Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 19 de 19
Filtrar
1.
Anal Methods ; 16(17): 2702-2706, 2024 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-38625145

RESUMO

Herein, a novel ratiometric sensor for fluorimetric and smartphone-assisted visual detection of Al3+ in environmental water was developed based on the target-regulated formation of Eu metal-organic frameworks (Eu MOFs). By employing 2-[4-(2-hydroxyethyl) piperazin-1-yl] ethanesulfonic acid (Hepes), Eu3+ and tetracycline (TC) as raw materials, Eu MOFs with red emission were facilely synthesized through the coordination of Eu3+ with Hepes and TC. However, upon the introduction of Al3+, a higher affinity of TC towards Al3+ resulted in the formation of a TC-Al3+ complex with green fluorescence and inhibited the generation of Eu MOFs. This led to an increase in green fluorescence and a decrease in red fluorescence accompanied by the fluorescence color of the solution changing from red to green under the illumination of the UV lamp. Thus, a ratiometric sensor for fluorimetric and the smartphone-assisted visual detection of Al3+ was established. The ratiometric sensor exhibited high sensitivity for Al3+ detection with a detection limit of 0.14 µM for fluorescence detection and 1.21 µM for visual detection. Additionally, the proposed strategy was successfully applied to detect Al3+ in the environmental water samples with satisfactory results, indicating great application prospects for environmental monitoring.

2.
Front Cardiovasc Med ; 10: 1126889, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36970336

RESUMO

Objectives: The aim of this study is to assess the influence of cardiopulmonary coupling (CPC) based on RCMSE on the prediction of complications and death in patients with acute type A aortic dissection (ATAAD). Background: The cardiopulmonary system may be nonlinearly regulated, and its coupling relationship with postoperative risk stratification in ATAAD patients has not been studied. Methods: This study was a single-center, prospective cohort study (ChiCTR1800018319). We enrolled 39 patients with ATAAD. The outcomes were in-hospital complications and all-cause readmission or death at 2 years. Results: Of the 39 participants, 16 (41.0%) developed complications in the hospital, and 15 (38.5%) died or were readmitted to the hospital during the two-year follow-up. When CPC-RCMSE was used to predict in-hospital complications in ATAAD patients, the AUC was 0.853 (p < 0.001). When CPC-RCMSE was used to predict all-cause readmission or death at 2 years, the AUC was 0.731 (p < 0.05). After adjusting for age, sex, ventilator support (days), and special care time (days), CPC-RCMSE remained an independent predictor of in-hospital complications in patients with ATAAD [adjusted OR: 0.8 (95% CI, 0.68-0.94)]. Conclusion: CPC-RCMSE was an independent predictor of in-hospital complications and all-cause readmission or death in patients with ATAAD.

3.
Front Genet ; 13: 1004610, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36386814

RESUMO

Chronic kidney disease (CKD) is a serious disease that endangers human health. It is reported that inhibiting renal cell apoptosis can delay the progress of CKD. Our previous study found that the mice with protein phosphatase Mg2+/Mn2+ dependent 1K (PPM1K) gene deletion had obvious symptoms of glomerular vascular and interstitial vascular dilatation, congestion and hemorrhage, glomerular hemorrhage and necrosis, interstitial fibrous tissue proliferation, decreased urinary creatinine clearance, and increased urinary protein level. In addition, studies have found that PPM1K is essential for cell survival, apoptosis and metabolism. However, no study has confirmed that PPM1K can inhibit renal cell apoptosis. In this study, PPM1K was overexpressed in human kidney-2 cells (HK-2), and the biological process of differentially expressed genes and its effect on apoptosis were comprehensively screened by RNA sequencing (RNA-seq). Through sequencing analysis, we found that there were 796 differentially expressed genes in human renal tubular epithelial cells transfected with PPM1K gene, of which 553 were down-regulated and 243 were up-regulated. Enrichment analysis found that differentially expressed genes may play an important role in amino acid metabolism and biosynthesis. In the GO analysis functional pathway list, we also found that multiple genes can be enriched in apoptosis related pathways, such as G0S2, GADD45A, TRIB3, VEGFA, NUPR1 and other up-regulated genes, and IL-6, MAGED1, CCL2, TP53INP1 and other down-regulated genes. Then we verified these differentially expressed genes by RT-PCR, and found that only the RT-PCR results of G0S2, VEGFA and NUPR1 were consistent with the transcriptome sequencing results. We believe that G0S2, VEGFA, NUPR1 and other genes may participate in the apoptosis process of HK-2 cells induced by PPM1K.In conclusion, these findings provide some data support for the study of HK-2 cell apoptosis mechanism, and also provide a scientific theoretical basis for further study of the effect of PPM1K on kidney disease.

