7
-tert-Butyldimethylsilyl-10-hydroxycamptothecin
J ournal of Medicinal Chemistry, 2000, Vol. 43, No. 21 3977
iodopyridone 6 (0.11 g, 0.23 mmol), DME (3.0 mL), DMF (0.75
mL) and NaH (0.01 g, 0.24 mmol) were combined at 0 °C.
Flame-dried LiCl (0.02 g, 0.46 mmol) was added and the
mixture was stirred vigorously at 22 °C. After 35 min, the
silylpropargyl bromide 5 (0.12 g, 0.46 mmol) was added and
the reaction mixture was heated at 60 °C for 16 h. Workup
and chromatography gave the desired propargylpyridone 8
127.6, 127.9, 129.9, 131.3, 132.0, 135.1, 142.5, 146.4, 148.0,
150.2, 151.0, 157.5, 174.0; HRMS (EI) m/z calcd for C25
27
H -
+
ClN
2
O
4
Si (M ) 482.1429, found 482.1408; LRMS (EI) m/z 482
+
(M ), 453, 438, 425, 382, 361, 275, 149.
(20S)-10-Acet oxy-7-ch lor op r op yld im et h ylsilylca m p -
toth ecin (16). Following the procedure outlined for 12,
iodopyridone 6 (51 mg, 0.1 mmol), p-acetoxyphenylisonitrile
11 (48.3 mg, 0.3 mmol) and hexamethylditin (50 mg, 0.15
mmol) in benzene (1.5 mL) gave 16 (24.6 mg, 45%), after
(
0.058 g, 50%) as a 93:7 mixture of alkyl chloride to bromide
1
20
based on the H NMR spectrum: [R] +37.7 (c 0.2, CHCl
IR (CHCl
2
6
3
);
D
-
1
20
D
3
, cm ) 1046, 1139, 1158, 1227, 1530, 1651, 1743,
chromatography (CH Cl /acetone 20:1), as a tan solid: [R]
2
2
1
-1
183, 2959, 3026, 3532; H NMR (300 MHz, CDCl
3
) δ 0.20 (s,
+29.9 (c 0.2, CHCl ); IR (CHCl , cm ) 1168, 1195, 1219, 1232,
1
3
3
H), 0.70-0.80 (m, 2 H), 1.01 (t, J ) 7 Hz, 3 H), 1.70-1.95
1259, 1601, 1659, 1743, 3027; H NMR (300 MHz, CDCl ) δ
3
(
m, 4 H), 3.56 (t, J ) 7 Hz, 2 H), 3.69 (s, 1 H), 5.08 (d, J ) 17
Hz, 1 H), 5.16 (d, J ) 16 Hz, 1 H), 5.20 (d, J ) 17 Hz, 1 H),
.54 (d, J ) 16 Hz, 1 H), 7.23 (s, 1 H); 13C NMR (75 MHz,
CDCl ) δ -2.0, 7.8, 13.6, 27.6, 31.7, 44.6, 47.7, 66.4, 71.9, 89.6,
9.2, 100.1, 116.7, 118.3, 148.8, 158.0, 173.3; HRMS (EI) m/z
0.68 (s, 6 H), 1.05 (t, J ) 7 Hz, 3 H), 1.19-1.27 (m, 2 H), 1.70-
1.80 (m, 2 H), 1.80-1.98 (m, 2 H), 2.42 (s, 3 H), 3.49 (t, J ) 7
Hz, 2 H), 3.77 (br s, 1 H), 5.31 (d, J ) 16 Hz, 1 H), 5.31 (s, 2
H), 5.75 (d, J ) 16 Hz, 1 H), 7.56 (dd, J ) 9 Hz, J ) 2 Hz, 1
5
3
1
2
9
H), 7.66 (s, 1 H), 8.02 (d, J ) 2 Hz, 1 H), 8.25 (d, J ) 9 Hz, 1
+
13
calcd for C26
LRMS (EI) m/z 507 (M ) 472, 430, 392, 348, 336, 131, 116,
03, 93, 78, 57.
