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1.
Infect Drug Resist ; 17: 1539-1544, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38650755

RESUMEN

Objective: Our aim was to highlight the clinical characteristics and determine the risk factors associated with severe and non-severe COVID-19 infection. Study Method: A retrospective review was conducted on clinical data obtained from patients with COVID-19 infection, admitted to the emergency department between November 2022 and January 2023. Total of 1684 participants were categorized into severe (312 cases,18.53%) and non-severe (1,372 cases,81.47%) cohorts. Logistic regression was utilized for multivariate analysis, with a P-value less than 0.05 signifying a significant difference between the groups. Results: The study consisted of 952 males (56.53%) and 732 females (43.47%) participants. The age distribution ranged from 18 to 93 years in both cohorts. There were statistically significant differences between the clinical symptoms of the severe and non-severe cohorts (P < 0.05). According to the multivariate statistical analysis, patients with more pronounced clinical manifestations had significantly elevated values related to age(P < 0.05), diabetes(P < 0.01), hypertension(P < 0.01), C-reactive protein (CRP) (P < 0.05), and lactate dehydrogenase (LDH) (P < 0.01) as compared to those presenting with milder symptoms. Conclusion: The primary clinical presentations in both the cohorts were mostly similar. Predominant factors contributing to the severity of COVID-19 infection were age, diabetes, hypertension, elevated CRP levels, and increased LDH.

2.
Zhongguo Gu Shang ; 37(4): 358-62, 2024 Apr 25.
Artículo en Chino | MEDLINE | ID: mdl-38664205

RESUMEN

OBJECTIVE: To investigate the clinical efficacy of body-surface guide plates for lateral segmental positioning in the thoracolumbar spine. METHODS: From March 2018 to March 2021, 768 gerontal patientss underwent percutaneous vertebroplasty with balloon dilatation due to thoracolumbar compression fracturess, 356 males and 412 females. aged from 64 to 92 years old with an average of (77.9±13.5) years old. All patients were treated in hospital within 1 week after injury. All patients underwent preoperative localization, and were divided into localization plate group and locator group according to different localization methods. There were 390 patients in the localization plate group, 180 males and 210 females, aged from 64 to 92 years old, with an average age of (78.4±14.3) years old. There were 378 patients in the locator group, 176 males and 202 females, aged from 64 to 90 years old, with an average age of (77.5±13.4) years old. After preliminary positioning with the above two methods, skin markers were made, cloth was routinely disinfected, and the spinal lateral position was fluoroscopically examined after the fine needle was inserted into the marked point and the vertical body at the near tail end. The accuracy of the original positioning method was evaluated. The number of times, time and accuracy of positioning of the two groups of patients were compared and analyzed. RESULTS: The specific data of patient positioning in the two groups were collected for statistical analysis. The number of times of fluoroscopy in the positioning plate group and the locator group was(3.3±0.5) times and (5.0±1.2) times, and the positioning time was (60.4±9.4) s and (105.0±30.9) s, respectively. The accuracy of fluoroscopy was 97.5% (380/390) and 85.7% (324/378), respectively, with statistical significance (P<0.05). CONCLUSION: The lateral segmental positioning plate of the body surface spine has the advantages of simple operation, accurate positioning, and reducing X-ray radiation for patients, which is worthy of clinical application.


Asunto(s)
Vértebras Lumbares , Humanos , Masculino , Femenino , Anciano , Persona de Mediana Edad , Anciano de 80 o más Años , Vértebras Lumbares/cirugía , Placas Óseas , Vértebras Torácicas/cirugía , Vertebroplastia/métodos , Fracturas de la Columna Vertebral/cirugía , Posicionamiento del Paciente/métodos , Fracturas por Compresión/cirugía
3.
Adv Sci (Weinh) ; 9(29): e2202914, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-35981886

RESUMEN

Immunotherapy, the most promising strategy of cancer treatment, has achieved promising outcomes, but its clinical efficacy in pancreatic cancer is limited mainly due to the complicated tumor immunosuppressive microenvironment. As a highly inflammatory form of immunogenic cell death (ICD), pyroptosis provides a great opportunity to alleviate immunosuppression and promote systemic immune responses in solid tumors. Herein, membrane-targeted photosensitizer TBD-3C with aggregation-induced emission (AIE) feature to trigger pyroptosis-aroused cancer immunotherapy via photodynamic therapy (PDT) is applied. The results reveal that pyroptotic cells induced by TBD-3C could stimulate M1-polarization of macrophages, cause maturation of dendritic cells (DCs), and activation of CD8+ cytotoxic T-lymphocytes (CTLs). Pyroptosis-aroused immunological responses could convert immunosuppressive "cold" tumor microenvironment (TME) to immunogenic "hot" TME, which not only inhibits primary pancreatic cancer growth but also attacks the distant tumor. This work establishes a platform with high biocompatibility for light-controlled antitumor immunity and solid tumor immunotherapy aroused by cell pyroptosis.