4.
Artigo em Inglês | MEDLINE | ID: mdl-35795276

RESUMO

Objective: Cervical cancer is a common cancer in women. The drug resistance of chemotherapeutic agents has always been an urgent problem to be solved in clinics. The purpose of this study was to determine the role of tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein gamma polypeptide (YWHAG) in cervical cancer and explore the effect of Curcuma on cervical cancer and its possible mechanism. Methods: YWHAG expression in cervical cancer was confirmed using The Cancer Genome Atlas (TCGA) database. Then, the effects of YWHAG on the proliferation and invasion of HeLa and C33A cervical cancer cells were detected by the cell counting kit-8 (CCK-8) and transwell assay. The relationship between YWHAG and the pentose phosphorylation pathway was further studied. CCK-8, Edu, and quantitative real-time polymerase chain reaction were used to confirm that Curcuma inhibited the sensitivity of YWHAG to cisplatin chemotherapy and to detect the expression of apoptosis-related proteins. Results: YWHAG was highly expressed in cervical cancer and was associated with poor prognosis. The proliferation and invasion abilities of HeLa and C33A cells decreased after YWHAG knockout. The TCGA database of cervical cancer showed a positive correlation between YWHAG and hypoxia-inducible factor-1 subunit alpha (HIF-1α) expression. YWHAG expression increased with HIF-1α overexpression. YWHAG knockdown reduced the protein expression in the pentose phosphorylation pathway. Curcumenol inhibited YWHAG expression. Compared with cisplatin alone, curcumenol combined with cisplatin can reduce cell proliferation and invasion and reduce matrix metalloproteinase (MMP) 2 and MMP9 expression. It can also increase apoptosis, decrease B cell lymphoma 2 (Bcl-2) expression, and increase the expression of Bcl-2 antagonist X, caspase-3, and polyadenosine diphosphate-ribose polymerase. Conclusion: YWHAG can interact with HIF-1α to affect the proliferation and invasion of cervical cancer cells. YWHAG knockout can reduce the expression of pentose phosphorylation pathway-related proteins. Curcumenol can enhance cisplatin to inhibit cancer cell proliferation, migration, and invasion and promote tumor cell apoptosis. The combination of drugs may promote the apoptosis of cervical cancer cells through the YWHAG pathway.

5.
Front Cardiovasc Med ; 8: 609590, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34746245

RESUMO

Background: High-power radiofrequency (RF) catheter ablation was considered as a promising alternative strategy to conventional-power ablation in the treatment of patients with atrial fibrillation (AF). This study sought to compare the efficacy and safety of high-power energy delivery to that of conventional-power setting in AF catheter ablation. Methods: We performed a systematic review of relevant literature in Pubmed, Embase, Cochrane library, and Google Scholar database. Sixteen eligible studies totaling 3,307 patients (1,929 for high-power ablation; 1,378 for conventional-power ablation) met inclusion criteria. Results: During a median 12 month follow-up, high-power ablation showed a significantly higher AF/atrial tachycardia-free survival rate in comparison with conventional-power ablation (risk ratio [RR] 1.09, 95% CI 1.02 to 1.15, p = 0.008). Notably, a high-power strategy convincingly decreased the procedure time (weighted mean difference [WMD] -46.11 min, 95% CI -59.15 to -33.07, p < 0.001) and RF ablation time (WMD -19.19 min, 95% CI -24.47 to -13.90, p < 0.001), along with reduced fluoroscopy time (WMD -7.82 min, 95% CI -15.13 to -0.68, p = 0.036). In addition, there was no perceptible difference in the potential risk of procedure-related complications between these two approaches (RR 0.81, 95% CI 0.48 to 1.37, p = 0.428). Conclusions: High-power RF catheter ablation was associated with an improvement in long-term sinus rhythm maintenance for treatment of AF, without exacerbating the risk of adverse events during the procedure. Impressively, high-power pulmonary vein isolation had the potential to shorten the application duration and minimize fluoroscopic exposure.

