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1.
J Org Chem ; 86(22): 16121-16127, 2021 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-33599123

RESUMO

The study reported an electrochemically mediated method for the preparation of 2,1-benzoxazoles from o-nitrophenylacetylenes. Different from the traditional electrochemical reduction of nitro to nitroso, the nitro group directly underwent a cyclization reaction with the alkyne activated by selenium cation generated by the anodic oxidation of diphenyl diselenide and finally produced the desired products.

2.
Org Biomol Chem ; 18(28): 5315-5333, 2020 07 22.
Artigo em Inglês | MEDLINE | ID: mdl-32638806

RESUMO

In general, halogenide anions are anodically oxidized into active species, which can be elemental halogen, halogen cations, or halogen radicals. These species subsequently react with substrates, such as olefins, ketones, or amines, to generate halogenated products. We review the mechanisms of these reactions.

3.
Org Biomol Chem ; 18(26): 4936-4940, 2020 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-32583841

RESUMO

A convenient and efficient palladium-catalyzed approach has been developed for the synthesis of 5-amino-1,2,4-oxadiazoles from amidoximes and isocyanides. Various 5-amino-1,2,4-oxadiazoles were obtained in moderate to high yields under mild conditions. The key to the success of this strategy involves new C-N bond and C-O bond formation via palladium-catalyzed isocyanide insertion.

4.
Org Biomol Chem ; 18(20): 3832-3837, 2020 05 27.
Artigo em Inglês | MEDLINE | ID: mdl-32396933

RESUMO

An environmentally benign electrochemically enabled site-selective functionalization of indole or aniline derivatives with hexafluoroisopropanol in the presence of tetrabutyl ammonium hexafluorophosphate as the redox catalyst and electrolyte was demonstrated in this work. Under mild electro-oxidation conditions, a series of hexafluoroisopropoxy indole and aniline derivatives with pharmacological activity were obtained. This conversion does not need transition metals and oxidants, and has good functional group tolerance. The in vitro cytotoxicity of all compounds was evaluated by the MTT assay against four human cancer cell lines. The results revealed that hexafluoroisopropoxy indoles have good antitumor activity and compound 2i increased the intracellular levels of ROS and inhibited apoptosis in HeLa cells.

6.
Nat Prod Res ; 34(18): 2689-2693, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30856009

RESUMO

In this study, antitumor activity and composition analysis of the core of Camellia osmantha fruit were investigated. The cores were extracted by 80% ethanol to obtain the crude extract (TF), which was successively distributed by different concentrations of ethanol with MCI resin to obtain three different parts (Frs 1 to 3). Cytotoxicity activities showed that TF, Fr-2, and Fr-3 exhibited good inhibition against T-24 with IC50 values of 6.7 ± 1.3, 6.9 ± 0.9, and 6.7 ± 1.7 µg/mL, respectively. Fr-3 has a strong inhibitory activity on T-24 cells, mainly due to effectively increasing the release of intracellular calcium ions and reactive oxygen species. In addition, Fr-3 can inhibit T-24 cells migration and invasion. Further composition analysis on Fr-3 was detected by LC-Q-TOFMS implying the main components to be ellagic acid and its derivatives.


Assuntos
Antineoplásicos Fitogênicos/isolamento & purificação , Camellia/química , Frutas/química , Neoplasias da Bexiga Urinária/tratamento farmacológico , Antineoplásicos Fitogênicos/farmacologia , Cálcio/metabolismo , Camellia/anatomia & histologia , Linhagem Celular Tumoral , Ácido Elágico/análise , Humanos , Invasividade Neoplásica/prevenção & controle , Extratos Vegetais/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Neoplasias da Bexiga Urinária/patologia
7.
Org Lett ; 22(2): 724-728, 2020 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-31886680

RESUMO

C-centered radical cyclization under electrochemical conditions is a feasible strategy for constructing cyclic structures. Reported herein is the electrochemical synthesis of highly functionalized 1-naphthols using alkynes and 1,3-dicarbonyl compounds by (4 + 2) annulation of C-centered radical. Electrolysis was conducted with Cp2Fe as redox catalyst, thereby eliminating the use of oxidants and transition-metal catalysts. The synthesized 1-naphthol compounds showed good antitumor activity in vitro, and further studies indicated that compound 3bl induced tumor cell apoptosis.

