Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 166
Filtrar
1.
Zhongguo Dang Dai Er Ke Za Zhi ; 23(8): 814-820, 2021 Aug 15.
Artigo em Inglês, Chinês | MEDLINE | ID: mdl-34511171

RESUMO

OBJECTIVES: To study the survival rate and the incidence of complications of very preterm infants and the factors influencing the survival rate and the incidence of complications. METHODS: The medical data of the very preterm infants with a gestational age of <32 weeks and who were admitted to the Department of Neonatology in 11 hospitals of Jiangsu Province in China from January 2018 to December 2019 were retrospectively reviewed. Their survival rate and the incidence of serious complications were analyzed. A multivariate logistic regression analysis was used to evaluate the risk factors for death and serious complications in very preterm infants. RESULTS: A total of 2 339 very preterm infants were enrolled, among whom 2 010 (85.93%) survived and 1 507 (64.43%) survived without serious complications. The groups with a gestational age of 22-25+6 weeks, 26-26+6 weeks, 27-27+6 weeks, 28-28+6 weeks, 29-29+6 weeks, 30-30+6 weeks, and 31-31+6 weeks had a survival rate of 32.5%, 60.6%, 68.0%, 82.9%, 90.1%, 92.3%, and 94.8% respectively. The survival rate tended to increase with the gestational age (P<0.05) and the survival rate without serious complications in each gestational age group was 7.5%, 18.1%, 34.5%, 52.2%, 66.7%, 75.7%, and 81.8% respectively, suggesting that the survival rate without serious complications increased with the gestational age (P<0.05). The multivariate logistic regression analysis showed that high gestational age, high birth weight, and prenatal use of glucocorticoids were protective factors against death in very preterm infants (P<0.05), and 1-minute Apgar score ≤3 was a risk factor for death in very preterm infants (P<0.05); high gestational age and high birth weight were protective factors against serious complications in very preterm infants who survived (P<0.05), while 5-minute Apgar score ≤3 and maternal chorioamnionitis were risk factors for serious complications in very preterm infants who survived (P<0.05). CONCLUSIONS: The survival rate is closely associated with gestational age in very preterm infants. A low 1-minute Apgar score (≤3) may increase the risk of death in very preterm infants, while high gestational age, high birth weight, and prenatal use of glucocorticoids are associated with the reduced risk of death. A low 5-minute Apgar score (≤3) and maternal chorioamnionitis may increase the risk of serious complications in these infants, while high gestational age and high birth weight may reduce the risk of serious complications.


Assuntos
Doenças do Prematuro , Recém-Nascido Prematuro , Feminino , Idade Gestacional , Humanos , Recém-Nascido , Recém-Nascido de muito Baixo Peso , Gravidez , Estudos Retrospectivos , Taxa de Sobrevida
2.
J Org Chem ; 86(17): 11905-11914, 2021 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-34344150

RESUMO

Aiming at the valuable methylation process, readily available and inexpensive N,N,N',N'-tetramethylethylenediamine (TMEDA) was first identified as a new methyl source in photoredox-catalyzed transformation in this work. By virtue of this simple methylating reagent, a facile and practical protocol for the direct C-H methylation of N-heteroarenes was developed, featuring mild reaction conditions, broad substrate scope, and scalability. Mechanistic studies disclosed that a sequential photoredox, base-assisted proton shift, fragmentation, and tautomerization process was essentially involved.

3.
Org Lett ; 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-34061549

RESUMO

We herein report an unprecedented photoinduced cyclization/defluorination domino process of N-allylbromodifluoroacetamide with cyclic secondary amines. Consequently, a wide array of valuable 3-fluoro-1,5-dihydro-2H-pyrrol-2-ones were facilely prepared from readily available starting materials under mild conditions. Preliminary mechanistic investigations suggest that a radical chain propagation and amine-promoted defluorination pathway are presumably involved in this transformation.

