Synonyms: Pregn-4-en-20-one,6a-fluoro-3b,11b,16a,17-tetrahydroxy-, cyclic 16,17-acetal with acetone,3-acetate (7CI,8CI); 6bH-Naphth[2',1':4,5]indeno[1,2-d][1,3]dioxole,pregn-4-en-20-one deriv.; 3b-Acetoxy-6a-fluoro-11b-hydroxy-16a,17-(isopropylidenedioxy)pregn-4-en-20-one; Ay 13643-5