8.
Org Lett ; 21(24): 9841-9845, 2019 12 20.
Artigo em Inglês | MEDLINE | ID: mdl-31829020

RESUMO

We developed an electrochemically enabled dehydrogenative annulation reaction of amides and alkynes for the synthesis of antitumor polycyclic isoquinolinones through a double C-H activation route. No external oxidant is required in this reaction, and electricity is used for Ru catalyst circulation. The most remarkable feature of this reaction is the effective improvement of product regioselectivity under mild electrolytic conditions in comparison with previously set strong oxidant conditions.

9.
Chem Commun (Camb) ; 55(73): 10924-10927, 2019 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-31441488

RESUMO

Two positively-charged naphthotubes with imidazolium as the bridges were synthesized and their structures have been characterized by 1H NMR, MS, and X-ray crystallography. These naphthotubes are capable of binding aromatic hydrocarbons. Surprisingly, the binding affinities are much higher in CD3CN than in CD2Cl2. The solvent effect on the ion pairing interactions and competitive binding of CD2Cl2 was invoked to explain this unusual phenomenon.

10.
Fitoterapia ; 138: 104345, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31470063

RESUMO

The present study reports the phytochemical investigation of n-butanol-soluble extracts of Glechoma longituba. Five new oleanane-type triterpenoid saponins with an 11α, 12α-epoxy unit, named glechomanosides A - E, were isolated from the n-butanol soluble fraction of G. longituba. Their chemical structures were established using HRESIMS, IR, 1D NMR, and 2D NMR techniques. The compounds were all evaluated for their antithrombus activities by monitoring thrombin time (TT), prothrombin time (PT), activated partial thromboplastin time (APTT), and antiplatelet aggregation assays. These results suggest that G. longituba might be a candidate plant source of an interesting antithrombotic activity.


Assuntos
Plaquetas/efeitos dos fármacos , Lamiaceae/química , Ácido Oleanólico/análogos & derivados , Saponinas/farmacologia , Animais , China , Feminino , Masculino , Camundongos , Estrutura Molecular , Ácido Oleanólico/isolamento & purificação , Ácido Oleanólico/farmacologia , Tempo de Tromboplastina Parcial , Compostos Fitoquímicos/isolamento & purificação , Compostos Fitoquímicos/farmacologia , Agregação Plaquetária , Tempo de Protrombina , Coelhos , Saponinas/isolamento & purificação , Tempo de Trombina
11.
Org Lett ; 21(13): 4929-4932, 2019 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-31082239

RESUMO

An efficient strategy for the synthesis of benzofuro[2,3- b]pyrazines was developed. These tricyclic scaffolds were formed through a multistep cascade sequence, which includes double insertion of isonitriles and chemoselective bicyclization. In this reaction, a nanopalladium was used as a recyclable catalyst. Product 3w exhibited excellent anticancer activity toward T-24 (IC50 = 12.5 ± 0.9 µM) and HeLa (IC50 = 14.7 ± 1.6 µM) cells. We also explored the action mechanism of 3w on T-24 cells.


