Directed biosynthesis of novel derivatives of echinomycin. II. Purification and structure elucidation

1984 ◽  
Vol 30 (6) ◽  
pp. 730-738 ◽  
Author(s):  
D. Gauvreau ◽  
M. J. Waring
Keyword(s):  
High Performance ◽  
Reversed Phase ◽  
Aromatic Acids ◽  
Antibacterial Assay ◽  
New Antibiotics ◽  
Field Desorption Mass Spectrometry ◽  
Directed Biosynthesis ◽  
Phase Systems ◽  
Derivatives Of ◽  
Acid Precursor

New antibiotics produced by Streptomyces echinatus A8331 cultured in the presence of heterocyclic aromatic acids can be separated and purified by high-performance liquid chromatography using reversed phase columns. Natural quinoxaline antibiotics and certain quinoline derivatives can also be efficiently separated in normal phase systems. Details of purification procedures are described together with experiments to characterise the new antibiotics by field desorption mass spectrometry and proton magnetic resonance. Mono- and bis-substituted derivatives of echinomycin containing the following replacement chromophores have been isolated: 7-chloroquinoxaline-2-carbonyl, thieno[3,2-b]pyridine-5-carbonyl, and 6-methylquinoline-2-carbonyl. With a 6-methylquinoline-2-carboxylic acid precursor the analogues containing one or two replacement chromophores are each separable into two distinct components. One of the bis-substituted 6-methylquinoline products appears inactive in an antibacterial assay and behaves as a triostin analogue, presumably an immediate precursor of the corresponding echinomycin derivative.

scholarly journals Pressurized planar electrochromatography of DNS amino acids derivatives in silica gel and silanized silica gel systems with formic acid addition to the water mobile phase

2021 ◽  
Author(s):  
Adam Chomicki ◽  
Tadeusz H. Dzido
Keyword(s):  
Amino Acids ◽  
Silica Gel ◽  
High Performance ◽  
Reversed Phase ◽  
Mobile Phases ◽  
Phase Systems ◽  
Silanized Silica ◽  
Layer Chromatography ◽  
Derivatives Of ◽  
Electrophoretic Effect

AbstractPressurized planar electrochromatography (PPEC) of dansyl (DNS) derivatives of amino acids in normal- and reversed-phase systems is presented. The results have been obtained for mobile phases with different acetonitrile (ACN) concentrations (0–85%). The data obtained show differences in separation selectivity between high-performance thin-layer chromatography (HPTLC) and PPEC systems. These differences originate from the electrophoretic effect which is involved in the PPEC system, contrary to the HPTLC one.

scholarly journals Preparation and Hydro-Lipophilic Properties of Selected Novel Chlorinated and Brominated N-Arylcinnamamides

Proceedings ◽  
2019 ◽  
Vol 41 (1) ◽  
pp. 11
Author(s):  
Tomas Strharsky ◽  
Timotej Jankech ◽  
Jiri Kos ◽  
Kristina Maricakova ◽  
Andrea Pramukova ◽  
...  
Keyword(s):  
High Performance ◽  
Chemical Structure ◽  
Antimicrobial Agents ◽  
Reversed Phase ◽  
Log P ◽  
Organic Modifier ◽  
Chromatography Method ◽  
P Values ◽  
Liquid Chromatography Method ◽  
Derivatives Of

A series of six di- and tri-halogenated N-arylcinnamanilides designed as anti-inflammatory and antimicrobial agents was prepared and characterized. Since it is known that lipophilicity significantly influences the biological activity of compounds, the hydro-lipophilic properties of these di- and tri-substituted N-arylcinnamanilides were investigated in the study. All the discussed derivatives of cinnamic acid were analyzed using the reversed-phase high performance liquid chromatography method to measure lipophilicity. The procedure was performed under isocratic conditions with methanol as an organic modifier in the mobile phase using an end-capped non-polar C18 stationary reversed-phase column. In the present study, the correlations between the logarithm of the capacity factor k and log P/Clog P values calculated in various ways as well as the relationships between the lipophilicity and the chemical structure of the studied compounds are discussed.

scholarly journals Degradation of Benzo[a]pyrene by Mycobacterium vanbaalenii PYR-1

2004 ◽  
Vol 70 (1) ◽  
pp. 340-345 ◽  
Author(s):  
Joanna D. Moody ◽  
James P. Freeman ◽  
Peter P. Fu ◽  
Carl E. Cerniglia
Keyword(s):  
High Performance ◽  
Culture Media ◽  
Optical Purity ◽  
Fission Products ◽  
Reversed Phase ◽  
Environmental Pollutant ◽  
Ring Fission ◽  
Uv Visible ◽  
Derivatives Of ◽  
Absolute Stereochemistry