4.
Zhongguo Dang Dai Er Ke Za Zhi ; 23(6): 593-598, 2021 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-34130781

RESUMO

OBJECTIVE: To evaluate the clinical features of preterm infants with a birth weight less than 1 500 g undergoing different intensities of resuscitation. METHODS: A retrospective analysis was performed for the preterm infants with a birth weight less than 1 500 g and a gestational age less than 32 weeks who were treated in the neonatal intensive care unit of 20 hospitals in Jiangsu, China from January 2018 to December 2019. According to the intensity of resuscitation in the delivery room, the infants were divided into three groups:non-tracheal intubation (n=1 184), tracheal intubation (n=166), and extensive cardiopulmonary resuscitation (ECPR; n=116). The three groups were compared in terms of general information and clinical outcomes. RESULTS: Compared with the non-tracheal intubation group, the tracheal intubation and ECPR groups had significantly lower rates of cesarean section and use of antenatal corticosteroid (P < 0.05). As the intensity of resuscitation increased, the Apgar scores at 1 minute and 5 minutes gradually decreased (P < 0.05), and the proportion of infants with Apgar scores of 0 to 3 at 1 minute and 5 minutes gradually increased (P < 0.05). Compared with the non-tracheal intubation group, the tracheal intubation and ECPR groups had significantly higher mortality rate and incidence rates of moderate-severe bronchopulmonary dysplasia and serious complications (P < 0.05). The incidence rates of grade Ⅲ-Ⅳ intracranial hemorrhage and retinopathy of prematurity (stage Ⅲ or above) in the tracheal intubation group were significantly higher than those in the non-tracheal intubation group (P < 0.05). CONCLUSIONS: For preterm infants with a birth weight less than 1 500 g, the higher intensity of resuscitation in the delivery room is related to lower rate of antenatal corticosteroid therapy, lower gestational age, and lower birth weight. The infants undergoing tracheal intubation or ECRP in the delivery room have an increased incidence rate of adverse clinical outcomes. This suggests that it is important to improve the quality of perinatal management and delivery room resuscitation to improve the prognosis of the infants.


Assuntos
Cesárea , Recém-Nascido Prematuro , Peso ao Nascer , China , Feminino , Idade Gestacional , Humanos , Lactente , Recém-Nascido , Gravidez , Estudos Retrospectivos
5.
J Hazard Mater ; 419: 126484, 2021 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-34186427

RESUMO

An aromatic heterocyclic compound, 2-aminobenzothiazole (ABT), was used to decorate graphene oxide (GO) by a facile hydrothermal self-assembly procedure. The developed three-dimensional (3D) GO-ABT composite aerogels could be utilized as high-powered and sustainable adsorbents for the enrichment and recovery of low concentration rare earth elements (REEs) from aqueous solutions. The composition and microstructure of GO-ABT composites were explored various characterization methods. The enrichment properties of GO-ABT composites for REEs were investigated in detail, revealing the existence of S-, N- and -NH2 in ABT, as well as the carboxyl and hydroxyl groups of GO which might act as the major REE binding sites. The adsorption of GO-ABT composites for low concentration REEs could reach equilibrium in 30 min. Our investigations confirmed that the optimal pH value of GO-ABT composites for REEs was pH 4.0-5.0. For the adsorbent regeneration study, 50.0 mg of GO-ABT15:1/120 °C/6 h composite was used toward 20.0 mL of Er3+ solutions. After ten regeneration cycles, the adsorption rates of GO-ABT composites for Er3+ remained around 100%, and the desorption rates maintained over 90%. The long-term storage of the adsorbent did not affect its adsorption ability, while desorption rates increased, indicating it possessed relatively higher stability.

