Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 39
Filtrar
1.
Inorg Chem ; 63(1): 554-563, 2024 Jan 08.
Artículo en Inglés | MEDLINE | ID: mdl-38151237

RESUMEN

The meaningful and rational engineering of porphyrin-based catalysts with multimetallic active sites is very attractive toward photocatalytic hydrogen generation from water decomposition. Herein, three metal organic frameworks (MOFs) based on meso-tetrakis(4-carboxylphenyl)porphyrin (TCPP) were successfully constructed under solvothermal conditions. As a novel architectured photocatalyst (triclinic, C48H29N4O10PdYb), Pd/Yb-PMOF manifested diverse metal active sites, suitable bandgap positions, prominent visible light-collecting capacity, excellent carrier transfer efficiency, and obvious synergistic effect between ytterbium and palladium ions. Consequently, such a bimetallic MOF exhibited strengthened photocatalytic hydrogen evolution performance. Concretely, its hydrogen generation efficiency was up to 3196.42 µmol g-1 h-1 with 2 wt % Pt as a cocatalyst under visible light illumination. Our work demonstrates a promising strategy for highly efficient visible-light catalysts based on bimetallic-trimmed porphyrin MOFs.

2.
Artículo en Inglés | MEDLINE | ID: mdl-38977468

RESUMEN

OBJECTIVE: This study is to define a subclassification system of jugular foramen paragangliomas (JFPs) and to demonstrate corresponding microsurgical outcomes of JFPs. STUDY DESIGN: Retrospective study. SETTING: A single-center study. METHODS: We conducted a retrospective review of the clinical data of 44 patients with JFPs who underwent surgical management. Extrabulbar(Be) tumor and intrabulbar(Bi) tumor are defined based on the growth patterns, receiver operating characteristic (ROC) curves of the imaging profile were generated and was confirmed based on intraoperative findings. Area Under Curve (AUC), accuracy, sensitivity, and specificity for diagnostic imaging were revealed. We also compared the correlation between the two growth patterns with Fisch's classification, blood loss, lower cranial nerves (LCNs) deficit. RESULTS: There are 27 (69%) cases of Bi tumor and 17 (39%) cases of Be tumor. Significant radiomics features between the two growth patterns were demonstrated, ROC curves achieved excellent AUCs for MRI sequences (T1W1 MRI, MR contrast-enhanced sequence, MR complex sequences and MR complex + DSA by 0.833, 0.833, 0.875, 0.944) and had statistically significant in diagnosis of two growth patterns (P<0.05). There was no statistical correlation between growth patterns of JFPs and intra-operative blood loss. Preoperative LCNs deficits and Fisch's classification of tumors were correlated with the growth patterns of JFPs (P < 0.05). CONCLUSION: We proposetd two growth patterns of JFPs in term of the inferior petrous sinus involvement. Identification of Bi or Be growth patterns preoperatively is helpful to design optimal surgical strategies and minimize postoperative complications.

3.
J Org Chem ; 88(11): 7469-7476, 2023 Jun 02.
Artículo en Inglés | MEDLINE | ID: mdl-37166112

RESUMEN

An efficient method for C(sp3)-CHF bond formation was successfully developed by copper-catalyzed cross-coupling of allyl phosphate with 2-fluoro-2-(trimethylsilyl)acetate. Under moderate circumstances, the conversion was carried out in a good strategic range to provide a series of monofluoroalkylation products in high yields, which also demonstrates the practicality of gram-scale reactions.

