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1.
Phys Chem Chem Phys ; 26(17): 13506-13514, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38651980

RESUMO

Fluorescent probes have become promising tools for monitoring the concentration of peroxynitrite, which is linked to many diseases. However, despite focusing on developing numerous peroxynitrite based fluorescent probes, limited emphasis is placed on their sensing mechanism. Here, we investigated the sensing mechanism of a peroxynitrite fluorescent probe, named BHID-Bpin, with a focus on the relevant excited state dynamics. The photoexcited BHID-Bpin relaxes to its ground state via an efficient nonradiative process (∼300 ps) due to the presence of a minimum energy conical intersection between its first excited state and ground state. However, upon reacting with peroxynitrite, the Bpin moiety is cleaved from BHID-Bpin and BHID is formed. The formed BHID exhibits strong dual band fluorescence which is caused by an ultrafast excited-state intramolecular proton transfer process (∼1 ps).

2.
Angew Chem Int Ed Engl ; 63(30): e202405765, 2024 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-38721653

RESUMO

In this study, peptide-based self-assembled nanosheets with a thickness of approximately 1 nm were prepared using a hierarchical covalent physical fabrication strategy. The covalent alternating polymerization of helical peptide E3 with an azobenzene (AZO) structure yielded copolymers CoP(E3-AZO), which physically self-assembled into ultrathin nanosheets in an unanticipated two-dimensional horizontal monolayer arrangement. This special monolayer arrangement enabled the thickness of the nanosheets to be equal to the cross-sectional diameter of a single linear copolymer, which is a rare phenomenon. Molecular dynamics simulations suggested that the synergistic effect of multiple molecular interactions drives the self-assembly of CoP(E3-AZO) into nanosheets and that various methods, including phototreatment, pH adjustment, the addition of additives, and introduction of cosolvents, can alter the molecular interactions and modulate the self-assembly of CoP(E3-AZO), yielding diverse nanostructures. Remarkably, the ultrathin nanosheets selectively inhibited cancer cells at certain concentrations.


Assuntos
Nanoestruturas , Peptídeos , Nanoestruturas/química , Peptídeos/química , Humanos , Simulação de Dinâmica Molecular , Compostos Azo/química , Antineoplásicos/farmacologia , Antineoplásicos/química
3.
Lab Invest ; 103(11): 100234, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37574009

RESUMO

Coinfection with multiple high-risk human papillomavirus (hrHPV) is frequently observed in cervical specimens; however, the clinical significance of concomitant multiple hrHPV infections is poorly understood, and the published results remain inconsistent. A retrospective study at a tertiary care institution was performed, evaluating Tellgenplex human papillomavirus (HPV) 27 genotyping or YanengBio HPV 23 genotyping results and immediate cervical histologic diagnosis (within 6 months after HPV genotyping), between November 2015 and October 2022. Among 49,299 cases with hrHPV genotyping and histologic diagnosis, 24,361 cases were diagnosed as cervical intraepithelial neoplasia (CIN) and squamous cell carcinoma. Among women with cervical squamous lesions, 86.5% (21,070/24,361) had hrHPV infections, and concomitant multiple hrHPV infections accounted for 24.7% of hrHPV-positive cases (5210/21,070). The hrHPV-positive rates in these cervical squamous lesions increased progressively with disease severity; however, the percentages of concomitant multiple hrHPV infection rates among hrHPV-positive cases decreased significantly with increasing degree of squamous abnormalities. There was no increased detection rate of CIN3+ (CIN3 and squamous cell carcinoma) in cases with concomitant 2 or 3 hrHPV genotype infections when compared with those with corresponding single hrHPV infections. Conversely, some combinations of multiple hrHPV infections demonstrated a decrease in the detection rates of CIN3+ lesions. In this large cohort, our results demonstrated that multiple hrHPV infections do not carry an increased risk for developing CIN3+ lesions when compared to the corresponding single-genotype infection. The reduced risk of CIN3+ in women infected with some combinations of hrHPV genotypes compared to those with single-genotype infections supports the concept of intergenotypic competition of hrHPV genotypes in cervical squamous lesions.