6.
Zhongguo Yi Xue Ke Xue Yuan Xue Bao ; 43(2): 159-165, 2021 Apr 28.
Artigo em Chinês | MEDLINE | ID: mdl-33966692

RESUMO

Objective To investigate the clinical features of neuromyelitis optica spectrum disorders(NMOSD)with connective tissue diseases(CTD). Methods Clinical data of 16 NMOSD-CTD patients and 54 NMOSD patients admitted to the Second Affiliated Hospital of Fujian Medical University from January 2015 to February 2020 were collected.The initial symptom,intracranial lesion,spinal cord lesion,laboratory examination and treatment response were compared between the two groups. Results The incidence of Sjögren's syndrome(SS)was the highest(10/16,62.5%)in NMOSD-CTD group.The NMOSD-CTD group had significantly higher positive rate of aquaporin-4 immunoglobulin G(AQP4-IgG)in serum or cerebrospinal fluid(100% vs. 70.2%,P=0.009),higher positive rates of serum anti-nuclear antibodies,anti Sjögren's syndrome A antibodies and anti-Ro52 autoantibodies(P<0.001),as well as higher proportion of patients with the expanded disability status scale score ≥ 6(50.0% vs. 22.2%,P=0.035)than the NMOSD group.There was no significant difference between the two groups in the age of onset,visiting age,recurrence frequency,disease course,distribution of intracranial lesions,spinal cord involvement,or the effective rate of glucocorticoid pulse therapy(all P>0.05).Conclusions NMOSD is often complicated with CTD,and SS is the most common one.The positive rate of serum or cerebrospinal AQP4-IgG and the seropositivity of several other autoantibodies in NMOSD-CTD patients were higher than those in NMOSD patients.Neurological impairment in NMOSD-CTD patients were severer,which should arouse attention of clinicians.


Assuntos
Doenças do Tecido Conjuntivo , Neuromielite Óptica , Aquaporina 4 , Autoanticorpos , Doenças do Tecido Conjuntivo/complicações , Doenças do Tecido Conjuntivo/epidemiologia , Humanos , Imunoglobulina G , Neuromielite Óptica/epidemiologia
7.
Org Lett ; 23(7): 2538-2542, 2021 04 02.
Artigo em Inglês | MEDLINE | ID: mdl-33739847

RESUMO

Compounds bearing fluorinated moieties are pervasive in a wide range of pharmaceuticals and agrochemicals. The installation of fluorinated units is a persistently vital task in synthetic chemistry, where facile and manipulable assays are highly demanding. Herein, we establish a general and programmable fluorination strategy for the modular assembly of mono- and difluoromethylarenes through the controllable deprotonation and fluorination of phosphonium ylides. Moreover, the rational combination of the reaction sequence allows the rapid construction of diversified fluorine-containing arenes.

8.
Parasitol Res ; 120(4): 1281-1289, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33615408

RESUMO

Cryptosporidium is a genus of single-celled protozoa, infecting a wide range of animals and humans. Although Cryptosporidium infections of cattle have been reported in some provinces in China, there is no available information on the prevalence and predominant species of Cryptosporidium in cattle in Jiangxi province. To investigate the prevalence of Cryptosporidium in cattle in Jiangxi province of China, 556 fecal samples were collected from eight farms in four cities and the SSU rRNA locus of Cryptosporidium was amplified from the DNA of each fecal sample by PCR. The overall prevalence of Cryptosporidium was 12.8% (71/556) in cattle in Jiangxi province, with 24.3% (54/222) in Nanchang city, 7.8% (13/166) in Gao'an city, 3.7% (4/108) in Xinyu city, and 0.0% (0/60) in Ji'an city. The differences of the prevalence rates by region, breed, and age groups were statistically significant. All positive PCR products of Cryptosporidium were successfully sequenced and identified as three Cryptosporidium species, namely Cryptosporidium bovis (1/556, 0.18%), Cryptosporidium ryanae (7/556, 1.3%), and Cryptosporidium andersoni (63/556, 11.3%). Furthermore, 36 C. andersoni isolates were successfully classified into three MLST (multilocus sequence typing) subtypes based on four genetic loci (MS1, MS2, MS3, and MS16). The predominant MLST subtype was A4, A4, A4, A1 (n = 30). These findings not only revealed the prevalence and predominant species of Cryptosporidium in cattle in Jiangxi province, but also provided a baseline for studying the genetic structure of C. andersoni, offering a novel resource for better understanding of the epidemiology of Cryptosporidium infection in cattle in Jiangxi province, southeastern China.


