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C. Li et al. / Steroids 75 (2010) 859–869
2. Experimental
2.2.1.2. 17ˇ-Acetoxylandrost-4,6-dien-3-one (7). To a solution of
compound 6 (0.58 g, 2.0 mmol) in dichloromethane (30 ml) were
added DMAP (0.25 g, 2.0 mmol) and acetic anhydride (0.4 ml,
4.0 mmol). After completing the addition, the mixture was stirred at
room temperature for half an hour. The solution was washed with
NaHCO3 (50 ml), 1 M HCl (200 ml), and brine (200 ml), respectively,
and then dried in vacuo. This gave 0.63 g product 7 as yellow solid
(96%). 1H NMR (500 MHz, CDCl3) ı (ppm): 6.14 (m, 2H, 6-H and 7-
H), 5.69 (s, 1H, 5-H) 2.07 (s, 3H, 17-CH3CO), 1.12 (s, 3H, 18-CH3),
0.91 (s, 3H, 19-CH3).
Melting points were determined on a melting point appara-
tus and are uncorrected. 1H NMR spectra were measured on a
Bruker 500 MHz/400 MHz spectrometer at 25 ◦C in CDCl3 with
TMS as the internal standard. Chemical shifts are given in ppm
(ı-scale), and coupling constants and widths of multiplets are
given in Hz. 13C NMR spectra were measured on a spectrometer
(
13C at 100 MHz). HR-MS were recorded on a Bruker micrOTOF II
spectrometer (ESI ionization). The ␣/ methyl isomer ratio in the
products of 1,6-conjugate addition was determined by 1H NMR
analyses of the crude reaction mixtures. Optical rotations were
measured in dichloromethane. Thin-layer chromatography (TLC)
was performed on silica gel.
2.2.1.3. 17ˇ-Acetoxyl-7˛-methylandrost-4-en-3-one (8) and 17ˇ-
acetoxyl-7ˇ-methylandrost-4-en-3-one (9). Compound
7 (0.5 g,
1.53 mmol) was methylated as described in synthesis of 3 and 4
to give 0.38 g of product (75%), and both isomers 8 and 9 was in a
5:1 ratio. Further purification with chromatography could gave 7␣-
and 7-epimers, respectively. 1H NMR spectrum of ␣-isomer (8),
ı (ppm): 5.73 (s, 1H, 4-H), 4.61 (t, 1H, 17-H, J = 8.5 Hz), 2.05 (s, 3H,
COCH3), 1.20 (s, 3H, 18-CH3), 0.85 (s, 3H, 19-CH3), 0.77 (d, 3H, 7␣-
CH3, J = 7.5 Hz); 1H NMR spectrum of -isomer (9), ı (ppm): 5.71 (s,
1H, 4-H), 4.56 (t, 1H, 17-H, J = 8.5 Hz), 2.05 (s, 3H, COCH3), 1.16 (s,
3H, 18-CH3), 1.05 (d, 3H, 7␣-CH3, J = 6.5 Hz), 0.85 (s, 3H, 19-CH3);
13C NMR spectrum ␣-isomer (8), ı (ppm): 11.9, 12.6, 17.8, 20.5,
21.1, 22.8, 27.3, 30.9, 33.9, 35.9, 36.4, 37.9, 38.7, 40.7, 42.4, 46.1,
46.5, 82.4. 125.8, 169.4, 171.0, 198.9; HR-MS for C22H33O3 required
345.2430, found 345.2416.
2.1. Synthesis of 3-methyl steroids
2.1.1. Androst-3,5-dien-7,17-dione (2)
To a solution of 3-hydroxyandrost-5-en-7,17-dione (1, 2.0 g,
6.6 mmol) in methanol (80 ml) was added 70% aqueous HClO4
(4 ml). The reaction mixture was stirred for 12 h, then diluted with
iced water and neutralized with sodium bicarbonate. Some white
solid precipitated. The mixture was extracted with ethyl acetate
(3× 20 ml), and the combined extracts were purified by chro-
matography (EtOAc/petroleum ether) to give 2 (1.5 g, 80%). m.p.
167–168 ◦C; 1H NMR (500 MHz, CDCl3), ı (ppm): 0.93 (s, 3H, 18-
CH3), 1.15 (s, 3H, 19-CH3), 5.65 (s, 1H, 6-H), 6.12–6.24 (m, 2H, 3-H
and 4-H).
2.2.2. 7˛-Methyl-17ˇ-acetoxyl-nortestosterone (13) and
7ˇ-methyl-17ˇ-acetoxyl-nortestosterone (14)
2.1.2. 3˛-Methylandrost-5-en-7,17-dione (3) and
2.2.2.1. 3,17ˇ-Diacetoxyl-3,5-estradiene (11). 19-Nortestosterone
(10, 5.0 g, 18.2 mmol), 20 ml of acetic anhydride and 24 ml of acetyl
chloride were mixed and refluxed for 3.5 h. After completion of
the reaction the acetyl chloride was distilled under normal pres-
sure, then the excess of acetic anhydride was removed. This gave
a yellow solid which was dissolved in ethyl acetate (100 ml), then
washed twice with brine, dried over Na2SO4 and evaporated to dry-
ness to give 6.0 g of 11 with a yield of 92%. m.p. 165–169 ◦C; 1H
NMR: (500 MHz, CDCl3), ı (ppm): 5.77 (d, 1H, J = 2.0 Hz), 5.48 (t, 1H,
J = 2.5 Hz), 4.62 (t, 1H, J = 8.5 Hz), 2.45 (m, 1H), 2.13 (s, 3H, CH3CO),
2.05 (s, 3H, CH3CO), 0.82 (s, 3H, 18-Me).
