The Experts below are selected from a list of 348 Experts worldwide ranked by ideXlab platform

Mohammad Gholinejad - One of the best experts on this subject based on the ideXlab platform.

Paul Kosma - One of the best experts on this subject based on the ideXlab platform.

  • synthesis of neoglycoproteins containing o methylated trisaccharides related to excretory secretory antigens of toxocara larvae
    Carbohydrate Research, 2003
    Co-Authors: Hassan Amer, Andreas Hofinger, Paul Kosma
    Abstract:

    Abstract The disaccharides allyl β- d -galactopyranosyl-(1→3)-2-acetamido-2-deoxy-β- and α- d -galactopyranoside 10a and 10b and the trisaccharides allyl 2- O -methyl-α- l -fucopyranosyl-(1→2)-β- d -galactopyranosyl-(1→3)-2-acetamido-2-deoxy-β- and α- d -galactopyranoside 18a and 18b have been prepared using stepwise assembly of the sugar units. The glycosidic linkages were formed employing the trichloroacetimidate procedure for the attachment of the galactopyranosyl residue and N -iodosuccinimide/triflic acid activation of an ethyl 1-thiofucopyranoside donor for fucosylation. Deprotection furnished the allyl glycosides which were converted into cysteamine-spacered ligands, activated with Thiophosgene and subsequently linked to bovine serum albumin. The neoglycoproteins serve as immunoreagents to determine epitope specificities of monoclonal antibodies directed against highly immunogenic O -glycans located at the surface of Toxocara larvae.

  • synthesis of a neoglycoprotein containing the lewis x analogous trisaccharide β d galpnac 1 4 α l fucp 1 3 β d glcpnac
    Carbohydrate Research, 1998
    Co-Authors: Johannes Bartek, Renate Muller, Paul Kosma
    Abstract:

    Abstract The trisaccharide allyl glycoside 36 and related disaccharide part structures have been prepared using the 2-trichloroacetamido-2-deoxy- α - d -galactopyranosyl trichloroacetimidate derivative 9 as glycosyl donor under promotion with TMSOTf or Sn(OTf) 2 , respectively, to produce the β -( 1 → 4) linkage to suitably protected glucosamine derivatives in fair yields. Fucosylation was effected employing the ethyl 1-thio glycosyl donor 20 in the presence of IDCP. Deprotection of the intermediates afforded the disaccharide allyl glycosides β - d -Gal p NAc-( 1 → 4)- β - d -Glc p NAc 13 , β - d -Gal p NClAc-( 1 → 4)- β - d -Glc p NAc 14 , α - l -Fuc p -( 1 → 3)- β - d -Glc p NAc 24 , α - l -Fuc p -( 1 → 4)- β - d -Glc p NAc 31 and the branched trisaccharide allyl glycoside β - d -Gal p NAc-( 1 → 4)[ α - l -Fuc p -( 1 → 3)]- β - d -Glc p NAc 36 . The trisaccharide which corresponds to a structural motif occurring in N-glycoprotein glycans from human urokinase, human recombinant protein C, phospholipase A 2 as well as O-glycans, was converted into a neoglycoprotein following introduction of a cysteamine-derived spacer group and subsequent activation with Thiophosgene.

Otto A Gansow - One of the best experts on this subject based on the ideXlab platform.

  • synthesis of 2 p thiocyanatobenzyl 1 4 7 triazacyclononane 1 4 7 triacetic acid application of the 4 methoxy 2 3 6 trimethylbenzenesulfonamide protecting group in the synthesis of macrocyclic polyamines
    Bioconjugate Chemistry, 1993
    Co-Authors: Thomas J Mcmurry, Martin W Brechbiel, Chuanchu Wu, Otto A Gansow
    Abstract:

