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871.
Abdelmaoujoud Taia Mohamed Essaber Ali Oubella Abdeljalil Aatif Jacques Bodiguel Brigitte Jamart-Grégoire 《合成通讯》2020,50(13):2052-2065
AbstractWe report the synthesis of new series of heterocyclic systems eugenol 1 derivatives by the mixed condensation reaction of 1,3-dipolar azide and the oxide of p-chlorophenylnitrile on the 4-allyl-2-methoxy-1-(prop-2-yn-1-yloxy)benzene 2. The mono and bicycloadducts, whose structure is homologous to compounds having a broad spectrum of activity, were obtained in good yields. The monocondensation reaction of azides on 4-allyl-2-methoxy-1-(prop-2-yn-1-yloxy)benzene 2 is completely chemoselective, regioselective and stereospecific. The condensation of nitrile oxide on 1,2,3-triazole monocycloadducts prepared was chemoselective and regioselective. The structure of all cycloadducts were characterized and confirmed by the 1H, 13C, 2D nuclear magnetic resonance and mass spectrometry analysis. All the newly synthesized mono and bis-heterocyclic compounds have been selected for their antiproliferative activity against HT-1080 fibrosarcoma, A549 lung carcinoma, and MCF-7 and MDA-MB-231 breast carcinoma cell lines. Among the derivatives, only the compounds 4a, 4b, 5a, 5b, 5d, 5e and 5g showed significant cytotoxicity with IC50 values ranging from 15.31 to 18.81?µM against HT-1080 cells, and 17.32 to 25.94?µM against the other cell lines. 相似文献
872.
873.
874.
Imbert D Comby S Chauvin AS Bünzli JC 《Chemical communications (Cambridge, England)》2005,(11):1432-1434
The novel hydroxyquinoline-containing tetrapodal ligand forms water soluble and stable chelates and is a good sensitizer of the NIR luminescence of its Nd(III) and Yb(III) complexes; its easy synthesis opens the way for potential biomedical applications. 相似文献
875.
Layer-Anions in the Crystal Structures of the Isotypic Compounds Sr2[Ga2S5], Ba2[In2S3], and Ba2[In2Se5] The compounds Sr2[Ga2S5], Ba2[In2S5], and Ba2[In2Se5] have been prepared from stoichiometric mixtures of the elements at temperatures between 1150°C and 1250°C. They are isotypic (space group Pbca, Z = 8) with the lattice constants see ?Inhaltsübersicht”?. In the anionic part of the structure GaS4-(InS4-/InSe4)-tetrahedra share three common vertices to form layers with rings built by four and eight tetrahedra. The cations are placed between the sheets and have the coordination number seven. 相似文献
876.
Thiohydroxamic esters (mixed anhydrides) of aromatic and α,β-unsaturated carboxylic acids undergo clean decarboxylative bromination on treatment with bromotrichloromethane in the presence of a radical initiator. 相似文献
877.
González LJ Castellanos-Serra L Badock V Díaz M Moro A Perea S Santos A Paz-Lago D Otto A Müller EC Kostka S Wittmann-Liebold B Padrón G 《Electrophoresis》2003,24(1-2):237-252
An efficient method for digestion and extraction of proteolytic peptides from silver-stained proteins was applied to the characterization of nuclear proteins from the small cell lung cancer H82 (ATCC HTB 175) cell line previously separated by high-resolution large format two-dimensional gel electrophoresis. From 68 spots, evenly distributed on the gel area and representing a wide range of spot intensities, 63 (92%) were successfully identified by matrix-assisted laser desorption/ionization (MALDI) or electrospray ionozation-mass spectrometry (ESI-MS). In five cases where the identification was not possible, the presence of an intense background apparently due to the leakage of polymers from the microtubes or other plastics, was detected. Extensive analysis of peptide sequences by ESI MS/MS experiments allowed the identification of post-translational modifications, such as acetylation, phosphorylation, deamidation of asparagine residues and the presence of isoaspartic acid. A new protein variant not reported in sequence databases was also detected. 相似文献
878.
Albach C Damoc E Denzinger T Schachner M Przybylski M Schmitz B 《Analytical and bioanalytical chemistry》2004,378(4):1129-1135
Mass spectrometry has been shown in recent years to be a powerful tool to determine accurate molecular masses and sequences of peptides and proteins and post-translational modifications such as glycosylation, phosphorylation, and sulfation. For glycosylation, it has been increasingly recognized to be of pivotal importance to identify whether potential glycosylation sites are actually modified by glycans, because functions of proteins may be modulated or depend on the presence of glycans at specific sites. Several recent reports have established that mass spectrometric techniques such as matrix-assisted laser desorption/ionization or electrospray ionization mass spectrometry (MALDI-TOF or ESI-MS, respectively) with or without preceding HPLC and in combination with PNGase F treatment are suited to analyze whether consensus sequences for N-glycosylation are glycosylated or not. Here we report the mass spectrometric analysis of the six potential N-glycosylation sites of the neural cell adhesion molecule NCAM from adult mouse brain. Unmodified peptides and glycopeptides each carrying a single glycosylation site were generated from NCAM by AspN and trypsin treatment and submitted to reversed-phase HPLC with or without prior enzymatic release of N-glycans. The resulting peptides were analyzed by MALDI-TOF-MS. In addition, high-resolution Fourier transform–ion cyclotron resonance (MALDI-FTICR) mass spectrometry was performed after in-gel deglycosylation and subsequent trypsin digestion. By using these procedures all six consensus sequences were shown to be glycosylated; the observation of an unmodified peptide with the consensus sequence N-1 indicates only partial glycosylation at this site.Abbreviations amu
atomic mass units
- AspN
endoproteinase AspN
- CAM
cell adhesion molecule
- ESI
electrospray ionization
- FTICR
Fourier transform–ion cyclotron resonance
- IgSF
immunoglobulin superfamily
- MALDI-TOF
matrix-assisted laser desorption ionization–time of flight
- MS
mass spectrometry
- NCAM
neural cell adhesion molecule
- PNGase F
peptide-N
4-(N-acetyl--glucosaminyl)asparagine amidase
- PSA
polysialic acid
- TFA
trifluoroacetic acid 相似文献
879.
Malkoch M Thibault RJ Drockenmuller E Messerschmidt M Voit B Russell TP Hawker CJ 《Journal of the American Chemical Society》2005,127(42):14942-14949
The development of selective chemistries that are orthogonal to the diverse array of functional groups present in many polymeric systems is becoming an important tool for the synthesis and use of macromolecules in fields ranging from biomedical devices to nanotechnology. By combining copper-catalyzed cycloaddition chemistry with other synthetic transformations such as esterification, amidation, etc., highly efficient and modular simultaneous and cascade functionalization strategies have been developed. These single-step strategies for preparing multifunctional macromolecules represent a significant advance as compared to traditional multistep approaches, and the utility of these concepts is demonstrated by selective preparation of a diverse range of orthogonally functionalized vinyl polymers. 相似文献
880.
Both enantiomers of the polyketide-derived lactone citreofuran (4) have been prepared. The enantiopure building blocks were obtained on a chemoenzymatic route ((S)-6) and by a chiral pool synthesis ((R)-6). The crucial step in the synthesis, a macrolactonization, was accomplished under Mitsunobu conditions. 相似文献