketimines as 2C synthons. The chiral phosphoric-acid-catalyzed system uses a concerted π-π interaction/dual H-bond control strategy to catalytically direct the asymmetric aniline, which undergoes a highly chemo-, regio-, and enantioselective [3 + 2] cascade annulation, furnishing a series of optically active tetra-hydroindole pyrazolinones with two contiguous chiral aza-quaternary carbon centers in excellent yields with excellent enantioselectivities. This method features a relatively broad substrate scope for amines and 2-naphthylamines and highlights the emerging value of direct chiral indolizations from simple amine sources in organic synthesis.
View Article and Find Full Text PDFHerein, we have reported a nickel-catalyzed cascade reductive thiolation of aryl halides with sulfinates driven by paired electrolysis. This protocol uses sulfinates as the sulfur source, and various thioethers could be synthesized under mild conditions. By mechanism exploration, we find that a cascade chemical step is allowed on the electrode interface and could alter the reaction pathway in paired electrolysis, whose findings could help the discovery of novel cascade reactions with unique reactivity.
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