54793-60-1Relevant articles and documents
Champacyclin, a new cyclic octapeptide from Streptomyces strain C42 isolated from the Baltic Sea
Pesic, Alexander,Baumann, Heike I.,Kleinschmidt, Katrin,Ensle, Paul,Wiese, Jutta,Suessmuth, Roderich D.,Imhoff, Johannes F.
, p. 4834 - 4857 (2014/02/14)
New isolates of Streptomyces champavatii were isolated from marine sediments of the Gotland Deep (Baltic Sea), from the Urania Basin (Eastern Mediterranean), and from the Kiel Bight (Baltic Sea). The isolates produced several oligopeptidic secondary metabolites, including the new octapeptide champacyclin (1a) present in all three strains. Herein, we report on the isolation, structure elucidation and determination of the absolute stereochemistry of this isoleucine/leucine (Ile/Leu = Xle) rich cyclic octapeptide champacyclin (1a). As 2D nuclear magnetic resonance (NMR) spectroscopy could not fully resolve the structure of (1a), additional information on sequence and configuration of stereocenters were obtained by a combination of multi stage mass spectrometry (MSn) studies, amino acid analysis, partial hydrolysis and subsequent enantiomer analytics with gas chromatography positive chmical ionization/electron impact mass spectrometry (GC-PCI/EI-MS) supported by comparison to reference dipeptides. Proof of the head-to-tail cyclization of (1a) was accomplished by solid phase peptide synthesis (SPPS) compared to an alternatively side chain cyclized derivative (2). Champacyclin (1a) is likely synthesized by a non-ribosomal peptide synthetase (NRPS), because of high content of (D)-amino acids. The compound (1a) showed antimicrobial activity against the phytopathogen Erwinia amylovora causing the fire blight disease of certain plants.
PhFl polystyrene: A new resin for solid phase organic synthesis
Bleicher, Konrad H.,Wareing, James R.
, p. 4587 - 4590 (2007/10/03)
A 9-phenylfluoren-9-yl polystyrene based resin is described for the attachment of nitrogen and oxygen nucleophiles. Higher acid stability compared to standard trityl resins makes this solid support an interesting alternative in solid phase organic synthes
New hydroxyethylamine HIV protease inhibitors that suppress viral replication
Rich,Vara Prasad,Sun,Green,Mueller,Houseman,MacKenzie,Malkovsky
, p. 3803 - 3812 (2007/10/02)
The synthesis of analogues of AcSerLeuAsn[Phe-HEA-Pro]IleValOMe (1, JG- 365; where HEA stands for the hydroxyethylamine unit 2), a tight-binding inhibitor of HIVP, are reported. Systematic modification of the P3 and P3' regions of the inhibitors has led to smaller HIVP inhibitors that inhibit viral replication in HIV-infected and SIV-infected cell cultures. Six aliphatic and/or aromatic derivatives were prepared by replacing residues in the P3 regions of BocLeuAsn[Phe-HEA-Pro]IleValOMe. Aromatic side chains at P3 gave better inhibitors than aliphatic side chains. The better inhibitors in this series contained a β-naphthylalanine or a biphenyl unit at P3. A second series of HIVP inhibitors were obtained by converting the P3 group into acyl groups. CbzAsn[Phe-HEA-Pro]IlePheOMe and Qua-Asn-[Phe-HEA-Pro]-Ile- Phe-OMe (where Qua = quinolin-2-ylcarbonyl) are potent HIVP inhibitors with K(i) values equal to 1.0 and 0.1 nM, respectively. The inhibition constants were determined by using the continuous fluorometric assay developed by Toth and Marshall. The activities of the protease inhibitors for inhibition of SIV replication were determined in vitro using CEMx174 cells. Inhibition of HIV infection was determined essentially as reported by Pauwels and co-workers. The anti-HIV assay was carried out in culture using CEM cells (a CD4+ lymphocyte line) infected with virus strain HTLV-III(b) with a multiplicity of infection of 0.1. Several analogues inhibited the cytopathic effect at concentrations of 0.1-0.8 μg/mL. These results establish that good inhibitors of HIV protease that inhibit viral replication in infected lymphocytes in in vitro cell assays can be obtained from JG-365 when the AcSerLeu unit is replaced by aromatic acyl derivatives.
