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1.
Artigo em Inglês | MEDLINE | ID: mdl-38570724

RESUMO

PURPOSE: This study analyzes the relationship between human papillomavirus (HPV) infection, vaginal microecology, and cervical lesions to provide a basis for the prevention and treatment of cervical cancer (CC) in the Xinjiang region. METHODS: Real-time quantitative PCR was used for HPV genotyping and viral load. The Gram staining and dry biochemical enzyme kit were utilized to diagnose vaginal secretions. The χ2 test and Logistic regression analysis were used for statistical analysis. RESULTS: The HPV infection rate among women in the Xinjiang region was 30.29%, of which the single HPV infection accounts for 77%. HPV16 and HPV52 were the main infection types. There was significant differences in the HPV infection rate and infection types among the Han, Uighur, Hui, and Kazakh ethnic groups. The viral load of HPV16 and HPV52 increases with the upgrade of cervical lesions. There were significant differences in vaginal microecology evaluation indicators H2O2, SNA, LE, GUS, trichomonas, clue cells, and lactobacilli among different ethnic groups. HPV negative patients with varying grades of cervical lesions exhibit a notable variance in H2O2 and LE, which is statistically significant. Single HPV infection and high viral load HPV significantly increase the risk of CC. CONCLUSIONS: This study indicates that HPV infection and vaginal microecology differ among ethnic groups, which have a strong correlation with the progression of CC, offering guidance on CC screening and interventions in the Xinjiang area.

2.
Nature ; 618(7964): 294-300, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36940729

RESUMO

Chiral amines are commonly used in the pharmaceutical and agrochemical industries1. The strong demand for unnatural chiral amines has driven the development of catalytic asymmetric methods1,2. Although the N-alkylation of aliphatic amines with alkyl halides has been widely adopted for over 100 years, catalyst poisoning and unfettered reactivity have been preventing the development of a catalyst-controlled enantioselective version3-5. Here we report the use of chiral tridentate anionic ligands to enable the copper-catalysed chemoselective and enantioconvergent N-alkylation of aliphatic amines with α-carbonyl alkyl chlorides. This method can directly convert feedstock chemicals, including ammonia and pharmaceutically relevant amines, into unnatural chiral α-amino amides under mild and robust conditions. Excellent enantioselectivity and functional-group tolerance were observed. The power of the method is demonstrated in a number of complex settings, including late-stage functionalization and in the expedited synthesis of diverse amine drug molecules. The current method indicates that multidentate anionic ligands are a general solution for overcoming transition-metal-catalyst poisoning.


Assuntos
Alquilação , Aminas , Catálise , Cobre , Amidas/química , Aminas/química , Cobre/química , Ligantes , Preparações Farmacêuticas/química
3.
Front Neurol ; 14: 1133893, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36937511

RESUMO

Introduction: Disorders of consciousness (DoCs) are a frequent complication of brain injury disease, and effective treatments are currently lacking. Transauricular vagus nerve stimulation (tVNS) has been proposed as a promising therapeutic method for neurological disorders such as epilepsy and depression. In our previous study, we demonstrated that vagus nerve stimulation promoted recovery in rats with DoCs caused by traumatic brain injury. However, the clinical effect of vagus nerve stimulation on consciousness disorders is unclear. We aimed to investigate the therapeutic efficacy and safety of tVNS in patients with DoCs. Methods: We conducted a randomized, double-blinded, sham-controlled trial. Patients (N = 60) with DoCs, including minimally conscious state (MCS) and vegetative state/unresponsive wakefulness syndrome, were enrolled and randomized to groups receiving either active or sham tVNS. A frequency of 20 Hz and pulse wave of 200 us was used in the active-tVNS protocol, which was performed in the auricular branch of the vagus nerve in the left outer ear. The sham-tVNS protocol was the same as the active-tVNS protocol although without current input. Both groups of patients also received conventional treatments. Consciousness was evaluated according to the Coma Recovery Scale-Revised before and after the 4-week intervention. We also recorded the type and number of behavioral responses. Safety was primarily assessed according to the incidence of treatment-emergent adverse events. Each patient's heart rate and blood pressure were monitored during all treatment sessions. Results: Ultimately, 57 patients completed the study: 28 patients underwent active tVNS and 29 patients underwent sham tVNS. No significant differences were observed in Coma Recovery Scale-Revised scores between the active- and sham-tVNS groups before the tVNS sessions. Compared with patients in the sham-tVNS group (9.28 ± 4.38), patients with DoCs treated with active tVNS showed improved consciousness (10.93 ± 4.99), although not statistically significant. Further analysis revealed obvious differences between patients with MCS receiving active and sham tVNS, but no significant difference in patients with vegetative state/unresponsive wakefulness syndrome in both groups. All side effects were considered common medical conditions with no obvious correlation to tVNS. Conclusion: These preliminary data provide early evidence that tVNS may be an effective and safe approach for promoting the recovery of consciousness, especially in patients with MCS. Clinical trial registration: https://www.chictr.org.cn/edit.aspx?pid=175938&htm=4, identifier: ChiCTR2200066629.