    A synthesis of the bifunctional chelator 2-(p-thiocyanatobenzyl)-1,4,7-triazacyclononane-1,4,7-triacetic acid [2-(p-NCS-Bz)-NOTA] is described which illustrates the especial utility of the (4-methoxy-2,3,6-trimethylphenyl)sulfonyl (Mtr) protecting group as an alternative to the p-tolylsulfonyl (Ts) moiety commonly used for Richman-Atkins type cyclizations. Reaction of N,N'-bis(p-tolylsulfonyl)-1-(p-benzamidobenzyl)ethylenediami ne with N,N-bis[2-[(p-tolylsulfonyl)oxy]ethyl]-p-toluenesulfonamide gave 2-(p-benzamidobenzyl)-1,4,7-tris(p-tolylsulfonyl)-1,4,7-tria zacyclononane in 55% yield, whereas the analogous reaction using the Mtr-protected starting materials gave the corresponding Mtr-protected macrocycle in 34% yield. However, deprotection of the Ts- and Mtr-protected macrocycles (H2SO4, 90 degrees C) afforded 2-(p-benzamidobenzyl)-1,4,7-triazacyclononane in 23% and 60% yield, respectively, illustrating the relatively facile cleavage of the Mtr moiety. A modest improvement in overall percent conversion of (p-nitrobenzyl)ethylenediamine into substituted macrocyclic polyamine was observed when comparing the Mtr vs Ts protection (12.6 vs 10.6%). The macrocyclic triamine was converted to 2-(p-NCS-Bz)-NOTA by alkylation with bromoacetic acid (pH 9, 73%) followed by hydrolysis of the benzamide protecting group (6 M HCl, 70 degrees C, 87%) and reaction with Thiophosgene (90%). The serum stability of the 67Cu complexes of 1,4,7-triazacyclononane (I), 2-(p-nitrobenzyl)-1,4,7,10-tetraazacy-clododecane (II), 2-(p-nitrobenzyl)-1,4,8,11-tetraazacyclotetradecane (III), 2-(p-PhCONH-Bz)-NOTA (IV), 2-(p-nitrobenzyl)-1,4,7,10-tetraazadodecane-1,4,7,10-tetraacetic acid (V), 2-(p-nitrobenzyl)-1,4,8,11-tetraazatetradecane-1,4,8,11-tetraaceti c acid (VI), and the acyclic ligand 1-(p-nitrobenzyl)-4-methyldiethylenetriamine-N,N,N',N", N"-pentaacetic acid (VII) was measured at 37 degrees C (5% CO2) and showed the following order of relative stability: I < VII << VI << IV < V approximately equal to II approximately equal to III.

D C Moule - One of the best experts on this subject based on the ideXlab platform.

  • symmetry segregation of the vibronic levels within the s1 s0 system of Thiophosgene cl2cs by optical optical double resonance spectroscopy
    Journal of Chemical Physics, 2007
    Co-Authors: Takashige Fujiwara, Edward C Lim, D C Moule
    Abstract:

    The first singlet-singlet electronic system, S1←S0, in Thiophosgene has been recorded as a laser induced fluorescence (LIF) excitation and an optical-optical double resonance (OODR) spectrum under jet-cooled conditions. In the OODR process, the sum of the frequencies of the pump and probe lasers must be fixed to the energy difference between a pair of vibronic levels in the S2(v′) and S0(v″) states. Detection is through the fluorescence from the S2 state. The blocking of a spectrum into its four possible symmetry components is obtained by adjusting the total pump+probe energy such that it matches the energy difference between symmetry selected levels in the S2 and S0 electronic states. In this method the pump laser is used to excite a group of “hot” sequence bands that involve combinations of the ν4 and ν6 antisymmetric vibrations. The additional data that were collected by this method were used to update and refine the analyses of the spectrum. Magnetic dipole transitions are reported for the first time.

Billinghurst B. E. - One of the best experts on this subject based on the ideXlab platform.