Assuntos
Doenças dos Bovinos/epidemiologia , Criptosporidiose/epidemiologia , Cryptosporidium/genética , Cryptosporidium/isolamento & purificação , Animais , Sequência de Bases , Bovinos , Doenças dos Bovinos/parasitologia , China/epidemiologia , Criptosporidiose/parasitologia , Cryptosporidium/classificação , DNA de Protozoário/genética , Fezes/parasitologia , Genótipo , Tipagem de Sequências Multilocus , Filogenia , Reação em Cadeia da Polimerase , Prevalência
9.
Org Lett ; 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33587645

RESUMO

Reported herein is the design and synthesis of new O-perhalopyridin-4-yl hydroxylamines as shelf-stable and versatile amidyl-radical precursors. The novel amination reagents can be easily prepared via a single synthetic step from inexpensive commercially available starting materials using monoprotected HONH2 as amino source. The synthetic potency of the developed reagents was well demonstrated by direct amination of a series of quinoxalin-2(1H)-ones and their analogues under photocatalytic conditions, even without any additive and photocatalysts.

10.
Org Lett ; 2021 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-33481615

RESUMO

An organocatalyzed enantiodivergent synthesis of a multifunctionalized spirooxindole-norcamphor scaffold via a [4 + 2]-annulation between cyclicα, ß-unsaturated ketone and methylene indolinones has been established. The presence of CaCl2 in DMF could reverse the enantioselectivity to facilely deliver the enantiomers of the corresponding spirooxindoles. Both enantiomers of the corresponding spirooxindoles were obtained in excellent yield and diastereo-/enantioselectivity by employing one single prolinosulfonamide catalyst.

11.
Perit Dial Int ; 41(1): 118-121, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32223521

RESUMO

A simple, noninvasive method for removing peritoneal dialysis (PD) catheters, called the "pull technique," has become popular in recent years. Physicians still worry, however, about the range of its application and possible complications such as infection of the retained cuff and breakage. We, therefore, applied this technique in patients and enriched its administration for removing PD catheters. Altogether, 24 PD catheter removals in 24 patients were reviewed during the period from July 2018 to October 2019 in our hospital. Using the pull technique, the PD catheter's superficial cuff was dissected using an electronic knife, and the deep cuff was retained. All patients' catheters were successfully removed with no breakage. No incision or retained cuff was infected during the follow-up period (1.1-15.6 months). The appropriate peak force of pull traction was approximately 12-13 pounds, not very different from the mean maximum tensile force of 21.48 pounds for silicone tube breakage. The use of intermittent (rather than sustained) traction may reduce the breakage risk of the silicone tube. This method is a safe, practical, minimally invasive method for removing PD catheters, and it is suitable for application on special patients with peritonitis or who are on an immunosuppressant.