4.
J Dig Dis ; 23(8-9): 462-472, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-36208049

RESUMO

OBJECTIVES: This study aimed to assess the efficacy and safety of probiotics for Helicobacter pylori (H. pylori) eradication therapy as well as their effects on gastric microbiota. METHODS: Patients who had failed H. pylori eradication therapy for at least twice were prospectively enrolled during March 2019 and March 2021. A 2-week administration of compound Lactobacillus acidophilus probiotic (1 g thrice daily) followed by a 10-day quadruple bismuth-containing H. pylori eradication therapy was administrated. Endoscopy was performed, and gastric biopsy samples were obtained for drug sensitivity testing and 16S rRNA gene sequencing before and after probiotic treatment. Eradication was evaluated by the 13 C-urea breath test at least 4 weeks after treatment completion. Adverse events (AEs) were recorded. RESULTS: Thirty-seven patients were included. Probiotic supplementation had no effects on the diversity, community structure, and composition of gastric microbiota and no inhibition on H. pylori activity. However, it increased some of the beneficial bacteria such as Blautia, Dorea, and Roseburia (P < 0.05). The overall eradication rate was 97.3% (95% confidence interval [CI] 91.8%-100%). AEs, mainly dizziness, nausea, diarrhea, and chest distress, were detected in six individuals, all of which were resolved upon cessation of antibiotic administration. Dyspeptic symptoms were improved after probiotic supplementation and at treatment completion (both P < 0.001). CONCLUSIONS: H. pylori-infected individuals might benefit from probiotics followed by a quadruple bismuth-containing eradication therapy. Further studies with large sample sizes are warranted.


Assuntos
Infecções por Helicobacter , Helicobacter pylori , Microbiota , Probióticos , Humanos , Infecções por Helicobacter/tratamento farmacológico , Bismuto/uso terapêutico , RNA Ribossômico 16S , Probióticos/efeitos adversos , Antibacterianos/efeitos adversos , Quimioterapia Combinada , Resultado do Tratamento
5.
J Am Chem Soc ; 144(38): 17319-17329, 2022 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-36048164

RESUMO

The enantioconvergent cross-coupling of racemic alkyl halides represents a powerful tool for the synthesis of enantioenriched molecules. In this regard, the first-row transition metal catalysis provides a suitable mechanism for stereoconvergence by converting racemic alkyl halides to prochiral radical intermediates owing to their good single-electron transfer ability. In contrast to the noble development of chiral nickel catalyst, copper-catalyzed enantioconvergent radical cross-coupling of alkyl halides is less studied. Besides the enantiocontrol issue, the major challenge arises from the weak reducing capability of copper that slows the reaction initiation. Recently, significant efforts have been dedicated to basic research aimed at developing chiral ligands for copper-catalyzed enantioconvergent radical cross-coupling of racemic alkyl halides. This perspective will discuss the advances in this burgeoning area with particular emphasis on the strategic chiral anionic ligand design to tune the reducing capability of copper for the reaction initiation under thermal conditions from our research group.


