SYNTHETIC STUDIES ON TERPENIC COMPOUNDS - XV. SYNTHESIS OF METHYL 14β-HYDROXY-7β:8β,9β:11β,12α:13α-TRIEPOXYABIETAN-18-OATE, COMPLETE B/C RING MODEL OF ANTILEUKEMIC TRIPTOLIDES, FROM LEVOPIMARIC ACID

Article abstract of DOI:10.1016/0040-4020(82)85092-8

Stereospecific construction of the hydroxytriepoxide system present in triptolide 1 and tripdiolide 2 has been explored starting from levopimaric acid 3. 8α:14α,12α:13α-Diepoxide 9 derived from 3 was converted to the epoxy dienone 16 by four steps process.The 9,11-epoxide group was introduced stereospecifically by oxidation with m-chloroperbenzoic acid to produce diepoxide 20.Epoxidation of the 14β-hydroxy derivative 33 with m-chloroperbenzoic acid or by a photochemical method afforded the title compound 36 which possesses the complete B/C ring functionality of 1 and 2.The stereochemistry of the epoxy rings in 36 was confirmed by X-ray crystallographic analysis of the isomeric triepoxide 37.The result of antitumor tests of the stereoisomeric epoxides obtained in this study is described.