7736 Journal of Medicinal Chemistry, 2010, Vol. 53, No. 21
Lajiness et al.
ESI-TOF HRMS m/z 650.2167 (M þ Hþ, C36H32ClN5O5 requires
650.2165).
was treated with triethylamine (4.00 mL, 28.8 mmol). The resulting
suspension was stirred at 0 °C for 2 h. The solution was filtered, and
the filtrate was concentrated under reduced pressure. The residue was
dissolved in ethyl acetate, washed with 1 N HCl, H2O, and saturated
aqueous NaCl, and dried (MgSO4). The solution was concentrated,
and the resulting yellow solid was triturated with hexanes to provide
13 as a pure white solid (4.1 g, 52%). H NMR (acetone-d6, 400
MHz) δ 10.03 (s, 1H), 7.85 (d, J=8.4 Hz, 2H), 7.50 (d, J=8.4 Hz,
2H), 2.48 (s, 3H), 1.29 (s, 9H).
tert-Butyl Pivaloyl(N-tosyloxy)carbamate (14). A solution of
13 (1.00 g, 3.48 mmol) and trimethylacetyl chloride (2.14 mL,
17.4 mmol) in THF (10 mL) at 0 °C was treated with triethyl-
amine. The solution was warmed to room temperature and stirred
overnight (16 h). The reaction mixture was diluted with ethyl
acetate, washed with H2O and saturated aqueous NaCl, and
dried (MgSO4). The solution was concentrated and the residue
purified by flash chromatography to provide 14 as a white solid
(1.29 g, 99%). 1H NMR (acetone-d6, 400 MHz) δ 7.90 (d, J =
8.4 Hz, 2H), 7.59 (d, J=8.0 Hz, 2H), 2.51 (s, 3H), 1.30 (s, 9H),
1.28 (s, 9H). 13C NMR (acetone-d6, 150 MHz) δ 183.7, 175.4,
148.4, 132.9, 131.9, 131.3, 87.4, 45.1, 28.7, 27.6, 22.6. IR (film)
1S-5: [R]23D þ6.6 (c 0.58, THF), natural enantiomer.
1R-5: [R]23D -6.0 (c 0.40, THF), unnatural enantiomer.
N-(2-(1-(Chloromethyl)-5-(pivalamidooxy)-2,3-dihydro-1H-
benzo[e]indole-3-carbonyl)-1H-indol-5-yl)-1H-indole-2-carboxamide
(Trimethylacetamide Prodrug 6). A solution of seco-CBI-indole2
(11, 33.9 mg, 0.0634 mmol) in 1:1 ether:dioxane (0.1 mL) at 0 °C
was treated with LiHMDS (0.190 mL, 0.190 mmol, 1.0 M in THF).
The solution was stirred for 30 min, after which 15 (51.6 mg,
0.190 mmol) was added and the solution was warmed to room
temperature and stirred for 4 h. The reaction mixture was diluted
with ethyl acetate, washed with H2O and saturated aqueous
NaCl, and dried (MgSO4). The solution was concentrated and
purified by recrystallization (THF:hexanes) ꢀ4 to afford 6 as a
pale-yellow solid (45.5 mg, 65%). 1H NMR (DMSO-d6, 400 MHz)
δ 11.87 (s, 1H), 11.72 (s, 1H), 10.17 (s, 1H), 8.25 (s, 1H), 8.09 (br
s, 1H), 8.08 (d, J=8.8 Hz, 1H), 7.94 (d, J=8.4 Hz, 1H), 7.68 (d,
J=8.0 Hz, 1H), 7.583 (d, J=8.8 Hz, 1H), 7.575 (t, J=6.8 Hz,
1H), 7.48 (d, J=8.4 Hz, 1H), 7.45 (t, J=8.4 Hz, 1H), 7.44 (d, J=
8.4 Hz, 1H), 7.43 (s, 1H), 7.26 (s, 1H), 7.22 (t, J =8.0 Hz, 1H),
7.07 (t, J=7.6 Hz, 1H), 4.87 (t, J=10 Hz, 1H), 4.63 (dd, J=11,
2.0 Hz, 1H), 4.34 (m, 1H), 4.08 (dd, J=11, 3.2 Hz, 1H), 3.97 (dd,
J=12, 7.2 Hz, 1H), 1.20 (s, 9H). 13C NMR (THF-d8, 150 MHz)
δ 161.6, 160.7, 159.1, 153.6, 143.8, 138.4, 135.0, 133.7, 133.6, 132.9,
131.7, 129.4, 128.3, 126.5, 124.9, 124.6, 124.5, 123.7, 122.6, 120.9,
120.1, 118.3, 113.9, 113.1, 112.8, 106.9, 106.7, 103.2, 56.2, 50.2,
47.6, 44.3, 30.0. IR (film) νmax 3442, 3347, 3222, 2968, 1650, 1613,
1552 cm-1. ESI-TOF HRMS m/z 656.2030 (M þ Naþ, C36H32Cl-
N5O4 requires 656.2035).