Assuntos
Cobre , Níquel , Catálise , Elétrons , Ligantes
6.
Nat Chem ; 14(8): 949-957, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35618768

RESUMO

In contrast with the well-established enantioconvergent radical C(sp3)-C cross-coupling of racemic secondary alkyl electrophiles, the corresponding coupling of tertiary electrophiles to forge all-carbon quaternary stereocentres remains underexplored. The major challenge arises from the steric hindrance and the difficult enantio-differentiation of three distinct carbon substituents of prochiral tertiary radicals. Here we demonstrate a general copper-catalysed enantioconvergent C(sp3)-C(sp) cross-coupling of diverse racemic tertiary alkyl halides with terminal alkynes (87 examples). Key to the success is the rational design of chiral anionic N,N,N-ligands tailor-made for the computationally predicted outer-sphere radical group transfer pathway. This protocol provides a practical platform for the construction of chiral C(sp3)-C(sp/sp2/sp3) bonds, allowing for expedient access to an array of synthetically challenging quaternary carbon building blocks of interest in organic synthesis and related areas.


Assuntos
Alcinos , Cobre , Carbono/química , Ligantes , Níquel/química
7.
J Am Chem Soc ; 143(37): 15413-15419, 2021 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-34505516

RESUMO

α-Chiral alkyl primary amines are virtually universal synthetic precursors for all other α-chiral N-containing compounds ubiquitous in biological, pharmaceutical, and material sciences. The enantioselective amination of common alkyl halides with ammonia is appealing for potential rapid access to α-chiral primary amines, but has hitherto remained rare due to the multifaceted difficulties in using ammonia and the underdeveloped C(sp3)-N coupling. Here we demonstrate sulfoximines as excellent ammonia surrogates for enantioconvergent radical C-N coupling with diverse racemic secondary alkyl halides (>60 examples) by copper catalysis under mild thermal conditions. The reaction efficiently provides highly enantioenriched N-alkyl sulfoximines (up to 99% yield and >99% ee) featuring secondary benzyl, propargyl, α-carbonyl alkyl, and α-cyano alkyl stereocenters. In addition, we have converted the masked α-chiral primary amines thus obtained to various synthetic building blocks, ligands, and drugs possessing α-chiral N-functionalities, such as carbamate, carboxylamide, secondary and tertiary amine, and oxazoline, with commonly seen α-substitution patterns. These results shine light on the potential of enantioconvergent radical cross-coupling as a general chiral carbon-heteroatom formation strategy.

8.
BMJ Open ; 11(8): e046515, 2021 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-34344676

RESUMO

OBJECTIVES: The objective was to examine care willingness and demand of residents under 60 years of age after retirement. SETTING: The staged cluster sampling method was used between August and October 2018 in Dujiangyan, Sichuan Province, China. PARTICIPANTS: 2282 participants under 60 years of age were surveyed in 2018 by the staged cluster sampling method in China. PRIMARY AND SECONDARY OUTCOME MEASURES: The results of care willingness and demand were assessed by multiple comparisons of χ2 test and multivariable logistic regression. RESULTS: The respondents who preferred institution-based care, home-based care and community-based care accounted for 39.5%, 38.3% and 20.2% respectively, whereas only 2.1% preferred home-based self-care. The main reasons for the respondents to choose institution-based care included better medical care (31.9%), better daily care (27.0%), burden reduction for children (26.3%), better accommodation (22.8%), satisfied living environment (21.6%) and low consumption (12.3%). The factors that affected care willingness and demand included age, ethnicity, educational attainment, marital status, occupation and the current type of residence. CONCLUSIONS: The results revealed the care willingness and demand of residents under 60 years of age after retirement and relevant decision factors. This study provides a certain theoretical and practical significance for the development of the care willingness mode and promotes the cognition of policy-makers and researchers, and also provides the basis for decision-making.