Asunto(s)
Neoplasias Pancreáticas , Microambiente Tumoral , Humanos , Factores Inmunológicos/farmacología , Inmunoterapia/métodos , Neoplasias Pancreáticas/terapia , Fármacos Fotosensibilizantes/farmacología , Piroptosis , Neoplasias Pancreáticas
4.
J Nanobiotechnology ; 20(1): 85, 2022 Feb 17.
Artículo en Inglés | MEDLINE | ID: mdl-35177078

RESUMEN

The therapeutic effect of chemotherapeutics such as gemcitabine against pancreatic cancer is considerably attenuated by immune-suppressive tumor microenvironment. Improvement of chemotherapeutic efficacy by targeting tumor-associated macrophage and reprograming tumor microenvironment to enhance their efficacy may become a promising strategy. To this end, we developed a biomimetic dual-targeting nanomedicine (PG@KMCM) where gemcitabine-loaded poly (lactic-co-glycolic acid) (PLGA) nanoparticles are coated with a layer of bioengineered cancer cell membrane that stably expresses peptides targeting M2-like macrophages (M2pep) while reserving tumor-associated antigens (TAAs). The PG@KMCM nanomedicine enables the simultaneous targeted delivery of gemcitabine to pancreatic tumor sites and TAMs to potentiate its therapeutic effects. Furthermore, the combination of an immune checkpoint inhibitor (PD-L1 antibody) with PG@KMCM synergistically enhanced the anti-tumoral effect by reprogramming the immune-suppressive tumor microenvironment, including the elimination of PD-L1-positive macrophages and the downregulation of PD-L1 expression. Our study proved dual-targeting PG@KMCM nanomedicine in combination with PD-L1 immune checkpoint inhibitor therapy is able to effectively reprogram the tumor microenvironment and kill pancreatic cancer cells to enhance overall therapeutic potential.


Asunto(s)
Nanomedicina , Neoplasias Pancreáticas , Biomimética , Línea Celular Tumoral , Humanos , Inmunoterapia , Neoplasias Pancreáticas/tratamiento farmacológico , Microambiente Tumoral
5.
Org Biomol Chem ; 17(29): 7042-7054, 2019 07 24.
Artículo en Inglés | MEDLINE | ID: mdl-31304502

RESUMEN

A sequential Rh(i)-catalyzed vinylation/[2 + 1]carbocyclization between enynes and diazo compounds has been developed. This transformation features a wide range of enynes and acceptor/acceptor diazo compounds, providing easy access to versatile vinyl-substituted azabicyclo[3.1.0]hexanes having a broad tolerance to functional groups.

6.
Vet Microbiol ; 231: 226-231, 2019 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-30955814

RESUMEN

The porcine respiratory and reproductive syndrome virus (PRRSV) nucleocapsid (N) protein is a multiphosphorylated protein.It has been proved that the phosphorylation of N protein could regulate the growth ability of PRRSV in Marc-145 cells. However, further investigation is needed to determine whether phosphorylation of the N protein could affect PRRSV virulence in piglets. In this study, we confirmed that the mutations could impair PRRSV replication ability in porcine primary macrophages (PAMs) as they did in Marc-145 cells. The animal experiments suggested that the pathogenicity of the mutated virus (A105-120) was significantly reduced compared with parent strain (XH-GD). Our results suggested that the phosphorylation of the N protein contributes to virus replication and virulence. This study is the first to identify a specific modification involved in PRRSV pathogenicity. Mutation of PTMs sites is also a novel way to attenuate PRRSV virulence. The mutations could be a marker in a vaccine. In conclusion, our study will improve our understanding of the molecular mechanisms of PRRSV pathogenicity.


