Synthesis of novel lupane triterpenoid-indazolone hybrids with oxime ester linkage
作者:Tatyana S. Khlebnicova、Yuri A. Piven、Alexander V. Baranovsky、Fedor A. Lakhvich、Svetlana V. Shishkina、Daina Zicāne、Zenta Tetere、Irisa Rāviņa、Viktors Kumpiņš、Inese Rijkure、Inese Mieriņa、Uldis Peipiņš、Māris Turks
DOI:10.1016/j.steroids.2016.08.002
日期:2017.1
An efficient protocol for the synthesis of novel lupane triterpenoid-indazolone hybrids with oxime ester linkage has been developed from naturally accessible precursor betulin. For the first time a series of betulonic acid-indazolone hybrids have been synthesized via an acylation of corresponding 6,7-dihydro-1H-indazol-4(5H)-one oximes with betulonic acid chloride. Diastereoselective reduction of the obtained betulonic acid conjugates with NaBH4 resulted in a formation of betulinic acid-indazolone hybrids in excellent yields. The configuration of the key compounds has been fully established by X-ray and 2D NMR analysis. (C) 2016 Elsevier Inc. All rights reserved.