  • High-resolution synchrotron infrared spectroscopy of Thiophosgene: The \u3bd 1, \u3bd 5, 2\u3bd4, and \u3bd2+2\u3bd6 bands
    Elsevier, 2015
    Co-Authors: Mckellar A. R. W., Billinghurst B. E.
    Abstract:

    Thiophosgene (Cl2CS) is a favorite model system for studies of photophysics, vibrational dynamics, and intersystem interactions. But its infrared spectra tend to be very congested due to hot bands and multiple isotopic species. This paper reports the first detailed study of the \u3bd 1 (~1139cm- 1) and \u3bd 5 (~820cm-1) fundamental bands for the two most abundant isotopologues, 35Cl2CS and 35Cl37ClCS, based on spectra with a resolution of about 0.001cm-1 obtained at the Canadian Light Source far-infrared beamline using synchrotron radiation and a Bruker IFS125 Fourier transform spectrometer. The 2\u3bd 4 (~942cm- 1) and \u3bd 2 +2\u3bd 6 (~1104cm-1) bands are also studied here, but the \u3bd 2 + \u3bd 6 band (~795cm- 1) resisted full analysis.Peer reviewed: YesNRC publication: Ye

  • High-resolution synchrotron infrared spectroscopy of Thiophosgene: The \u3bd2 and \u3bd4 fundamental bands near 500 cm 121
    2010
    Co-Authors: Mckellar A. R. W., Billinghurst B. E.
    Abstract:

    Thiophosgene (Cl2CS) is a favorite model system for studies of photophysics, vibrational dynamics, and intersystem interaction effects. But there are no previous rotationally-resolved infrared studies because the spectra are very congested due to hot bands and multiple isotopic species. This paper reports a detailed study of the \u3bd2 (not, vert, similar504 cm 121) and \u3bd4 (not, vert, similar471 cm 121) fundamental bands for the two most abundant isotopomers, 35Cl2CS and 35Cl37ClCS, based on spectra with observed line widths of not, vert, similar0.0008 cm 121 obtained at the Canadian Light Source far-infrared beamline using synchrotron radiation and a Bruker IFS125 Fourier transform spectrometer.Peer reviewed: YesNRC publication: Ye

  • THE FAR INFRARED SPECTRUM OF Thiophosgene: ANALYSIS OF THE \nub{2} FUNDAMENTAL BAND AT 500 \wn
    'The Ohio State University Libraries', 2009
    Co-Authors: Mckellar A. R. W., Billinghurst B. E.
    Abstract:

    For example: P.D. Chowdary, B. Strickler, S. Lee, and M. Gruebele, \textit{Chem. Phys. LettersJ.H. Carpenter, D.F. Rimmer, J.G. Smith, and D.H. Whiffen, \textit{J. Chem. Soc. Faraday Trans. 2Author Institution: Steacie Institute for Molecular Sciences, National Research; Council of Canada, Ottawa, ON K1A 0R6, Canada; Canadian Light Source, 101 Perimeter Road, University of; Saskatchewan, Saskatoon, SK S7N 0X4, CanadaThiophosgene (Cl$_2$CS) is a model system for studies of vibrational dynamics. Many hundreds of vibrational levels in the ground electronic state have been experimentally observed, allowing a detailed anharmonic force field to be developed including all six vibrational modes. \textbf{434}, 182 (2007).} But there have been no previous high resolution studies of this molecule in the infrared, presumably because its mass and multiple isotopic species result in very congested spectra. Here we report a detailed study of the strong \nub{2} fundamental band (symmetric C $-$ Cl stretch) based on a spectrum obtained using synchrotron radiation with the Bruker IFS125 FT spectrometer at the Canadian Light Source far infrared beamline. Thiophosgene is an interesting example of an accidentally near-symmetric oblate rotor. Indeed, its inertial axes switch with isotopic substitution: for $^{35}$Cl$_2$CS, the C$_{2v}$ symmetry axis coincides with the $a$ inertial axis, but for $^{37}$Cl$_2$CS, this changes to the $b$ axis. Fortunately for us, the ground state microwave spectrum has been well studied. \textbf{71}, 1752 (1971).} Even so, it has required the full spectral resolution of the present results, with observed line widths of about 0.0008 \wn, to achieve a true line-by-line analysis