1
ν
max 2978, 2936, 1808, 1737 cm-1. ESI-TOF HRMS m/z 394.1294
(M þ Naþ, C17H25NO6S requires 394.1295).
N-(Tosyloxy)pivalamide (15). A vial containing 14 (91 mg,
0.245 mmol) was treated with 4 N HCl in EtOAc (10 mL). The
reaction mixture was stirred at room temperature for 2 h. The
solvent was evaporated under a stream of N2 to provide 15 as the
HCl salt (68 mg, 91%). 1H NMR (acetone-d6, 400 MHz) δ 10.88
(s, 1H), 7.85 (d, J=8.4 Hz, 2H), 7.47 (d, J=8.0 Hz, 2H), 2.46 (s,
3H), 1.08 (s, 9H). 13C NMR (acetone-d6, 150 MHz) δ 177.8,
147.7, 133.1, 131.4, 130.5, 54.0, 28.1, 22.6. IR (film) νmax 3197,
2977, 1695 cm-1. ESI-TOF HRMS m/z 272.0941 (M þ Hþ,
C12H17NO4S requires 272.0951).
1S-6: [R]23D þ9.0 (c 0.20, THF), natural enantiomer.
1R-6: [R]23D -8.8 (c 0.25, THF), unnatural enantiomer.
tert-Butyl(3-(5-(1H-indole-2-carboxamido)-1H-indole-2-carbo-
nyl)-1-(chloromethyl)-2,3-dihydro-1H-benzo[e]indol-5-yl)oxy-
(methyl)carbamate (N-Methyl-tert-Butylcarbamate Prodrug 8).
A solution of 5 (15.2 mg, 0.0234 mmol) in THF (0.1 mL) at -78 °C
was treated with LiHMDS (23 μL, 0.023 mmol, 1.0 M in THF)
and was stirred for 15 min. Me2SO4 (2.2 μL, 0.023 mmol) was
added, and the solution was warmed to room temperature and
stirred for 2 h. The solvent was removed under a stream of N2,
and the residue was purified by PTLC (1:1 THF:toluene) to
afford 8 as a pale-yellow solid (5.5 mg, 35%). 1H NMR (DMSO-
d6, 600 MHz) δ 11.79 (s, 1H), 11.74 (s, 1H), 10.19 (s, 1H), 8.28
(s, 1H), 8.25 (s, 1H), 8.07 (d, J=7.8 Hz, 1H), 7.89 (d, J=8.4 Hz,
1H), 7.68 (d, J=7.8 Hz, 1H), 7.64 (t, J=7.8 Hz, 1H), 7.60 (d, J=
8.4 Hz, 1H), 7.54 (t, J = 7.8 Hz, 1H), 7.50 (d, J = 8.4 Hz, 1H),
7.48 (d, J=7.8 Hz, 1H), 7.44 (s, 1H), 7.29 (s, 1H), 7.22 (t, J=7.8Hz,
1H), 7.07 (t, J=7.2 Hz, 1H), 4.92 (t, J=10 Hz, 1H), 4.68 (d, J=
10 Hz, 1H), 4.45 (m, 1H), 4.11 (dd, J=11, 3.0 Hz, 1H), 4.04 (dd,
J=11, 6.6 Hz, 1H), 3.39 (s, 3H), 1.35 (s, 9H). 13C NMR (DMSO-d6,
150 MHz) δ 160.1, 159.8, 157.1, 146.9, 141.5, 136.6, 133.4, 131.8,
131.7, 130.8, 129.5, 127.7, 127.0, 125.2, 124.0, 123.48, 123.46, 122.7,
122.0, 121.6, 119.8, 112.8, 112.3, 112.2, 110.3, 106.9, 106.0, 103.3,
82.2, 66.9, 54.8, 47.7, 41.1, 26.9. IR (film) νmax 3286, 2976, 1715, 1632,
1502 cm-1. ESI-TOF HRMS m/z 686.2153 (M þ Naþ, C37H34Cl-
N5O5 requires 686.2141).
