114175-99-4 2,7,8-Trioxabicyclo(3.2.1)octane-1-ethanethioic acid, 3-((7alpha,20S)-7-hydroxy-3-oxopregna-1,4-dien-20-yl)-5,6,6-trimethyl-, S-methyl ester, (1S-exo)- Petuniasterone A