Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 8 de 8
Filtrar
Más filtros












Base de datos
Intervalo de año de publicación
1.
J Am Chem Soc ; 146(4): 2769-2778, 2024 Jan 31.
Artículo en Inglés | MEDLINE | ID: mdl-38240486

RESUMEN

Emerging techniques are revolutionizing the realm of chemical synthesis by introducing new avenues for C-H bond functionalization, which have been exploited for the synthesis of pharmaceuticals, natural compounds, and functional materials. Allylic C-H bond oxidation of alkenes serves as possibly the most employed C-H bond functionalization reaction. However, sustainable and selective approaches remain scarce, and the majority of the existing conditions still hinge on hazardous oxidants or costly metal catalysts. In this context, we introduce a heterogeneous iron catalyst that addresses the above-mentioned concerns by showcasing the aerobic oxidation of steroids, terpenes, and simple olefins to the corresponding enone products. This novel method provides a powerful tool for the arsenal of allylic C-H bond oxidation while minimizing the environmental concerns.

2.
Mol Biotechnol ; 64(11): 1234-1243, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-35532870

RESUMEN

MiR-99a-5p participates in processes and pathogenesis of varying diseases. However, the molecular mechanism of miR-99a-5p in human cervical squamous cell carcinoma (CSCC) remains unclear. Here, we found that miR-99a-5p was lowly expressed in CSCC cells and negatively associated with overall survival. In addition, cellular experiments including CCK8, wound healing, Transwell and flow cytometry assays disclosed that transfection of miR-99a-5p mimic could suppress the cell activity, cell migratory, and invasive abilities, and promote cell apoptosis, thus inhibiting the tumor progression of CSCC cells. Luciferase reporter gene assay indicated that miR-99a-5p targeted 3'-UTR of CDC25A. Also, enforced CDC25A level rescued the impact of miR-99a-5p on CSCC progression. Silencing CDC25A could restrain the mRNA and protein levels of IL-6 in CSCC. CDC25A overexpression or IL-6 treatment could attenuate inhibiting impact of miR-99a-5p overexpression on epithelial-mesenchymal transition (EMT). These findings suggested that miR-99a-5p may play an anti-tumor role in tumor metastasis by targeting CDC25A/IL6 to hamper EMT process, which revealed a novel molecular mechanism in CSCC.


Asunto(s)
Carcinoma de Células Escamosas , Transición Epitelial-Mesenquimal , MicroARNs , Neoplasias del Cuello Uterino , Femenino , Humanos , Regiones no Traducidas 3' , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/metabolismo , Fosfatasas cdc25/genética , Fosfatasas cdc25/metabolismo , Línea Celular Tumoral , Movimiento Celular/genética , Proliferación Celular/genética , Transición Epitelial-Mesenquimal/genética , Regulación Neoplásica de la Expresión Génica , Interleucina-6/genética , Interleucina-6/metabolismo , MicroARNs/genética , MicroARNs/metabolismo , Neoplasias del Cuello Uterino/genética , Neoplasias del Cuello Uterino/metabolismo
3.
Angew Chem Int Ed Engl ; 61(19): e202114817, 2022 May 02.
Artículo en Inglés | MEDLINE | ID: mdl-35014760

RESUMEN

The cyclization reactions of propargylic alcohols and propargylic amines with CO2 are important in industrial applications, but it was a great challenge that non-noble-metal catalysts catalyzed both reactions under mild conditions. Herein, the catalyst Cu2 O@ZIF-8 was prepared by encapsulating Cu2 O nanoparticles into robust ZIF-8, and it can effectively catalyze the cyclization of both propargylic alcohols and propargylic amines with CO2 into valuable α-alkylidene cyclic carbonates and oxazolidinones with turnover numbers (TONs) of 12.1 and 19.6, which can be recycled at least five times. The mechanisms were further uncovered by NMR, FTIR, 13 C isotope-labeling experiments and DFT calculations, in which Cu2 O and DBU can synergistically activate the C≡C bond and the hydroxy/amino group of substrates. Importantly, it is the first example of a noble-metal-free catalyst that can catalyze both propargylic alcohols and propargylic amines with CO2 simultaneously.

4.
Inorg Chem ; 60(17): 13425-13433, 2021 Sep 06.
Artículo en Inglés | MEDLINE | ID: mdl-34369141

RESUMEN

The coupling reaction of propargylic amines and carbon dioxide (CO2) to synthesize 2-oxazolidinones is an important reaction in industrial production, and yet harsh reaction conditions and noble-metal catalysts are often required to achieve high product yields. Herein, one novel noble-metal-free three-dimensional framework, [Mg3Cu2I2(IN)4(HCOO)2(DEF)4]n (1), assembled by magnesium and copper clusters was synthesized and applied to this reaction. Compound 1 displays excellent solvent stability. Importantly, 1, acting as heterogeneous catalyst, can highly catalyze the cyclization of propargylic amines with CO2 under atmospheric pressure at room temperature, which can be recycled at least five times without an obvious decrease of the catalytic activity. NMR spectroscopy, coupled with 13C-isotope- and deuterium-labeling experiments, clearly clarifies the mechanism of this catalytic system: CO2 was successfully captured and converted to the product of 2-oxazolidinones, the C≡C bond of propargylic amines can be effectively activated by 1, and proton transfer was involved in the reaction process. Density functional theory calculations are further conducted to uncover the reaction path and the crucial role of compound 1 during the reaction.

5.
Inorg Chem ; 60(12): 9122-9131, 2021 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-34061517

RESUMEN

A new porous copper-organic framework assembled from 12-nuclear [Cu12] nanocages {[Cu2(L4-)(H2O)2]·4DMA·2H2O}n (1) (H4L = 5,5'-(butane-1,4-diyl)-bis(oxy)-diisophthalic acid) was successfully prepared and structurally characterized. Compound 1 feathering of a 3D framework with two types of 1D nanotubular channels and a large specific surface area can effectively enrich various harmful dyes. Additionally, due to the carbon dioxide (CO2) interactions with open Cu(II) sites and the electron-rich ether oxygen atoms of ligand in 1, it exhibits a highly selective CO2 uptake. Interestingly, 1 can effectively catalyze the cycloaddition reaction of CO2 with various epoxides under mild conditions, which is ascribed to the Lewis acid Cu(II) sites in the framework of 1. Importantly, 1 acting as a heterogeneous catalyst can be recycled at least 10 times without an obvious loss of catalytic activity, and the CO2 cycloaddition mechanism was further uncovered by density functional theory (DFT) calculations. This study can greatly enrich the MOF catalysts system of CO2 conversion and also provide a valuable guidance for the design of efficient MOFs catalysts.

6.
Prenat Diagn ; 41(6): 681-689, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33411373

RESUMEN

OBJECTIVES: To study the feasibility of using unbalanced embryos as a reference in distinguishing euploid carrier and noncarrier embryos by single nucleotide polymorphism (SNP) array-based preimplantation genetic testing (PGT) for reciprocal translocations. METHODS: After comprehensive chromosome screening (CCS), euploid embryos were identified as normal or carriers using a family member as a reference. Next, unbalanced embryos were used as a reference, and the results were compared with the previous ones. Karyotypes of transferred embryos were validated by prenatal diagnosis. RESULTS: Of 995 embryos from 110 couples, 288 were found to be euploid. Using a family member as a reference, 142 and 144 embryos were tested to be euploid noncarrier and carrier respectively, and the remaining 2 embryos were undetermined. When unbalanced embryos were selected as references, all the results were consistent with the previous ones. A total of 107 embryos were transferred, resulting in 66 clinical pregnancies. Karyotypes of prenatal diagnosis were all in accordance with the results of tested embryos. CONCLUSIONS: SNP array-based haplotyping is a rapid and effective way to distinguish between euploid carrier and noncarrier embryos. In case no family member is available as a reference, unbalanced embryos can be used for identification of euploid carrier and noncarrier embryos.


Asunto(s)
Heterocigoto , Polimorfismo de Nucleótido Simple/genética , Translocación Genética/genética , Adulto , Transferencia de Embrión/métodos , Estudios de Factibilidad , Femenino , Pruebas Genéticas/métodos , Humanos , Masculino
7.
Inorg Chem ; 59(20): 15111-15119, 2020 Oct 19.
Artículo en Inglés | MEDLINE | ID: mdl-32997940

RESUMEN

Two structurally similar metal-organic frameworks (MOFs) [Dy2Cu4I3(IN)7(DMF)2]·DMF (1) and [Dy2Cu4I3(IN)7(DMA)2]·DMA (2) (HIN = isonicotinic acid) feathering different coordinated solvent molecules were successfully isolated by tuning the types of solvents in the reaction system. Structural tests indicate that 1 and 2 are both built from 1D Dy(III) chains and copper iodide clusters [Cu4I3], generating into three-dimensional frameworks with an open 1D channel along the a axis. 1 and 2 display extensive and excellent solvent stability. Magnetic studies of 1 and 2 indicate that they exhibit interesting solvent-dependent magnetization dynamics. Importantly, 1 and 2 can act as highly effective catalysts for the carboxylic cyclization of propargyl alcohols with carbon dioxide (CO2) under ambient operating conditions. Additionally, the substrate scope was further explored over compound 1 based on the optimal conditions, and it exhibits efficient cyclic carboxylation of various terminal propargylic alcohols with CO2. This research offers an effective approach for the solvent-guided synthesis of MOFs materials and also presents the great application value of MOFs in CO2 chemical conversion.

8.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 42(5): 308-9, 2007 May.
Artículo en Chino | MEDLINE | ID: mdl-17686287

RESUMEN

OBJECTIVE: To observe and compare the curative effect of pingyangmycin and sodium morrhuae respectively in the treatment of oral and maxillofacial venous malformation. METHODS: Forty cases of oral and maxillofacial venous malformation were induced in this study, 20 of which were given local injection of low dose of pingyangmycin, and 20 given local injection of 5% sodium morrheate. The therapeutic effects were observed. RESULTS: The effective cases of pingyangmycin was 19, and the effective cases of sodium morrhuate was 12. The side effect was found in 10 cases of, and in 15 cases sodium morrhuate group, the former was mainly pingymangmycin group systemic, the later was mainly local. The difference was significant between the two groups (P < 0.05). CONCLUSIONS: Pingyangmycin is more effective in effective rate and side effect treatment of venous hemangioma than sodium morrhuate.


Asunto(s)
Bleomicina/análogos & derivados , Soluciones Esclerosantes/uso terapéutico , Morruato de Sodio/administración & dosificación , Malformaciones Vasculares/terapia , Adolescente , Adulto , Bleomicina/administración & dosificación , Bleomicina/uso terapéutico , Niño , Preescolar , Femenino , Estudios de Seguimiento , Humanos , Lactante , Inyecciones Intralesiones , Masculino , Persona de Mediana Edad , Morruato de Sodio/uso terapéutico , Resultado del Tratamiento , Adulto Joven
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...