Read by QxMD icon Read


Yuhan Yang, Bo Li, Wenmin Liu, Rumeng Zhang, Lintao Yu, Qin-Ge Ma, Rongrong Lv, Donghua Du, Ting Li
A Cp*CoIII-catalyzed C2-selective C-H alkenylation/ annulation cascade transformation of 1-(pyridin-2-yl)-1H-indoles with internal alkynes to afford pyrido[2',1':2,3]pyrimido[1,6-a]indol-5-iums is presented. Moreover, 6,7-dihydro-4H-pyrido[2',1':2,3]pyrimido[1,6-a]indole, a new functionalized N-fused indole core heterocycle, could be constructed effectively via reduction of pyrido[2',1':2,3]pyrimido[1,6-a]indol-5-ium by NaBH4.
October 25, 2016: Journal of Organic Chemistry
Tathyana Mar Amorim Franco, Subray S Hegde, John S Blanchard
The biosynthetic pathway of the branched-chain amino acids is essential for M. tuberculosis growth and survival. We report here the kinetic and chemical mechanism of the pyridoxal 5'-phosphate (PLP)-dependent branched-chain aminotransferase, IlvE, from M. tuberculosis (MtIlvE). This enzyme is responsible for the final step of the synthesis of the branched-chain amino acids isoleucine, leucine and valine. As seen in other aminotransferases, MtIlvE displays a ping-pong kinetic mechanism. pK values were identified from the pH dependence on V as well as V/K, indicating that the phosphate ester of the PLP cofactor, as well as the α-amino group from L-glutamate and the active site Lys204, play roles in acid-base catalysis and binding, respectively...
October 25, 2016: Biochemistry
Mustafa Ceylan, Umit M Kocyigit, Necibe Canan Usta, Belma Gürbüzlü, Yusuf Temel, Saleh H Alwasel, İlhami Gülçin
Benzothiazepine compounds have a wide range of applications such as antibacterial, antidepressants, anticonvulsants, antihypertensives, antibiotics, antifungal, hypnotic, enzyme inhibitors, antitumor, anticancer and anti-HIV agents. In this study, the synthesis of novel tetralone-based benzothiazepine derivatives (1-16) and their in vitro antibacterial activity and human carbonic anhydrase isoenzymes I and II (hCA I and II) inhibitory effects were investigated. Both isoenzymes were purified by sepharose-4B-l-tyrosine-sulfanilamide affinity chromatography from fresh human red blood cells...
October 25, 2016: Journal of Biochemical and Molecular Toxicology
Peter Werner Roesky, Claude Kiefer, Sebastian Bestgen, Michael T Gamer, Michael Kühn, Sergei Lebedkin, Florian Weigend, Manfred M Kappes
Bis-phenylpropynyl-functionalized imidazolium salts and their corresponding gold and copper NHC complexes were prepared in order to investigate their potential application for the synthesis of heterometallic coinage metal compounds. By transmetallation reactions with different precious metal sources including copper and silver phenylacetylides [MCCPh]x (M = Cu, Ag), polynuclear molecules were obtained, which were further investigated for their photoluminescence properties. Additionally, one gold NHC complex was post-functionalized by autocatalytic hydration of the alkynyl side chains...
October 25, 2016: Chemistry: a European Journal
Mohammad Shakir, Summaiya Hanif, Md Fazle Alam, Hina Younus
Novel bio-relevant monometallic Schiff base complexes of the type, [Cu(L(1))2] (1), [Zn(L(1))2]·2H2O (2), [Cu(L(2))2]·2H2O (3) and [Zn(L(2))2]·H2O (4) [L(1)(E)-3-(((3-chloro-4-hydroxyphenyl)imino)methyl)naphthalen-2-ol and L(2)(E)-2-chloro-4-((1-(5-chloro-2-hydroxyphenyl)ethylidene)amino)phenol] were synthesized and characterized. A comparative account of analytical, spectroscopic (FT-IR, (1)H and (13)C NMR, Mass, UV-vis and EPR), thermal (TGA/DTA), XRD and SEM studies revealed a correlation between the structure and function of these biologically active molecular entities...
October 11, 2016: Journal of Photochemistry and Photobiology. B, Biology
Alexander Arlt, Niels Böhnke, Sebastian Horstmann, Arnoldus W P Vermeer, Stefan Werner, Robert Velten
During our continuous search for new resistance-breaking insecticides applicable to malaria vector control, a new class of α,β-unsaturated imines was identified by applying the principle of conformational rigidification as a powerful tool for compound optimisation. Herein we describe the successful synthesis of these compounds and their biological test results. Our lead compound 16 from this insecticidal class outperforms market standards, notably for the control of mosquito strains that exhibit either metabolic or target-site resistance to these established insecticides...