12.
Phytochem Anal ; 32(2): 141-152, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31512326

RESUMO

INTRODUCTION: Polygoni Orientalis Fructus (POF) is a clinically effective Chinese medicine. Raw POF (RPOF) and POF Tostus (POFT) are used separately in clinics. However, incomplete progress has been made on quality control. OBJECTIVE: To establish a comprehensive method for quality assessment of RPOF and POFT and to discriminate these two varieties. METHODOLOGY: High-performance liquid chromatography combined with the diode array detector (HPLC-DAD) methods were developed for fingerprinting and quantitative analysis of seven major compounds in RPOF and POFT, and the main components were determined by HPLC-DAD coupled with Fourier-transform ion cyclotron resonance-mass spectrometry. Chemometric approaches were performed to discriminate RPOF and POFT and to screen discriminatory components. RESULTS: Fingerprints were established and 12 common peaks were identified, cannabisin G and cannabisin E were firstly identified from POF. In quantitative analysis, all analytes showed good regression (R > 0.9996) within test ranges and the recovery of the method was in the range 96.6-104.3%. Fingerprints in conjunction with similarity analysis and hierarchical clustering analysis (HCA) demonstrated the consistent quality of RPOF and showed a clear discrimination between RPOF and POFT. Principal component analysis, partial least-squares discriminant analysis, and heatmap-HCA on quantitative data not only gave a clear differentiation between RPOF and POFT, but they also suggested that quercetin, 3,5,7-trihydroxychromone, and N-trans-feruloyltyramine acted as the main factors responsible for the sample differences. CONCLUSIONS: Chromatographic analysis in combination with chemometric analysis provides a simple and reliable method of comparing and evaluating the qualities of RPOF and POFT.


Assuntos
Medicamentos de Ervas Chinesas , Cromatografia Líquida de Alta Pressão , Frutas , Análise de Componente Principal , Controle de Qualidade
13.
Nat Prod Res ; 35(1): 49-56, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31342796

RESUMO

Three new flavonoids, pinocembrin-7-O-[3″-O-galloyl]-ß-D-glucose (1), pinocembrin-7-O-[2″-O-galloyl-4″,6″-hexahydroxydiphenoyl]-ß-D-glucose (2), 2',6'-dihydroxydihydrochalcone-4'-O-[2″-O-galloyl-4″,6″-hexahydroxydiphenoyl]-ß-D-glucopyranoside (3), and 12 known compounds (4-15) were isolated from Penthorum Chinense Pursh. The structures of all compounds were established mainly by NMR and MS experiments as well as the necessary chemical evidence. The anti-hyperlipidemic activities of the three new flavonoids were predicted by molecular docking.


Assuntos
Flavonoides/química , Flavonoides/farmacologia , Hipolipemiantes/farmacologia , Magnoliopsida/química , Flavonoides/isolamento & purificação , Hipolipemiantes/química , Espectroscopia de Ressonância Magnética , Simulação de Acoplamento Molecular , Estrutura Molecular , Extratos Vegetais/química
14.
Cancer Epidemiol Biomarkers Prev ; 30(1): 217-228, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33144283

RESUMO

BACKGROUND: Accumulating evidence suggests a relationship between endometrial cancer and ovarian cancer. Independent genome-wide association studies (GWAS) for endometrial cancer and ovarian cancer have identified 16 and 27 risk regions, respectively, four of which overlap between the two cancers. We aimed to identify joint endometrial and ovarian cancer risk loci by performing a meta-analysis of GWAS summary statistics from these two cancers. METHODS: Using LDScore regression, we explored the genetic correlation between endometrial cancer and ovarian cancer. To identify loci associated with the risk of both cancers, we implemented a pipeline of statistical genetic analyses (i.e., inverse-variance meta-analysis, colocalization, and M-values) and performed analyses stratified by subtype. Candidate target genes were then prioritized using functional genomic data. RESULTS: Genetic correlation analysis revealed significant genetic correlation between the two cancers (rG = 0.43, P = 2.66 × 10-5). We found seven loci associated with risk for both cancers (P Bonferroni < 2.4 × 10-9). In addition, four novel subgenome-wide regions at 7p22.2, 7q22.1, 9p12, and 11q13.3 were identified (P < 5 × 10-7). Promoter-associated HiChIP chromatin loops from immortalized endometrium and ovarian cell lines and expression quantitative trait loci data highlighted candidate target genes for further investigation. CONCLUSIONS: Using cross-cancer GWAS meta-analysis, we have identified several joint endometrial and ovarian cancer risk loci and candidate target genes for future functional analysis. IMPACT: Our research highlights the shared genetic relationship between endometrial cancer and ovarian cancer. Further studies in larger sample sets are required to confirm our findings.

