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1.
Biomed J ; : 100632, 2023 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-37467969

RESUMEN

BACKGROUND: Biomarker dynamics in different time-courses might be the primary reason why a static measurement of a single biomarker cannot accurately predict sepsis outcomes. Therefore, we conducted this prospective hospital-based cohort study to simultaneously evaluate the performance of several conventional and novel biomarkers of sepsis in predicting sepsis-associated mortality on different days of illness among patients with suspected sepsis. METHODS: We evaluated the performance of 15 novel biomarkers including angiopoietin-2, pentraxin 3, sTREM-1, ICAM-1, VCAM-1, sCD14 and 163, E-selectin, P-selectin, TNF-alpha, interferon-gamma, CD64, IL-6, 8, and 10, along with few conventional markers for predicting sepsis-associated mortality. Patients were grouped into quartiles according to the number of days since symptom onset. Receiver operating characteristic curve (ROC) analysis was used to evaluate the biomarker performance. RESULTS: From 2014 to 2017, 1,483 patients were enrolled, of which 78% fulfilled the systemic inflammatory response syndrome criteria, 62% fulfilled the sepsis-3 criteria, 32% had septic shock, and 3.3% developed sepsis-associated mortality. IL-6, pentraxin 3, sCD163, and the blood gas profile demonstrated better performance in the early days of illness, both before and after adjusting for potential confounders (adjusted area under ROC curve [AUROC]:0.81-0.88). Notably, the Sequential Organ Failure Assessment (SOFA) score was relatively consistent throughout the course of illness (adjusted AUROC:0.70-0.91). CONCLUSION: IL-6, pentraxin 3, sCD163, and the blood gas profile showed excellent predictive accuracy in the early days of illness. The SOFA score was consistently predictive of sepsis-associated mortality throughout the course of illness, with an acceptable performance.

2.
ACS Appl Mater Interfaces ; 15(18): 21953-21964, 2023 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-37129106

RESUMEN

Electric cell-substrate impedance sensing (ECIS) is an innovative approach for the label-free and real-time detection of cell morphology, growth, and apoptosis, thereby playing an essential role as both a viable alternative and valuable complement to conventional biochemical/pharmaceutical analysis in the field of diagnostics. Constant improvements are naturally sought to further improve the effective range and reliability of this technology. In this study, we developed poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) conducting polymer (CP)-based bioelectrodes integrated into homemade ECIS cell-culture chamber slides for the simultaneous drug release and real-time biosensing of cancer cell viability under drug treatment. The CP comprised tailored PEDOT:PSS, poly(ethylene oxide) (PEO), and (3-glycidyloxypropyl)trimethoxysilane (GOPS) capable of encapsulating antitumor chemotherapeutic agents such as doxorubicin (DOX), docetaxel (DTX), and a DOX/DTX combination. This device can reliably monitor impedance signal changes correlated with cell viability on chips generated by cell adhesion onto a predetermined CP-based working electrode while simultaneously exhibiting excellent properties for both drug encapsulation and on-demand release from another CP-based counter electrode under electrical stimulation (ES) operation. Cyclic voltammetry curves and surface profile data of different CP-based coatings (without or with drugs) were used to analyze the changes in charge capacity and thickness, respectively, thereby further revealing the correlation between their drug-releasing performance under ES operation (determined using ultraviolet-visible (UV-vis) spectroscopy). Finally, antitumor drug screening tests (DOX, DTX, and DOX/DTX combination) were performed on MCF-7 and HeLa cells using our developed CP-based ECIS chip system to monitor the impedance signal changes and their related cell viability results.


Asunto(s)
Doxorrubicina , Humanos , Impedancia Eléctrica , Células HeLa , Liberación de Fármacos , Reproducibilidad de los Resultados , Doxorrubicina/farmacología
3.
Polymers (Basel) ; 14(23)2022 Dec 02.
Artículo en Inglés | MEDLINE | ID: mdl-36501655

RESUMEN

In order to discuss the polymerization effect from the substituted position and methoxy group of Type I photinitiators, a series of naphthalene-based oxime esters was designed and synthesized. Compared to the 2-naphthalene-substituted compound, the UV absorption region of the 1-naphthalene-based compound was greatly improved. In addition, the methoxy substitution exhibited longer absorption characteristics than did the methoxy-free one. The photochemical reaction behavior of these novel compounds was also studied by photolysis, cyclic voltammetry (CV), and electron spin resonance (ESR) experiments. Finally, the initiation abilities of naphthalene-based oxime esters toward trimethylolpropane triacrylate (TMPTA) monomer were conducted through the photo-DSC instrument under UV and a 405@nm LED lamp. Remarkedly, the naphthalene-based oxime ester (NA-3) that contains 1-naphthalene with o-methoxy substituent showed the rather red-shifted absorption region with the highest final conversion efficiency under UV (46%) and 405@nm LED (41%) lamp irradiation.

