| abstract |
Prednisolone derivs. are of formula (I). In (I) R1 is 1-8C alkanoyl or benzoyl. X is F, Cl or 3-8C alkanoyloxy. They are prepd. e.g. by reacting the corresp. 9.11-epoxide with HF. (I) have powerful local antiinflammatory properties (often superior to the best known corticoids) but only very weak systemic effects. They are useful for treating e.g. contact dermatitis, eczema, pruritis, psoriasis, etc. and can also be formulated for inhalation to treat allergic disorders such as bronchial asthma or rhinitis. (I) are prepd. from diosgenin relatively cheaply with overall yields of around 15%, c.f. 0.5-5% for known corticoids. In an example, 17alpha-acetoxy-9alpha-fluoro-11beta-hydroxy-21-propionyloxy-1,4-- pregnadiene-3,20-dione was made from 17alpha, 21-(1-ethoxyethylidenedioxy)-9alpha-F-11beta-hydroxy-1,4-pregnadi- ene-3,20-dione by reacting with acetic acid, then propionic anhydride. |