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A. Casimiro-Garcia et al. / Bioorg. Med. Chem. 9(2001) 2827–2841
mixture was extracted with ethyl acetate (5Â15 mL).
The combined organic extracts were washed with brine
(1Â25 mL), dried over Na2SO4, filtered and the solvent
removed. The residue was flash chromatographed on
silica gel (35 g; column: 2Â26.5 cm), eluting with
CHCl3–THF–formic acid (300:60:1), followed by
CHCl3–MeOH–formic acid (90:10:1 to 65:35:1). In this
manner, compound 19 was obtained in excellent yield
(0.11 g, 96%) as a pale brown solid. The analytical
sample was obtained by precipitation from acetone–di-
chloromethane–hexanes: mp >200 ꢁC (decomposition);
1H NMR (300 MHz, acetone-d6) d 7.91 (d, J=2.1 Hz,
1H), 7.90 (d, J=2.0 Hz, 1H), 7.89 (d, J=1.9 Hz, 1H),
7.87 (d, J=2.6 Hz, 1H), 7.77 (d, J=2.8 Hz, 1H), 7.76
(d, J=2.6 Hz, 1H), 7.68 (d, J=1.3 Hz, 2H), 6.37 (t,
J=7.5 Hz, 2H), 2.38 (m, 4H), 2.0–1.0 (m, 28H), 0.93 (s,
3H), 0.76 (s, 3H); IR (film) 3500–2500, 2920, 2850, 1681,
1600, 1455, 1232, 1182, 800 cmꢀ1; PD-MS m/z 1051
(MH+) and 1074 (M+Na). Anal. calcd for C55H56Cl4O12:
C, 62.86; H, 5.37. Found: C, 62.66; H, 5.44.
3H), 3.46 (d, J=6.6 Hz, 2H); IR (film) 2952, 1732, 1477,
1436, 1266, 1204, 997 cmꢀ1
.
5ꢀ-3ꢁ,17ꢁ-(Dicarboxymethyl)androstane (23). Ester 10
(0.152 g, 0.376 mmol) was dissolved in THF (10 mL),
8 N NaOH (1.0 mL) was added, and the mixture was
heated under reflux for 24 h. The solvent was evapo-
rated and the residue was diluted with water (15 mL),
washed with ethyl acetate (2Â10 mL), and acidified with
concd HCl. The mixture was refrigerated overnight. The
precipitated solid was separated by filtration and
washed with water. The product was dried under high
vacuum to afford 23 (0.122 g, 86.2%) as a white solid.
The analytical sample was prepared by recrystallization
from methanol: mp 234–237 ꢁC; H NMR (300 MHz,
1
CD3OD) d 2.32 (dd, J=14.5 and 4.8 Hz, 1H), 2.16 (d,
J=6.8 Hz, 2H), 2.07 (dd, J=14.4 and 10.0 Hz, 1H),
2.0–0.83 (m, 24H), 0.78 (s, 3H), 0.60 (s, 3H); IR (film)
3200–2500, 2914, 2846, 1723, 1702, 1409, 1286, 1242,
900 cmꢀ1; PD-MS m/z 376 (MH+). Anal. calcd for
C23H36O4: C, 73.37; H, 9.64. Found: C, 73.06; H, 9.41.
N-tert-Butoxycarbonyl-30,300-dichloro-40,400-dimethoxy-50,
500-bis(methoxycarbonyl)-3,3-diphenyl-2-propenylamine (21).
A slurry of TiCl4–THF 1:2 complex (0.47 g, 1.407
mmol) and Zn dust (0.184 g, 2.814 mmol) in THF (15
mL) was heated under reflux for 2 h. A solution of
benzophenone 12 (0.200 g, 0.469 mmol) and aldehyde
20 (0.112, 0.703 mmol) in THF (10 mL) was then added.
The black mixture was heated at reflux for 3 h. It was
cooled and 10% aq K2CO3 (30 mL) was added, and the
mixture stirred overnight at rt. The mixture was filtered
through a Celite pad and washed with ethyl acetate
(2Â20 mL). The layers were separated and the aqueous
one was extracted with ethyl acetate (2Â15 mL). The
combined organic extracts were washed with brine
(1Â20 mL), dried over MgSO4, filtered, and the solvent
removed. Purification by flash chromatography on silica
gel (30 g; column: 2Â24 cm), eluting with hexanes–ethyl
acetate (3:1), afforded 21 (61 mg, 23%) as a thick oil in
low yield: 1H NMR (300 MHz, CDCl3) d 7.50 (d, J=2.1
Hz, 1H), 7.44 (d, J=1.7 Hz, 1H), 7.30 (d, J=2.1 Hz,
1H), 7.29 (d, J=2.5 Hz, 1H), 6.04 (t, J=6.5 Hz, 1H),
4.61 (bs, 1H), 3.97 (s, 3H), 3.91 (s, 3H), 3.90 (s, 3H),
3.89 (s, 3H), 3.77 (t, J=6.7 Hz, 2H), 1.42 (s, 9H); IR
(film) 3386, 2951, 1734, 1715, 1477, 1250, 1167, 998
cmꢀ1; PD-MS m/z 554 (MH+) and 498 (MH+ꢀC4H8)+.