Assuntos
Nitrilas/química , Nitrilas/síntese química , Fenóis/química , Fenóis/síntese química , Pirazinas/química , Pirazinas/síntese química , Antineoplásicos/síntese química , Antineoplásicos/química , Catálise , Técnicas de Química Sintética , Porosidade
12.
Angew Chem Int Ed Engl ; 58(8): 2448-2453, 2019 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-30600893

RESUMO

Heterogeneous, metal, single-site catalysts often exhibit higher catalytic performance than other catalysts because of their maximized atom efficiency of 100 %. Reported herein is a precoordination/solvothermal polymerization strategy to fabricate a stable mononuclear Pd-metalized porous organic polymer catalyst (Pd@POP). Pd@POP was easy to use in regioselective organic reactions because the internal structure of this Pd@POP can be easily modified. The catalyst was used to solve the intractable regioselectivity problems of Heck reactions. Pd@POP-9 can efficiently activate the ends of olefins, thereby leading to high selectivity for substitution at the external position. To understand the reason underlying the high selectivity and activity of the catalyst, the systemic characterization of Pd@POP-9 and density-functional theory calculations were conducted. This Heck reaction is the first to be catalyzed by a recyclable mononuclear metal catalyst with unprecedented catalytic activity and regioselectivity.

13.
Hum Immunol ; 80(3): 195-203, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30576702

RESUMO

T cell receptors (TCRs) are a class of T cell surface molecules that recognize the antigen-derived peptides presented by the major histocompatibility complex (MHC) and are able to trigger a series of immune responses. TCRs are important members of the adaptive immune system that arose in the jawed fish 500 million years ago. T cell receptor beta variable (TRBV) genes have been widely used to characterize TCR repertoires. Studying the evolution of TRBV may help us to better understand the adaptive immune system. To investigate TRBV evolution and its impacts on the usages of TRBV genes in human populations, we compared the TRBV genes and their homologous sequences among humans, mouse, rhesus and chimpanzee, analyzed the single-nucleotide polymorphisms (SNPs) located at TRBV loci, and sequenced TCR repertoires in the peripheral blood of 97 healthy donors. We found that functional TRBVs are more evolutionarily conserved but possess more SNPs in human populations than do nonfunctional (pseudo) TRBVs. Based on the conservation levels in the four species, we classified the functional TRBVs into 2 groups: old (conserved between mouse and humans) and new (conserved only in primates). The new TRBVs evolve faster and possess more SNPs than the old TRBVs. The variations in TRBV genes frequencies in the peripheral blood of healthy donors are negatively correlated with SNP density. These observations suggest that TRBV usages may be influenced by TCR-MHC co-evolution.


Assuntos
Evolução Molecular , Variação Genética , Genética Populacional , Polimorfismo de Nucleotídeo Único , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Animais , Voluntários Saudáveis , Humanos , Camundongos , Filogenia , Primatas , Linfócitos T/metabolismo
14.
Chem Asian J ; 14(1): 149-154, 2019 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-30203915

RESUMO

A Co(acac)2 /POL-Xantphos@10PPh3 -catalyzed hydrosilylation of unsymmetrical internal alkynes with Ph2 SiH2 has been developed for the synthesis of highly selective syn-α-vinylsilane products. Furthermore, terminal alkynes were also used and gave the products with excellent regioselectivity and a wide functional group tolerance. Because this porous organic polymer combines the selectivity and activity merits of Xantphos with the stability advantage derived from the high concentration of PPh3 , the Co(acac)2 /POL-Xantphos@10PPh3 can be recycled multiple times without loss of activity and selectivity. This heterogeneous catalyst is expected to find promising applications in industrial synthesis.