Methyl Hydroxycarbamate (16). A solution of hydroxylamine
hydrochloride (2.00 g, 28.8 mmol) in H2O (30 mL) at 0 °C was
treated with KOH (4.85 g, 86.4 mmol), and the reaction mixture
was stirred for 10 min. Dimethyl carbonate (2.42 mL, 28.8 mmol)
was added dropwise, and the reaction mixture was stirred at 5 °C
for 8 h. The reaction mixture was acidified with the addition of 1
N HCl and extracted with diethyl ether (3ꢀ100 mL). The ether
layers were combined and concentrated under reduced pressure
to provide 16 as a clear oil (308 mg, 12%). 1H NMR (acetone-d6,
400 MHz) δ 8.83 (s, 1H), 3.63 (s, 3H).
Methyl Tosyloxycarbamate (17). A solution of 16 (308 mg,
3.38 mmol) and TsCl (537 mg, 2.82 mmol) in diethyl ether (5 mL)
at 0 °C was treated with triethylamine (0.471 mL, 3.38 mmol).
The resulting suspension was stirred at 0 °C for 1 h, after which
the solution was diluted with ethyl acetate, washed with H2O
and saturated aqueous NaCl, and dried (MgSO4). The solution
was concentrated under reduced pressure to provide 17 as an
off-white solid (350 mg, 51%). 1H NMR (acetone-d6, 400 MHz)
δ 10.25 (br s, 1H), 7.85 (d, J=8.4 Hz, 2H), 7.50 (d, J=8.4 Hz,
2H), 3.60 (s, 3H), 2.48 (s, 3H). 13C NMR (acetone-d6, 125 MHz)
δ 158.3, 147.9, 133.0, 131.6, 131.2, 54.5, 22.6. IR (film)
ν
max 3222, 2964, 1730 cm-1. ESI-TOF HRMS m/z 268.0250
(M þ Naþ, C9H11NO5S requires 268.0250).
1S-8: [R]23D þ24 (c 0.45, THF), natural enantiomer.
1-(Tosyloxy)urea (18). A solution of hydroxyurea (2.00 g, 26.3
mmol) and TsCl (4.80 g, 25.0 mmol) in DMF (20 mL) at 0 °C was
treated with triethylamine (3.67 mL, 26.3 mmol). The solution was
stirred for 3 h at 0 °C, diluted with ethyl acetate, washed with H2O
and saturated aqueous NaCl, and dried (MgSO4). The solution
was concentrated under reduced pressure and purified by flash
chromatography to provide 18 as a white solid (716 mg, 12%). 1H
NMR (acetone-d6, 400 MHz) δ 9.33 (s, 1H), 7.89 (d, J=8.4 Hz,
2H), 7.50 (d, J = 8.0 Hz, 2H), 6.23 (br s, 2H), 2.48 (s, 3H). 13C
NMR (acetone-d6, 125 MHz) δ 160.7, 147.9, 132.9, 131.7, 131.2,
22.6. IR (film) νmax 3444, 3233, 3052, 2855, 1698 cm-1. ESI-TOF
HRMS m/z 253.0250 (M þ Naþ, C8H10N2O4S requires 253.0253).
In Vivo Antitumor Activity. DBA/2J mice were injected
intraperitoneal (ip) with syngeneic L1210 cells (1ꢀ106) on day 0.
1R-8: [R]23D -22 (c 0.43, THF), unnatural enantiomer.
tert-Butyl N-Hydroxycarbamate (12). A solution of hydroxyl-
amine hydrochloride (5.0 g, 72.0 mmol) and (BocO)2CO (15.7 g,
72.0 mmol) in 1:1 THF:H2O (160 mL) at 0 °C was treated
with NaHCO3 (12.1 g, 144 mmol). The solution was stirred
at 0 °C for 2 h, after which it was diluted with ethyl acetate,
washed with saturated aqueous NaHCO3, H2O, and saturated
aqueous NaCl, and dried (MgSO4). The solvent was removed
under reduced pressure to provide 12 as a white solid (9.25 g,
96%). 1H NMR (acetone-d6, 400 MHz) δ 8.39 (s, 1H), 7.64
(s, 1H), 1.40 (s, 9H).
tert-Butyl N-Tosyloxycarbamate (13). A solution of 12 (3.83 g,
28.8 mmol) and TsCl (5.23 g, 27.4 mmol) in THF (40 mL) at 0 °C