Acetic Anhydride → HCID 12852536, compound

HRID 267805Notes

Reaction equation

HRID 267805 reaction equation
[F:1][C@:2]12[C@@H:22]([OH:23])[CH2:21][C@@:20]3([CH3:24])[C@@H:12]([CH2:13][CH:14]=[C:15]3[C:16](=[O:19])[CH2:17][OH:18])[C@@H:11]1[CH2:10][CH2:9][C:8]1[C@:3]2([CH3:26])[CH:4]=[CH:5][C:6](=[O:25])[CH:7]=1.[C:27](OC(=O)C)(=[O:29])[CH3:28].B(F)(F)F.[CH3:38][CH2:39][O:40]CC>ClCCl>[C:27]([O:23][C@H:22]1[CH2:21][C@@:20]2([CH3:24])[C@@H:12]([CH2:13][CH:14]=[C:15]2[C:16](=[O:19])[CH2:17][O:18][C:39](=[O:40])[CH3:38])[C@H:11]2[C@@:2]1([F:1])[C@:3]1([CH3:26])[C:8]([CH2:9][CH2:10]2)=[CH:7][C:6](=[O:25])[CH:5]=[CH:4]1)(=[O:29])[CH3:28]

Participants

5

Reactant 3

HCID 7918Acetic AnhydrideHCID 8000Boron trifluoride etherate2×HCID 70580639HCID 70580639, compound

Product 1

HCID 12852536HCID 12852536, compound

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Procedure

A solution of 5 g of 9-fluoro-11β,21-dihydroxypregna-1,4,16-triene-3,20-dione, 21-acetate, 50 ml each of acetic anhydride and dichloromethane and 2.5 ml of boron trifluoride etherate is stirred at room temperature under nitrogen for 2.5 hours. Because the reaction is slow, another 1.5 ml of boron trifluoride etherate is added and the reaction is continued for another 1.5 hours. The resulting solution is diluted with 200 ml of dichloromethane, washed with a saturated sodium bicarbonate solution and water, dried over anhydrous sodium sulfate and evaporated in vacuo to give 5.2 g of a solid. This is chromatographed on a column of 100 g of silica gel. Elution with 1:4 hexane-chloroform gives 4.8 g of material. Crystallization from chloroform-hexane gives 4.2 g of the title compound, melting point 294-296°C.

Workup

  1. washwashed with a saturated sodium bicarbonate solution and water
  2. dry with materialdried over anhydrous sodium sulfate
  3. customevaporated in vacuo

Sources & evidence

ORD record
ord-1865f8d81ebd4e57821c3b6d4fe98b71
Source dataset
uspto-grants-1976_03
Patent number
US03944584

Reaction notes

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