4.
Biomolecules ; 10(4)2020 04 21.
Artículo en Inglés | MEDLINE | ID: mdl-32326356

RESUMEN

Immunogenic cell death (ICD) refers to a unique form of cell death that activates an adaptive immune response against dead-cell-associated antigens. Accumulating evidence indicates that the efficacy of conventional anticancer agents relies on not only their direct cytostatic/cytotoxic effects but also the activation of antitumor ICD. Common anticancer ICD inducers include certain chemotherapeutic agents (such as anthracyclines, oxaliplatin, and bortezomib), radiotherapy, photodynamic therapy (PDT), and oncolytic virotherapies. However, most chemotherapeutic reagents are inefficient or fail to trigger ICD. Therefore, better understanding on the molecular determinants of chemotherapy-induced ICD will help in the development of more efficient combinational anticancer strategies through converting non- or relatively weak ICD inducers into bona fide ICD inducers. In this study, we found that sequential, but not concurrent, treatment of cancer cells with interferon ß (IFNß), a type I IFN, and cisplatin (an inefficient ICD inducer) can enhance the expression of ICD biomarkers in cancer cells, including surface translocation of an endoplasmic reticulum (ER) chaperone, calreticulin (CRT), and phosphorylation of the eukaryotic translation initiation factor alpha (eIF2α). These results suggest that exogenous IFNß may activate molecular determinants that convert cisplatin into an ICD inducer. Further bioinformatics and in vitro experimental analyses found that interferon regulatory factor 1 (IRF1) acted as an essential mediator of surface CRT exposure by sequential IFNß-cisplatin combination. Our findings not only help to design more effective combinational anticancer therapy using IFNß and cisplatin, but also provide a novel insight into the role of IRF1 in connecting the type I IFN responses and ICD.


Asunto(s)
Calreticulina/metabolismo , Cisplatino/farmacología , Factor 1 Regulador del Interferón/metabolismo , Interferón beta/farmacología , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Doxorrubicina/farmacología , Humanos , Muerte Celular Inmunogénica/efectos de los fármacos , Oxaliplatino/farmacología , Proteínas Proto-Oncogénicas c-jun/metabolismo
5.
ACS Appl Mater Interfaces ; 11(47): 43843-43856, 2019 Nov 27.
Artículo en Inglés | MEDLINE | ID: mdl-31663727

RESUMEN

Protein-bound uremic toxins (PBUTs) can cause noxious effects in patients suffering from renal failure as a result of inhibiting the transport of proteins and inducing their structural modification. They are difficult to remove through standard hemodialysis (HD) treatment. Herein, we report an organic bioelectronic HD device system for the effective removal of PBUTs through electrically triggered dissociation of protein-toxin complexes. To prepare this system, we employed electrospinning to fabricate electrically conductive quaternary composite nanofiber mats-comprising multiwalled carbon nanotubes (MWCNTs), poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS), poly(ethylene oxide) (PEO), and (3-glycidyloxypropyl)trimethoxysilane (GOPS)-on conventional polyethersulfone (PES) dialysis membranes. These composite nanofiber platforms exhibited (i) long-term water resistance (due to cross-linking among PSS, PEO, and GOPS), (ii) high adhesion strength on the PES membrane (due to GOPS functioning as an adhesion promoter), (iii) enhanced electrical properties [due to the MWCNTs and PEDOT:PSS promoting effective electrical stimulation (ES) operation in devices containing bioelectronic interfaces (BEI)], and (iv) good anticoagulant ability and negligible hemolysis of red blood cells. We employed this organic BEI electronic system as a novel single-membrane HD device to study the removal efficiency of four kinds of uremic toxins [p-cresol (PC), indoxyl sulfate, and hippuric acid as PBUTs; creatinine as a non-PBUT] as well as the effects of ES on lowering the protein binding ratio. Our organic BEI devices provided a high rate of removal of PC with low protein loss after 4 h of a simulated dialysis process. It also functioned with low complement activation, low contact activation levels, and lower amounts of platelet adsorption, suggesting great suitability for use in developing next-generation bioelectronic medicines for HD.