6.
Heart Vessels ; 36(5): 686-692, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33394104

RESUMO

The aim of this study is to assess serum human epididymis protein 4 (HE-4) levels as a biomarker for predicting the recurrence of atrial fibrillation (AF) after catheter ablation. This was a prospective observational study that enrolled one hundred eighty-four consecutive nonvalvular AF patients (65 persistent, 119 paroxysmal) who were eligible for their first ablation. Multiple Cox proportional hazards models and Kaplan-Meier curve analyses were used to test the association between serum HE-4 levels and AF recurrence after catheter ablation. During the 12-month follow-up, we observed that 47 patients (25.5%) experienced AF recurrence. Patients were divided into tertiles of HE-4 level (T1: < 50 pmol/L; T2: ≥ 50 pmol/L). The AF recurrence rate of higher serum HE-4 level patients was significantly increased (34.6% vs 13.8%, P < 0.001). Generalized additive models were used to visually assess functional relationships between the serum HE-4 levels and the risk of AF recurrence. When stratified with serum levels as the cut-off value, Kaplan-Meier analysis showed that patients with serum HE-4 levels (> 50 pmol/L) had a significantly increased risk of AF recurrence. In addition, multivariate Cox proportional hazard modelling revealed that HE-4 (≥ 50 pmol/L) (HR 2.65; 95% CI 1.34, 5.27, P = 0.005) was independent predictors of AF recurrence. Serum HE-4 levels in patients with AF are associated with postoperative recurrence of AF, and high HE-4 levels are an independent predictor of AF recurrence after ablation.


Assuntos
Fibrilação Atrial/sangue , Ablação por Cateter/métodos , Proteína 2 do Domínio Central WAP de Quatro Dissulfetos/metabolismo , Fibrilação Atrial/fisiopatologia , Fibrilação Atrial/cirurgia , Biomarcadores/sangue , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Recidiva , Estudos Retrospectivos , Fatores de Risco
7.
Oxid Med Cell Longev ; 2020: 1241065, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32685084

RESUMO

AIMS: Myocardial reperfusion damage after severe ischemia was an important issue during a clinical practice. However, the exacted pathogenesis involved remained unclear and also lacks effective interventions. Melatonin was identified to exert protective effects for alleviating the myocardial I/R injury. This meta-analysis was determined to evaluate the efficacy of melatonin treatment against reperfusion insult and further summarize potential molecular and cellular mechanisms. METHODS AND RESULTS: 15 eligible studies with 211 animals (108 received melatonin and 103 received vehicle) were included after searching the databases of PubMed, MEDLINE, Embase, and Cochrane. Pretreatment with melatonin was associated with a significant lower infarct size in comparison with vehicle in myocardial I/R damage (WMD: -20.45, 95% CI: -25.43 to -15.47, p < 0.001; I 2 = 91.4%, p < 0.001). Evidence from subgroup analyses and sensitivity analysis indicated the robust and consistent cardioprotective effect of melatonin, while the metaregression also did not unmask any significant interactions between the pooled estimates and covariates (i.e., sample size, state, species, study type, route of administration, and duration of reperfusion, along with timing regimen of pretreatment). Accordingly, melatonin evidently increased EF (WMD: 17.19, 95% CI: 11.08 to 23.29, p < 0.001; I 2 = 77.0%, p < 0.001) and FS (WMD: 14.18, 95% CI: 11.22 to 17.15, p < 0.001; I 2 = 3.5%, p = 0.387) in the setting of reperfusion damage. CONCLUSIONS: Melatonin preadministration conferred a profound cardioprotection against myocardial I/R injury in preclinical studies.