4.
Inorg Chem ; 62(21): 8315-8325, 2023 May 29.
Artículo en Inglés | MEDLINE | ID: mdl-37192403

RESUMEN

A novel three-dimensional lanthanide porphyrin-based MOF (Nd-PMOFs) was synthesized by using tetracarboxyphenyl porphyrin as the ligand and the lanthanide Nd as the coordination metal. Its specific crystal structure information was obtained by single-crystal diffraction with the space group C2/c and the empirical formula C72H45N6Nd2O15.25. This new Nd porphyrin-based MOF with an organic framework formed by a unique coordination method enables the effective separation of photogenerated electrons and holes under photoluminescence, giving it excellent photocatalytic property which could be verified by the characterization data. The photocatalytic performance was examined by taking tert-butyl hydroperoxide as the oxidant and Nd-PMOFs as the catalyst for photocatalytic oxidation of styrene to benzaldehyde with 91.4% conversion and 81.2% benzaldehyde selectivity under optimal reactions, which surpasses most of the results reported in the literature. Several styrenes with other substituents were screened to explore the general applicability of Nd-PMOF for photocatalysis of styrene, among which Nd-PMOFs also exhibited excellent photocatalytic performance. This work offers the possibility to apply lanthanide organometallic frameworks, which are widely used in fluorescent materials, to photocatalysis. In addition, it also provides a new method for the catalytic generation of benzaldehyde from styrene that is consistent with the needs of modern green development.

5.
Drug Dev Ind Pharm ; 49(10): 617-627, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37725481

RESUMEN

OBJECTIVE: To synthesis a novel 'Pharmaceutical Cocrystal' of berberine (BBR) with coformer 3-methylcinnamic acid (3MCA) for increasing its solubility and intestinal absorption property. SIGNIFICANCE: BBR-HCl has poor liposolubility, difficulty in penetrating the cell membrane and absorption in the gastrointestinal tract, low bioavailability, and limited clinical application. A new cocrystal is formed by the interaction between 3-MCA and BBR through molecular interaction, which improves the physicochemical properties, intestinal absorption property, and hygroscopicity. METHODS: The solvent evaporation method was used to synthesize BCR-3MCA cocrystal. The physicochemical properties of the crystals were confirmed by different spectral techniques, i.e. by X-ray diffraction (PXRD, SXRD), thermogravimetry and differential thermal analysis (DSC, TGA), and scanning electron microscopy (SEM). Hygroscopicity of the cocrystal was evaluated by dynamic water vapor sorption (DVS). The intestinal absorption property was evaluated by the Ussing chamber system. RESULTS: BBR and 3MCA can be directly self-assembled into uniform co-crystal by hydrogen bonds and π-π stacking interactions. Compared with BBR-HCl, the solubility of BBR-3MCA cocrystal in polar solvents of water, methanol, ethanol, and isopropanol increased by 13.9, 1.5, 4.7, and 15.8 times, respectively. The apparent absorption and the absorption rate constants were increased by 7.7 and 5.6 times, respectively. Surprisingly, BBR-3MCA co-crystal almost had no hygroscopicity. CONCLUSION: The absolute molecular structure of the co-crystal was further confirmed by single crystal X-ray diffraction. The hydrogen bonds drove the formation of X-like one-dimensional unit. Compared to the BBR-HCl, BBR-3MCA cocrystal displayed superior dissolution and solubility performance, improved physical-chemical properties and significantly improved intestinal absorption.


Asunto(s)
Berberina , Berberina/química , Fenómenos Químicos , Solubilidad , Cristalografía por Rayos X , Absorción Intestinal
6.
J Org Chem ; 86(18): 12676-12682, 2021 Sep 17.
Artículo en Inglés | MEDLINE | ID: mdl-34472854

RESUMEN

Sulfonyl oxime ethers undergo facile radical substitutions with various amines to yield the corresponding oxime ethers. An efficient arylation of sulfonyl oxime ethers was accomplished under ambient temperature and metal-free conditions, with a wide range of functional group tolerance. Mechanistic investigations indicate that a phenyl radical is involved in the catalytic cycle.

7.
J Org Chem ; 83(1): 499-504, 2018 01 05.
Artículo en Inglés | MEDLINE | ID: mdl-29214800

RESUMEN

A tunable method for the direct trifluoromethylthiolation of α,ß-unsaturated carboxylic acids was developed to afford trifluoromethylthiolated ketones or alkenes. The reaction proceeds smoothly under mild conditions and shows an excellent functional group tolerance.

