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Search for "SEM" in Full Text gives 107 result(s) in Beilstein Journal of Organic Chemistry.

Pyridinium based amphiphilic hydrogelators as potential antibacterial agents

  • Sayanti Brahmachari,
  • Sisir Debnath,
  • Sounak Dutta and
  • Prasanta Kumar Das

Beilstein J. Org. Chem. 2010, 6, 859–868, doi:10.3762/bjoc.6.101

Graphical Abstract
  • fluorescence spectroscopy. The topographical features of the soft matter were visualized using different microscopic techniques (scanning electron microscopy (SEM), atomic force microscopy (AFM)). Interestingly, these compounds were found to show excellent antibacterial activity against Gram-positive and Gram
  • and 2 (Figure 3). SEM image of hydrogel 1 showed an aggregated form of porous networks (Figure 3a), which were responsible for the entrapment of the solvent. In case of hydrogel 2, formation of thin intertwined fibrillar networks of 200–300 nm dimensions (Figure 3b) was observed. The fibrillar
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Published 21 Sep 2010

Chiral gels derived from secondary ammonium salts of (1R,3S)-(+)-camphoric acid

  • Tapas Kumar Adalder,
  • N. N. Adarsh,
  • Ravish Sankolli and
  • Parthasarathi Dastidar

Beilstein J. Org. Chem. 2010, 6, 848–858, doi:10.3762/bjoc.6.100

Graphical Abstract
  • table top rheology, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), single- and powder X-ray diffraction (SXRD and PXRD, respectively). Single crystal structures of two gelators and one nongelator, i.e., DBUAMC 3, DBAMC 6, and DCHADC 1, respectively were determined and
  • , respectively which clearly indicates that 1,2-dichlorobenzene gel of DBAMC 6 is stronger than the nitrobenzene gel of DBUAMC 3. To see the morphological features of the gel fibers, some selected xerogels were subjected to SEM (Figure 4). Highly entangled networks of fibers were seen in the chlorobenzene and
  • programmable melting point apparatus, India. IR spectra were obtained on a FT-IR instrument (FTIR-8300, Shimadzu). The elemental compositions of the purified compounds were confirmed by elemental analysis (Perkin-Elmer Precisely, Series-II, CHNO/S Analyzer-2400). Scanning electron microscopy (SEM) was carried
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Published 21 Sep 2010

Synthesis, spectral characterization, electron microscopic study and thermogravimetric analysis of a phosphorus containing dendrimer with diphenylsilanediol as core unit

  • E. Dadapeer,
  • B. Hari Babu,
  • C. Suresh Reddy and
  • Naga Raju Charmarthi

Beilstein J. Org. Chem. 2010, 6, 726–731, doi:10.3762/bjoc.6.85

Graphical Abstract
  • molecule was studied by scanning electron microscopy (SEM), whilst the molecular decomposition of the dendrimer G6 was investigated by both thermogravimetric analysis (TGA) and differential thermal analysis (DTA). Scanning electronic microscopic study In order to get a deeper insight into the properties of
  • the surface of our phenyl –OH terminated dendrimer, it was examined by SEM. It revealed that highly resolved patterns with a line width of 1 µm. Figure 1 indicates the dispersion of layered polymeric form of the molecule. The most widely used layered material has negative charges or basic sites on the
  • SEM. It reveals the dispersion of layered polymeric form of the molecule due to presence of Si at the core. The thermal stability and changes in weight in relation to change in temperature and the heat of the final dendritic molecule G6 were studied by TGA-DTA analysis. It reveals that the compound G6
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Published 11 Aug 2010

A thermally-induced, tandem [3,3]-sigmatropic rearrangement/[2 + 2] cycloaddition approach to carbocyclic spirooxindoles

  • Kay M. Brummond and
  • Joshua M. Osbourn

Beilstein J. Org. Chem. 2010, 6, No. 33, doi:10.3762/bjoc.6.33

Graphical Abstract
  • alkyne terminus and increasing the number of carbon atoms in the tether. Groups such as methyl (Me), methoxymethyl (MOM), and 2-(trimethylsilyl)ethoxymethyl (SEM) were found to be well tolerated. Substrates possessing either a phenyl or a silyl group on the alkyne terminus also gave good yields of the
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Published 08 Apr 2010

Synthesis and properties of calix[4]arene telluropodant ethers as Ag+ selective sensors and Ag+, Hg2+ extractants

  • Yang Lu,
  • Yuanyuan Li,
  • Song He,
  • Yan Lu,
  • Changying Liu,
  • Xianshun Zeng and
  • Langxing Chen

Beilstein J. Org. Chem. 2009, 5, No. 59, doi:10.3762/bjoc.5.59

Graphical Abstract
  • ]arene 10 and 12. Selectivity coefficients (logK) of the electrodes based on ionophores 6–8, 10 and 12.a The percentage of metal picrates extracted from the aqueous to the organic phase by calixarenes 6–8, 10, and 12. Acknowledgments The Project partially sponsored by SRF for ROCS, SEM, the Natural
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Published 28 Oct 2009

Gold film- catalysed benzannulation by Microwave- Assisted, Continuous Flow Organic Synthesis (MACOS)

  • Gjergji Shore,
  • Michael Tsimerman and
  • Michael G. Organ

Beilstein J. Org. Chem. 2009, 5, No. 35, doi:10.3762/bjoc.5.35

Graphical Abstract
  • assessment of different types of metal films for their utility in benzannulation. The morphology of Cu, Pd, Ag, and Au films can be compared in the scanning electron microscopy (SEM) images in Figure 2. The films are generally prepared in a reducing environment (see Experimental), thus they are expected to
  • , 124.6, 122.2, 51.0, 45.7, 20.4. HRMS calcd. for C29H28N2O2: 436.2151; found 436.2147. Mechanism of Au(III)-catalyzed benzannulation between aromatic carbonyls and alkynes. X-ray analysis of the metal films used in this benzannulation study. Panels a–e are scanning-electron micrographs (SEM) of all films
  • Western, University of Western Ontario, London, ON for the SEM and EDX measurements.
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Published 21 Jul 2009

Recent progress on the total synthesis of acetogenins from Annonaceae

  • Nianguang Li,
  • Zhihao Shi,
  • Yuping Tang,
  • Jianwei Chen and
  • Xiang Li

Beilstein J. Org. Chem. 2008, 4, No. 48, doi:10.3762/bjoc.4.48

Graphical Abstract
  • the OH group by reduction of the tosylate 207 with LiBEt3H yielded the SEM ether 208. Conversion to the vinyl iodide 209 followed by Pd0-catalyzed coupling with the (S)-alkynyl butenolide 210 gave the asiminocin precursor 211. Selective hydrogenation of the enyne moiety with diimide and cleavage of
  • the SEM protecting groups completed the synthesis of triol 198, which exhibited 1H and 13C NMR spectra indentical to those of asiminocin [81]. Total synthesis of asiminecin In 1997, Marshall’s group reported the total synthesis of asiminecin (212) starting from aldehyde 204 and the OTBS allylic
  • stannane 205 (Scheme 28) [82]. Addition of the latter to the former in the presence of InCl3 afforded the anti adduct 213 which was protected as the SEM ether 214. Hydrogenation followed by OTBS cleavage with TBAF and selective silylation of the primary alcohol with TBSCl and Et3N-DMAP led to the secondary
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Review
Published 05 Dec 2008
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