A Bro̷nsted acid-catalyzed [5 + 1] annulation of 2-(1-indol-2-yl)phenols, a class of indole-based 1,5-CO-synthons, with aldehydes has been established. By this approach, various indole-fused dihydrochromanes were synthesized in moderate to good yields (up to 99%) with excellent regioselectivities. Control experiments not only showed the H-bonding interaction between the NH group of the substrates─and the acid catalyst is vital to realize this transformation─but also indicated that an indolylmethanol-type intermediate was possibly formed via the first step of nucleophilic addition of indole C3-position to aldehydes during the reaction process.
View Article and Find Full Text PDFCardiovascular diseases have posed a great threat to human health. Fortunately, gene therapy holds great promise in the fight against cardiovascular disease (CVD). In gene therapy, it is necessary to select the appropriate carriers to deliver the genes to the target cells of the target organs.
View Article and Find Full Text PDFPseudomonas aeruginosa, a versatile bacterium, has dual significance because of its beneficial roles in environmental soil processes and its detrimental effects as a nosocomial pathogen that causes clinical infections. Understanding adaptability to environmental stress is essential. This investigation delves into the complex interplay of two-component system (TCS), specifically ParRS and CprRS, as P.
View Article and Find Full Text PDFColor centers in silicon carbide have become potentially versatile quantum sensors. Particularly, wide temperature-range temperature sensing has been realized in recent years. However, the sensitivity is limited due to the short dephasing time of the color centers.
View Article and Find Full Text PDFDevelopment of simple chiral materials with tunable circularly polarized photoluminescence (CPPL) and circularly polarized electroluminescence (CPEL) for efficient circularly polarized organic light-emitting diodes (CP-OLEDs) is the key toward future 3D displays. In this study, four pairs of chiral 1,2-diaminocyclohexane-based fluorescence enantiomers were efficiently prepared with high yields (up to 92%) and enantiomeric excesses (ee >99%). By the introduction of -methyl, carbazole, and diphenylamine-donating groups, these materials showed multicolor CPPL and CPEL from blue (420 nm) to red (610 nm) with good thermal and conformational stability.
View Article and Find Full Text PDFAn organocatalytic [4 + 1] cyclization of o-QMs with MBH carbonates has been established using naphthylindole-derived phosphine (NIP) as an organocatalyst. By using this approach, a series of 2,3-dihydrobenzofuran derivatives have been synthesized in high yields and excellent diastereoselectivities (up to 99% yield, >95:5 dr). This reaction not only has established the first [4 + 1] cyclization of o-QMs with MBH carbonates but also represents the first application of naphthylindole-derived phosphines as organocatalysts in catalytic reactions.
View Article and Find Full Text PDFBACKGROUND This study aimed to explore the feasibility and efficacy of bone cement-augmented short-segmental pedicle screw fixation in treating Kümmell disease. MATERIAL AND METHODS From June 2012 to June 2015, 18 patients with Kümmell disease with spinal canal stenosis were enrolled in this study. Each patient was treated with bone cement-augmented short-segment fixation and posterolateral bone grafting, and posterior decompression was performed when needed.
View Article and Find Full Text PDFThe first catalytic asymmetric dearomative [3 + 2] cycloaddition of 3-nitroindoles with vinylcyclopropanes has been established, which constructed chiral cyclopenta[b]indoline scaffolds in generally high enantioselectivities (up to 97% ee). This reaction also represents the first application of all-carbon 1,3-dipoles in catalytic asymmetric dearomative [3 + 2] cycloadditions of 3-nitroindoles. This approach will not only advance the catalytic asymmetric dearomatization reactions of electron-deficient indoles but also provide an efficient method for constructing chiral cyclopenta[b]indoline scaffolds.
View Article and Find Full Text PDFThe first catalytic asymmetric α-arylation of pyrazol-5-ones has been established by using 2-indolylmethanols as direct electrophilic arylation reagents under the cooperative catalysis of Pd(0) and a chiral phosphoric acid, which afforded the α-arylation products of pyrazol-5-ones in generally high yields and good enantioselectivities (up to 99% yield, >99% ee).
View Article and Find Full Text PDFThe first [4+3] cycloaddition of ortho-hydroxybenzyl alcohols has been established by making use of N,N'-cyclic azomethine imines as suitable 1,3-dipoles under Brønsted acid catalysis. By using this strategy, biologically important seven-membered heterocyclic scaffolds have been constructed in good yields and excellent diastereoselectivities (up to 92% yield, most >95 : 5 dr).
View Article and Find Full Text PDFThe first organocatalytic asymmetric formal alkenylation of multicyclic alcohols using non-metal-based alkenes instead of alkenyl metals as a source of an alkenyl group has been established via chiral phosphoric acid catalyzed tandem reactions. This transformation directly assembles isoindolo-β-carboline-derived hydroxylactams with o-hydroxystyrenes via an asymmetric cascade vinylogous addition/hydrogen elimination reaction sequence, offering an easy access to functionalized chiral isoindolo-β-carbolines with one quaternary stereogenic center in high chemo-, (E/Z)-, and enantioselectivities (up to >95:5 cr, >95:5 E/Z, 97:3 er). This approach also represents the first catalytic asymmetric formal alkenylation of isoindolo-β-carboline-derived hydroxylactams, which provides a useful strategy for functionalization of isoindolo-β-carbolines and synthesis of chiral isoindolo-β-carboline derivatives.
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