Asunto(s)
Nanotubos de Carbono/química , Proteínas/química , Diálisis Renal/instrumentación , Toxinas Biológicas/química , Uremia/terapia , Adsorción , Cresoles/sangre , Cresoles/química , Electrónica/instrumentación , Hipuratos/sangre , Hipuratos/química , Humanos , Indicán/sangre , Indicán/química , Polímeros/química , Toxinas Biológicas/sangre , Uremia/sangre
6.
Eur J Med Chem ; 100: 151-61, 2015 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-26081023

RESUMEN

Numerous FLT3 inhibitors have been explored as a viable therapy for the treatment of acute myeloid leukemia (AML). However, clinical data have been underwhelming due to incomplete inhibition of FLT3 or the emergence of resistant mutations treated with these older agents. We previously developed a series of 3-phenyl-1H-5-pyrazolylamine derivatives as highly potent and selective FLT3 inhibitors with good in vivo efficacy using an intravenous (IV) route. However, the poor bioavailability of these pyrazole compounds limits the development of these promising antileukemic compounds for clinical use. Herein, we describe a novel class of 5-phenyl-thiazol-2-ylamine compounds that are multi-targeted FLT3 inhibitors. From this class of compounds, compound 7h was very potent against AML cell lines and exhibited excellent oral efficacy in AML xenograft models. In addition, further studies demonstrated that compound 7h exhibited potent in vitro and in vivo activities against clinically relevant AC220 (3)-resistant kinase domain mutants of FLT3-ITD.


Asunto(s)
Antineoplásicos/farmacología , Resistencia a Antineoplásicos/efectos de los fármacos , Neoplasias Experimentales/tratamiento farmacológico , Mutación Puntual/efectos de los fármacos , Inhibidores de Proteínas Quinasas/farmacología , Tiazoles/farmacología , Tirosina Quinasa 3 Similar a fms/antagonistas & inhibidores , Animales , Antineoplásicos/síntesis química , Antineoplásicos/química , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Masculino , Ratones , Ratones Endogámicos ICR , Ratones Desnudos , Estructura Molecular , Neoplasias Experimentales/patología , Inhibidores de Proteínas Quinasas/síntesis química , Inhibidores de Proteínas Quinasas/química , Ratas , Ratas Sprague-Dawley , Relación Estructura-Actividad , Tiazoles/síntesis química , Tiazoles/química , Tirosina Quinasa 3 Similar a fms/genética , Tirosina Quinasa 3 Similar a fms/metabolismo
7.
Eur J Med Chem ; 90: 428-35, 2015 Jan 27.
Artículo en Inglés | MEDLINE | ID: mdl-25461891

RESUMEN

Hepatitis B virus (HBV) is a causative reagent that frequently causes progressive liver diseases, leading to the development of acute, chronic hepatitis, cirrhosis, and eventually hepatocellular carcinoma (HCC). Despite several antiviral drugs including interferon-α and nucleotide derivatives are approved for clinical treatment for HBV, critical issues remain unresolved, e.g., low-to-moderate efficacy, adverse side effects, and resistant strains. In this study, novel Paeonol-phenylsulfonyl derivatives were synthesized and their antiviral effect against HBV was evaluated. The experimental results indicated that these compounds process significant antiviral potential, including the inhibition of viral antigen expression and secretion, and the suppression of HBV viral DNA replication. Among compounds synthesized in this research, compound 2-acetyl-5-methoxyphenyl 4-methoxybenzenesulfonate (7f) had the most potent inhibitory activity with IC50 value of 0.36 µM, and high selectivity index, SI (TC50/IC50) 47.75; which exhibited an apparent inhibition effect on viral gene expression and viral propagation in cell culture model. So, we believe our compounds could serve as reservoir for antiviral drug development.


