Unser 10. Leibniz Plant Biochemistry Symposium am 7. und 8. Mai war ein großer Erfolg. Thematisch ging es in diesem Jahr um neue Methoden und Forschungsansätze der Naturstoffchemie. Die exzellenten Vorträge über Wirkstoffe…
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…
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
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.