ChEBI: Betamethasone phosphate is a steroid phosphate that is the 21-O-phospho derivative of betamethasone. It has a role as an anti-inflammatory agent and an immunosuppressive agent. It is a steroid phosphate, an 11beta-hydroxy steroid, a fluorinated steroid, a 17alpha-hydroxy steroid, a 20-oxo steroid, a 3-oxo-Delta(1),Delta(4)-steroid and a tertiary alpha-hydroxy ketone. It is functionally related to a betamethasone. It is a conjugate acid of a betamethasone phosphate(2-).
A solution of bistriethylamine phosphate was prepared by slowly adding 2.36
ml of 85% phosphoric acid to 20 ml of acetonitrile containing 9.9 ml, of
triethylamine at 20°C. This solution was added to a stirred mixture of 4.70 g
of 9α-fluoro-11β,17α,21-trihydroxy-16α-methyl-1,4-pregnadiene-3,20-dione
21-methanesulfonate and 20 ml of acetonitrile. The mixture was heated under
reflux for 4 h and then evaporated under reduced pressure to a volume of 12
ml. This mixture was a concentrated solution of 9α-fluoro-11β,17α,21-
trihydroxy-16α-methyl-1,4-pregnadiene-3,20-dione 21-phosphate
triethylamine salt with some inorganic phosphate.
The salt of 9α-fluoro-11β,17α,21-trihydroxy-16α-methyl-1,4-pregnadiene-
3,20-dione 21-phosphate may be converted to 9α-fluoro-11β,17α,21-
trihydroxy-16α-methyl-1,4-pregnadiene-3,20-dione 21-phosphate by
treatment with acid (for example HCl).