Assuntos
Serviços de Assistência Domiciliar , Criança , China , Estudos Transversais , Humanos , Modelos Logísticos , Inquéritos e Questionários
9.
Sichuan Da Xue Xue Bao Yi Xue Ban ; 52(2): 267-273, 2021 Mar.
Artigo em Chinês | MEDLINE | ID: mdl-33829701

RESUMO

OBJECTIVE: To investigate the potential association between multimorbidity and the handgrip strength of middle-aged and older adults. METHODS: The baseline (2011) and second-round follow-up (2015) data of China Health and Retirement Longitudinal Study (CHARLS) were used. Adults≥40 were selected as the subjects of the study. Variables incorporated in the study included handgrip strength, chronic disease prevalence, demographic variables, and health behavior variables. Generalized estimating equations were used to analyze the longitudinal association between handgrip strength and multimorbidity. RESULTS: A total of 28 368 middle-aged and older adults were included in the baseline and follow-up samples, with an average age of (59.1±9.7) years old, the oldest being 96 while the youngest being 40. Among them, 6 239 were male, accounting for 47.3%. In the second-round follow-up, 9 186 baseline respondents and 5 994 new respondents were covered, reaching a total of 15 180 respondents. Compared with the baseline, a higher proportion of the second-round follow-up respondents were female ( P=0.033) and were older ( P<0.001). From the baseline to the second-round follow-up, Q1, the lowest grip strength category, increased from 23.4% to 26.6%, while Q4, the highest grip strength category, decreased from 26.5% to 21.2%. The prevalence of having more than three chronic diseases increased from 18.2% to 24.2% and the prevalence of having more than five chronic diseases increased from 3.3% to 6.2%. After adjusting for confounding variables, the interaction items of handgrip strength and time showed statistical significance. After stratification by gender, the interaction items of male handgrip strength and follow-up time were statistically significant in both models ( P<0.05). The marginal effect graph of the interactive item showed that the multimorbidity prevalence of respondents with lower handgrip levels grew faster with age. Individual effect analysis showed that the correlation between handgrip strength and multimorbidity was not statistically significant at baseline, but the follow-up done four years afterwards showed statistical significant correlation between handgrip strength and multimorbidity. CONCLUSION: Respondents with lower baseline handgrip strength are associated with increasingly higher risk of multimorbidity over time. Handgrip strength can be used as an effective screening tool for middle-aged and older adults in China to identify those at higher risks of multimorbidity of chronic diseases.


Assuntos
Força da Mão , Multimorbidade , Idoso , China/epidemiologia , Doença Crônica , Estudos Transversais , Feminino , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade
10.
Sichuan Da Xue Xue Bao Yi Xue Ban ; 52(1): 87-91, 2021 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-33474895

RESUMO

OBJECTIVE: To understand the level of job satisfaction and work engagement of physicians in public hospitals, to analyze the interaction between job satisfaction and work engagement, and to discuss how each dimension of job satisfaction affects work engagement so as to provide information and reference for improving the level of work engagement of physicians in public hospitals. METHODS: Covering 6 public hospitals in Sichuan (3 tertiary-level hospitals and 3 secondary-level hospitals), 638 questionnaires were obtained from physicians through convenient sampling for data description and analysis. Pearson correlation method was used to analyze the correlation between job satisfaction and work engagement, and multiple linear stepwise regression method was used to analyze work engagement and the influencing factors of each dimension. RESULTS: With regard to job satisfaction, physicians showed high levels of satisfaction in personal safety (3.77±0.87), leadership identification and support (3.59±0.77), and job pressure (3.51±0.81). The mean points of work engagement and each dimension were as follows: total mean points of work engagement (4.02±0.99), dedication (4.21±1.13), absorption (4.19±1.08) and vigor (3.63±1.04). In job satisfaction, salary and benefits, work environment, social recognition, organizational management, leadership identification and support are positively correlated to work engagement and all dimensions. In job satisfaction, 5 dimensions, including social recognition, leadership recognition and support, work achievement, personal safety and organizational management, had a significant influence on work engagement and all dimensions. CONCLUSION: Emphasis on the high-level needs for recognition and self-actualization of doctors, doctor-patient communication, and personal development of doctors may improve doctors' job satisfaction and work engagement.


