Popis: |
Die Unempfindlichkeit des 2,2-Dimethyl-2H-chromen-Systems gegen Oxidation mit TI(NO3)3 ermoglichte die von 6-Acetyl-5-hydroxy-2,2-dimethyl-2H-chromen (9) ausgehende Synthese des Isoflavons Jamaicin (1) und des Pterocarpans Leiocarpin (4) durch oxidative Umlagerung der entsprechenden Chalcone (6, 8). Oxidative Rearrangement of Chalcones by Thallium(III) Nitrate, VI1 Synthesis of the Isoflavonoids Jamaicin and Leiocarpin Inertness of the 2,2-dimethyl-2H-chromene system towards oxidation by Tl(NO3)3 makes possible the synthesis of the isoflavone jamaicin (1) and of the pterocarpan leiocarpin (4) from 6-acetyl-5-hydroxy-2,2-dimethyl-2H-chromene (9) by oxidative rearrangement of the corresponding chalcones (6,8). |