October 2016: Chimia
Oliver R Oakley, Kee Jun Kim, Po-Ching Lin, Radwa Barakat, Joseph A Cacioppo, Zhong Li, Alex Whitaker, Kwang Chul Chung, Wenyan Mei, CheMyong Ko
17β-estradiol is a potent sex hormone synthesized primarily by gonads in females and males that regulates development and function of the reproductive system. Recent studies show that 17β-estradiol is locally synthesized in non-reproductive tissues and regulates a myriad of events, including local inflammatory responses. In this study, we report that mesenteric lymph nodes and Peyer's patches are novel sites of de novo synthesis of 17β-estradiol. These secondary lymphoid organs are located within or close to the gastrointestinal tract, contain leukocytes, and function at the forefront of immune surveillance...
October 25, 2016: Endocrinology
Masahiko Horiba, Takao Yamaguchi, Satoshi Obika
We previously reported the synthesis and evaluation of 2'-O,4'-C-spirocyclopropylene-bridged nucleic acid (scpBNA) bearing a thymine (T) nucleobase. Oligonucleotides (ONs) modified with scpBNA-T exhibited strong binding affinity to complementary single-stranded RNA (ssRNA) and high enzymatic stability. These biophysical properties suggest that scpBNAs are well suited for use in antisense strategies. Herein we describe the synthesis of scpBNA monomers bearing 5-methylcytosine (mC), adenine (A), and guanine (G) nucleobases for use in a variety of sequences...
October 25, 2016: Journal of Organic Chemistry
Moumita Jash, Bimolendu Das, Chinmay Chowdhury
A Pd(II)-catalyzed direct synthesis of benzo[a]carbazoles has been achieved through aminopalladation of alkynes, followed by intramolecular nucleophilic addition of the generated carbon-palladium bond to a tethered cyano/aldehyde group. Compared to literature procedures, this synthetic approach is operationally simple, uses simple substrates, and offers a fast intramolecular assembly resulting in the direct synthesis of benzo[a]carbazoles in which a wide variation of substituents at different sites is well-tolerated, leaving enough opportunity for diversification...
October 25, 2016: Journal of Organic Chemistry
Ross S Firestone, Scott A Cameron, Peter C Tyler, Rodrigo Gay Ducati, Adam Z Spitz, Vern L Schramm
5'-Methylthioadenosine phosphorylase (MTAP) and 5'-methylthioadenosine nucleosidase (MTAN) catalyze the phosphorolysis and hydrolysis of 5'-methylthioadenosine (MTA), respectively. Both enzymes have low KM values for their substrates. Kinetic assays for these enzymes are challenging, as the ultraviolet absorbance spectra for reactant MTA and product adenine are similar. We report a new assay using 2-amino-5'-methylthioadenosine (2AMTA) as an alternative substrate for MTAP and MTAN enzymes. Hydrolysis or phosphorolysis of 2AMTA forms 2,6-diaminopurine, a fluorescent and easily quantitated product...
October 25, 2016: Analytical Chemistry
Otmar M Ten Kate, Rong-Jun Xie, Chun-Yun Wang, Shiro Funahashi, Naoto Hirosaki
Novel Sr2-yEuyB2-2xSi2+3xAl2-xN8+x phosphors were investigated as a function of the boron and aluminum over silicon ratio and as a function of the Eu(2+) concentration. Samples were prepared via solid-state reaction synthesis by carefully controlling the synthesis conditions and composition. At high boron and aluminum content, that is, x = 0, a Eu(2+) 5d-4f emission is observed of which the maximum shifts from 595 nm for low Eu concentrations (y = 0.005) toward 623 nm for high Eu concentrations (y = 0.5). The samples can be excited by UV or blue light up to ∼475 nm...
October 25, 2016: Inorganic Chemistry
Jipeng Fu, Su Zhang, Ran Pang, Yonglei Jia, Wenzhi Sun, Haifeng Li, Lihong Jiang, Chengyu Li
Infrared (IR) light-emitting materials have wide applications. However, variety and economical accesses to obtain IR materials and devices are still limited, because the IR-emitting materials are always suffering from two obstacles, namely, lower absorption and lower emission efficiency. In this work, using a modified high-temperature solid-state reaction an efficient short-wavelength IR luminescent material is successfully synthesized. On the basis of the excellent luminescent properties, a convenient IR light-emitting diode (LED) device is fabricated by combining the novel IR material with a commercial UV LED chip...
October 25, 2016: Inorganic Chemistry
Fangfang Chen, Yunhong Dong, Yanxia Zhao
A dual responsive molecularly imprinted polymer sensitive to both photonic and magnetic stimuli was successfully prepared for the detection of four sulfonamides in aqueous media. The photoresponsive magnetic molecularly imprinted polymer was prepared by surface imprinted polymerization using superparamagnetic Fe3 O4 nanoparticles functionalized with a silica layer as a support, water-soluble 4-[(4-methacryloyloxy)phenylazo]benzenesulfonic acid as the functional monomer, and sulfadiazine as the template. The magnetic molecularly imprinted polymers showed specific affinity to sulfadiazine and its structural analogs in aqueous media...