Assuntos
Satisfação no Emprego , Médicos , Estudos Transversais , Hospitais Públicos , Humanos , Inquéritos e Questionários , Engajamento no Trabalho
11.
Angew Chem Int Ed Engl ; 60(4): 2160-2164, 2021 01 25.
Artigo em Inglês | MEDLINE | ID: mdl-33052624

RESUMO

In contrast to the wealth of asymmetric transformations for generating central chirality from alkyl radicals, the enantiocontrol over the allenyl radicals for forging axial chirality represents an uncharted domain. The challenge arises from the unique elongated linear configuration of the allenyl radicals that necessitates the stereo-differentiation of remote motifs away from the radical reaction site. We herein describe a copper-catalyzed asymmetric radical 1,4-carboalkynylation of 1,3-enynes via the coupling of allenyl radicals with terminal alkynes, providing diverse synthetically challenging tetrasubstituted chiral allenes. A chiral N,N,P-ligand is crucial for both the reaction initiation and the enantiocontrol over the highly reactive allenyl radicals. The reaction features a broad substrate scope, covering a variety of (hetero)aryl and alkyl alkynes and 1,3-enynes as well as radical precursors with excellent functional group tolerance.

12.
J Am Chem Soc ; 142(46): 19652-19659, 2020 11 18.
Artigo em Inglês | MEDLINE | ID: mdl-33146993

RESUMO

A copper-catalyzed enantioconvergent Suzuki-Miyaura C(sp3)-C(sp2) cross-coupling of various racemic alkyl halides with organoboronate esters has been established in high enantioselectivity. Critical to the success is the use of a chiral cinchona alkaloid-derived N,N,P-ligand for not only enhancing the reducing capability of copper catalyst to favor a stereoablative radical pathway over a stereospecific SN2-type process but also providing an ideal chiral environment to achieve the challenging enantiocontrol over the highly reactive radical species. The reaction has a broad scope with respect to both coupling partners, covering aryl- and heteroarylboronate esters, as well as benzyl-, heterobenzyl-, and propargyl bromides and chlorides with good functional group compatibility. Thus, it provides expedient access toward a range of useful enantioenriched skeletons featuring chiral tertiary benzylic stereocenters.

13.
Neural Regen Res ; 15(12): 2262-2269, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32594047

RESUMO

The exact mechanisms associated with secondary brain damage following traumatic brain injury (TBI) remain unclear; therefore, identifying the critical molecular mechanisms involved in TBI is essential. The mRNA expression microarray GSE2871 was downloaded from the Gene Expression Omnibus (GEO) repository. GSE2871 comprises a total of 31 cerebral cortex samples, including two post-TBI time points. The microarray features eight control and seven TBI samples, from 4 hours post-TBI, and eight control and eight TBI samples from 24 hours post-TBI. In this bioinformatics-based study, 109 and 66 differentially expressed genes (DEGs) were identified in a Sprague-Dawley (SD) rat TBI model, 4 and 24 hours post-TBI, respectively. Functional enrichment analysis showed that the identified DEGs were significantly enriched in several terms, such as positive regulation of nuclear factor-κB transcription factor activity, mitogen-activated protein kinase signaling pathway, negative regulation of apoptotic process, and tumor necrosis factor signaling pathway. Moreover, the hub genes with high connectivity degrees were primarily related to inflammatory mediators. To validate the top five hub genes, a rat model of TBI was established using the weight-drop method, and real-time quantitative polymerase chain reaction analysis of the cerebral cortex was performed. The results showed that compared with control rats, Tnf-α, c-Myc, Spp1, Cxcl10, Ptprc, Egf, Mmp9, and Lcn2 were upregulated, and Fn1 was downregulated in TBI rats. Among these hub genes, Fn1, c-Myc, and Ptprc may represent novel biomarkers or therapeutic targets for TBI. These identified pathways and key genes may provide insights into the molecular mechanisms of TBI and provide potential treatment targets for patients with TBI. This study was approved by the Experimental Animal Ethics Committee of the First Affiliated Hospital of Nanchang University, China (approval No. 003) in January 2016.

14.
Angew Chem Int Ed Engl ; 59(39): 16926-16932, 2020 09 21.
Artigo em Inglês | MEDLINE | ID: mdl-32584490

RESUMO

We describe a photoinduced copper-catalyzed asymmetric radical decarboxylative alkynylation of bench-stable N-hydroxyphthalimide(NHP)-type esters of racemic alkyl carboxylic acids with terminal alkynes, which provides a flexible platform for the construction of chiral C(sp3 )-C(sp) bonds. Critical to the success of this process are not only the use of the copper catalyst as a dual photo- and cross-coupling catalyst but also tuning of the NHP-type esters to inhibit the facile homodimerization of the alkyl radical and terminal alkyne, respectively. Owing to the use of stable and easily available NHP-type esters, the reaction features a broader substrate scope compared with reactions using the alkyl halide counterparts, covering (hetero)benzyl-, allyl-, and aminocarbonyl-substituted carboxylic acid derivatives, and (hetero)aryl and alkyl as well as silyl alkynes, thus providing a vital complementary approach to the previously reported method.

