Dichloromethane → 17,21-Diacetoxy-6-methylene-4-pregnene-3,20-dione
Reaction equation
[C:1]([O:4][C@:5]1([C@:29]2([CH3:30])[C@H:15]([C@H:16]3[C@H:26]([CH2:27][CH2:28]2)[C@:24]2([CH3:25])[C:19](=[CH:20][C:21](=[O:31])[CH2:22][CH2:23]2)[CH2:18][CH2:17]3)[CH2:14][CH2:13]1)[C:6](=[O:12])[CH2:7][O:8][C:9](=[O:11])[CH3:10])(=[O:3])[CH3:2].O=P12OP3(OP(OP(O3)(O1)=O)(=O)O2)=O.[CH2:46](Cl)Cl>COCOC>[C:1]([O:4][C@:5]1([C@:29]2([CH3:30])[C@H:15]([C@H:16]3[C@H:26]([CH2:27][CH2:28]2)[C@:24]2([CH3:25])[C:19](=[CH:20][C:21](=[O:31])[CH2:22][CH2:23]2)[C:18](=[CH2:46])[CH2:17]3)[CH2:14][CH2:13]1)[C:6](=[O:12])[CH2:7][O:8][C:9](=[O:11])[CH3:10])(=[O:3])[CH3:2]Participants
Procedure
A solution of 5.0 g of 17,21-diacetoxy-4-pregnene-3,20-dione in 35 ml of anhydrous methylene chloride and 22.5 ml of methylal is combined in incremental portions at room temperature with a mixture of 1.0 g of phosphorus pentoxide and 7.5 g of silica gel. The mixture is agitated for 3 days at room temperature and then another 11 ml of methylal, 500 mg of phosphorus pentoxide, and 3.75 g of silica gel are added. After another 2 days, the reaction mixture is vacuum-filtered, the residue is washed thoroughly with methylene chloride, and evaporated to dryness under vacuum. The crude product is purified on 350 g of silica gel with a hexane/ethyl acetate gradient (0-50% ethyl acetate), thus obtaining 3.6 g of 17α,21-diacetoxy-6-methylene-4-pregnene-3,20-dione, mp 227°-228° C. [α]D25 =+165° (chloroform).
Workup
- waitAfter another 2 days
- filtrationthe reaction mixture is vacuum-filtered
- washthe residue is washed thoroughly with methylene chloride
- customevaporated to dryness under vacuum
- customThe crude product is purified on 350 g of silica gel with a hexane/ethyl acetate gradient (0-50% ethyl acetate)
Sources & evidence
- ORD record
- ord-4f9d0d0d87674fb89a42961937347e3b
- Source dataset
- uspto-grants-1982_03
- Patent number
- US04322349
Reaction notes
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