A practical and metal-free approach for the regioselective selenation of chromones employing Selectfluor reagent under mild conditions is described. The developed method is suitable for a wide substrate scope and affords 3-selenylated chromones in good to excellent yield with high selectivity. An ionic mechanism is proposed for this transformation.
View Article and Find Full Text PDFA mild and efficient transition-metal-free radical difluorobenzylation/cyclization of unactivated alkenes toward the synthesis of difluorobenzylated polycyclic quinazolinone derivatives with easily accessible α,α-difluoroarylacetic acids has been developed. This transformation has the advantages of wide functional group compatibility, a broad substrate scope, and operational simplicity. This methodology provided a highly attractive access to pharmaceutically valuable ArCF-containing polycyclic quinazolinones.
View Article and Find Full Text PDFObjective: To evaluate the efficacy and safety of fecal microbiota transplantation (FMT) in functional gastrointestinal disorders (FGIDs) in children with abdominal bloating and changes in their gut microbiome and metabolome.
Methods: Twelve pediatric FGID patients with predominant abdominal bloating who underwent FMT were enrolled in the study. Fourteen healthy controls and four stool donors were included for analysis.
A practical synthetic route to construct a variety of 3-benzyl spiro[4,5]trienones was developed transition-metal Cu/Ag-catalyzed oxidative -annulation of activated alkynes with unactivated toluenes using TBPB as an oxidant under microwave irradiation. This method allows the formation of two carbon-carbon bonds and one carbon-oxygen bond in a single reaction through a sequence of C-H oxidative coupling, -carbocyclization and dearomatization. The advantages of this protocol are its operational simplicity and broad substrate scope, and the ability to afford the desired products in moderate to good yields.
View Article and Find Full Text PDFA silver-catalyzed efficient and direct C-H carbamoylation of quinolines with oxamic acids to access carbamoylated quinolines has been developed through oxidative decarboxylation reaction. The reaction proceeds smoothly over a broad range of substrates with excellent functional group tolerance and excellent yields under mild conditions.
View Article and Find Full Text PDFHeiner syndrome (HS) is a food hypersensitivity disease that is mostly caused by cow's milk. The main features may include chronic or recurrent respiratory syndromes, pulmonary infiltrates on radiography, and even pulmonary hemosiderosis. However, gastrointestinal symptoms are rare in HS, which can lead to a misdiagnosis when the chief complaint is about the gastrointestinal system.
View Article and Find Full Text PDFBackground: Fecal microbiota transplantation (FMT) is the administration of fecal bacterial liquid from healthy donors to a recipient's digestive tract, which is recommended as a therapeutic method for recurrent infection (CDI). Many clinical trials focusing on different diseases are in progress. To date, scarce research and long-term follow-up have been conducted on FMT in children or on the proper guidelines.
View Article and Find Full Text PDFA facile TBHP-mediated direct oxidative coupling of quinoxalin-2(1H)-ones with arylaldehydes has been developed under metal-free conditions. This method provided a convenient and efficient approach to various 3-acylated quinoxalin-2(1H)-ones from readily available starting materials with excellent regioselectivity. This reaction proceeded efficiently under mild conditions over a broad range of substrates and with functional group tolerance.
View Article and Find Full Text PDFDecarboxylative alkylation or acylation reactions of simple pyrimidines have been developed in aqueous media. Using aliphatic carboxylic acids or 2-oxocarboxylic acids and pyrimidines as substrates and silver as the catalyst, the 4-substituted alkyl or acyl pyrimidines were isolated in moderate to good yields.
View Article and Find Full Text PDFA silver-catalyzed efficient and practical synthesis of 3-acyl-4-arylquinolin-2(1H)-ones or 3-acyl-4-aryldihydroquinolin-2(1H)-ones through intermolecular radical addition/cyclization in aqueous solution is reported. This method provides a novel, highly efficient, and straightforward route to substituted quinolin-2-ones or 3,4-dihydroquinolin-2-ones in one step. A possible mechanism for the formation of quinolin-2-ones is proposed.
View Article and Find Full Text PDFMetals such as cadmium and arsenic are ubiquitous toxicants that cause a variety of adverse health effects. Heat shock proteins (HSPs) response to metal-induced stress and protect cells from further damage. However, the intracellular signalling pathways responsible for activation of HSPs expression are not fully understood.
View Article and Find Full Text PDFTo study the effect of organic Se on spatial learning and memory deficits induced by Pb exposure at different developmental stages, and its relationship with alterations of synaptic structural plasticity, postnatal rat pups were randomly divided into five groups: Control; Pb (Weaned pups were exposed to Pb at postnatal day (PND) 21-42); Pb-Se (Weaned pups were exposed to Se at PND 43-63 after Pb exposure); maternal Pb (mPb) (Parents were exposed to Pb from 3 weeks before mating to the weaning of pups); mPb-Se (Parents were exposed to Pb and weaned pups were exposed to Se at PND 43-63). The spatial learning and memory of rat pups was measured by Morris water maze (MWM) on PND 63. We found that rat pups in Pb-Se group performed significantly better than those in Pb group (p<0.