Anal. calcd for C26H29Cl2NO8: C, 56.33; H, 5.27; N,
2.53. Found: C, 56.49; H, 5.49; N, 2.86.
5ꢀ-3ꢁ,17ꢁ-Di[N-30,30-(300,3000-dicarbomethoxy-500,5000-di-
chloro-400,4000-dimethoxydiphenyl)-20-propenyl-acetamido]-
androstane (24). A solution of acid 23 (0.061 g, 0.162
mmol) and Et3N (0.27 mL, 1.944 mmol) in dry DMF (5
mL) was stirred under Ar. HOBt (0.087 g, 0.648 mmol)
was added, followed by amine–HCl 22 (0.166 g, 0.341
mmol). EDCI-HCl (0.124 g, 0.648 mmol) was then
incorporated. The reaction mixture was stirred at room
temperature for 24 h. The mixture was partitioned
between water (60 mL) and Et2O–EtOAc (30:15 mL).
The aqueous layer was extracted with a 2:1 mixture of
Et2O–EtOAc (4Â30 mL). The combined organic
extracts were washed with brine (1Â30 mL), dried over
MgSO4, filtered, and the solvent removed. Purification
by flash chromatography on silica gel (30 g; column:
2Â25.5 cm), eluting with ethyl acetate–hexanes (1:1,
followed by 2:1) afforded 24 as a yellowish solid in low
yield (45 mg, 22%): mp 172–175 ꢁC; 1H NMR
(300 MHz, CDCl3) d 7.47 (d, J=2.2 Hz, 2H), 7.45 (d,
J=2.1 Hz, 2H), 7.32 (d, J=2.1 Hz, 2H), 7.28 (d, J=2.3
Hz, 2H), 6.02 (t, J=6.8 Hz, 2H), 5.59 (t, J=5.3 Hz,
2H), 3.96 (s, 6H), 3.90 (s, 6H), 3.89 (s, 6H), 3.88 (s, 6H),
2.35–0.80 (m, 24H), 2.24 (dd, J=13.7 and 4.5 Hz, 1H),
2.14 (d, J=2.1 Hz, 2H), 2.03 (dd, J=7 and 2.3 Hz, 4H),
1.89 (dd, J=14.4 and 10.0 Hz, 1H), 0.72 (s, 3H), 0.54 (s,
3H); 13C NMR (75 MHz, CDCl3) d 173.1, 172.4, 165.6,
165.4, 155.5, 155.2, 139.3, 137.4, 134.8, 134.2, 132.6,
130.8, 130.0, 129.6, 128.3, 126.9, 126.7, 62.1, 62.0, 55.3,
54.6, 52.6, 47.4, 46.3, 44.6, 42.2, 38.7, 38.2, 37.5, 37.4,
35.8, 35.7, 35.5, 35.3, 31.9, 28.7, 28.2, 24.5, 20.7, 12.7,
12.3; IR (film) 3287, 2932, 1735, 1643, 1537, 1477, 1435,
1264, 1207, 998, 738 cmꢀ1; PD-MS m/z 1249 (MH+).
Anal. calcd for C65H74Cl4N2O14: C, 62.50; H, 5.97; N,
2.24. Found: C, 62.42; H, 5.98; N, 2.27.
30,300-Dichloro-40,400-dimethoxy-50,500-bis(methoxycarbonyl)-
3,3-diphenyl-2-propenylamine (22). The crude product
from the McMurry coupling obtained as described
above was stirred with TFA–CH2Cl2 (1:2 mL) at room
temperature for 1 h. Solvent and excess TFA were eva-
porated off. The residue was purified by flash chroma-
tography on silica gel (30 g; column: 2Â30 cm), eluting
with 100% CH2Cl2, and then CH2Cl2–MeOH–NH4OH
(200:10:0.1 to 200:20:0.1). Amine 22 (82 mg, 38%) was
5ꢀ-3ꢁ,17ꢁ-Di[N-30,30-(300,3000-dicarboxy-500,5000-dichloro-
400,4000-dimethoxydiphenyl)-20-propenyl-acetamido]andros-
tane (25). Ester 24 (0.073 g, 0.058 mmol) was dissolved
in THF (8 mL). A 0.5 N NaOH solution (2 mL) was
added. The reaction mixture was stirred at 65 ꢁC over-
night. The solvent was removed, the residue diluted with
1
obtained as an orange thick oil: H NMR (300 MHz,
CDCl3) d 7.52 (d, J=2.2 Hz, 1H), 7.44 (d, J=2.2 Hz,
1H), 7.30 (d, J=1.5 Hz, 1H), 7.28 (d, J=2.2 Hz, 1H),
6.13 (t, J=6.9 Hz, 1H), 4.40 (bs, 2H, exchangeable with
D2O), 3.96 (s, 3H), 3.90 (s, 3H), 3.88 (s, 3H), 3.87 (s,