Asunto(s)
Mutación , Síndrome Respiratorio y de la Reproducción Porcina/virología , Virus del Síndrome Respiratorio y Reproductivo Porcino/patogenicidad , Virulencia/genética , Animales , Línea Celular , Replicación del ADN , Proteínas de la Nucleocápside/química , Fosforilación , Síndrome Respiratorio y de la Reproducción Porcina/patología , Virus del Síndrome Respiratorio y Reproductivo Porcino/genética , ARN Viral/genética , Porcinos , Replicación Viral
7.
Org Lett ; 20(13): 3980-3983, 2018 07 06.
Artículo en Inglés | MEDLINE | ID: mdl-29939031

RESUMEN

An unprecedented intermolecular nucleophilic attack of C═X bonds (X = O and S) on the rhodium(I)-carbenes has been developed. This transformation allows for the coupling-cyclization of aroylamides with α-diazoketones and provides concise access to 2,4,5-trisubstituted 1,3-oxazoles and 1,3-thiazoles with a broad tolerance of functional groups.

8.
Int J Surg ; 51: 191-198, 2018 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-29360613

RESUMEN

OBJECTIVE: Hepatectomy for hepatolithiasis can be performed by following an open approach or a minimally invasive surgery (MIS) approach. MIS is associated with theoretical advantages, but there is no consensus regarding to the best treatment method for hepatolithiasis. The objective of this study was to evaluate the clinical outcomes of MIS hepatectomy compared with those of open hepatectomy in hepatolithiasis patients. METHODS: A systematic literature search was performed using PubMed, Embase and Cochrane Library databases. The data were analyzed with Stata version 12.0 software. Meta-regression analysis was used to explore the potential sources of heterogeneity. Egger's tests and Begg's funnel plots were employed to evaluate the publication biases. RESULTS: In total, 12 nonrandomized controlled trials were identified. Compared with open hepatectomy, the volume of intraoperative blood loss was significantly less in MIS hepatectomy (SMD = -0.226, P = 0.000). The intraoperative blood transfusion rate was also lower in MIS hepatectomy (RR = 0.569, P = 0.003). A shorter length of postoperative hospital stay was noted with MIS hepatectomy (SMD = -0.537, P = 0.000). MIS hepatectomy resulted in a lower rate of postoperative complications than open hepatectomy (RR = 0.595, P = 0.000). However, MIS hepatectomy resulted in a longer operation time (SMD = 0.473, P = 0.005). No significant differences were noted between MIS and open hepatectomy in the initial stone clearance rate (RR = 1.33, P = 0.218), the final stone clearance rate (RR = 1.040, P = 0.131), the stone recurrence rate (RR = 0.558, P = 0.072) or the cholangitis recurrence rate (RR = 0.610, P = 0.285). CONCLUSIONS: MIS hepatectomy is a safe approach for hepatolithiasis patients. MIS hepatectomy significantly reduces intraoperative blood loss, blood transfusion, postoperative hospital stay time and complications. The stone clearance and recurrence rates were similar for MIS hepatectomy and open hepatectomy. Additional well-designed randomized controlled trials and Western studies are needed to confirm these findings.


Asunto(s)
Hepatectomía/métodos , Litiasis/cirugía , Hepatopatías/cirugía , Procedimientos Quirúrgicos Mínimamente Invasivos/métodos , Humanos , Tiempo de Internación , Recurrencia
9.
Org Lett ; 18(5): 1154-7, 2016 Mar 04.
Artículo en Inglés | MEDLINE | ID: mdl-26883677

RESUMEN

A novel procedure for the Cu-catalyzed systematic synthesis of phenanthridinium bromide is reported. This transformation was achieved with direct construction of central pyridinium core by using an in situ formed biaryl imine as a substrate. Tolerance of a very wide variety of N-substituents is indicated; this has never previously been disclosed by other reports. Application of this method to synthesis of the natural alkaloid bicolorine, and its derivatives, was also carried out in only three synthetic steps from commercially available compounds.


Asunto(s)
Alcaloides/síntesis química , Cobre/química , Hidrocarburos Bromados/síntesis química , Fenantridinas/síntesis química , Alcaloides/química , Catálisis , Hidrocarburos Bromados/química , Estructura Molecular , Fenantridinas/química
10.
Exp Gerontol ; 57: 29-40, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-24802989

RESUMEN

We and others previously reported that the pro-inflammatory cytokine tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß) and IL-6 significantly accumulate with age in mouse lung. This is accompanied by elevated phosphorylation of p38. Here, we further investigate whether aging affects activation of p38 signaling and the inflammatory reaction after exposure to lipopolysaccharide (LPS) in the lungs of mice in vivo and humans ex vivo. The data showed that activation of p38 peaked at 0.5h and then rapidly declined in young (2-month-old) mouse lung, after intranasal inhalation challenge with LPS. In contract, activation of p38 peaked at 24h and was sustained longer in aged (20-month-old) mice. As well as altered p38, activations of its upstream activator MKK and downstream substrate NF-κB were also changed in the lungs of aged mice, which corresponded with the absence in the early phase but delayed increases in concentrations of TNF-α, IL-1ß and IL-6. Consistent with the above observations in mice, similar patterns of p38 signaling also occurred in human lungs. Compared with younger lungs from adult-middle aged subjects, the activation of p38, MKK and NF-κB, as well as the production of pro-inflammatory cytokines were significantly increased in the lungs of older subjects ex vivo. Exposure of human lung cells to LPS induced rapid activation of p38, MKK and NF-κB in these cells from adult-middle aged subjects, but not older subjects, with increases in the production of the pro-inflammatory cytokines. The LPS-induced rapid activation in the lung cells from adult-middle aged subjects occurred as early as 0.25h after exposure, and then declined. Compared with adult-middle aged subjects, the LPS exposure did not induce marked changes in the early phase, either in the activation of p38, MKK and NF-κB, or in the production of TNF-α, IL-1ß or IL-6 in the lung cells from older subjects. In contrast, these changes occurred relatively late, peaked at 16h and were sustained longer in the lungs of older subjects. These data support the hypothesis that the sustained activation of the p38 signaling pathway at baseline and the absence in the early phase but delayed of p38 signaling pathway response to LPS in the elderly may play important roles in increased susceptibility of aged lungs to inflammatory injury.


Asunto(s)
Envejecimiento/metabolismo , Pulmón/metabolismo , Sistema de Señalización de MAP Quinasas , Estrés Fisiológico , Adulto , Anciano , Envejecimiento/patología , Animales , Citocinas/metabolismo , Humanos , Lipopolisacáridos , Pulmón/patología , Masculino , Ratones Endogámicos C57BL , Persona de Mediana Edad , FN-kappa B/metabolismo , beta-Galactosidasa/metabolismo
11.
Org Lett ; 15(11): 2742-5, 2013 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-23672507

RESUMEN

Novel procedures for the [Pd]/[Ag]/TFA system catalyzed cascade reactions of nitrile directed remote C-H and dual C-H bond activation with insertion of nitrile were developed, which afforded variously polysubstituted fluorenones in moderate to good yields with tolerance of a wide variety of substrates.


Asunto(s)
Fluorenos/síntesis química , Nitrilos/química , Paladio/química , Catálisis , Fluorenos/química , Enlace de Hidrógeno , Estructura Molecular , Estereoisomerismo
12.
Exp Gerontol ; 48(8): 717-26, 2013 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23583952

RESUMEN

Aging is an inevitable process associated with immune imbalance, which is characterized by a progressive functional decline in major organs, including lung. However, effects of altered Th1/Th2 commitment on lung senescence are largely unknown. To examine effects of altered Th1/Th2 balance on lung aging, we measured proportions of Th1 and Th2 cells and expression of cytokines, chemokines, collagen deposition and other relevant physiological and pathological parameters in 2- and 20-months-old (mo) CXCR3-deficient (CXCR3(-/-)) C57BL/6J mice compared with wild-type (WT) mice. There was a significant weight-loss observed in 20-mo CXCR3(-/-) mice compared with the same aged WT group. Although lung function and structure changed with age in both groups, central airway resistance (Rn), tissue elastance (H) and damping (G) were significantly lower in 20-mo CXCR3(-/-) mice than those of WT mice. In contrast, the whole lung volume (V(L)), the mean linear intercept length of alveolar (L(m)), and the total lung collagen content were significantly elevated in 20-mo CXCR3(-/-) mice. With aging, the lungs of WT mice had typical Th1-type status (increased population of Th1 cells and concentrations of cytokine IFN-γ and CXCR3 ligands) while CXCR3(-/-) mice showed Th2-type polarization (decreased proportion of Th1 cells and concentrations of CXCR3 ligands but increased level of IL-4). Our data suggest that Immunosenescence is associated with lung aging, and that altered Th1/Th2 imbalance favors Th2 predominance in CXCR3(-/-) mice, which contributes to the process of accelerated lung aging in this model.


Asunto(s)
Envejecimiento/patología , Pulmón/patología , Receptores CXCR3/deficiencia , Células TH1/patología , Balance Th1 - Th2 , Células Th2/patología , Envejecimiento/metabolismo , Animales , Recuento de Células , Quimiocinas/metabolismo , Colágeno/metabolismo , Citocinas/metabolismo , Pulmón/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Modelos Animales , Tamaño de los Órganos , Receptores CXCR3/genética , Receptores CXCR3/metabolismo
13.
Electrophoresis ; 29(12): 2587-92, 2008 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-18576403

RESUMEN

A rapid test of whether a laboratory sample contains any microorganisms is important and necessary for many areas of science and technology. Currently, most of the standard procedures for the detection of aerobic bacteria, anaerobic bacteria and fungi, require the preparation of microbial cultures in respective growth media, which are dramatically slow. Different approaches providing fast analysis such as CE are becoming more desired. To compensate for the natural electrophoretic heterogeneity of microbes, various buffer additives were examined to stack all bacteria and fungi in a sample plug into a single peak. This peak was removed from the molecular contaminants in the sample to prevent false positives. Both cationic surfactants and ionic liquids (IL) were investigated as run buffer additives and they are both widely applicable to different species of bacteria and fungi. Given that high concentrations of surfactants can potentially lyse cells, dicationic IL offer attractive auxiliary buffer additives for use in CE-based sterility tests. The analysis can be completed in 10 min, thus providing a great advantage over traditional direct inoculation methods that require several weeks to complete.


Asunto(s)
Técnicas Microbiológicas/métodos , Tensoactivos , Bacterias , Cationes , Electroforesis Capilar/métodos , Hongos , Imidazoles/química , Compuestos de Amonio Cuaternario/química
14.
Anal Chem ; 80(7): 2612-6, 2008 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-18315009

RESUMEN

The analysis of anions remains an important task for many areas of science, and new sensitive analytical methods continue to be of great interest. In this study, we present the use of 17 tricationic reagents for use as gas-phase ion pairing agents for divalent anions. When the anion pairs with the tricationic reagent, an overall positive charge is retained and enables detection by ESI-MS in the positive mode. The 17 tricationic reagents were made from 1 of 4 core structures and 7 terminal charged groups. The effect of these structural elements on the detection sensitivity of the complex is examined empirically. A comparison of signal-to-noise ratios achieved in positive and negative modes also is presented.

15.
J Chromatogr A ; 1191(1-2): 199-204, 2008 May 16.
Artículo en Inglés | MEDLINE | ID: mdl-18262198

RESUMEN

A new chiral stationary phase for gas chromatography was prepared by covalently attaching a diproline chiral selector that has proven to be effective in liquid chromatography to a methylhydrosiloxane-dimethylsiloxane copolymer. With this new chiral stationary phase for GC, racemic aromatic alcohols could be resolved without derivatization. Racemic aromatic and aliphatic amines could also be resolved after derivatization of the amino groups with trifluoroacetic anhydride or isopropyl isocyanate. On this stationary phase, the isopropyl isocyanate derivatives of amines showed higher enantioselectivity than the trifluoroacetic anhydride derivatives. In both the enantiomeric separations of alcohols and derivatized amines, the aromatic racemic analytes showed higher enantioselectivities than their aliphatic analogs. Some of the alpha-amino and alpha-hydroxy aromatic acids could also be separated after derivatization to N-trifluoroacetyl methyl esters for amino acids or O-trifluoroacetyl methyl esters for hydroxyl acids.