15.
Front Cell Dev Biol ; 8: 585541, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33195232

RESUMO

Circular RNA (circRNA) has been increasingly proven as a new type of promising therapeutic RNA molecule in a variety of human diseases. However, the role of circRNA in bronchopulmonary dysplasia (BPD) has not yet been elucidated. Here, a new circRNA circABCC4 was identified from the Agilent circRNA chip as a differentially expressed circRNA in BPD. The relationship between circABCC4 level and BPD clinicopathological characteristics was analyzed. The function of circABCC4 was evaluated by performing CCK-8 and apoptosis analysis in vitro and BPD model analysis in vivo. RNA immunoprecipitation (RIP), luciferase reporter and rescue experiments were used to elucidate the interaction between circABCC4 and miR-663a. Luciferase reporter assay and rescue experiments were used to elucidate the interaction between PLA2G6 and miR-663a. CircABCC4 and PLA2G6 levels were increased, while miR-663a levels were decreased in the BPD group, compared to the control group. MiR-663a inhibited apoptosis by repressing PLA2G6 expression, while circABCC4 enhanced the apoptosis and inhibited the proliferation of A549 cells by sponging miR-663a and increasing PLA2G6 expression. In conclusion, circABCC4 promotes the evolving of BPD by spongening miR-663a and up-regulating PLA2G6 expression, which makes circABCC4 an ideal molecular target for early diagnosis and intervention of BPD.

16.
Zhongguo Dang Dai Er Ke Za Zhi ; 22(9): 980-983, 2020 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-32933630

RESUMO

OBJECTIVE: To study the expression level of cAMP response element-binding protein (CREB) in children with recurrent wheezing under three years of age and its effect on the expression of the serum orosomucoid 1-like protein 3 (ORMDL3) gene. METHODS: Thirty-six children with recurrent wheezing under three years of age who visited the hospital from June 2017 to June 2019 were selected as the recurrent wheezing group. Twenty-four healthy children from physical examination were selected as the control group. The CREB expression level in peripheral blood was measured by quantitative real-time PCR. Human bronchial epithelial cells (BEAS-2B) were cultured, and dual-luciferase reporter assay and quantitative real-time PCR were used to investigate the effects of overexpression and siRNA interference of CREB on the promoter activity and mRNA expression of the ORMDL3 gene in the BEAS-2B cells. RESULTS: The expression level of CREB in the recurrent wheezing group was significantly higher than that in the control group (P<0.001). In BEAS-2B cells, overexpression of CREB significantly up-regulated the promoter activity and mRNA expression of the ORMDL3 gene (P<0.05), while siRNA interference of CREB significantly reduced the promoter activity and mRNA expression of the ORMDL3 gene (P<0.05). CONCLUSIONS: The expression of CREB is increased in children with recurrent wheezing, and CREB may be involved in the pathogenesis of recurrent wheezing by regulating expression of the ORMDL3 gene.


Assuntos
Proteínas de Membrana/genética , Sons Respiratórios , Pré-Escolar , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico , Células Epiteliais , Humanos , Regiões Promotoras Genéticas
17.
Zhongguo Zhong Yao Za Zhi ; 45(9): 2138-2143, 2020 May.
Artigo em Chinês | MEDLINE | ID: mdl-32495563

