Reaction #527906

Reaction equation

water

bromoacetaldehyde diethylacetal

NaH

17-ethylenedioxy-androstan-3β-ol

→

3β-(2,2-diethoxyethoxy)-17-ethylenedioxy-androstane

Solvents

tetrahydrofuran

Conditions

Workup

1. 1
   workup.ADDITIONwere added at room temperature under nitrogen atmosphere
2. 2
   workup.WAITthe suspension was kept at the same temperature for 4 hrs
3. 3
   workup.DISTILLATIONthe tetrahydrofuran was distilled under reduced pressure
4. 4
   ExtractionThe residue was extracted with methylene chloride
5. 5
   Dryingthe organic layer was dried over anhydrous sodium sulfate
6. 6
   Otherevaporated to dryness under reduced pressure
7. 7
   OtherThe crude product was purified by flash-chromatography (SiO2)

Procedure

To a suspension of 5.5 g of NaH (60% dispersion in mineral oil) in 400 ml of dry tetrahydrofuran 8.5 g of 17-ethylenedioxy-androstan-3β-ol were added at room temperature under nitrogen atmosphere. The mixture was kept at 40° C. for 2 hrs, then 26 ml of bromoacetaldehyde diethylacetal were added and the suspension was kept at the same temperature for 4 hrs; 50 ml of water were added cautiously, and the tetrahydrofuran was distilled under reduced pressure. The residue was extracted with methylene chloride, the organic layer was dried over anhydrous sodium sulfate and evaporated to dryness under reduced pressure. The crude product was purified by flash-chromatography (SiO2) using n-hexane/ethyl acetate 80/20 as eluant to give 7.5 g of 3β-(2,2-diethoxyethoxy)-17-ethylenedioxy-androstane as a thick oil.

Source