9.
Org Biomol Chem ; 15(17): 3590-3593, 2017 May 03.
Artículo en Inglés | MEDLINE | ID: mdl-28397930

RESUMEN

A copper(i)-catalyzed ring-opening cyanation of cyclopropanols was developed. The reaction provides an alternative method to achieve ß-cyano ketones efficiently. This reaction exhibits good functional group compatibility under mild conditions and can be scaled up to the gram scale. Preliminary mechanistic studies suggest that the reaction might go through a free radical process.


Asunto(s)
Cobre/química , Éteres Cíclicos/química , Nitrilos/química , Catálisis , Cetonas/química
10.
J Org Chem ; 80(18): 9314-20, 2015 Sep 18.
Artículo en Inglés | MEDLINE | ID: mdl-26300494

RESUMEN

A transition-metal-free synthetic method of various ynones via decarboxylative alkynylation of α-keto acids is described. The reaction is carried out under mild conditions and exhibits remarkable tolerance of functional groups. The mechanism of a radical process is proposed in the reaction.

11.
Org Biomol Chem ; 13(26): 7159-63, 2015 Jul 14.
Artículo en Inglés | MEDLINE | ID: mdl-26062850

RESUMEN

A copper-catalysed ring-opening trifluoromethylation reaction of cyclopropanols has been developed. Various ß-trifluoromethyl ketones are obtained in good to excellent yields under mild reaction conditions. The present method also exhibits good functional-group compatibility. The mechanism of this new ring-opening trifluoromethylation reaction was investigated by radical trapping reactions.


Asunto(s)
Cobre/química , Éteres Cíclicos/química , Hidrocarburos Fluorados/química , Catálisis , Metilación
12.
Org Lett ; 26(1): 236-240, 2024 Jan 12.
Artículo en Inglés | MEDLINE | ID: mdl-38149800

RESUMEN

Herein, a three-component 1,2-thiosulfonylation of alkenes with thiophenols and sulfonyl chlorides via synergistic photoredox and iron catalysis is described. Compared with previous studies, this protocol avoids tedious pre-synthesis of thiosulfonates and employs more readily accessible sulfonyl chlorides as a sulfonation reagent. Moreover, the reaction exhibits high compatibility with styrenes and unactivated alkenes as well as diverse sulfonyl chlorides, especially sulfamoyl chlorides. Preliminary mechanism investigations reveal that a radical pathway is involved in the catalytic cycle.

13.
Artículo en Inglés | MEDLINE | ID: mdl-38751096

RESUMEN

OBJECTIVE: The purpose of this study was to define an improved staging system for adenoid cystic carcinoma (ACC) in the external auditory canal (EAC) based on biological behaviors, image findings, and the prognosis of patients with ACC in the EAC. STUDY DESIGN: A retrospective study. SETTING: A single center data. METHODS: We performed a single-institution retrospective review of 154 patients with ACC in the EAC between January 2004 and September 2021. Risk factors associated with disease-free survival (DFS) and cancer-specific survival (CSS) of ACC in the EAC were identified using univariate and multivariate cox regression analysis. Then an improved staging system was proposed and compared with the Pittsburgh-modified tumor, node, and metastasis (TNM) staging system for statistical differences in DFS and CSS. RESULTS: An improved staging system of ACC in the EAC was defined, in which stage T4 were subclassified into T4a and T4b and were statistically different from the Pittsburgh-modified TNM staging system in DFS and CSS. We also found that the dura mater, facial nerve, sigmoid sinus, deep lobe of parotid gland, and parapharyngeal space involvement were significantly associated with poor prognosis of ACC in the EAC. CONCLUSION: The improved staging system is more accurate in predicting survival prognosis than Pittsburgh-modified TNM staging system for patients with ACC in the EAC, and may provide more efficient guidance of treatment strategy. SUMMARY: The improved staging system of ACC in the EAC is more accurately to predict survival prognosis, and provide guidance of treatment plan than Pittsburgh-modified TNM staging system.