Assuntos
Melatonina/uso terapêutico , Traumatismo por Reperfusão Miocárdica/tratamento farmacológico , Animais , Modelos Animais de Doenças , Melatonina/farmacologia , Camundongos , Ratos
8.
Int J Biol Sci ; 16(11): 1972-1988, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32398964

RESUMO

Silibinin is a traditional medicine and utilized for liver protection with antioxidant, anti-inflammation and anti-apoptosis properties. However, its role in myocardial I/R injury and the mechanism involved is currently unknown. In the present study, Silibinin treatment improves cardiac function and limits infarct size, and subsequently inhibits fibrotic remodeling in mice with myocardial I/R injury. Mechanistically, silibinin reduces cardiomyocytes apoptosis, attenuates mitochondrial impairment and endoplasmic reticulum (ER) stress, alleviates ROS generation, neutrophil infiltration and cytokines release. Consistently, silibinin prevents H9C2 cells from hypoxia/reperfusion-induced cell death, oxidative stress and inflammation in vitro. Furthermore, H9C2 cells treated with silibinin blocks NF-κB signaling activation by inhibiting IKKα phosphorylation, IκBα degradation and p65 NF-κB nuclear translocation during hypoxia/ reperfusion. In addition, silibinin plus BAY 11-7082 (a selected NF-κB inhibitor) do not provide incremental benefits in improving myocytes apoptosis, oxidative stress and inflammation in comparison with NF-κB signaling inhibition only. Thus, silibinin-mediated cardioprotection in myocardial I/R injury is associated with decreased apoptosis, oxidative stress and inflammatory response through deactivation of NF-κB pathway.


Assuntos
Isquemia Miocárdica/patologia , Isquemia Miocárdica/prevenção & controle , Miócitos Cardíacos/efeitos dos fármacos , Nitrilas/farmacologia , Traumatismo por Reperfusão/tratamento farmacológico , Silibina/farmacologia , Sulfonas/farmacologia , Animais , Caspases/genética , Caspases/metabolismo , Linhagem Celular , Sobrevivência Celular , Regulação da Expressão Gênica/efeitos dos fármacos , Masculino , Malondialdeído , Camundongos , Camundongos Endogâmicos C57BL , Substâncias Protetoras/farmacologia , Espécies Reativas de Oxigênio/metabolismo
9.
Clin Chim Acta ; 502: 201-206, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31758935

RESUMO

BACKGROUND: Previous studies have shown that plasma cancer antigen-125 (CA-125) is closely related to heart failure and new-onset atrial fibrillation (AF), but no study reported the relationship between CA-125 concentrations and advanced recurrence of AF ablation. This research is the first to describe CA-125 as a biomarker for the recurrence of AF after ablation. METHODS: A total of 422 AF patients undergoing catheter ablation were included in this study. RESULTS: During the 1-y follow-up, 326 patients (77.25%) maintained a sinus rhythm, whereas 83 patients (20.44%) presented AF recurrence. The patients with AF recurrence showed higher CA-125 concentrations at baseline than those with maintained sinus rhythm (P = 0.0001). Multivariate Cox proportional hazards regression analyses revealed that persistent AF (HR 2.212; 95% CI: 1.396-3.504, P = 0.001) and CA-125 concentration (HR, 1.003; 95% (CI): 1.000-1.005, P = 0.019) were independent predictors of AF recurrence. According to the receiver operating characteristic (ROC) analysis, CA-125 yielded an optimal cut-off value of 11.05 U/ml, and its sensitivity and specificity reached 65.6% and 85.0%, respectively. In addition, the area under the curve (AUC) value spanned 80.3% (95% CI: 0.750-0.857, P < 0.0001). Moreover, the results of the subgroup analysis indicated that patients with persistent atrial fibrillation have higher concentrations of CA-125 and have an increased risk of the recurrence of AF. CONCLUSIONS: High CA-125 concentration is an independent predictor of AF recurrence after 1 y of AF ablation, especially in patients with persistent AF.