20S)-7-ter t-Bu tyld im eth ylsilylca m p toth ecin (12). Pro-
H
30ClIN
2
O
4
+
Si (M ) 507.0130, found 507.0124;
H); C NMR (125 MHz, CDCl ) δ 0.0, 7.9, 14.5, 21.5, 27.5,
3
31.7, 47.4, 51.9, 66.4, 72.8, 97.8, 118.5, 118.7, 124.9, 132.3,
1
132.4, 135.6, 142.2, 145.9, 146.2, 149.2, 150.2, 150.9, 157.5,
+
(
169.1, 174.0; HRMS (EI) m/z calcd for C27
H
29ClN
2
O
6
Si (M )
+
pargylpyridone 7 (48.7 mg, 0.1 mmol), benzene (1.4 mL),
phenylisonitrile 10 (31.1 mg, 0.3 mmol) and hexamethylditin
540.1483, found 540.1479; LRMS (EI) m/z 540 (M ), 498, 454,
441, 377, 291, 109, 93.
(
50 mg, 0.15 mmol) were added sequentially to a Pyrex
(20S)-10-Hyd r oxy-7-ter t-bu tyld im eth ylsilylca m p toth -
ecin (14). Camptothecin derivative 12 (13.4 mg, 0.026 mmol)
was suspended in MeOH (0.2 mL) and H O (0.2 mL) and K -
pressure tube. The contents were sealed under Ar and irradi-
ated at 70 °C with a 275-W GE Sunlamp. After 9 h, the solvent
was evaporated, and the residue was subjected to flash
chromatography (CH
acetone 9:1) to yield 12 (24.8 mg, 54%) as a light brown
2
2
CO (7.2 mg, 0.05 mmol) was added generating a dark solu-
3
2
Cl
2
/MeOH 96:4, followed by CH
2
Cl
2
/
tion. After 3 h the mixture was acidified with acetic acid (4
drops), diluted with saturated brine (5 mL) and extracted
with EtOAc (10 × 15 mL). The combined organic phase was
2
D
0
-1
solid: [R] +35.5 (c 0.2, CHCl
3
); IR (CHCl
3
, cm ) 1045, 1158,
1
3
1
5
7
7
(
7
1
198, 1257, 1555, 1600, 1658, 1741, 2859, 2932, 2960, 2980,
dried (Na
2 4
SO ) and evaporated. Purification by preparative
1
028; H NMR (300 MHz, CDCl
3
) δ 0.69 (s, 6 H), 0.98 (s, 9 H),
TLC (5:1 CH
2
Cl
2
:acetone) gave 14 (10.6 mg, 85%) as a yellow
2
0
1
.03 (t, J ) 7 Hz, 3 H), 1.86 (m, J ) 7 Hz, 2 H), 3.86 (s, 1 H),
.29 (d, J ) 16 Hz, 1 H), 5.31 (s, 2 H), 5.73 (d, J ) 16 Hz, 1 H),
.60 (t, J ) 6 Hz, 1 H), 7.60 (t, J ) 7 Hz, 1 H), 7.66 (s, 1 H),
.74 (t, J ) 7 Hz, 1 H), 8.20 (t, J ) 8 Hz, 2 H); 13C NMR
solid: [R] +17.4 (c 0.2, 3:1 CH Cl /MeOH); H NMR (300
D
2
2
MHz, 3:1 CDCl /CD OD) δ 0.66 (s, 6 H), 0.88-1.05 (m, 12 H),
3
3
1.80-2.00 (m, 2 H), 5.25-5.30 (m, 3 H), 5.70 (d, J ) 16 Hz, 1
H), 7.37 (dd, J ) 9 Hz, J ) 2 Hz, 1 H), 7.54 (d, J ) 2 Hz, 1 H),
1
2
75 MHz, CDCl
2.8, 97.7, 118.2, 127.0, 129.5, 129.6, 130.8, 132.7, 136.0,
3
) δ -0.56, 7.80, 19.2, 27.1, 31.6, 52.4, 66.3,
7.60 (s, 1 H), 8.05 (d, J ) 9 Hz, 1 H); 13C NMR (125 MHz, (3:1)
CDCl :CD OD) δ -2.0, 6.7, 18.4, 26.2, 30.4, 52.1, 65.0, 72.4,
3
3
43.0, 146.4, 148.0, 150.1, 150.6, 157.4, 173.9; HRMS (EI)
97.2, 110.6, 117.3, 121.9, 130.4, 134.2, 135.9, 140.4, 142.1,
+
m/z calcd for C26
H
30
N
2
O
4
+
Si (M ) 462.1974, found 462.1975;
145.7, 146.8, 151.1, 156.0, 157.2, 173.2; HRMS (EI) m/z calcd
LRMS (EI) m/z 462 (M ), 450, 361, 331, 304, 245, 223,
7.
