11beta,21-dihydroxy-16beta,17-(isopropylidenedioxy)pregna-1,4-diene-3,20-dione 21-pivalate

2,2-Dimethylpropionic acid 11β-hydroxy-16β,17-[(1-methylethylidene)bis(oxy)]-3,20-dioxopregna-1,4-dien-21-yl ester