(16?)-21-Hydroxy-16,17-[(1-methylethylidene)bis(oxy)]-pregna-1,4,9(11)-triene-3,20-dione;16?,17,21-Trihydroxy-pregna-1,4,9(11)-triene-3,20-dione cyclic 16,17-acetal with acetone; 2H-Naphth[2',1':4,5]indeno[1,2-d][1,3]dioxole Pregna-1,4,9(11)-triene-3,20-dione deriv.; 21-Hydroxy-16?,17?-(isopropylidenedioxy)pregna-1,4,9(11)triene-3,20-dione