October 25, 2016: Journal of Separation Science
Malachi W Gillick-Healy, Elizabeth V Jennings, Helge Muller-Bunz, Yannick Ortin, Kirill Nikitin, Declan G Gilheany
The energy barriers in our recently discovered Walden inversion of chlorophosphonium salts are similar to those in Cope rearrangements of caged cyclic hydrocarbons. We have therefore designed a molecular system integrating the two processes, thereby producing the first embodiment in a chemical species of two entirely different and independent stereomutation mechanisms at the same nominal asymmetric centre. Thus, the energy barrier to the rearrangement of 9-phenyl-9-phosphabarbaralane oxide, easily prepared by a new high-yielding synthesis, was found to be ca...
October 25, 2016: Chemistry: a European Journal
Jun Ye, Wei Chen, Zhi-Yong Wu, Jin-Hui Zhang, He Fei, Li-Wen Zhang, Ya-Hui Wang, Ya-Ping Chen, Xiao-Mei Yang
Epithelial ovarian cancer (EOC) is the major cause of deaths from gynecologic malignancies, and metastasis is the main cause of cancer related death. Collagen triple helix repeat containing-1 (CTHRC1) is a secreted protein that has the ability to inhibit collagen matrix synthesis. In this study, we found that high CTHRC1 expression was associated with poor prognosis of EOC. In vitro experiments showed that CTHRC1 promoted migration and invasion of ovarian cancer cells. CTHRC1 had no effect on ovarian cancer cells viability...
October 24, 2016: Oncology Reports
Wenjie Li, Fei Cao, Juan Li, Zhixin Wang, Yu Ren, Zheyong Liang, Peijun Liu
Simvastatin (SIM), a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, has been reported to inhibit the activity of hepatitis B virus (HBV), however, the mechanism underlying its antiviral function remains unknown. Minichromosome maintenance (MCM) 7, a component of the MCM complex, has been reported to act as an important host factor aiding virus genome replication in host cells. The present study demonstrated that downregulation of MCM7 inhibited the expression of proteins transferred by adenoviral vectors...
October 20, 2016: Molecular Medicine Reports
Liyan Wen, Sha Yang, Ping Zhu, Yingxin Yu, Xiaoyan Qiu, Ning Fu, Yanjun Liu
Cancer-associated antigen 215 (CA215) is an immunoglobulin molecule expressed by numerous tumor types. Membrane‑bound and soluble CA215 have been detected in the majority of cancer cells and rarely identified in normal tissues. In addition, CA215C is a carbohydrate‑associated epitope in the variable region of CA215, which is specifically recognized by the monoclonal antibody, RP215. However, CA215C is not a suitable vaccine candidate as it is a thymus‑independent antigen. In the present study, RP215 was used as a target to screen short peptide mimics of CA215C from a phage display peptide library...
October 19, 2016: Molecular Medicine Reports
Rajeev K Dubey, Nick Westerveld, Stephen J Eustace, Ernst J R Sudhölter, Ferdinand C Grozema, Wolter F Jager
Nucleophilic aromatic substitution reactions on 1,7-dibromoperylene-3,4,9,10-tetracarboxylic monoimide dibutylester, using phenol and pyrrolidine reagents, have been exploited to synthesize perylenes with four different substituents at the perylene core. The first substitution is always regiospecific at the imide-activated 7-position. A second substitution reaction does not always replace the bromine at C-1, but may replace a phenol substituent at the highly activated 7-position. Exploiting this reactivity pattern, a "mixed" 1,7-diphenoxy, 1,7-dipyrrolidinyl, and two 1-phenoxy-7-pyrrolidinyl derivatives have been synthesized...
October 25, 2016: Organic Letters
Zu-Feng Xiao, Ting-Hui Ding, Sheng-Wei Mao, Zaher Shah, Xiao-Shan Ning, Yan-Biao Kang
A heterogeneous iridium-complex-catalyzed N-O-cleaving rearrangement/cyclization of 2,3-dihydroisoxazoles with alkenes has been developed. It provides divergent access to multiple substituted pyrrolidines, pyrroles, and carbazoles. The iridium catalyst remains highly catalytic active after seven cycles. The gram-scale synthesis afforded a carbazole with strong bluish-violet fluorescence.
October 25, 2016: Organic Letters
Su Chen, Pengbo Zhang, Wanyun Shu, Yuzhen Gao, Guo Tang, Yufen Zhao
Pyrrolo[1,2-a]indole is a common structural motif found in many natural products and pharmaceuticals. A silver-mediated oxidative phosphinoylation of N-propargyl-substituted indoles was used to construct a variety of 2-phosphinoyl-9H-pyrrolo[1,2-a]indoles under mild conditions. This transformation offers a straightforward route to the formation of the C-P bond, cyclization, and isomerization in one step.
October 25, 2016: Organic Letters
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"