15.
Front Immunol ; 9: 2729, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30524447

RESUMO

There is increasing evidence that deep sequencing-based T cell repertoire can sever as a biomarker of immune response in cancer patients; however, the characteristics of T cell repertoire including diversity and similarity, as well as its prognostic significance in patients with cervical cancer (CC) remain unknown. In this study, we applied a high throughput T cell receptor (TCR) sequencing method to characterize the T cell repertoires of peripheral blood samples from 25 CC patients, 30 cervical intraepithelial neoplasia (CIN) patients and 20 healthy women for understanding the immune alterations during the cervix carcinogenesis. In addition, we also explored the signatures of TCR repertoires in the cervical tumor tissues and paired sentinel lymph nodes from 16 CC patients and their potential value in predicting the prognosis of patients. Our results revealed that the diversity of circulating TCR repertoire gradually decreased during the cervix carcinogenesis and progression, but the circulating TCR repertoires in CC patients were more similar to CIN patients than healthy women. Interestingly, several clonotypes uniquely detected in CC patients tended to share similar CDR3 motifs, which differed from those observed in CIN patients. In addition, the TCR repertoire diversity in sentinel lymphatic nodes from CC patients was higher than in tumor tissues. More importantly, less clonotypes in TCR repertoire of sentinel lymphatic node was associated with the poor prognosis of the patients. Overall, our findings suggested that TCR repertoire might be a potential indicator of immune monitoring and a biomarker for predicting the prognosis of CC patients. Although functional studies of T cell populations are clearly required, this study have expanded our understanding of T cell immunity during the development of CC and provided an experimental basis for further studies on its pathogenesis and immunotherapy.


Assuntos
Biomarcadores Tumorais , Regiões Determinantes de Complementaridade , Receptores de Antígenos de Linfócitos T , Neoplasias do Colo do Útero , Adulto , Biomarcadores Tumorais/sangue , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/imunologia , Regiões Determinantes de Complementaridade/sangue , Regiões Determinantes de Complementaridade/genética , Regiões Determinantes de Complementaridade/imunologia , Feminino , Humanos , Linfonodos/imunologia , Linfonodos/metabolismo , Linfonodos/patologia , Pessoa de Meia-Idade , Prognóstico , Receptores de Antígenos de Linfócitos T/sangue , Receptores de Antígenos de Linfócitos T/genética , Receptores de Antígenos de Linfócitos T/imunologia , Neoplasias do Colo do Útero/sangue , Neoplasias do Colo do Útero/diagnóstico , Neoplasias do Colo do Útero/genética , Neoplasias do Colo do Útero/imunologia
16.
Org Lett ; 20(24): 7748-7752, 2018 12 21.
Artigo em Inglês | MEDLINE | ID: mdl-30495967

RESUMO

A porous organic polymer (POL-Xantphos) was synthesized and employed as a heterogeneous ligand for selective hydrosilylation of alkynes. It exhibits high selectivity and catalytic efficiency toward a broad range of alkynes. Owing to the confinement effect of the micropore structure, POL-Xantphos was far superior to the monomeric Xantphos ligands in controlling the selectivity. By performing hydrosilylation in a flow reactor system, separation and regeneration of the Ni/POL-Xantphos catalyst are easily achieved without any loss in selectivity or activity.

17.
Org Lett ; 20(22): 7117-7120, 2018 11 16.
Artigo em Inglês | MEDLINE | ID: mdl-30362763

RESUMO

Palladium-catalyzed three-component reactions between terminal alkynes, isonitriles, and sodium carboxylates have been developed. This novel and operationally simple methodology provides an alternative for the synthesis of N-acyl propiolamide derivatives under mild conditions using isonitriles as the amine source and sodium carboxylates as the oxygen and acyl source.