Assuntos
Fibrilação Atrial/sangue , Fibrilação Atrial/cirurgia , Antígeno Ca-125/sangue , Ablação por Cateter , Idoso , China , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Recidiva , Estudos Retrospectivos
10.
Oxid Med Cell Longev ; 2019: 5793867, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31182995

RESUMO

AIMS: Myocardial ischemia/reperfusion (I/R) injury is a leading cause of cardiomyocyte loss and subsequent ventricular dysfunction after restoring the coronary blood flow and contributes to considerable increase in morbidity and mortality. Resveratrol has been declared to confer cardioprotection against in vivo and ex vivo myocardial I/R injury. Here, we have sought to investigate the effects of preconditioning with resveratrol on myocardial I/R damage across the small animal studies. METHODS AND RESULTS: The MEDLINE, Google Scholar, PubMed, and Cochrane databases were searched for preclinical studies investigating resveratrol vs. vehicle published from the inception to July 2018. Eventually, 10 in vivo and 7 ex vivo studies with 261 animals (130 for resveratrol; 131 for vehicle) were included for meta-analysis. Pooled estimates for primary outcomes demonstrated that pretreatment with resveratrol significantly reduced the infarct size after myocardial I/R injury irrespective of in vivo (weighted mean difference (WMD): -13.42, 95% CI: -16.63 to -10.21, P ≤ 0.001) or ex vivo (WMD: -15.05, 95% CI: -18.23 to -11.86, P ≤ 0.001) studies. Consistently, stratified analysis according to the reperfusion duration, route of administration, or timing regimen of pretreatment all showed the infarct-sparing benefit of resveratrol. Metaregression did not indicate any difference in infarct size based on species, sample size, state, route of administration, reperfusion duration, and timing regimen of pretreatment. Meanwhile, sensitivity analysis also identified the cardioprotection of resveratrol with robust results in spite of significant heterogeneity. CONCLUSIONS: Preconditioning with resveratrol appears to prevent the heart from I/R injury in comparison with vehicle, as evidenced by limited infarct size in a preclinical setting. Studies with large animals or randomized controlled trials will add more evidence and provide the rationale for clinical use.


Assuntos
Traumatismo por Reperfusão Miocárdica/tratamento farmacológico , Resveratrol/uso terapêutico , Animais , Traumatismo por Reperfusão Miocárdica/metabolismo , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/metabolismo
11.
Biol Trace Elem Res ; 179(1): 59-69, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28111709

RESUMO

Sodium fluoride (NaF) is a source of fluoride ions used in many applications. Previous studies found that NaF suppressed the proliferation of osteoblast MC3T3 E1 cells and induced the apoptosis of chondrocytes. However, little is known about the effects of NaF on human lung BEAS-2B cells. Therefore, we investigated the mode of cell death induced by NaF and its underlying molecular mechanisms. BEAS-2B cells were treated with NaF at concentrations of 0, 0.25, 0.5, 1.0, 2.0, and 4.0 mmol/L. Cell viability decreased and apoptotic cells significantly increased as concentrations of NaF increased over specific periods of time. The IC50 of NaF was 1.9 and 0.9 mM after 24 and 48 h, respectively. The rates of apoptosis increased from 4.8 to 37.7% after NaF exposure. HE staining, electron microscopy, and single cell gel electrophoresis revealed that morphological changes of apoptosis increased with exposure concentrations. RT-PCR and Western blotting were used to detect the apoptotic pathways. The expressions of bax, caspase-3, caspase-9, p53, and the cytoplasmic CytC of the NaF groups increased, while bcl-2 and mitochondrial CytC decreased compared with that of the control group (P < 0.05). Further, the fluorescence intensities of ROS in the NaF groups were higher than those in the control group, and the membrane potential of mitochondria in the NaF group was significantly lower than that of the control group (P < 0.05). These findings suggested that NaF induced apoptosis in the BEAS-2B cells through mitochondria-mediated signal pathways. Our study provides the theoretical foundation and experimental basis for exploring the mechanisms of human lung epithelial cell damage and cytotoxicity induced by fluorine.


Assuntos
Apoptose/efeitos dos fármacos , Fluoreto de Sódio/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Relação Dose-Resposta a Droga , Humanos , Microscopia Eletrônica de Varredura , Espécies Reativas de Oxigênio/metabolismo
12.
Beilstein J Org Chem ; 10: 1681-5, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25161727

RESUMO

We report the first total synthesis of trachycladines A (10 steps, 34.2% overall yield) and B (11 steps, 35.0% overall yield) by using 5-deoxy-1,2,3-tri-O-acetyl-ß-D-ribofuranose as the starting material. The critical step was the SnCl4 assisted regio- and steroselective deprotection of perbenzylated 1-O-methyl-5-deoxyribofuranose. The enzyme adenylate deaminase (EC 3.5.4.6) was successfully applied to the chemoenzymatic synthesis of trachycladines B.

