(6R,9S,13S,18R)-1alpha-Hydroxy-15-oxo-6,11alpha:6,18:18,20-triepoxy-6,7-secokaura-16-ene-7-oic acid 7,1-lactone

(6R,9S,13S,18R)-1alpha-Hydroxy-15-oxo-6,11alpha:6,18:18,20-triepoxy-6,7-secokaura-16-ene-7-oic acid 7,1-lactone