1alpha-hydroxy-3betaH-3alpha,4alpha-epoxy-4,10-dimethyl-5alphaH,7alphaH,8betaH,10alphaH-guai-1(13)-ene-7,8-olide
1alpha-hydroxy-3betah-3alpha,4alpha-epoxy-4,10-dimethyl-5alphah,7alphah,8betah,10alphah-guai-1(13)-ene-7,8-olide