13.
J Org Chem ; 78(20): 10233-9, 2013 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-24007305

RESUMO

A straightforward and efficient protocol for the construction of structurally and biologically interesting chiral flavanoids incorporating three privileged structures, i.e., chromanone, dihydropyran, and indole, has been developed on the basis of chiral bifunctional tertiary amine thiourea-catalyzed asymmetric inverse-electron-demand Diels-Alder reaction of chromone heterodienes and 3-vinylindoles, which were used as dienophiles.


Assuntos
Aminas/química , Cromonas/química , Indóis/química , Compostos de Vinila/química , Catálise , Reação de Cicloadição , Elétrons , Estrutura Molecular , Estereoisomerismo
14.
Chemistry ; 19(30): 9754-9, 2013 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-23832817

RESUMO

Carbon-carbon bond formation: A highly efficient method for the oxo-hetero-Diels-Alder reaction of 2-oxoindolin-3-ylidenes based on chiral calcium phosphate is described. In general, adducts were obtained with high yields and excellent diastereo- and enantioselectivities (up to 96 % yield, >99:1 endo/exo, >99 % ee; see scheme, Boc = tert-butoxycarbonyl).

16.
Chemistry ; 19(6): 1914-8, 2013 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-23281117

RESUMO

Anything between ureas? Spiro[isoxazolidine-3,3'-oxindole]s have been constructed by employing methyleneindolinones and nitrones as the starting materials through [3+2] annulation catalyzed by a bisthiourea. Products with three contiguous stereocenters, including one spiroquaternary stereocenter, are obtained in good yields with excellent enantio- and diastereoselectivity. The bisthiourea catalyst acts as a multiple-hydrogen-bond donor to simultaneously activate both substrates.


Assuntos
Indóis/química , Indóis/síntese química , Compostos de Espiro/química , Compostos de Espiro/síntese química , Tioureia/química , Catálise , Ciclização , Ligação de Hidrogênio , Estrutura Molecular , Oxindóis , Estereoisomerismo
17.
Molecules ; 16(4): 2971-81, 2011 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-21471936

RESUMO

Chiral C2-symmetric diamines have emerged as versatile auxiliaries or ligands in numerous asymmetric transformations. Chiral 2,2'-bispyrrolidine-based salan ligands were prepared and applied to the asymmetric aryl transfer to aldehydes with arylboronic acids as the source of transferable aryl groups. The corresponding diarylmethanols were obtained in high yields with moderate to good enantioselectivitives of up to 83% ee.


Assuntos
Aldeídos/química , Pirrolidinas/química , Catálise , Cromatografia Líquida de Alta Pressão , Cromatografia Gasosa-Espectrometria de Massas , Ligantes , Estereoisomerismo
18.
Org Lett ; 11(8): 1745-8, 2009 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-19296648

RESUMO

A novel approach to the synthesis of purines bearing functionalized carbon substituents or methyl in position 6 was developed. Under different reaction conditions, 6-halopurine derivatives could react with ethyl acetoacetate efficiently to yield 2-(purin-6-yl)acetoacetic acid ethyl esters, (purin-6-yl)acetates and 6-methylpurines respectively. No metal catalyst and ligand were required.


Assuntos
Acetoacetatos/química , Hidrocarbonetos Halogenados/química , Purinas/química , Purinas/síntese química , Técnicas de Química Combinatória , Ésteres , Estrutura Molecular
19.
J Org Chem ; 73(6): 2450-3, 2008 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-18302414

RESUMO

A novel one-step method for preparing C-5-substituted Omicron(6),5'-cyclopyrimidine nucleoside analogues is reported. This method employs molecular iodine to mediate the cyclization from the 5'-Omicron-hydroxyl group of the sugar ring and C-6 at the position of the nitrogen base in ammonia water under mild conditions without any other aprotic organic solvent.


Assuntos
Amônia/química , Nucleosídeos de Pirimidina/síntese química , Ciclização , Soluções , Água/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA