Uroš Urleb

University of Ljubljana, Ljubljana, Ljubljana, Slovenia

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Publications (9)11.32 Total impact

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    ABSTRACT: Synthese von N-Acylamino-ethoxyessigsäure-Derivaten
    Archiv der Pharmazie 09/2006; 325(4):251 - 252. · 1.54 Impact Factor
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    ABSTRACT: Peptidosulfonamides are an emerging group of peptidomimetics with a variety of applications in medicinal chemistry. We present a novel approach to the synthesis of peptidosulfonamides, and apply it to a series of new potential inhibitors of the bacterial peptidoglycan biosynthesis enzymes MurD and MurE. The synthesis was conducted via N-phthalimido β-aminoethanesulfonyl chlorides, which are new building blocks for the synthesis of peptidosulfonamides. In the most crucial step, sulfonic acids or their sodium salts were converted into the corresponding sulfonyl chlorides using an excess of either SOCl2 or SOCl2/DMF, and then coupled to the C-protected amino acid. None of the compounds significantly inhibited MurD, however, some inhibited MurE; one had an IC50 below 200 μM, which constitutes a promising starting point for further development. Molecular modelling simulations were performed on two analogues to investigate the absence of inhibitory activity of the sulfonamide compounds on MurD.Graphical abstract
    Tetrahedron. 01/2006; 62(47):10980-10988.
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    ABSTRACT: Diethyl phosphonates were conveniently converted into ethyl 4-aminophenyl and ethyl 4-[amino(hydroxyimino)methyl]phenyl phosphonates as potentially useful intermediates for the preparation of functionalized phenyl phosphonates.
    Tetrahedron Letters 01/2002; 43(1):167-170. · 2.40 Impact Factor
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    Nataša Smola, Uroš Urleb
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    ABSTRACT: Near-infrared (NIR) spectroscopy, in combination with chemometrics, enable the analysis of raw materials without time-consuming sample preparation methods. The aim of our work was to estimate critical parameters in the analytical specification of oxytetracycline, and consequently the development of a method for quantification and qualification of these parameters by NIR spectroscopy. A Karl Fischer (K.F.) titration to determine the water content, a colorimetric assay method, and Fourier transform-infrared (FT-IR) spectroscopy to identify the oxytetracycline base, were used as reference methods, respectively. Multivariate calibration was performed on NIR spectral data using principal component analysis (PCA), partial least-squares (PLS 1) and principal component regression (PCR) chemometric methods. Multivariate calibration models for NIR spectroscopy have been developed. Using PCA and the Soft Independent Modelling of Class Analogy (SIMCA) approach, we established the cluster model for the determination of sample identity. PLS 1 and PCR regression methods were applied to develop the calibration models for the determination of water content and the assay of the oxytetracycline base. Comparing the PLS and PCR regression methods we found out that the PLS is better established by NIR, especially as the spectroscopic data (NIR spectra) are highly collinear and there are many wavelengths due to non-selective wavelengths. The calibration models for NIR spectroscopy are convenient alternatives to the colorimetric method and to the K.F. method, as well as to FT-IR spectroscopy, in the routine control of incoming material.
    Analytica Chimica Acta 01/2000; 410:203-210. · 4.39 Impact Factor
  • Stanislav Gobec, Uroš Urleb
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    ABSTRACT: Orthogonally protected Abu(P) (benzyl (2R,S)-4-diethylphosphonyl-2-phthalimido butanoate 4) has been synthesized. It has been used as a key intermediate for the synthesis of two new phthalimido-desmuramyldipeptide analogs containing diethylphosphnate moiety at the position of ω-carboxylic group of Glu.
    Phosphorus Sulfur and Silicon and The Related Elements - PHOSPHOR SULFUR SILICON. 01/2000; 156(1):125-133.
  • Stanislav Gobec, UroŠ Urleb
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    ABSTRACT: Muramyldipeptide (MDP) is the minimal bacterial cell wall moiety with imniunomodulating activity [I]. It is known that N-acetylglucosamine part is not essential lor immunomodulating activity and it can be replaced by phthalimido 01 adamantyl substituted side chains [2]. In our previous work we have modified the peptide backbone of phthaliniido-MDP analogs by introducing the phosphonamide 01 phosphinamide moiety at the end of the acyclic side chain or between Ala and Glu [3, 4]. We report the synthesis of phthalimido-MDP analog 2, where the o-carboxylic group of Glu is replaced by phosphonate moiety. Compound 1, which is orthogonally protected D,L-Abu(P), was prepared from benzyl 4-bromo-2-phthalimidobutyrate and triethyl phosphite. After removal of the phthalimide protecting group the obtained compound was coupled with Boc-L-Ah. Boc group was removed and the product was coupled with 5-phthalimidopentanoic acid to give 2. Both benzyl and ethyl protection can be selectively removed under mild conditions (catalytic hydrogenation. Nal).
    Phosphorus Sulfur and Silicon and The Related Elements - PHOSPHOR SULFUR SILICON. 01/1999; 147(1):97-97.
  • Stanislav Gobec, Uroš Urleb
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    ABSTRACT: New desmuramyldipeptide analogs with modified peptide backbones were synthesized. The peptide bond between Ala and Glu was replaced by a phosphonamidate methyl ester moiety. The amide bond at the end of the acyclic side chain was replaced by a phosphinamide moiety.
    International Journal of Peptide Research and Therapeutics 01/1998; 5(2):109-114. · 1.28 Impact Factor
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    ABSTRACT: Two phosphono desmuramyldipeptide analogs, 6 and 11, were synthesized and evaluated for immunomodulatory activity. Phthalimido-and adamantyl-substituted side chains as a replacement for the N-acetylmuraminic acid were coupled with appropriate dipeptides using DPPA as the coupling reagent. Introduction of a phosphonamidate moiety in compound 6 resulted in lower biological activity.
    Letters in Peptide Science 01/1995; 2(3):193-197.
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    ABSTRACT: (+)-(S)-Ibuproxam, a prodrug of (+)-(S)-ibuprofen, the pharmacologically active component of ibuprofen, was synthesized in order to minimize side effects (especially gastric irritation) and reduce effective dose. The low water solubility of (+)-(S)-ibuproxam, which prevents rapid dissolution and absorption from the gastrointestinal tract, was overcome by complexation with β-cyclodextrin and its derivatives. The inclusion complex formation was confirmed by differential scanning calorimetry (DSC), by 1H-NMR spectroscopy, and X-ray powder diffractometry. The physicochemical characteristics of ibuproxam were significantly improved by the complexation. © 1995 Wiley-Liss, Inc.
    Chirality 12/1994; 7(4):206 - 210. · 1.72 Impact Factor