3ˇ-methylandrost-5-en-7,17-dione (4)
To a solution of compound 2 (0.57 g, 2.0 mmol) and CuBr (6.0 mg,
0.04 mmol) in THF (10 ml) at 20 ◦C, under N2, was added 2.37 mol/L
Me3Al solution (0.94 ml, 2.2 mmol). After completing the addition,
trimethylsilyl chloride (TMSCl) (0.26 g, 2.4 mmol) was then added,
and the resulting mixture was stirred at room temperature for 2 h.
H2O (0.2 ml) was added, and the solution was stirred for 24 h. The
mixture was filtered, and solid was washed twice with THF and
separated by chromatography to give both isomers 3 and 4 with ca.
6:1 ratio. The total yield was 65%. 1H NMR spectrum of ␣-isomer
(3), ı (ppm): 5.75 (s, 1H, 6-H), 1.24 (s, 3H, 18-H), 0.93 (s, 3H, 19-
H), 0.90 (d, 3H, 3␣-CH3, J = 7.0 Hz); 1H NMR spectrum of -isomer
(4), ı (ppm): 5.31 (s, 1H, 6-H), 1.24 (s, 3H, 18-CH3), 0.92 (d, 3H, 3-
CH3, J = 7.0 Hz), 0.89 (s, 3H, 19-CH3); 13C NMR spectrum of ␣-isomer
(3), ı (ppm): 13.8, 17.4, 17.7, 20.3, 24.3, 27.4, 28.9, 30.8, 33.2, 35.7,
39.0, 39.3, 44.4, 45.9, 47.9, 50.4, 126.5, 168.2, 200.9, 220.5; 13C NMR
spectrum of -isomer (4), ı (ppm): 13.7, 18.5, 20.4, 21.2, 22.7, 25.7,
29.4, 30.7, 32.6, 35.5, 37.4, 44.5, 47.3, 48.6, 50.2, 53.3, 129,2, 139.0,
208.7, 220.0; Compound 3: [␣]D = −118.3 (c = 1.0 in CH2Cl2); EI-MS
m/z (%): 300 (M+, 100), 285 (12), 267 (20), 203 (57), 177 (74), 150
(71), 135 (48), 121 (66); HR-MS for C20H28O2Na required 323.1987,
found 323.1982 [M+Na]+.
2.2.2.2. 17ˇ-Acetoxyl-4,6-estradiene-3-one (12). A solution of com-
pound 11 (3.5 g, 9.77 mmol) in DMF (23 ml) and water (0.7 ml) was
cooled to 0 ◦C. 1.85 g (10 mmol) of NBS was added in portions. After
stirring for 45 min at room temperature LiBr (1.69 g, 20 mmol) and
Li2CO3 (3.42 g, 46 mmol) were added, and the mixture was stirred
for 20 min followed by 45 min stirring at 110 ◦C. The mixture was
poured into a solution of water (135 ml) with acetic acid (11.3 ml),
and extracted with dichloromethane (3× 100 ml). The combined
organic extracts were washed with brine, dried over Na2SO4, fil-
tered, and evaporated to dryness to give 12 as yellow solid with
(2.4 g, 80%). m.p. 104–105 ◦C; 1H NMR: (500 MHz, CDCl3) ı: 6.18
(d, 2H, 6H and 7H, J = 3.9 Hz), 5.78 (s, 1H, 4-H), 4.63 (t, 1H, 17-H,
J = 8.3 Hz), 2.06 (s, 3H, CH3CO), 0.88 (s, 3H, 18-Me).
2.2. Synthesis of 7-methyl steroids
2.2.1. 17ˇ-Acetoxyl-7˛-methylandrost-4-en-3-one (8) and
17ˇ-acetoxyl-7ˇ-methylandrost-4-en-3-one (9)
2.2.2.3. 7˛-Methyl-17ˇ-acetoxyl-nortestosterone (13) and 7ˇ-
methyl-17ˇ-acetoxyl-nortestosterone (14). Compound 12 (0.5 g,
1.58 mmol) was methylated as described in synthesis of 3 and 4
to give 0.41 g product (79%), and both isomers 13 and 14 was in
a 5:1 ratio. Further purification with chromatography gave 7␣-
and 7-epimers, respectively. m.p. 141–142 ◦C; 1H NMR of 13
(500 MHz, CDCl3), ı (ppm): 5.86 (s, 1H, 4-H) 4.64 (bt, 1H, J = 7.4 Hz),
2.07 (s, 3H, 17-CH3CO), 0.88 (s, 3H, 18-CH3), 0.78 (s, 3H, 7␣-CH3);
1H NMR of 14 (500 MHz, CDCl3), ı (ppm): 5.78 (s, 1H), 3.61 (bt, 1H,
J = 7.5 Hz), 1.04 (s, 3H, 7-CH3), 0.80 (s, 3H, 18-CH3).
2.2.1.1. 17ˇ-Hydroxylandrost-4,6-dien-3-one (6). Testosterone (5,
1.0 g, 3.5 mmol) and tetrachlorobenzoquinone (2.4 g, 9.7 mmol)
were dissolved in 70 ml of t-butanol, and the solution was refluxed,
under N2, for 7 h. After the solvent was removed, the residue was
dissolved in dichloromethane (50 ml) and washed with 5% aqueous
NaOH and water, dried over anhydrous Na2SO4, and evaporated to
dryness to give 6 as a yellow solid (0.58 g, 59%). 1H NMR (500 MHz,
CDCl3), ı (ppm): 6.08 (m, 2H, 6-H and 7-H), 5.66 (s, 1H, 5-H), 1.10
(s, 3H, 18-CH3), 0.82 (s, 3H, 19-CH3).