18.
Cancer Immunol Immunother ; 67(11): 1743-1752, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30167861

RESUMO

PURPOSE: CD8+ T cells are primarily cytotoxic cells that provide immunological protection against malignant cells. Considerable evidence suggests that the T-cell repertoire is closely associated with the host immune response and the development of cancer. In this study, we explored the characteristics of the circulating CD8+ T-cell repertoire and their potential value in predicting the clinical response of breast cancer patients to chemotherapy. EXPERIMENTAL DESIGN: We applied a high-throughput TCR ß-chain sequencing method to characterize the CD8+ T-cell repertoire of the peripheral blood from 26 breast cancer patients. In addition, changes in the circulating CD8+ T-cell repertoire during chemotherapy were analyzed. RESULTS: We found that the HEC ratios of the CD8+ T-cell repertoires from HER2+ breast cancer patients were significantly higher than those of HER2- patients, suggesting that the HER2 protein is released into circulation where it is targeted by CD8+ T cells. Several Vß and CDR3 motifs preferentially used in HER2+ patients were identified. Besides, we found that the circulating CD8+ T-cell repertoires evolved during chemotherapy and correlated with patient clinical responses to chemotherapy. Increased CD8+ T-cell repertoire heterogeneity during chemotherapy was associated with a better clinical response. CONCLUSIONS: Although functional studies of clonally expanded CD8+ T-cell populations are clearly required, our results suggest that the circulating CD8+ T-cell repertoire reflects the characteristics of the tumor-associated biomolecules released into the blood and correlates with the clinical responses of the patients to chemotherapy which might assist in making treatment decisions.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias da Mama/imunologia , Linfócitos T CD8-Positivos/imunologia , Regiões Determinantes de Complementaridade/metabolismo , Receptor ErbB-2/metabolismo , Receptores de Antígenos de Linfócitos T alfa-beta/metabolismo , Adulto , Idoso , Sequência de Aminoácidos , Biomarcadores Tumorais/análise , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Feminino , Seguimentos , Humanos , Pessoa de Meia-Idade , Prognóstico , Homologia de Sequência
19.
Org Lett ; 20(16): 4819-4823, 2018 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-30088774

RESUMO

An unexpected cyclization of thioamides with p-quinone methides promoted by acridinium salt under the irradiation of visible light furnished 1,2,4-dithiazoles in moderate to good yields. In addition, the reaction of the obtained 1,2,4-dithiazoles with isocyanides offered a new entry for the synthesis of thiazol-5(4 H)-imines in moderate yields.

20.
Cancer Immunol Immunother ; 67(11): 1719-1730, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30155576

RESUMO

The T-cell immune responses in nasopharyngeal carcinoma patients have been extensively investigated recently for designing adoptive immunotherapy or immune checkpoint blockade therapy. However, the distribution characteristics of T cells associated with NPC pathogenesis are largely unknown. We performed deep sequencing for TCR repertoire profiling on matched tumor/adjacent normal tissue from 15 NPC patients and peripheral blood from 39 NPC patients, 39 patients with other nasopharyngeal diseases, and 33 healthy controls. We found that a lower diversity of TCR repertoire in tumors than paired tissues or a low similarity between the paired tissues was associated with a poor prognosis in NPC. A more diverse TCR repertoire was identified in the peripheral blood of NPC patients relative to the controls; this was related to a significant decrease in the proportion of high-frequency TCR clones in NPC. Higher diversity in peripheral blood of NPC patients was associated with a worse prognosis. Due to the peculiarity of the Vß gene usage patterns in the peripheral blood of NPC patients, 15 Vß genes were selected to distinguish NPC patients from controls by the least absolute shrinkage and selection operator analysis. We identified 11 clonotypes shared by tumors and peripheral blood samples from different NPC patients, defined as "NPC-associated" that might have value in adoptive immunotherapy. In conclusion, we here report the systematic and overall characteristics of the TCR repertoire in tumors, adjacent normal tissues, and peripheral blood of NPC patients. The data obtained may be relevant to future clinical studies in the setting of immunotherapy for NPC patients.


Assuntos
Carcinoma/imunologia , Carcinoma/mortalidade , Neoplasias Nasofaríngeas/imunologia , Neoplasias Nasofaríngeas/mortalidade , Linfócitos T/imunologia , Adolescente , Adulto , Idoso , Carcinoma/terapia , Estudos de Casos e Controles , Terapia Combinada , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Carcinoma Nasofaríngeo , Neoplasias Nasofaríngeas/terapia , Prognóstico , Taxa de Sobrevida , Adulto Jovem
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