16.alpha.,17-(Isopropylidenedioxy)progesterone 16.alpha.,17-Dihydroxypregn-4-ene-3,20-dione cyclic acetal with acetone 16.alpha.,17.alpha.-Isopropylidenedioxyprogesterone 4968-09-6 Algestone acetonide Alphasone Acetonide NSC26104 Pregn-4-ene-3,20-dione, 16,17-[(1-methylethylidene)bis(oxy)], (16.alpha.)- Pregn-4-ene-3,20-dione, 16,17-[(1-methylethylidene)bis(oxy)]-, (16.alpha.)- Pregn-4-ene-3,20-dione, 16.alpha.,17-(isopropylidenedioxy)- Pregn-4-ene-3,20-dione, 16.alpha.,17-dihydroxy-, cyclic acetal with acetone Progesterone 16,17-acetonide Progesterone, 16.alpha.,17-(isopropylidenedioxy)- W 3395 W3395