Assuntos
Carcinoma de Células Escamosas , Infecções por Papillomavirus , Displasia do Colo do Útero , Neoplasias do Colo do Útero , Humanos , Feminino , Neoplasias do Colo do Útero/diagnóstico , Neoplasias do Colo do Útero/epidemiologia , Neoplasias do Colo do Útero/patologia , Papillomavirus Humano , Estudos Retrospectivos , Incidência , Infecções por Papillomavirus/diagnóstico , Infecções por Papillomavirus/epidemiologia , Infecções por Papillomavirus/complicações , Displasia do Colo do Útero/diagnóstico , Displasia do Colo do Útero/epidemiologia , Displasia do Colo do Útero/patologia , Carcinoma de Células Escamosas/epidemiologia , Carcinoma de Células Escamosas/patologia , Papillomaviridae/genética , Genótipo
4.
J Med Virol ; 95(1): e28302, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36369778

RESUMO

Our aim was to conduct a large epidemiologic analysis of the distribution of human papilloma virus (HPV) genotypes associated with cervical neoplasias and cancers at a major Chinese gynecologic center. The pathologic database was searched for cervical histopathologic diagnoses with prior HPV genotyping from liquid cervical cytology specimens obtained ≤6 months before biopsy. HPV testing was performed by using the Tellgenplex HPV27 or YanengBio HPV23 genotyping assays. A total of 40 352 cases meeting study criteria were identified. High risk human papillomavirus (hrHPV) was detected in 94.1% of squamous cancers compared to in only 83.3% of cervical adenocarcinomas. The prevalence of multiple HPV infections was highest in cervical intraepithelial neoplasia 1 (CIN1) (33.8%) and decreased with increasing severity of squamous lesions. The distribution of HPV genotypes was similar between CIN1 and histopathologic-negative cases. HPV16 was one of the three most common hrHPV genotypes before all histopathologic abnormalities, ranging from 72.0% for cervical cancers, 38.7% for CIN2/3/AIS, 13.1% for CIN1, and 9.1% for biopsy-negative cases. HPV16 and HPV18 accounted for over 87.2% of detected hrHPV genotypes for all glandular intraepithelial neoplastic lesions and cancers, whereas squamous lesions did not show this pattern. 80.3% of cervical cancers were associated with genotypes covered by HPV16/18 vaccines and 89.6% with genotypes covered by 9-valent vaccination.


Assuntos
Carcinoma de Células Escamosas , Infecções por Papillomavirus , Displasia do Colo do Útero , Neoplasias do Colo do Útero , Feminino , Humanos , Neoplasias do Colo do Útero/diagnóstico , Papillomavirus Humano , Papillomavirus Humano 16/genética , Infecções por Papillomavirus/complicações , Papillomavirus Humano 18/genética , Displasia do Colo do Útero/epidemiologia , Papillomaviridae/genética , Genótipo , Carcinoma de Células Escamosas/complicações
5.
J Sep Sci ; 46(16): e2300148, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37415310

RESUMO

The Yuquan capsules is a commonly used traditional Chinese Patent Medicine used for the treatment of diabetes mellitus. In this study, a high-throughput analytical method for identifying the chemical composition of Yuquan capsules was established for the first time by using ultra-performance liquid chromatography-quadrupole time of flight mass spectrometry. The data obtained were subjected to fragment analysis and this was combined with UNIFI processing of natural products. One-hundred sixteen compounds were characterized from Yuquan capsules. Twelve of the bioactive compounds were quantitatively analyzed by ultra-performance liquid chromatography-tandem triple quadrupole mass spectrometry. This study was undertaken to obtain a comprehensive chemical profile analysis as well as to evaluate the overall quality of Yuquan capsules. The results will provide a reference for the quality evaluation of different Yuquan preparations. In addition, the data will enable basic pharmacodynamic research into these extensively used capsules.


Assuntos
Medicamentos de Ervas Chinesas , Medicamentos de Ervas Chinesas/análise , Cromatografia Líquida de Alta Pressão/métodos , Cápsulas , Cromatografia Gasosa-Espectrometria de Massas , Espectrometria de Massas , Cromatografia Líquida , Medicina Tradicional Chinesa
6.
J Sep Sci ; 46(2): e2200311, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36349515

RESUMO

Abrus mollis Hance is a traditional Chinese medicine that is widely used to treat acute and chronic hepatitis, steatosis, and fibrosis. Its therapeutic qualities of it have long been acknowledged, although the active ingredients responsible for its efficacy and the mechanisms of its action are unknown. In this study, the chemical constituents absorbed into the blood from Abrus mollis Hance were assessed by using liquid chromatography-quadrupole-time-of-flight mass spectrometry and the data was analyzed with the UNIFI screening platform. The results obtained were compared to existing chromatographic-mass spectrometry information, including retention times and molecular weights as well as known reference compounds. 41 chemical constituents were found in Abrus mollis Hance, and these included 16 flavonoids, 13 triterpenoids, five organic acids, and two alkaloids. Experimentally it was found that Abrus mollis Hance had a therapeutic benefit when treating α-naphthalene isothiocyanate-induced acute liver injury in rats. In addition, 11 blood prototypical constituents, including six flavonoids, three triterpenoids, and two alkaloids, were found in serum samples following intragastric administration of Abrus mollis Hance extracts to rats. This novel study can be used for the quality control and pharmacodynamic assessment of Abrus mollis Hance in order to assess its efficacy in the therapeutic treatment of patients.


