Reaction #81461

Reaction equation

sodium hydroxide

hydrochloric acid

3-[2,3,5,6-tetrafluoro-4-(trifluoromethyl)phenoxy]-17-(3-pyridyl)androsta-3,5,16-triene

ethanol

→

title compound

Yield 71.0%

17-(3-Pyridyl)androsta-4,16-dien-3-one

Yield 71.0%

Solvents

water

THF

Conditions

Workup

1. 1
   Temperaturethe mixture heated
2. 2
   Temperatureto cool
3. 3
   Extractionextracted with diethyl ether (3×30 ml)
4. 4
   Dryingdried (Na2CO3)
5. 5
   Concentrationconcentrated
6. 6
   WashChromatography, on elution with diethyl ether

Procedure

To a solution of 3-[2,3,5,6-tetrafluoro-4-(trifluoromethyl)phenoxy]-17-(3-pyridyl)androsta-3,5,16-triene (0.423 g, 0.75 mmol) in THF (5 ml) was added ethanol (5 ml) followed by aqueous hydrochloric acid (1M, 5 ml) and the mixture heated, with stirring, by an oil bath at 65° C. for 48 h and allowed to cool. The mixture was poured into water (20 ml), neutralised with aqueous sodium hydroxide (1M), and extracted with diethyl ether (3×30 ml). The ether extracts were combined, dried (Na2CO3), and concentrated. Chromatography, on elution with diethyl ether, afforded the title compound (185 mg, 71%) which crystallised from diethyl ether, m.p. 148°-150° C. IR νmax 1674 cm-1 ; 1H-NMR(CDCl3) inter alia δ 1.07(3H,s,18-CH3), 1.24(3H,s,19-CB3), 5.76(1H,m,Py 6-H), 5.99(1H,m,16-H), 7.23(1H,m,Py 5-H), 7.64(1H,m,Py 4-H), 8.47(1H,m,Py 6-H), 8.62(1H,m,Py 2-H); MS m/z, 347 (M+).

Source