De novo consecutive chemo/regioselective IBX mediated oxidation of andrographolide and its derivatives |
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| Authors: | Sudhakar Mokenapelli Madhu Gutam Ramana Govu Vijay Kumar Pasala Jayaprakash Rao Yerrabelly |
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| Affiliation: | Natural Products Laboratory, Department of Chemistry, Osmania University, Hyderabad, Telangana State, India |
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| Abstract: | A new IBX mediated protocol for regio/chemoselective oxidation of andrographolide (1), a labdane diterpenoid isolated from Andrographis paniculata, is developed. After the initial success of this protocol with andrographolide (1) to provide 19-dehydroandrographolide (5) or 3,19-didehydroandrographolide (6) as major products, the procedure was further applied for the oxidation of hydroxyl functionality in andrographolide derivatives, namely 2, 3, 14, and 16. The process was equally suitable on scales of milligram to gram with ease. Deprotection of C-19-OTBDMS in compounds 15 and 18 was achieved using TBDMS-Cl in acetonitrile-water (8:2) system in good yields. |
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| Keywords: | Andrographolide chemo/regioselective oxidation isolation labdane diterpenoid 2-Iodoxybenzoicacid (IBX) |
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