View Article and Find Full Text PDFA silver-catalyzed tandem decarboxylative radical addition/cyclization of N-arylcinnamamides with aliphatic carboxylic acids is reported. This method affords a novel and straightforward route to various 3,4-disubstituted dihydroquinolin-2(1H)-ones in aqueous solution.
View Article and Find Full Text PDFA novel and easy practical direct synthesis of α-ketoamides has been developed without metals in water. This procedure was catalyzed by nBu(4)NI using TBHP as oxidant from simple substrates, aryl methyl ketones and dialkylformamides.
View Article and Find Full Text PDFObjective: To explore potential epigenetic biomarkers for toxic effects, tumor-related chemical prevention and biological monitor by a genome-wide screening for differential DNA methylation during human cell malignant transformation in vitro.
Methods: The two in vitro cell transformation models included B(a)P-induced human bronchial epithelial cell introduced by H-Ras (HBER) cell transformation and simian vacuolating virus 40 small T antigen induced (SV40 ST-induced) HBER cell transformation. Methylated genes were collected by methylated DNA immunoprecipitation and whole genome amplification (MeDIP-WGA) at three time points during cell transformation which represented different transformation stage.
Zhongguo Dang Dai Er Ke Za Zhi
January 2010
Zhonghua Yu Fang Yi Xue Za Zhi
June 2008
Objective: To establish human bronchial epithelial cell lines over expressing oncogene and to investigate its application in detection of carcinogen-induced cell transformation.
Methods: Mediated by retrovirus infection, human telomerase catalytic subunit, hTERT was introduced into immortal human bronchial epithelial cells (16HBE) and followed by introduction of the oncogenic allele H-Ras(V12), or c-Myc or empty vector, creating cell lines 16HBETR, 16HBETM and 16HBETV, respectively. Biological characteristics of these cell lines including morphology, proliferation, and chromosomal aberration were examined to access whether they were transformed.
Objective: To construct Thr461 --> Asn461 and Ile462 --> Val462 mutation vector of P4501A1 gene and to provide scientific base for deeply researching on the function of cytochrome 1A1 gene (CYP1A1) and the mechanism of carcinogenesis.
Methods: According to cDNA sequence of human CYP1A1 gene, universal primers (Pm3/Pm4) and mutant primers (Pt15/Pt16 and Pt17/Pt18) containing restriction enzyme site and mutation site were designed. The first set of primers involving Pm3/Pt16 and Pm3/Pt18 amplified a forward 1.
An efficient route to synthesize 3''- and 4'''-vinyl rutin esters has been developed by enzyme-catalyzed regioselective acylation of rutin with divinyl dicarboxylates in organic media. Alkaline protease from Bacillus subtilis provided 3''-O-substituted vinyl rutin esters in pyridine, and Novozym 435 gave 4'''-O-substituted vinyl rutin esters in tert-butanol.
View Article and Find Full Text PDFHydrolase-catalyzed Michael addition of imidazole derivatives to acrylic monomers in organic medium was described. A serial of N-substituted imidazole derivatives were successfully synthesized in moderate yields by the catalysis of hydrolases in organic medium. Nine commercially available hydrolases from different sources were screened and all of them were found to be able to catalyze this type of addition reaction.
View Article and Find Full Text PDFCarbohydr Res
September 2005
Comparative studies of enzymatic synthesis of glucose esters under ultrasound and shaking were carried out in nonaqueous media. The influence of solvents, enzymes, chain length of the acyl donors, the power of the ultrasound bath, and intermittent ultrasound on the enzymatic synthesis was investigated. Among the eight solvents selected, pyridine was the most appropriate with alkaline protease from Bacillus subtilis whether under ultrasound or shaking.
View Article and Find Full Text PDFThree beta-cyclodextrin (beta-CD) conjugates of non-steroidal anti-inflammatory drugs were synthesized by enzymatic methods. Transesterification of beta-CD with vinyl ester of indomethacin, ketoprofen and etodolac was performed by the catalysis of alkaline protease from Bacillus subtilis in anhydrous DMF for 3 days. The drug molecules were selectively conjugated onto one of the secondary hydroxyl groups of beta-CD through ester-linkage to improve their poor water solubility and absorption characteristics.
View Article and Find Full Text PDFThis paper describes highly selective transesterification reactions, catalyzed by an alkaline protease from Bacillus subtilis in pyridine, of several mono- and di-saccharides with divinyl dicarboxylates ranging from 4 to 10 carbon atoms. A series of polymerizable vinyl fatty acid sugar esters were obtained with good selectivity and high yields. Most products had high proportions of the alpha anomer.
View Article and Find Full Text PDFTransesterification of cyclomaltoheptaose (beta-CD) with divinyl butanedioate, divinyl hexanedioate, and divinyl decanedioate, catalyzed by the alkaline protease from Bacillus subtilis in anhydrous DMF for 5 days, furnished the corresponding vinyl-beta-CD derivatives. The products were characterized by ESI-MS, (1)H NMR, (13)C NMR, IR, and DSC. The results indicated the products to be monosubstituted esters, with monoacylation occurring at the C-2 secondary hydroxyl groups of beta-CD.
View Article and Find Full Text PDF