Asunto(s)
Alcoholes/aislamiento & purificación , Aminas/aislamiento & purificación , Cromatografía de Gases/métodos , Aminoácidos/aislamiento & purificación , Cromatografía de Gases/instrumentación , Hidroxiácidos/aislamiento & purificación , Prolina/análogos & derivados , Prolina/química , Siloxanos/síntesis química , Estereoisomerismo
17.
Chirality ; 19(2): 99-105, 2007 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-17096376

RESUMEN

A chiral column, with decaproline as the chiral selector, has broad chiral selectivity. To understand the separation mechanism of this chiral column, multiple spectroscopic techniques, including optical rotation, electronic circular dichroism, infrared absorption and vibrational circular dichroism, have been used here to study the conformation of the decaproline oligomer in isopropanol(IPA)/dichloromethane(DCM) mixtures. These studies indicate that decaproline oligomer adopts polyproline II conformation in IPA/DCM solvent system (0% IPA approximately 100% IPA). Hydrogen bonding interactions between C=O groups of decaproline and IPA molecules increase as the content of IPA in the solvent mixture increases up to 60% and become less significant from then onwards. These spectroscopic observations are found to have a good correlation with the enantiomeric separation of racemic 2,2,2-trifluoro-1-[10-(2,2,2-trifluoro-1-hydroxy-ethyl-anthracen-9-yl]-ethanol by the decaproline column.


Asunto(s)
2-Propanol , Dicroismo Circular , Cloruro de Metileno , Prolina/análogos & derivados , Solventes , Rotación Óptica , Espectrofotometría Infrarroja
18.
J Chromatogr A ; 1113(1-2): 109-15, 2006 Apr 28.
Artículo en Inglés | MEDLINE | ID: mdl-16563406

RESUMEN

Seven new stationary phases with different number of proline units and/or different linkage to silica gel were prepared and evaluated in order to improve the performance of proline chiral stationary phases. The average separation factor achieved with the 53 analytes increases with the number of proline units in the stationary phases. When the proline peptides are directly attached to the 3-methylaminopropyl silica gel without using the 6-methylaminohexanoic acid linker, the stationary phases perform better overall. For decaproline chiral stationary phase 8, the separation also depends on the mobile phase system used. For this stationary phase, the CH2Cl2/hexanes/2-propanol system significantly outperforms the 2-propanol/hexanes system. For the 53 analytes tested, the separation factors achieved with this stationary phase compare well with those for three commercial columns.


Asunto(s)
Cromatografía/instrumentación , Prolina/química , Estereoisomerismo
19.
J Chromatogr A ; 1109(2): 307-11, 2006 Mar 24.
Artículo en Inglés | MEDLINE | ID: mdl-16483587

RESUMEN

The role of 9-fluorenylmethoxycarbonyl (Fmoc) in previously reported proline enantioselective stationary phases was investigated. Seven stationary phases in which the Fmoc group was replaced by other groups were prepared and evaluated in normal phase mode. The Fmoc group proved nonessential for the broad enantioselectivity observed, as the stationary phase with a trimethylacetyl (Tma) group proved much more effective than the one with the Fmoc group. For the 53 analytes studied, the stationary phase with the Tma group resolved 39, while the one with the Fmoc group resolved 19. Separation factors achieved for the stationary phase with the Tma group are also significantly higher than those for the stationary phase with the Fmoc group. The stationary phase with the (-)-2-(2,4,5,7-tetranitro-9-fluorenylideneaminooxy)propionyl (Tapa) group provides very different selectivity profile when compared to the one with the Tma group. In most of the proline stationary phases studied, pi-pi interaction is not the dominant interaction for the enantioselective recognition.


Asunto(s)
Fluorenos/química , Prolina/química , Estereoisomerismo
20.
J Chromatogr A ; 1102(1-2): 176-83, 2006 Jan 13.
Artículo en Inglés | MEDLINE | ID: mdl-16266709

RESUMEN

Several new stationary phases were prepared to study the structure-activity relationship of the chiral resolution of racemic 1,1'-bi-2-naphthol with a modified dipeptide Asn-Asn selector. The number of amino acid, the side chain protecting groups of the amino acid, and the Fmoc end-capping group all proved important for enantioselectivity. The linker also influenced enantioselectivity. Influence of the length of the linker appears to be related to the accessibility of chiral selectors. The bond through which the selector is attached to the linker proved important. Based on these results, it is postulated that hydrogen bonding interactions between one side chain amide group of one Asn and the oxygen on the backbone of another Asn with the two hydroxyl groups of the analyte play an important role in the resolution of racemic 1,1'-bi-2-naphthol with the modified dipeptide Asn-Asn selector.


Asunto(s)
Dipéptidos/química , Naftoles/aislamiento & purificación , Indicadores y Reactivos/química , Estereoisomerismo
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