A biomimetic synthesis of calothrixin B

Oxidation of the indolo[2,3-a]carbazole 15, readily obtained in six steps from indigo, followed by deprotection results in formation of the indolo[3,2-j]phenanthridine quinone alkaloid calothrixin B 2, demonstrating the viability of the proposed biosynthetic route to this unique ring system.

Graphical abstractOxidation of the indolo[2,3-a]carbazole 15 results in the biomimetic synthesis of calothrixin B 2.Figure optionsDownload full-size imageDownload as PowerPoint slide