Omanische Heilpflanze im Fokus der Phytochemie IPB-Wissenschaftler und Partner aus Dhofar haben jüngst die omanische Heilpflanze Terminalia dhofarica unter die phytochemische Lupe genommen. Die Pflanze ist reich an…
Geschmack ist vorhersagbar: Mit FlavorMiner. FlavorMiner heißt das Tool, das IPB-Chemiker und Partner aus Kolumbien jüngst entwickelt haben. Das Programm kann, basierend auf maschinellem Lernen (KI), anhand der…
An ancient reaction vessel: TobZ carbamoylates the antibiotic tobramycin to form nebramycin 5′. The YrdC‐like domain (blue) catalyzes the formation of the novel intermediate carbamoyladenylate, which is channeled through a common “reaction chamber” to the Kae1‐like domain (brown), site of carbamoyl transfer.
Publikation
Neves Filho, R. A. W.; Stark, S.; Westermann, B.; Wessjohann, L. A.;The multicomponent approach to N-methyl peptides: total synthesis of antibacterial (–)-viridic acid and analoguesBeilstein J. Org. Chem.82085-2090(2012)DOI: 10.3762/bjoc.8.234
Two syntheses of natural viridic acid, an unusual triply N-methylated peptide with two anthranilate units, are presented. The first one is based on peptide-coupling strategies and affords the optically active natural product in 20% overall yield over six steps. A more economical approach with only four steps leads to the similarly active racemate by utilizing a Ugi four-component reaction (Ugi-4CR) as the key transformation. A small library of viridic acid analogues is readily available to provide first SAR insight. The biological activities of the natural product and its derivatives against the Gram-negative bacterium Aliivibrio fischeri were evaluated.
Publikation
van Berkel, S. S.; Brauch, S.; Gabriel, L.; Henze, M.; Stark, S.; Vasilev, D.; Wessjohann, L. A.; Abbas, M.; Westermann, B.;Traceless Tosylhydrazone-Based Triazole Formation: A Metal-Free Alternative to Strain-Promoted Azide-Alkyne CycloadditionAngew. Chem. Int. Ed.515343-5346(2012)DOI: 10.1002/anie.201108850
Triple‐T trick! Traceless tosylhydrazone‐based triazole formation is readily achieved by reacting primary amines with functional α,α‐dichlorotosylhydrozones under ambient conditions. This fast and efficient alternative affords exclusively 1,4‐substituted triazole “click products” with complete retention of configuration. Primary amines, inherent to many natural products, can be modified in this way without protecting group manipulations.
Publikation
Weissenborn, M. J.; Wehner, J. W.; Gray, C. J.; Šardzík, R.; Eyers, C. E.; Lindhorst, T. K.; Flitsch, S. L.;Formation of carbohydrate-functionalised polystyrene and glass slides and their analysis by MALDI-TOF MSBeilstein J. Org. Chem.8753-762(2012)DOI: 10.3762/bjoc.8.86
Glycans functionalised with hydrophobic trityl groups were synthesised and adsorbed onto polystyrene and glass slides in an array format. The adsorbed glycans could be analysed directly on these minimally conducting surfaces by MALDI-TOF mass spectrometry analysis after aluminium tape was attached to the underside of the slides. Furthermore, the trityl group appeared to act as an internal matrix and no additional matrix was necessary for the MS analysis. Thus, trityl groups can be used as simple hydrophobic, noncovalently linked anchors for ligands on surfaces and at the same time facilitate the in situ mass spectrometric analysis of such ligands.