Dexamethasone → Dexamethasone 9,11-epoxide

Participants

Reaction Steps

Dexamethasone (9α-fluoro-11β,17α,21-trihydroxy-16α-methylpregna-1,4-diene-3,20-dione) can also be prepared from 17β-hydroxy-16-methylenepregna-1,4,9(11)-triene-3,20-dione (VIIB, Example 18) by first transforming it to 17α,21-dihydroxy-16-methylenepregna-1,4,9(11)-triene-3,20-dione 21-acetate (IX) as described above and next transforming it to 17α,21-dihydroxy-16α-methylpregna-1,4,9(11)-triene-3,20-dione 21-acetate (XI) by the process of U.S. Pat. No. 3,130,209. 17α,21-Dihydroxy-16α-methylpregna-1,4,9(11)-triene-3,20-dioine 21-acetate (XI) is then epoxidized by means well known to those skilled in the art, see for example U.S. Pat. No. 3,980,778 Examples 2 and 7 to produce 9β,11β-epoxy-17α,21-dihydroxy-16α-methylpregna-1,4-diene-3,20-dione which is transformed to dexamethasone 21-acetate by the process of U.S. Pat. No. 3,007,923 Example 2.

Provenance & Evidence