15.
J Am Chem Soc ; 142(20): 9501-9509, 2020 05 20.
Artigo em Inglês | MEDLINE | ID: mdl-32338510

RESUMO

A copper-catalyzed intermolecular three-component asymmetric radical 1,2-carboalkynylation of alkenes has been developed, providing straightforward access to diverse chiral alkynes from readily available alkyl halides and terminal alkynes. The utilization of a cinchona alkaloid-derived multidentate N,N,P-ligand is crucial for the efficient radical generation from mildly oxidative precursors by copper and the effective inhibition of the undesired Glaser coupling side reaction. The substrate scope is broad, covering (hetero)aryl-, alkynyl-, and aminocarbonyl-substituted alkenes, (hetero)aryl and alkyl as well as silyl alkynes, and tertiary to primary alkyl radical precursors with excellent functional group compatibility. Facile transformations of the obtained chiral alkynes have also been demonstrated, highlighting the excellent complementarity of this protocol to direct 1,2-dicarbofunctionalization reactions with C(sp2/sp3)-based reagents.

16.
Medicine (Baltimore) ; 99(1): e18596, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31895808

RESUMO

Diabetic kidney disease (DKD) is a leading cause of end-stage renal disease. Because the molecular mechanisms of DKD are not fully understood, exploration of hub genes and the mechanisms underlying this disease are essential for elucidating the pathogenesis and progression of DKD. Accordingly, in this study, we performed an analysis of gene expression in DKD. The differentially expressed genes (DEGs) included 39 upregulated genes and 113 downregulated genes in the GSE30528 dataset and 127 upregulated genes and 18 downregulated genes in the GSE30529 dataset. Additionally, functional analyses were performed to determine the roles of DEGs using glomeruli samples from patients with DKD and healthy controls from the GSE30528 dataset and using tubule samples from patients with DKD and healthy controls from the GSE30529 dataset. These DEGs were enriched in pathways such as the Wnt signaling pathway, metabolic pathways, and the mammalian target of rapamycin signaling pathway in the GSE30528 dataset and the longevity regulating pathway and Ras signaling pathway in the GSE30529 dataset. Moreover, a protein-protein interaction network was constructed using the identified DEGs, and hub gene analysis was performed. Furthermore, correlation analyses between key genes and pathological characteristics of DKD indicated that CCR4, NTNG1, HGF and ISL1 are related to DKD, and NTNG1 and HGF may server as diagnostic biomarkers in DKD using the receiver-operator characteristic (ROC) curve. Collectively, our findings established 2 reliable biomarkers for DKD.


Assuntos
Nefropatias Diabéticas/metabolismo , Fator de Crescimento de Hepatócito/metabolismo , Rim/metabolismo , Netrinas/metabolismo , Biomarcadores/metabolismo , Estudos de Casos e Controles , Proteínas Ligadas por GPI/metabolismo , Humanos
17.
Nat Commun ; 10(1): 5689, 2019 12 12.
Artigo em Inglês | MEDLINE | ID: mdl-31831750

RESUMO

Transition metal-catalyzed enantioselective Sonogashira-type oxidative C(sp3)-C(sp) coupling of unactivated C(sp3)-H bonds with terminal alkynes has remained a prominent challenge. The difficulties mainly stem from the regiocontrol in unactivated C(sp3)-H bond functionalization and the inhibition of readily occurring Glaser homocoupling of terminal alkynes. Here, we report a copper/chiral cinchona alkaloid-based N,N,P-ligand catalyst for asymmetric oxidative cross-coupling of unactivated C(sp3)-H bonds with terminal alkynes in a highly regio-, chemo-, and enantioselective manner. The use of N-fluoroamide as a mild oxidant is essential to site-selectively generate alkyl radical species while efficiently avoiding Glaser homocoupling. This reaction accommodates a range of (hetero)aryl and alkyl alkynes; (hetero)benzylic and propargylic C(sp3)-H bonds are all applicable. This process allows expedient access to chiral alkynyl amides/aldehydes. More importantly, it also provides a versatile tool for the construction of chiral C(sp3)-C(sp), C(sp3)-C(sp2), and C(sp3)-C(sp3) bonds when allied with follow-up transformations.