14.
Laryngoscope ; 134(1): 419-425, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37421252

RESUMEN

OBJECTIVE: This study aimed to investigate the significance of parotid gland invasion in predicting distant metastasis of adenoid cystic carcinoma in the external auditory canal. STUDY DESIGN: Single-institution retrospective cohort study. METHODS: A retrospective review of patients with adenoid cystic carcinoma of the external auditory canal who underwent surgery was performed. Information on patient demographics, parotid gland invasion, tumor stage, perineural invasion, lymphovascular invasion, and follow-up data were collected and analyzed. RESULTS: One hundred twenty-nine patients were identified for review. Parotid gland invasion was noted in 45 patients (34.9%). Parotid gland invasion was significantly associated with tumor stage, perineural invasion, distant metastasis, and postoperative adjuvant therapy. Distant metastasis was noted in 30 patients (23.3%). Multivariate Cox proportional hazards analysis identified parotid gland invasion as an independent risk factor for predicting distant metastasis. The 5-year distant metastasis-free survival rate was 83.6% for patients without parotid gland invasion and 61.8% for patients with parotid gland invasion (p = 0.010). CONCLUSIONS: The parotid gland invasion rate is relatively high in adenoid cystic carcinoma of the external auditory canal and is significantly related to tumor stage. Parotid gland invasion is associated with worse distant metastasis-free survival. LEVEL OF EVIDENCE: 4 Laryngoscope, 134:419-425, 2024.


Asunto(s)
Carcinoma Adenoide Quístico , Glándula Parótida , Humanos , Glándula Parótida/cirugía , Estudios Retrospectivos , Carcinoma Adenoide Quístico/patología , Conducto Auditivo Externo/cirugía , Conducto Auditivo Externo/patología , Análisis Multivariante
15.
Org Lett ; 2024 Feb 22.
Artículo en Inglés | MEDLINE | ID: mdl-38385808

RESUMEN

An intermolecular Suzuki-Miyaura-type reaction of benzoyl fluorides with alkyl boronic acids to synthetic ketone was revealed by cooperative N-heterocyclic carbene (NHC) and photoredox catalysis. Various alkyl boric acids can be converted into alkyl radicals without external oxidants or activators. Moreover, the catalytic system was feasible for the difunctionalization of styrenes via a radical relay process. Mechanistic experiments suggested that the benzoate anion intermediate might play a unique role in this reaction system.

16.
ACS Appl Mater Interfaces ; 15(3): 4845-4856, 2023 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-36629327

RESUMEN

Selective reduction of nitroaromatics to the corresponding amines generally requires complex conditions, involving pressurized hydrogen, higher temperatures, or organic acids. In this work, we successfully prepared a series of porphyrin-based MOF photocatalysts (Pd-PMOFs, In-PMOFs, and In/Pd-PMOFs) via a facile solvothermal method for the efficient selective reduction of nitroaromatics to corresponding anilines with deionized water as the hydrogen donor. Being a new structured material (monoclinic, C52H40InN6O8Pd), on account of the abundant pore channels, strong light absorption capability, well-matched bandgap, as well as the coordination of indium ions and palladium ions, In/Pd-MOFs have excellent migration efficiency of photo-induced electrons and holes. Specifically, the In/Pd-PMOF photocatalyst manifested superior conversion (100%) and selectivity (≥80%) toward the screened nitro compounds under mild conditions. This work avoids the use of strong reductants, organic acids, and pressurized hydrogen gas as hydrogen sources, providing a promising concept for developing green catalytic systems.

