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Enantioselective syntheses of isotopically labelledα-amino acids Preparation of specifically13C-labelled L-lysines (1995)

Raap, J. ; Wolthuis, W. N. E. ; Hehenkamp, J. J. J. ; [et al.]

Springer

Amino acids 8 (1995), S. 171-186

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ISSN: 1438-2199

Keywords: Amino acids ; bis-lactim ether method ; 13C-isotope ; (2R)-[5-13C]-3,6-diethoxy-2,5-dihydro-2-isopropylpyrazine ; L-α-aminoadipic acid ; NMR spectroscopy ; Mass spectrometry

Source: Springer Online Journal Archives 1860-2000

Topics: Medicine

Notes: Summary [2-13C]-L-lysine, [3,4-13C2]-L-lysine and [5,6-13C2]-L-lysine are prepared from simple, commercially available, highly enriched starting materials as [2-13C]-glycine, ethyl [1,2-13C2]-bromo acetate, and [1,2-13C2]-acetonitrile. The introduction of the chiral center is based on a general method starting from the bis-lactim ether of cyclo-(D-Val-Gly). The synthesis of (2R)-[5-13C]-3,6-diethoxy-2,5-dihydro-2-isopropylpyrazine is described. The availability of our method for the preparation of specifically enriched bis-lactim ethers allows the synthesis of a great variety of site specific isotopically labelled (L- and D-)α-amino acids. Moreover, intermediate 4-[(2R,5S)-3,6-diethoxy-2,5-dihydro-2-isopropyl-5-pyrazinyl]butyronitrile is a valuable precursor in the synthesis of L-α-aminoadipic acid. The synthetic scheme in this publication makes both L-lysine and L-α-aminoadipic acid13C- or15N-labelled at any position, easily available. The isotopomers of lysine are obtained on a preparative scale in good yields, with 99%13C and high enantiomeric purity (〉97% e.e.). Three isotopomers are characterized using various spectroscopic techniques,e.g.,1H NMR,13C NMR and Mass spectrometry.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00806490

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Preparation of Site-Specific Isotopically Labelled Zervamicins, the Antibiotic Peptaibols Produced by Emericellopsis Salmosynnemata (1996)

Egorova-Zachernyuk, T. A. ; Shvets, V. I. ; Versluis, K. ; [et al.]

New York, NY [u.a.] : Wiley-Blackwell

Journal of Peptide Science 2 (1996), S. 341-350

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ISSN: 1075-2617

Keywords: Biosynthesis ; deuterium ; nitrogen 15 ; positive ion FAB mass spectrometry ; ion channel-forming peptide ; Chemistry ; Biochemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: A simple procedure for the preparation of the specifically labelled peptide antibiotic zervamicins IC, IIA and IIB has been developed. The zervamicin molecules are labelled with stable isotopes by culturing the Emericellopsis salmosynnemata on a well-defined synthetic medium containing the highly isotopically enriched amino acid. To obtain the peptide with the specifically and highly enriched amino acid residue, precautions have been taken to prevent any de novo biosynthesis of the particular amino acid from unlabelled precursors. The enrichment of the labelled peptide is determined by mass spectrometric analysis. Following this method we have incorporated [2′,4′, 5′,6′,7′-2H5]-L-Trp-1, [1′-15N]-L-Trp-1 and [2′, 3′,4′,5′,6′-2H5]-L- Phl-16 into zervamicins IC, IIA and IIB on the preparative scale and without scrambling of the label. Thus, using the procedures described, isotopically labelled zervamicins can be prepared, allowing them to be studied by solid- state NMR.

Additional Material: 3 Ill.