Asunto(s)
Acetofenonas/farmacología , Antivirales/farmacología , Diseño de Fármacos , Virus de la Hepatitis B/efectos de los fármacos , Acetofenonas/síntesis química , Acetofenonas/química , Antivirales/síntesis química , Antivirales/química , Supervivencia Celular , Relación Dosis-Respuesta a Droga , Células Hep G2 , Humanos , Pruebas de Sensibilidad Microbiana , Relación Estructura-Actividad , Células Tumorales Cultivadas
8.
PLoS One ; 9(1): e83160, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24416160

RESUMEN

Overexpression or/and activating mutation of FLT3 kinase play a major driving role in the pathogenesis of acute myeloid leukemia (AML). Hence, pharmacologic inhibitors of FLT3 are of therapeutic potential for AML treatment. In this study, BPR1J-340 was identified as a novel potent FLT3 inhibitor by biochemical kinase activity (IC50 approximately 25 nM) and cellular proliferation (GC50 approximately 5 nM) assays. BPR1J-340 inhibited the phosphorylation of FLT3 and STAT5 and triggered apoptosis in FLT3-ITD(+) AML cells. The pharmacokinetic parameters of BPR1J-340 in rats were determined. BPR1J-340 also demonstrated pronounced tumor growth inhibition and regression in FLT3-ITD(+) AML murine xenograft models. The combination treatment of the HDAC inhibitor vorinostat (SAHA) with BPR1J-340 synergistically induced apoptosis via Mcl-1 down-regulation in MOLM-13 AML cells, indicating that the combination of selective FLT3 kinase inhibitors and HDAC inhibitors could exhibit clinical benefit in AML therapy. Our results suggest that BPR1J-340 may be further developed in the preclinical and clinical studies as therapeutics in AML treatments.


Asunto(s)
Antineoplásicos/uso terapéutico , Benzamidas/uso terapéutico , Inhibidores de Histona Desacetilasas/uso terapéutico , Ácidos Hidroxámicos/uso terapéutico , Leucemia Mieloide Aguda/tratamiento farmacológico , Inhibidores de Proteínas Quinasas/uso terapéutico , Urea/análogos & derivados , Tirosina Quinasa 3 Similar a fms/antagonistas & inhibidores , Animales , Antineoplásicos/farmacocinética , Antineoplásicos/farmacología , Protocolos de Quimioterapia Combinada Antineoplásica/farmacología , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Apoptosis/efectos de los fármacos , Benzamidas/química , Benzamidas/farmacocinética , Benzamidas/farmacología , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Inhibidores de Histona Desacetilasas/farmacología , Ácidos Hidroxámicos/farmacología , Leucemia Mieloide Aguda/enzimología , Leucemia Mieloide Aguda/patología , Masculino , Ratones , Ratones Desnudos , Inhibidores de Proteínas Quinasas/farmacología , Ratas , Transducción de Señal/efectos de los fármacos , Urea/química , Urea/farmacocinética , Urea/farmacología , Urea/uso terapéutico , Vorinostat , Tirosina Quinasa 3 Similar a fms/metabolismo
9.
Bioorg Med Chem ; 21(11): 2856-67, 2013 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-23618709

RESUMEN

Preclinical investigations and early clinical trials suggest that FLT3 inhibitors are a viable therapy for acute myeloid leukemia. However, early clinical data have been underwhelming due to incomplete inhibition of FLT3. We have developed 3-phenyl-1H-5-pyrazolylamine as an efficient template for kinase inhibitors. Structure-activity relationships led to the discovery of sulfonamide, carbamate and urea series of FLT3 inhibitors. Previous studies showed that the sulfonamide 4 and carbamate 5 series were potent and selective FLT3 inhibitors with good in vivo efficacy. Herein, we describe the urea series, which we found to be potent inhibitors of FLT3 and VEGFR2. Some inhibited growth of FLT3-mutated MOLM-13 cells more strongly than the FLT3 inhibitors sorafenib (2) and ABT-869 (3). In preliminary in vivo toxicity studies of the four most active compounds, 10f was found to be the least toxic. A further in vivo efficacy study demonstrated that 10f achieved complete tumor regression in a higher proportion of MOLM-13 xenograft mice than 4 and 5 (70% vs 10% and 40%). These results show that compound 10f possesses improved pharmacologic and selectivity profiles and could be more effective than previously disclosed FLT3 inhibitors in the treatment of acute myeloid leukemia.


