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.; Morejon, M. C.; Westermann, B.; Wessjohann, L. A.;4-Isocyanopermethylbutane-1,1,3-triol (IPB): a convertible isonitrile for multicomponent reactionsTetrahedron Lett.535360-5363(2012)DOI: 10.1016/j.tetlet.2012.07.064
The synthesis and applications of 4-isocyanopermethylbutane-1,1,3-triol (IPB) as a new convertible isonitrile (isocyanide) for isocyanide-based multicomponent reactions (IMCRs) like Ugi, Ugi-Smiles, and Passerini reactions are described. The primary products obtained from these IMCRs can be converted into highly activated N-acylpyrroles, which upon treatment with nucleophiles can be transformed into carboxylic acids, esters, amides, alcohols, and olefins. In this sense the reagent can be seen as a neutral carbanion equivalent to formate (HO2C−), and carboxylates or carboxamides etc. (RNu-CO−).
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
Welsch, S. J.; Kalinski, C.; Umkehrer, M.; Ross, G.; Kolb, J.; Burdack, C.; Wessjohann, L. A.;Palladium and copper catalyzed cyclizations of hydrazine derived Ugi products: facile synthesis of substituted indazolones and hydroxytriazafluorendionesTetrahedron Lett.532298-2301(2012)DOI: 10.1016/j.tetlet.2012.02.095
Indazolones are medicinally relevant targets. Herein we disclose an improved synthesis to N′-(acetamido-2-yl)-substituted indazolones with four points of diversity introduced by Ugi-[M]-amination and -amidation. The ring closure can be achieved by either conventional palladium catalysis or with a ligandless copper protocol. When α-unbranched isocyanides were employed the sole cyclization products of the copper catalyzed reactions are the hitherto undescribed 2-hydroxy-3H-3,4a,9a-triaza-fluorene-4,9-diones.