ABSTRACT Metabolism of the environmental pollutant benzo[a]pyrene in the bacterium Mycobacterium vanbaalenii PYR-1 was examined. This organism initially oxidized benzo[a]pyrene with dioxygenases and monooxygenases at C-4,5, C-9,10, and C-11,12. The metabolites were separated by reversed-phase high-performance liquid chromatography (HPLC) and characterized by UV-visible, mass, nuclear magnetic resonance, and circular dichroism spectral analyses. The major intermediates of benzo[a]pyrene metabolism that had accumulated in the culture media after 96 h of incubation were cis-4,5-dihydro-4,5-dihydroxybenzo[a]pyrene (benzo[a]pyrene cis-4,5-dihydrodiol), cis-11,12-dihydro-11,12-dihydroxybenzo[a]pyrene (benzo[a]pyrene cis-11,12-dihydrodiol), trans-11,12-dihydro-11,12-dihydroxybenzo[a]pyrene (benzo[a]pyrene trans-11,12-dihydrodiol), 10-oxabenzo[def]chrysen-9-one, and hydroxymethoxy and dimethoxy derivatives of benzo[a]pyrene. The ortho-ring fission products 4-formylchrysene-5-carboxylic acid and 4,5-chrysene-dicarboxylic acid and a monocarboxylated chrysene product were formed when replacement culture experiments were conducted with benzo[a]pyrene cis-4,5-dihydrodiol. Chiral stationary-phase HPLC analysis of the dihydrodiols indicated that benzo[a]pyrene cis-4,5-dihydrodiol had 30% 4S,5R and 70% 4R,5S absolute stereochemistry. Benzo[a]pyrene cis-11,12-dihydrodiol adopted an 11S,12R conformation with 100% optical purity. The enantiomeric composition of benzo[a]pyrene trans-11,12-dihydrodiol was an equal mixture of 11S,12S and 11R,12R molecules. The results of this study, in conjunction with those of previously reported studies, extend the pathways proposed for the bacterial metabolism of benzo[a]pyrene. Our study also provides evidence of the stereo- and regioselectivity of the oxygenases that catalyze the metabolism of benzo[a]pyrene in M. vanbaalenii PYR-1.

scholarly journals Effect of mobile phase buffer pH on separation selectivity of some isoquinoline alkaloids in reversed-phase systems of Pressuriz

2015 ◽  
Vol 26 (3) ◽  
pp. 45-49
Author(s):  
Ewelina Kopciał ◽  
Beata Polak ◽  
Rafał Pietraś ◽  
Paulina Mączka ◽  
Tadeusz H. Dzido
Keyword(s):  
Mobile Phase ◽  
High Performance ◽  
Reversed Phase ◽  
Retardation Factor ◽  
Isoquinoline Alkaloids ◽  
Buffer Solution ◽  
Separation Selectivity ◽  
Phase Systems ◽  
Ph Range ◽  
Layer Chromatography

Separation of some isoquinoline alkaloids (narcotine, chelidonine, dihydrocodeine, cinchonine, berberine, cinchonidine, papaverine, apomorphine) has been investigated with pressurized planar electrochromatography (PPEC) and high-performance thin-layer chromatography (HPTLC) in reversed-phase systems. The mobile phase consisted of acetonitrile and aqueous buffer (disodium phosphate and citric acid). The influence of the mobile phase buffer pH on migration distance (PPEC) and retardation factor (HPTLC) of the solutes has been investigated and compared. The results show different separation selectivity in both PPEC and HPTLC systems especially at pH range of buffer solution of the mobile phase that facilitates ionization of the solutes investigated.

Prediction of Reversed-Phase Liquid Chromatography Retention Parameters for Phenylisothiocyanate Derivatives of Amino Acids

2014 ◽  
Vol 52 (1-2) ◽  
pp. 61-70
Author(s):  
S. Vorslova ◽  
J. Golushko ◽  
S. Galushko ◽  
A. Viksna
Keyword(s):  
Amino Acids ◽  
High Performance ◽  
Method Development ◽  
Initial Conditions ◽  
Reversed Phase ◽  
Fine Tuning ◽  
Model Parameters ◽  
Step Method ◽  
Retention Model ◽  
Derivatives Of

Abstract We report our experience with highly polar and charged analyte retention parameter prediction for a reversed-phase high-performance liquid chromatographic method. The solvatic retention model has been used to predict retention of phenylisothiocyanate derivatives of 25 natural amino acids under gradient elution conditions. Retention factors have been calculated from molecular parameters of analyte structures and from the column and eluent characteristics. A step-by-step method which includes the first guess prediction of initial conditions from structural formula and fine tuning of the retention model parameters using data from successive runs can substantially save method development time

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