Asunto(s)
Antineoplásicos/síntesis química , Benzamidas/síntesis química , Benzamidas/farmacología , Leucemia Mieloide Aguda/tratamiento farmacológico , Inhibidores de Proteínas Quinasas/síntesis química , Urea/análogos & derivados , Tirosina Quinasa 3 Similar a fms/antagonistas & inhibidores , Animales , Antineoplásicos/química , Antineoplásicos/farmacología , Benzamidas/química , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Descubrimiento de Drogas , Humanos , Concentración 50 Inhibidora , Leucemia Mieloide Aguda/enzimología , Leucemia Mieloide Aguda/patología , Ratones , Inhibidores de Proteínas Quinasas/química , Inhibidores de Proteínas Quinasas/farmacología , Sensibilidad y Especificidad , Relación Estructura-Actividad , Urea/síntesis química , Urea/química , Urea/farmacología , Ensayos Antitumor por Modelo de Xenoinjerto , Tirosina Quinasa 3 Similar a fms/química
10.
Bioorg Med Chem Lett ; 22(14): 4654-9, 2012 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-22726931

RESUMEN

A new class of FLT3 inhibitors has been identified based on the 3-phenyl-1H-5-pyrazolylamine scaffold. The structure-activity relationships led to the discovery of two carbamate series, and some potent compounds within these two series exhibited better growth inhibition of FLT3-mutated MOLM-13 cells than FLT3 inhibitors sorafenib (2) and ABT-869 (3). In particular, compound 8d exhibited the ability to regress tumors in mouse xenograft model using MOLM-13 cells.


Asunto(s)
Aminas/química , Inhibidores de Proteínas Quinasas/química , Pirazoles/química , Tirosina Quinasa 3 Similar a fms/antagonistas & inhibidores , Aminas/farmacología , Animales , Antineoplásicos/química , Antineoplásicos/farmacología , Línea Celular Tumoral , Humanos , Ratones , Estructura Molecular , Inhibidores de Proteínas Quinasas/farmacología , Relación Estructura-Actividad , Ensayos Antitumor por Modelo de Xenoinjerto
11.
Bioorg Med Chem ; 19(14): 4173-82, 2011 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-21708468

RESUMEN

Preclinical investigations and early clinical trial studies suggest that FLT3 inhibitors offer a viable therapy for acute myeloid leukemia. However, early clinical data for direct FLT3 inhibitors provided only modest results because of the failure to fully inhibit FLT3. We have designed and synthesized a novel class of 3-phenyl-1H-5-pyrazolylamine-derived compounds as FLT3 inhibitors which exhibit potent FLT3 inhibition and high selectivity toward different receptor tyrosine kinases. The structure-activity relationships led to the discovery of two series of FLT3 inhibitors, and some potent compounds within these two series exhibited comparable potency to FLT3 inhibitors sorafenib (3) and ABT-869 (4) in both wt-FLT3 enzyme inhibition and FLT3-ITD inhibition on cell growth (MOLM-13 and MV4;11 cells). In particular, the selected compound 12a exhibited the ability to regress tumors in mouse xenograft models using MOLM-13 and MV4;11 cells.


Asunto(s)
Antineoplásicos/farmacología , Descubrimiento de Drogas , Inhibidores de Proteínas Quinasas/farmacología , Pirazoles/farmacología , Sulfonamidas/farmacología , Tirosina Quinasa 3 Similar a fms/antagonistas & inhibidores , Animales , Antineoplásicos/síntesis química , Antineoplásicos/química , Bencenosulfonatos/química , Bencenosulfonatos/farmacología , Proliferación Celular/efectos de los fármacos , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Indazoles/química , Indazoles/farmacología , Ratones , Estructura Molecular , Niacinamida/análogos & derivados , Compuestos de Fenilurea/química , Compuestos de Fenilurea/farmacología , Inhibidores de Proteínas Quinasas/síntesis química , Inhibidores de Proteínas Quinasas/química , Pirazoles/síntesis química , Pirazoles/química , Piridinas/química , Piridinas/farmacología , Sorafenib , Estereoisomerismo , Relación Estructura-Actividad , Sulfonamidas/síntesis química , Sulfonamidas/química , Tirosina Quinasa 3 Similar a fms/metabolismo
12.
J Med Chem ; 53(18): 6572-83, 2010 Sep 23.
Artículo en Inglés | MEDLINE | ID: mdl-20718420