for C H N O Si (M ) 478.1924, found 478.1947 LRMS (EI)
+
2
6
30
2
+
5
5
m/z 478 (M ), 434, 421, 377, 304, 284, 227, 178, 149, 137, 109,
(
20S)-10-Acet oxy-7-ter t-b u t yld im et h ylsilylca m p t ot h -
97, 83, 69, 57.
ecin (13). Following the procedure outlined for 12, iodopyri-
done 6 (34.5 mg, 0.071 mmol), p-acetoxyphenylisonitrile 11
(20S)-10-H yd r oxy-7-ch lor op r op yld im et h ylsilylca m p -
toth ecin (17). Following the procedure for 14, MeOH (0.2 mL),
H O (0.2 mL) and K CO (6.1 mg, 0.04 mmol) was added to a
(
48.3 mg, 0.3 mmol), hexamethylditin (35 mg, 0.11 mmol)
2
2
3
and benzene (1.3 mL) gave 13 (21.3 mg, 41%) as a tan solid:
vial containing 16 (11.2 mg, 0.02 mmol). Workup and chro-
matography (CH Cl /acetone 5:1) gave 17 (4.8 mg, 44%) as a
2
D
0
-1
[
1
2
R] +36.2 (c 0.2, CH
2
Cl
2
); IR (CHCl
3
, cm ) 1045, 1166,
2
2
2
0
1
195, 1232, 1256, 1371, 1464, 1504, 1557, 1600, 1659, 1742,
859, 2885, 2902, 2931, 2958, 3000, 3029; H NMR (300 MHz,
yellow solid: [R] +22.5 (c 0.2, 3:1 CH Cl /MeOH); H NMR
D
2
2
1
(300 MHz, CDCl /CD OD) δ 0.65 (s, 6 H), 0.99 (t, J ) 7 Hz, 3
3
3
CDCl
3
) δ 0.69 (s, 6 H), 0.90 (s, 9 H), 1.04 (t, J ) 7 Hz, 3 H),
.80-2.00 (m, J ) 7 Hz, 2 H), 2.40 (s, 3 H), 3.81 (s, 1 H), 5.30
d, J ) 16 Hz 1 H), 5.31.(s, 2 H), 5.75 (d, J ) 16 Hz, 1 H), 7.53
dd, J ) 9 Hz, J ) 2 Hz, 1 H), 7.65 (s, 1 H), 8.08 (d, J ) 2 Hz,
H), 8.21 (d, J ) 9 Hz, 1 H); C NMR (125 MHz, CDCl
0.6, 7.9, 19.3, 21.5, 27.2, 31.7, 52.5, 66.5, 72.9, 97.7, 118.4,
H), 1.15-1.27 (m, 2 H), 1.65-1.80 (m, 2 H), 1.85-1.97 (m, 2
H), 3.45 (t, J ) 7 Hz, 2 H), 5.27 (d, J ) 16 Hz, 1 H), 5.27 (s, 2
H), 5.63 (d, J ) 16 Hz, 1 H), 7.44 (dd, J ) 9 Hz, J ) 2 Hz, 1
1
(
(
1
-
1
2
1
2
H), 7.53 (d, J ) 2 Hz, 1 H), 7.72 (s, 1 H), 8.12 (d, J ) 9 Hz, 1
1
3
13
3
) δ
H); C NMR (125 MHz, CDCl /CD OD) δ -0.4, 7.6, 14.2, 27.4,
3
3
31.3, 47.3, 52.0, 65.9, 72.8, 98.0, 109.7, 118.0, 122.8, 131.2,
133.9, 135.4, 141.1, 141.9, 145.8, 147.2, 151.0, 156.7, 157.6,
173.8; HRMS (EI) m/z calcd for C H ClN O Si (M ) 498.1378,
1
1
C
20.4, 124.8, 132.1, 133.2, 136.7, 142.8, 146.2, 146.4, 149.0,
