1096-38-4 16,17-Didehydroprogesterone 16-Dehydroprogesterone 3,20-Dioxopregna-4,16-diene EINECS 214-142-8 NSC 11037 NSC 9785 Pregna-4,16-diene-3,20-dione delta4,16-Pregnadiene-3,20-dione