A synthetic route from digitoxigenin to 20(22)-Vdihydro-23-deoxodigitoxigenin (10a) has been developed. Digi-toxigenin was acetylated, dehydrated, and selectively hydrogenated to give 3β-acetoxy-5β;20-card-14-enolide (4). Reduction with lithium aluminum hydride gave diol 5 which was cyclized to yield 3β-hydroxy-23-deoxo-5β,20-card-14-enolide (6). Introduction of the 14β-hydroxyl (10a) group was achieved by successive formation of the 14β-hydroxy-15α-bromo (7) and β-epoxide (8) derivatives followed by a reduction step.
ASJC Scopus subject areas
- Organic Chemistry