RESUMO

This study aims to establish an HPLC method for the simultaneous determination of 6 main components, including chlorogenic acid, 3,4-dicaffeoylquinic acid,3,5-dicaffeoylquinic acid,4,5-dicaffeoylquinic acid, pellitorine and neopellitorine B in Achil-leae Herba. HPLC analysis was performed on a Merck Purospher STAR RP-18 endcapped(4.6 mm×250 mm, 5 µm), with a mobile phase consisting of 0.05% phosphoric acid solution(A)-acetonitrile(B) at a flow rate of 1 mL·min~(-1)(0-7 min,12%-14% B;7-10 min,14%-17% B;10-25 min,17%-22% B;25-35 min,22%-35% B;35-51 min,35%-80% B;51-60 min,80%-90% B). The detection wavelength was 254 nm and the column temperature maintained at 30 ℃, and the injection volume was 5 µL. The standard curves revealed a good linear relationship. The contents of 6 components were 0.404%-2.116% for chlorogenic acid, 0.160%-0.892% for 3,4-dicaffeoylquinic acid, 0.608%-1.464% for 3,5-dicaffeoylquinic acid, 0.168%-0.868% for 4,5-dicaffeoylquinic acid, 0.122%-1.234% for pellitorine, 0.065%-0.312% for neopellitorine B, respectively. Both cluster and principal component analysis can distinguish the research data in anthesis and pre-anthesis by software Chempattern. There were obviously differences in the different harvest time. Therefore, attention should be paid to the harvesting time of the herb. The method can be used to determine the contents of six main components, and can provide reference for the improvement of quality standard of Achilleae Herba.


Assuntos
Medicamentos de Ervas Chinesas , Ácido Clorogênico , Cromatografia Líquida de Alta Pressão , Análise de Componente Principal
18.
J Org Chem ; 85(8): 5670-5682, 2020 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-32240591

RESUMO

A visible-light-induced, catalyst-free radical cross-coupling cyclization of diselenides or disulfides with N-allylbromodifluoroacetamide has been developed. This developed protocol exhibits good functional group tolerance and affords a variety of 4-thio- and 4-seleno-substituted 3,3-difluoro-γ-lactams in moderate to good yields. Based on control experiments, a plausible radical-radical cross-coupling pathway is proposed.

19.
Zhongguo Zhong Yao Za Zhi ; 45(4): 910-915, 2020 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-32237493

RESUMO

This work aims to establish an HPLC specific chromatogram and determine six components of Vernonia anthelmintica with chlorogenic acid, isochlorogenic acid B, isochlorogenic acid A, isochlorogenic acid C, scutellarein and luteolin as index components. HPLC analysis was performed on a Waters Xbridge C_(18) column(4.6 mm×250 mm, 5 µm) with gradient elution of acetonitrile-0.05% trifluoroacetic acid solution at a flow rate of 1.0 mL·min~(-1). The detection wave length was 360 nm and the column temperature was 30 ℃. Chemometrics software Chempattern was employed to analyze the data. HPLC specific chromatogram of V. anthelmintica was established and six characteristic peaks were marked. Six characteristic peaks were simultaneously determined by HPLC within 50 min. The contents of the six components in 13 batch samples of V. anthelmintica were 0.14%-0.68%, 0.44%-0.74%, 0.63%-1.01%, 0.14%-0.71%, 0.15%-0.26% and 0.010%-0.030%, respectively. The HPLC specific chromatogram of V. anthelmintica, together with determination of six components showed strong specificity, and it can be used for the quality control of the crude drug.


Assuntos
Medicamentos de Ervas Chinesas/química , Compostos Fitoquímicos/análise , Vernonia/química , Cromatografia Líquida de Alta Pressão , Controle de Qualidade
20.
Org Lett ; 22(5): 1742-1747, 2020 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-32052975

RESUMO

The first photoredox-catalyzed defluoroborylation of polyfluoroarenes with NHC-BH3 has been facilely achieved at room temperature via a single-electron-transfer (SET)/radical addition pathway. This new strategy makes full use of the advantage of photoredox catalysis to generate the key boryl radical via direct activation of a B-H bond. Good functional group tolerance and high regioselectivity offer this protocol incomparable advantages in preparing a wide array of valuable polyfluoroarylboron compounds. Moreover, both computational and experimental studies were performed to illustrate the reaction mechanism.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...