Assuntos
Abrus , Alcaloides , Medicamentos de Ervas Chinesas , Triterpenos , Ratos , Animais , Cromatografia Líquida de Alta Pressão/métodos , Abrus/química , Espectrometria de Massas , Medicamentos de Ervas Chinesas/análise , Flavonoides/análise , Triterpenos/análise
7.
Molecules ; 28(6)2023 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-36985466

RESUMO

Jigucao capsules (JGCC) have the effects of soothing the liver and gallbladder and clearing heat and detoxification. It is a good medicine for treating acute and chronic hepatitis cholecystitis with damp heat of the liver and gallbladder. However, the existing quality standard of JGCC does not have content determination items, which is not conducive to quality control. In this study, serum pharmacochemistry technology and UNIFI data processing software were used to identify the blood prototype components and metabolites under the condition of the obvious drug effects of JGCC, and the referenced literature reports and the results from in vitro analysis of JGCC in the early stage revealed a total of 43 prototype blood components and 33 metabolites in JGCC. Quality markers (Q-markers) were discovered, such as abrine, trigonelline, hypaphorine and isoschaftoside. In addition, ultra-high-performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-QQQ-MS) was used to determine the active ingredients in JGCC. The components of quantitative analysis have good correlation in the linear range with R2 ≥ 0.9993. The recovery rate is 93.15%~108.92% and the relative standard deviation (RSD) is less than 9.48%. The established UPLC-MS/MS quantitative analysis method has high sensitivity and accuracy, and can be used for the quality evaluation of JGCC.


Assuntos
Medicamentos de Ervas Chinesas , Espectrometria de Massas em Tandem , Espectrometria de Massas em Tandem/métodos , Cromatografia Líquida , Cromatografia Líquida de Alta Pressão/métodos , Medicamentos de Ervas Chinesas/química , Controle de Qualidade
8.
Angew Chem Int Ed Engl ; 62(39): e202309760, 2023 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-37578902

RESUMO

DNA-stabilized silver nanoclusters (DNA-AgNCs) are easily tunable emitters with intriguing photophysical properties. Here, a DNA-AgNC with dual emission in the red and near-infrared (NIR) regions is presented. Mass spectrometry data showed that two DNA strands stabilize 18 silver atoms with a nanocluster charge of 12+. Besides determining the composition and charge of DNA2 [Ag18 ]12+ , steady-state and time-resolved methods were applied to characterize the picosecond red fluorescence and the relatively intense microsecond-lived NIR luminescence. During this process, the luminescence-to-fluorescence ratio was found to be excitation-intensity-dependent. This peculiar feature is very rare for molecular emitters and allows the use of DNA2 [Ag18 ]12+ as a nanoscale excitation intensity probe. For this purpose, calibration curves were constructed using three different approaches based either on steady-state or time-resolved emission measurements. The results showed that processes like thermally activated delayed fluorescence (TADF) or photon upconversion through triplet-triplet annihilation (TTA) could be excluded for DNA2 [Ag18 ]12+ . We, therefore, speculate that the ratiometric excitation intensity response could be the result of optically activated delayed fluorescence.


Assuntos
Nanoestruturas , Prata , Prata/química , Nanoestruturas/química , DNA/química , Espectrometria de Fluorescência , Fótons
9.
Angew Chem Int Ed Engl ; 62(16): e202218892, 2023 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-36815469

RESUMO

Sulfone-embedded heterocyclics are of great interest in organic light-emitting diodes (OLEDs), however, exploring highly efficient narrowband emitters based on sulfone-embedded heterocyclics remains challenging. Herein, five emitters with different sulfur valence state and molecular rigidity, namely tP, tCPD, 2tCPD, tPD and tPT, are thoroughly analysed. With restricted twisting of flexible peripheral phenyl by strengthening molecular rigidity, molecular emission spectra can be enormously narrowed. Further, introducing the sulfone group with bending vibration in low-frequency region that suppresses high-frequency vibration, sharp narrow full-widths at half-maximum of 28 and 25 nm are achieved for 2tCPD and tPD, respectively. Maximum external quantum efficiencies of 22.0 % and 27.1 % are successfully realized for 2tCPD- and tPD-based OLED devices. These results offer a novel design strategy for constructing narrowband emitters by introducing sulfone group into a rigid molecular framework.

10.
J Sep Sci ; 45(3): 677-696, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34822724

RESUMO

Jigucao capsule is a well-known Chinese patent medicine for the treatment of acute and chronic hepatitis and cholecystitis. The chemical components of Jigucao capsule were not clear resulting from the paucity of relevant studies, which hindered the research of the pharmacological mechanism, the comprehensive development, and utilization of Jigucao capsule in clinical studies. By establishing a high-throughput ultra-performance liquid chromatography quadrupole time of flight mass spectrometry in combination with intelligent UNIFI software data processing platform to automatically characterize and identify the chemical profile of Jigucao capsule, 144 compounds were determined rapidly, including 34 terpenoids, 25 flavonoids, 22 steroids, 21 phenylpropanoids, 10 glycosides, six alkaloids, 13 organic acids, and other 13 components. These compounds may be the active components of Jigucao capsule. In this study, a rapid and robust method for comprehensively analyzing the chemical composition of Jigucao capsule was described and established for the first time. The results will provide a reference for the quality control of Jigucao capsule and the establishment of a higher quality standard, as well as for the pharmacodynamic material basis research.


Assuntos
Alcaloides , Medicamentos de Ervas Chinesas , Cromatografia Líquida de Alta Pressão/métodos , Medicamentos de Ervas Chinesas/análise , Flavonoides/análise , Espectrometria de Massas/métodos
11.
Zhongguo Zhong Yao Za Zhi ; 47(7): 1802-1813, 2022 Apr.
Artigo em Zh | MEDLINE | ID: mdl-35534250

RESUMO

This study analyzed the quality markers(Q-markers) of Yuquan Capsules(YQC) based on serum pharmacochemistry of Chinese medicine and detected the components and metabolites of YQC absorbed into the blood by UPLC-Q-TOF-MS and UNIFI systems. As a result, 32 components of YQC were detected, including 17 prototype components and 15 metabolized components. Among them, 12 prototype components(ginsenoside Rh_2, genistein, formononetin, puerarin, daidzein, schizandrin A, schizandrin B, schizandrin C, schizandrol A, schizandrol B, gomisin D, and ononin) and 12 metabolized components(ginsenoside Rg_1, ginsenoside Rg_2, ginsenoside Rg_3, ginsenoside Ro, 3'-methoxypuerarin, daidzin, astragaloside Ⅱ, astragaloside Ⅳ, glycyrrhizic acid, liquiritigenin, isoliquiritin, and verbascoside) showed inhibitory effects and pharmacological activities against diabetes, and these 24 blood-entering components against diabetes were identified as Q-markers of YQC.


Assuntos
Medicamentos de Ervas Chinesas , Ginsenosídeos , Cápsulas , Cromatografia Líquida de Alta Pressão , Medicamentos de Ervas Chinesas/farmacologia , Ginsenosídeos/análise , Medicina Tradicional Chinesa , Soro/química
12.
Angew Chem Int Ed Engl ; 61(26): e202202972, 2022 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-35438237

RESUMO

A unique family of chiral peraza N6 -macrocyclic ligands, which are conformationally rigid and have a tunable saddle-shaped cavity, is described. Utilizing their manganese(I) complexes, the first example of earth-abundant transition metal-catalyzed asymmetric formal anti-Markovnikov hydroamination of allylic alcohols was realized, providing a practical access to synthetically important chiral γ-amino alcohols in excellent yields and enantioselectivities (up to 99 % yield and 98 % ee). The single-crystal structure of a MnI complex indicates that the manganese atom coordinates with the chiral dialkylamine moiety in a bidentate fashion. Further DFT calculations revealed that five of the six nitrogen atoms in the ligand were engaged in multiple noncovalent interactions with Mn, an isopropanol molecule, and a ß-amino ketone intermediate via coordination, hydrogen bonding, and/or CH⋅⋅⋅π interactions in the transition state, showing a remarkable role of the macrocyclic framework.

13.
Angew Chem Int Ed Engl ; 61(34): e202205739, 2022 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-35766225

RESUMO

The enantioselective hydrogenation of arenols to corresponding chiral cyclic alcohols remains a challenge because of their aromaticity and the difficulty in controlling the regio-, chemo-, and stereoselectivity. In this work, the first highly efficient ruthenium-catalyzed enantioselective hydrogenation of 9-phenanthrols has been successfully realized under mild conditions via trapping the unstable keto tautomers. The method provides a facile access to a range of chiral 9,10-dihydrophenanthren-9-ols with up to 98 % yield and >99 % ee. The hydrogenation pathway includes base-promoted tautomerization of 9-phenanthrols and Ru-catalyzed asymmetric hydrogenation of the in situ generated unstable keto tautomers.

14.
Angew Chem Int Ed Engl ; 61(15): e202200638, 2022 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-35104023

RESUMO

A novel pH-responsive molecular shuttle based on a [2]rotaxane with a phosphine ligand has been designed and synthesized. In the rhodium-catalyzed hydrogenation of α,ß-dehydroamino acid esters and aryl enamides, ON/OFF-switchable catalysis was accomplished with high ON/OFF ratios by adjusting the movements of the rotaxane wheels located at the catalyst terminals with acid/base. Mechanistic studies using NMR spectroscopy and quasi in situ X-ray photoelectron spectroscopy revealed that RhIII -hydride species are possibly formed in a H2 atmosphere when the catalyst is in the OFF state. During the reaction, a heterolytic activation of dihydrogen occurs by the interlocked rotaxane dibenzylamine and RhI catalytic center acting as a frustrated Lewis pair. Subsequent homolytic splitting of dihydrogen with the newly formed RhI -hydride species generates RhIII -hydride species. These findings show that a substrate-selective hydrogenation can be achieved by using the OFF-state catalyst.

15.
J Org Chem ; 85(12): 8176-8184, 2020 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-32401502

RESUMO

A small library of diaza-crown ether-bridged chiral diphosphoramidite ligands was prepared. In the rhodium-catalyzed asymmetric hydrogenation and hydroformylation reactions, these ligands exhibited distinct properties in catalytic activity and/or enantioselectivity. Hydrogenated products with opposite absolute configurations could be obtained in high yields with excellent ee values by utilizing (S,S)-L1 and (S,S)-L3, respectively. Meanwhile, the addition of alkali metal cations caused variations in catalytic outcomes, showing the supramolecular tunability of these Rh/diphosphoramidite catalytic systems.

16.
Int J Clin Pract ; 74(9): e13506, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32270560

RESUMO

BACKGROUND: Tension-free vaginal tape obturator (TVT-O) and tension-free vaginal tape secur (TVT-S) are common surgeries for the treatment of stress urinary incontinence (SUI), several randomised controlled trials (RCTs) have compared the effects of TVT-O and TVT-S, yet the results remained inconsistent. Therefore, we attempted to conduct this systematic review and meta-analysis to analyse the role of TVT-O and TVT-S in patients with SUI. METHODS: We searched PubMed databases from inception date to Jan 15, 2020 for RCTs that compared TVT-O and TVT-S in SUI patients. Two authors independently screened and extracted data from the published articles. Summary odd ratios (OR) or mean differences (MD) with 95% confidence intervals (95% CI) were calculated for each outcome by fixed- or random-effects model. RESULTS: Seven RCTs with a total of 755 patients were identified, with 373 patients for TVT-O and 382 patients for TVT-S. TVT-O preceded TVT-S in the objective cure at 12 months (OR = 1.72, 95% CI 1.21-2.45), subjective cure (OR = 1.98, 95% CI 1.08-3.62); but TVT-S have more advantage in the incidence of postoperative thigh pain (OR = 18.94, 95% CI 7.01-51.15); no significant differences on the duration of operative procedure (OR = -1.09, 95% CI -2.37-0.18), urinary retention (OR = 0.77, 95% CI 0.36-1.62) and urinary infection (OR = 1.80, 95% CI 0.63-5.13) were found. CONCLUSIONS: TVT-O should be preferred for patients with SUI even though with higher risks of postoperative thigh pain when compared with TVT-S, more related studies are needed to identify the role of TVT-O and TVT-S for the treatment of SUI.


Assuntos
Slings Suburetrais , Incontinência Urinária por Estresse/cirurgia , Feminino , Humanos , Incidência , Pessoa de Meia-Idade , Razão de Chances , Dor Pós-Operatória/prevenção & controle , Resultado do Tratamento , Incontinência Urinária por Estresse/complicações , Procedimentos Cirúrgicos Urológicos/efeitos adversos , Procedimentos Cirúrgicos Urológicos/métodos
17.
Org Biomol Chem ; 17(20): 5099-5105, 2019 05 28.
Artigo em Inglês | MEDLINE | ID: mdl-31070209

RESUMO

A small library of tunable chiral pyridine-aminophosphine ligands were enantioselectively synthesized based on chiral 2-(pyridin-2-yl)-substituted 1,2,3,4-tetrahydroquinoline scaffolds, which were obtained in high yields and with excellent enantioselectivities via ruthenium-catalyzed asymmetric hydrogenation of 2-(pyridin-2-yl)quinolines. The protocol features a wide substrate scope and mild reaction conditions, enabling scalable synthesis. These chiral P,N ligands were successfully applied in the Ir-catalyzed asymmetric hydrogenation of benchmark olefins and challenging seven-membered cyclic imines including benzazepines and benzodiazepines. Excellent enantio- and diastereoselectivity (up to 99% ee and >20 : 1 dr), and/or unprecedented chemoselectivity were obtained in the asymmetric hydrogenation of 2,4-diaryl-3H-benzo[b]azepines and 2,4-diaryl-3H-benzo[b][1,4]diazepines.

18.
Angew Chem Int Ed Engl ; 58(47): 16831-16834, 2019 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-31486574

RESUMO

A highly enantioselective iridium- or ruthenium-catalyzed intermolecular reductive amination/asymmetric hydrogenation relay with 2-quinoline aldehydes and aromatic amines has been developed. A broad range of sterically tunable chiral N,N'-diaryl vicinal diamines were obtained in high yields (up to 95 %) with excellent enantioselectivity (up to >99 % ee). The resulting chiral diamines could be readily transformed into sterically hindered chiral N-heterocyclic carbene (NHC) precursors, which are otherwise difficult to access. The usefulness of this synthetic approach was further demonstrated by the successful application of one of the chiral vicinal diamines and chiral NHC ligands in a transition-metal-catalyzed asymmetric Suzuki-Miyaura cross-coupling reaction and asymmetric ring-opening cross-metathesis, respectively.

19.
Angew Chem Int Ed Engl ; 58(12): 3809-3813, 2019 03 18.
Artigo em Inglês | MEDLINE | ID: mdl-30523655

RESUMO

A rapid construction of enantioenriched benzo-fused quinolizidines, indolizidines, and their analogues by ruthenium-catalyzed asymmetric cascade hydrogenation/reductive amination of quinolinyl- and quinoxalinyl-containing ketones has been developed. This reaction proceeds under mild reaction conditions, affording chiral benzo-fused aliphatic N-heterocyclic compounds with structural diversity in good yields (up to 95 %) with excellent diastereoselectivity (up to >20:1 dr) and enantioselectivity (up to >99 % ee). Furthermore, this catalytic protocol is applicable to the formal synthesis of (+)-gephyrotoxin.

20.
Angew Chem Int Ed Engl ; 58(38): 13522-13531, 2019 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-31267665

RESUMO

Thermally activated delayed fluorescent (TADF) materials generally suffer from severe concentration quenching. Efficient non-doped TADF emitters are generally highly twisted aromatic amine-based compounds with isolated chemical moieties. Herein we demonstrate that co-facial packing and strong π-π intermolecular interactions give rise to bright TADF emissions in non-doped film and crystalline states within the compound 2,4-diphenyl-6-(thianthren-1-yl)-1,3,5-triazine (oTE-DRZ). Quantum chemistry simulations indicate that a disperse outer orbital of sulfur atoms, a folded thianthrene plane (for a reduced donor-acceptor distance), and a triazine acceptor with n-π* character, generate a spatially conjugated transition with a small singlet-triplet splitting energy. In company with a highly emissive non-doped film, the corresponding organic light-emitting diode achieved a 20.6 % external quantum efficiency, verifying its potential for high-performance optoelectronic applications. In a crystalline state, it was verified that intra- and intermolecular dual TADF assisted by a hidden room-temperature phosphorescent state. This state could preserve the long-lived excitons while suppressing non-radiation, and it could serve as a "spring-board" for cascade up-conversion processes. The oTE-DRZ crystal showed greenish-blue emission with a very high photoluminescent quantum yield of approximately 87 %, which is the highest among all TADF crystals reported to date.

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