Reaktion #215040

Reaktionsgleichung

Sodium acetate

acetic anhydride

(11β,16α)-9-fluoro-11,16,17-trihydroxy-3,20-dioxopregna-1,4-dien-21-oic acid, methyl ester

p-toluene sulfonic acid hydrate

→

title compound

11β,16α,17-Triacetyloxy-9-fluoro-3,20-dioxopregna-1,4-dien-21-oic acid, methyl ester

Lösungsmittel

acetic acid

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigethe solution is evaporated in vacuo
2. 2
   workup.ADDITIONThe residue is diluted with water
3. 3
   Extraktionextracted with chloroform
4. 4
   Extraktionthe chloroform extract
5. 5
   Waschenis washed with water
6. 6
   Trocknendried (MgSO4)
7. 7
   Sonstigeevaporated to a solid
8. 8
   SonstigeThe solid is crystallized from ethyl acetate

Vorschrift

A suspension of (11β,16α)-9-fluoro-11,16,17-trihydroxy-3,20-dioxopregna-1,4-dien-21-oic acid, methyl ester (150 mg) in a mixture of glacial acetic acid (5.0 ml) and acetic anhydride (5.0 ml) containing p-toluene sulfonic acid hydrate (150 mg) is stirred for 40 hours. Sodium acetate (300 mg) is added and the solution is evaporated in vacuo. The residue is diluted with water, extracted with chloroform and the chloroform extract is washed with water, dried (MgSO4) and evaporated to a solid. The solid is crystallized from ethyl acetate to afford the title compound (164 mg), melting point 317°-319° C. (dec.) (discoloration starts from ca. 280° C.).

Quelle