Pregnadiene

A pregnadiene is a diene derivative of a pregnane.^[1]

Dienes have two double bonds. The first is usually between carbon 4 and carbon 5 on ring A.

6-ene

The second can be between carbons 6 and 7 on ring B:

• 
  Chlormadinone acetate (progestin)
• 
  Cyproterone acetate (antiandrogen)
• 
  Dydrogesterone (progestin)
• 
  Megestrol acetate (progestin, antineoplastic, appetite stimulant)
• 
  Canrenone (aldosterone antagonist)
• 
  Medrogestone (progestin)

1-ene

The second can also be between carbons 1 and 2 on ring A:

• 
  Fluocinolone acetonide (glucocorticoid)
• 
  Triamcinolone (glucocorticoid)