Pyridine → 2,2,7,7-Tetramethyl-3,6-dioxa-2,7-disilaoctane

In a manner similar to that described in Tsunoda T., et al., Tet. Lett., 1980, 21(14), 1357-1358, Hwa et al., J. Org. Chem., 1987, 52(2), 188-191. A solution of 3β-acetoxy-17β-t-butyldimethylsilyloxy-androst-5-en-7-one (40.000 g, 86.821 mmol) from Example 16B or otherwise obtained and 1,2-bis(trimethylsiloxy)ethane (23.00 mL, 93.81 mmole) in CH2Cl2 (300 mL) is prepared at −78° C. Trimethylsilyl trifluoromethanesulfonate (0.20 mL, 1.035 mmol) is added under an inert atmosphere, the reaction is stirred for three hours, pyridine (2.00 mL, 24.73 mmol) is added and the stirred mixture is allowed to warm to room temperature. The organic solution is poured into saturated aqueous NaHCO3 (300 mL) and the resultant biphasic solution is extracted with EtOAc (3×300 mL). The combined organic extracts are washed with brine (200 mL), dried over MgSO4, filtered and evaporated to dryness. The residue is purified by flash chromatography (1:4 EtOAc/hexane) to give 7,7-ethylenedioxy-17β-t-butyldimethylsilylyoxy-androst-5-en-3-ol 3-acetate.

1. extractionthe resultant biphasic solution is extracted with EtOAc (3×300 mL)
2. washThe combined organic extracts are washed with brine (200 mL)
3. dry with materialdried over MgSO4
4. filtrationfiltered
5. customevaporated to dryness
6. customThe residue is purified by flash chromatography (1:4 EtOAc/hexane)

ORD record

ord-a9d7100f148b423dba69586b1e352b5d

Source dataset

uspto-grants-2002_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06365597B1