+
50.2, 150.8, 157.5, 169.1, 174.1; HRMS (EI) m/z calcd for
2
5
27
2
5
+
+
28
H
32
N
2
O
6
Si (M ) 520.2030, found 520.2014; LRMS (EI) m/z
found 498.1362; LRMS (EI) m/z 498 (M ), 454, 439, 419, 398,
+
5
20 (M ), 478, 463, 421, 377, 347, 320, 291, 57.
20S)-7-Ch lor op r op yld im eth ylsilylca m p toth ecin (15).
Using the conditions described for 12, iodopyridone 6 (75 mg,
.15 mmol), phenylisonitrile 10 (45.6 mg, 0.44 mmol) and
hexamethylditin (72 mg, 0.22 mmol) in benzene (2 mL) gave
377, 319, 291, 255, 174, 127, 111, 97, 85, 71, 57.
(
Ch em icals, Blood Com pon en ts, Dr u gs, an d Dr u g Stock
Solu tion P r ep a r a tion . Samples of camptothecin [obtained
from the National Cancer Institute (NCI), Bethesda, MD], SN-
38 (Yakult Honsha, Tokyo), CPT-11 (Yakult Honsha, Tokyo)
and topotecan (NCI, Bethesda, MD) were of high purity (>98%)
as determined by HPLC assays with fluorescence detection.
Stock solutions of the drugs were prepared in dimethyl
sulfoxide (ACS spectrophotometric grade, Aldrich, Milwaukee,
0
1
1
1
3
5 (38 mg, 53%), after chromatography (CH
2
Cl
2
/acetone 20:
2
0
-1
3 3
), as a tan solid: [R] +30.8 (c 0.2, CHCl ); IR (CHCl , cm )
D
158, 1199, 1220, 1260, 1556, 1600, 1659, 1742, 2937, 2961,
1
004, 3016; H NMR (300 MHz, CDCl ) δ 0.64 (s, 6 H), 0.98 (t,
3
-
3
J ) 7 Hz, 3 H), 1.12-1.25 (m, 2 H), 1.62-1.80 (m, 2 H), 1.80-
WI) at a concentration of 2 × 10 M and stored in the dark
at 4 °C. High-purity water was provided by a Milli-Q UV
PLUS. L-R-Dimyristoylphosphatidylcholine (DMPC) and l-R-
dimyristoylphosphatidylglycerol (DMPG) were obtained from
Avanti Polar Lipids, Alabaster, AL, and were used without
further purification. Crystallized HSA of high purity (>97%)
1
5
7
1
0
.95 (m, J ) 7 Hz, 2 H), 3.43 (t, J ) 7 Hz, 2 H), 3.85 (s, 1 H),
.25 (d, J ) 16 Hz, 1 H), 5.26 (s, 2 H), 5.69 (d, J ) 16 Hz, 1 H),
.58-7.69 (m, 2 H), 7.73 (t, J ) 8 Hz, 1 H), 8.13 (d, J ) 8 Hz,
H), 8.17 (d, J ) 8 Hz, 1 H); 13C NMR (125 MHz, CDCl
) δ
.2, 7.9, 14.7, 27.5, 31.7, 47.4, 51.9, 66.4, 72.8, 97.8, 118.4,
3