Reaktion #722215

Reaktionsgleichung

1α,3β-bis(tert-butyldimethylsilyloxy)-20(S)-hydroxypregna-5,7,16-triene

sodium hydride

15-crown-5

1-bromo-4-methyl-4-triethylsilyloxy-2-pentyne

→

title compound

Ausbeute 100.1%

1α,3β-bis(tert-butyldimethylsilyloxy)-20(S)-(4-methyl-4-triethylsilyloxy-2-pentynyloxy)pregna-5,7,16-triene

Ausbeute 100.1%

Lösungsmittel

water

tetrahydrofuran

Reaktionsbedingungen

Aufarbeitung

1. 1
   Extraktionextracted with ethyl acetate
2. 2
   WaschenThe extract was washed with brine
3. 3
   Trocknendried over magnesium sulfate
4. 4
   workup.DISTILLATIONthe solvent was distilled off under reduced pressure
5. 5
   SonstigeThe resulting residue was purified by preparative thin layer chromatography (0.5 mm×2, hexane

Vorschrift

A solution of 1α,3β-bis(tert-butyldimethylsilyloxy)-20(S)-hydroxypregna-5,7,16-triene (60.0 mg, 0.107 mmol), sodium hydride (60%, 17.1 mg, 0.428 mmol), 15-crown-5 (10 μl) and 1-bromo-4-methyl-4-triethylsilyloxy-2-pentyne (109 mg, 0.375 mmol) in tetrahydrofuran (1 ml) was stirred at 60° C. for 2 hours. The solution was cooled to room temperature and then taken into water and extracted with ethyl acetate. The extract was washed with brine and dried over magnesium sulfate, and the solvent was distilled off under reduced pressure. The resulting residue was purified by preparative thin layer chromatography (0.5 mm×2, hexane:ethyl acetate=40:1, developed once) to give the title compound as a colorless oil (82.4 mg, 99%).

Quelle