18.
Nat Chem ; 11(12): 1158-1166, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31636393

RESUMO

Continued development of the Sonogashira coupling has made it a well established and versatile reaction for the straightforward formation of C-C bonds, forging the carbon skeletons of broadly useful functionalized molecules. However, asymmetric Sonogashira coupling, particularly for C(sp3)-C(sp) bond formation, has remained largely unexplored. Here we demonstrate a general stereoconvergent Sonogashira C(sp3)-C(sp) cross-coupling of a broad range of terminal alkynes and racemic alkyl halides (>120 examples) that are enabled by copper-catalysed radical-involved alkynylation using a chiral cinchona alkaloid-based P,N-ligand. Industrially relevant acetylene and propyne are successfully incorporated, laying the foundation for scalable and economic synthetic applications. The potential utility of this method is demonstrated in the facile synthesis of stereoenriched bioactive or functional molecule derivatives, medicinal compounds and natural products that feature a range of chiral C(sp3)-C(sp/sp2/sp3) bonds. This work emphasizes the importance of radical species for developing enantioconvergent transformations.

19.
Angew Chem Int Ed Engl ; 57(26): 7668-7672, 2018 06 25.
Artigo em Inglês | MEDLINE | ID: mdl-29727502

RESUMO

A copper-catalyzed asymmetric radical oxytrifluoromethylation of alkenyl oxime and Togni's reagent has been successfully developed, thereby providing straightforward access to CF3 -containing isoxazolines bearing α-tertiary stereocenters with excellent yield and enantioselectivity. The key to success is the rational design of cinchona-alkaloid-based sulfonamides as neutral/anionic hybrid ligands to effectively control the stereochemistry in copper-catalyzed reactions involving free alkyl radical species. The utility of this method is illustrated by efficient transformation of the products into useful chiral CF3 -containing 1,3-aminoalcohols.

20.
Neural Regen Res ; 13(2): 244-251, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29557373

RESUMO

Orexins, produced in the lateral hypothalamus, are important neuropeptides that participate in the sleep/wake cycle, and their expression coincides with the projection area of the vagus nerve in the brain. Vagus nerve stimulation has been shown to decrease the amounts of daytime sleep and rapid eye movement in epilepsy patients with traumatic brain injury. In the present study, we investigated whether vagus nerve stimulation promotes wakefulness and affects orexin expression. A rat model of traumatic brain injury was established using the free fall drop method. In the stimulated group, rats with traumatic brain injury received vagus nerve stimulation (frequency, 30 Hz; current, 1.0 mA; pulse width, 0.5 ms; total stimulation time, 15 minutes). In the antagonist group, rats with traumatic brain injury were intracerebroventricularly injected with the orexin receptor type 1 (OX1R) antagonist SB334867 and received vagus nerve stimulation. Changes in consciousness were observed after stimulation in each group. Enzyme-linked immunosorbent assay, western blot assay and immunohistochemistry were used to assess the levels of orexin-A and OX1R expression in the prefrontal cortex. In the stimulated group, consciousness was substantially improved, orexin-A protein expression gradually increased within 24 hours after injury and OX1R expression reached a peak at 12 hours, compared with rats subjected to traumatic brain injury only. In the antagonist group, the wake-promoting effect of vagus nerve stimulation was diminished, and orexin-A and OX1R expression were decreased, compared with that of the stimulated group. Taken together, our findings suggest that vagus nerve stimulation promotes the recovery of consciousness in comatose rats after traumatic brain injury. The upregulation of orexin-A and OX1R expression in the prefrontal cortex might be involved in the wake-promoting effects of vagus nerve stimulation.

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