RESUMEN

Fibroblast activation protein (FAP) belongs to the prolyl peptidase family. FAP inhibition is expected to become a new antitumor target. Most known FAP inhibitors often resemble the dipeptide cleavage products, with a boroproline at the P1 site; however, these inhibitors also inhibit DPP-IV, DPP-II, DPP8, and DPP9. Potent and selective FAP inhibitor is needed in evaluating that FAP as a therapeutic target. Therefore, it is important to develop selective FAP inhibitors for the use of target validation. To achieve this, optimization of the nonselective DPP-IV inhibitor 8 led to the discovery of a new class of substituted 4-carboxymethylpyroglutamic acid diamides as FAP inhibitors. SAR studies resulted in a number of FAP inhibitors having IC(50) of <100 nM with excellent selectivity over DPP-IV, DPP-II, DPP8, and DPP9 (IC(50) > 100 µM). Compounds 18a, 18b, and 19 are the only known potent and selective FAP inhibitors, which prompts us to further study the physiological role of FAP.


Asunto(s)
Amidas/síntesis química , Gelatinasas/antagonistas & inhibidores , Proteínas de la Membrana/antagonistas & inhibidores , Ácido Pirrolidona Carboxílico/análogos & derivados , Ácido Pirrolidona Carboxílico/síntesis química , Amidas/farmacocinética , Amidas/farmacología , Animales , Dipeptidasas/antagonistas & inhibidores , Inhibidores de la Dipeptidil-Peptidasa IV , Dipeptidil-Peptidasas y Tripeptidil-Peptidasas/antagonistas & inhibidores , Endopeptidasas , Humanos , Ratones , Ratones Endogámicos BALB C , Ácido Pirrolidona Carboxílico/farmacocinética , Ácido Pirrolidona Carboxílico/farmacología , Serina Endopeptidasas , Estereoisomerismo , Relación Estructura-Actividad
13.
Langmuir ; 23(10): 5802-9, 2007 May 08.
Artículo en Inglés | MEDLINE | ID: mdl-17425346

RESUMEN

The chemical state and formation mechanism of Pt-Ru nanoparticles (NPs) synthesized by using ethylene glycol (EG) as a reducing agent and their stability have been examined by in situ X-ray absorption spectroscopy (XAS) at the Pt LIII and Ru K edges. It appears that the reduction of Pt(IV) and Ru(III) precursor salts by EG is not a straightforward reaction but involves different intermediate steps. The pH control of the reaction mixture containing Pt(IV) and Ru(III) precursor salts in EG to 11 led to the reduction of Pt(IV) to Pt(II) corresponding to [PtCl4](2-) whereas Ru(III)Cl3 is changed to the [Ru(OH)6](3-) species. Refluxing the mixture containing [PtCl4](2-) and [Ru(OH)6](3-) species at 160 degrees C for 0.5 h produces Pt-Ru NPs as indicated by the presence of Pt and Ru in the first coordination shell of the respective metals. No change in XAS structural parameters is found when the reaction time is further increased, indicating that the Pt-Ru NPs formed are extremely stable and less prone to aggregation. XAS structural parameters suggest a Pt-rich core and a Ru-rich shell structure for the final Pt-Ru NPs. Due to the inherent advantages of the EG reduction method, the atomic distribution and alloying extent of Pt and Ru in the Pt-Ru NPs synthesized by the EG method are higher than those of the Pt-Ru/C NPs synthesized by a modified Watanabe method.

14.
J Org Chem ; 68(22): 8704-7, 2003 Oct 31.
Artículo en Inglés | MEDLINE | ID: mdl-14575506

RESUMEN

An enantiospecific synthesis of Schinzer's ketone 3 from (R)-(+)-pulegone via alpha-carbonyl radical cyclization was accomplished. This work also constitutes an enantiospecific formal syntheses of (-)-pinguisenol and (-)-alpha-pinguisene. The intermediate ketone 4 would be useful for the synthesis of other pinguisane-type sesquiterpenes.


Asunto(s)
Compuestos Bicíclicos con Puentes/síntesis química , Sesquiterpenos/síntesis química , Ciclización , Cetonas/química , Espectroscopía de Resonancia Magnética , Modelos Químicos , Sesquiterpenos Policíclicos , Estereoisomerismo
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