17.
Sci Rep ; 13(1): 885, 2023 01 17.
Artículo en Inglés | MEDLINE | ID: mdl-36650202

RESUMEN

To compare the safety and effectiveness of surgical treatment of jugular paragangliomas (JPs) following the application of our modified surgical techniques. Fifty-six patients with JPs were analyzed for tumor classification, surgical outcomes, and intratumor blood vessels. The gross total resection in C1-2 (100%) was significantly greater than that in C3 and D (66.7%). Good postoperative facial nerve (FN) function (House-Brackmann I-II) was achieved in 89.5% C1-2 cases, which was not significantly different from C3 and D (93.3%) (P = 0.694). Preoperative and postoperative lower cranial nerve (LCN) deficits correlated with the Fisch's classification of tumors (P < 0.05), and intraoperative blood loss was greater in advanced tumors (P = 0.050). Further study showed that the cross-sectional area of intratumor blood vessels was positively associated with intraoperative blood loss (P < 0.001). Surgical excision of JPs is a safe and effective strategy, and early surgical treatment is a good option for patients with C1-2 tumors without surgical contraindications.


Asunto(s)
Pérdida de Sangre Quirúrgica , Paraganglioma , Humanos , Resultado del Tratamiento , Paraganglioma/cirugía , Estudios Retrospectivos , Complicaciones Posoperatorias
18.
Acta Otolaryngol ; 143(2): 147-155, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36883320

RESUMEN

BACKGROUND: Acquired cholesteatoma is characterized by hyper-keratinized squamous epithelium and bone destruction. However, direct evidence for hyper-keratinized epidermis promoting bone destruction is lacking. AIMS/OBJECTIVES: To determine whether higher degree of keratinization correlated with severe bone destruction and further offer direct evidence for keratinocyte-inducing osteoclastogenesis. MATERIALS AND METHODS: Histological changes and clinical relevance were analyzed in human-acquired cholesteatoma. Animal models were established by implanting autologous epidermis with different degrees of keratinization. The severity of bone resorption and the number of osteoclasts were compared in different keratinized groups. An in vitro coculture system was developed to mimic the progress of keratinocyte-inducing osteoclastogenesis. RESULTS: The matrix of cholesteatoma was composed of a thicker stratum corneum than normal skin. The stratum corneum thickness and the expression of Keratin 10 positively correlated to the severity of bone destruction. Animal models revealed that the bone destruction induced by a higher keratinized epidermis was more severe. Osteoclasts were detected in bone erosion areas, and the number of osteoclasts increased with the keratinization degrees of the graft. In vitro studies showed that keratinocytes directly promoted monocytes differentiating into osteoclasts. CONCLUSIONS AND SIGNIFICANCE: In acquired cholesteatoma, the degree of keratinization correlated with disease severity, and keratinocytes directly promote osteoclastogenesis.


Asunto(s)
Resorción Ósea , Colesteatoma , Animales , Humanos , Colesteatoma/patología , Osteoclastos/metabolismo , Osteoclastos/patología , Resorción Ósea/metabolismo , Queratinocitos/metabolismo , Queratinocitos/patología , Epitelio/metabolismo
19.
Org Lett ; 25(35): 6522-6527, 2023 Sep 08.
Artículo en Inglés | MEDLINE | ID: mdl-37642302

RESUMEN

A novel three-component α-acylated difunctionalization of alkenes strategy has been developed on the basis of a direct hydrogen atom transfer (HAT) process of photoinduced acyl azolium salts. With simple irradiation without the catalyst, a variety of olefins can be directly converted into ketone derivatives, including 1,4-dione, ß-silyl ketone, 1,5-dione, etc. Mechanistic investigations indicated that the unique reactivity of the acyl azonium triplet excited state is crucial to the strategy's success.

20.
Org Lett ; 25(21): 3916-3921, 2023 Jun 02.
Artículo en Inglés | MEDLINE | ID: mdl-37212481

RESUMEN

We report a copper metallaphotocatalytic 1,2-difunctionalization of terminal alkynes with N-hydroxyphthalimide (NHP) esters and readily available silyl reagents (TMSCN and TMSNCS) to access stereodefined trisubstituted alkenes, including (E)-alkenyl nitriles and thiocyanates. The reaction proceeds with excellent anti-stereoselectivity and demonstrates broad compatibility with a wide range of terminal alkynes and NHP esters as alkyl radical precursors. Experimental and computational studies have been performed to gain insight into the reaction mechanism.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA