dUTPase as a Potential Antiparasitic Drug Target
Journal of Medicinal Chemistry, 2005, Vol. 48, No. 19 5951
) 6.8 Hz, 1′-H), 8.10 (1H, d, J ) 8.1 Hz, 6-H); 13C NMR (75
MHz, CD3OD) δ 14.5 (CH2CH2CH2CH3), 23.8 (CH2CH2CH2-
CH3), 29.6 (CH2CH2CH2CH3), 37.2 (CH2CH2CH2CH3), 40.6 (2′-
CH2), 42.8 (5′-CH2), 73.5 (3′-CH), 87.1 (1′-CH), 87.6 (4′-CH),
103.2 (5-CH), 143.0 (6-CH), 152.51 (2-C), 166.6 (4-C), 177.0
(CONH); IR (KBr) 3332, 1727, 1667, 1639 cm-1; MS (CI) m/z
312 ([M + H]+, 7%), 329 ([M + NH4]+, 2%); HRMS (ES+) calcd
CH2), 43.5 (5′-CH2), 72.4 (3′-CH), 86.5 (1′-CH), 86.6 (4′-CH),
102.9 (5-CH), 120.7 (d, J ) 9.8 Hz, Ph-CH), 125.5 (Ph-CH),
130.2 (d, J ) 1.5 Hz, Ph-CH), 141.2 (6-CH), 150.6 (2-C), 151.3
(d, J ) 22.5 Hz, Ph-C), 164.0 (4-C); 31P NMR (121 MHz, CDCl3)
δ 2.4; IR (neat) 1697, 1681, 1257, 1192 cm-1; MS (CI) m/z 575
([M + H]+, 5%), 347 ([M-(PhO)2PO) + Na]+, 30%); HRMS (ES+)
calcd for C27H37O7N3SiP+ (M + H)+ 574.2133, found 574.2128.
for C14H22N3O5 (M + H)+ 312.1554, found 312.1554; Anal.
+
5′-tert-Butyldiphenylsilyloxy-2′,3′-dideoxy-3′-fluoro-
uridine (4b). A solution of tert-butyldiphenylsilyl chloride
(TBDPSCl) (0.238 g, 0.87 mmol) and imidazole (0.116 g, 1.70
mmol) in dry DMF (2 mL) was added dropwise at 0 °C to a
cooled solution of 2′,3′-dideoxy-3′-fluorouridine (0.176 g, 0.77
mmol) in dry DMF (2 mL). The reaction mixture was stirred
at 0 °C for 2 h and then at room temperature for 40 h. The
reaction was quenched by the addition of H2O (5 mL). The
crude mixture was extracted with CHCl3 (10 mL, 5 mL). The
combined organic layers were washed with saturated NaHCO3,
dried over MgSO4, and concentrated in vacuo. The crude oil
was chromatographed on a silica gel column (ISOLUTE SI)
eluted with a gradient of 0 f 5% CH3OH in CHCl3. Compound
4b was obtained as a white solid (0.331 g, 92%) from the
fractions with Rf ) 0.63 (10% CH3OH/CHCl3). mp 140-141
(C14H21O5N3) C, H, N.
5′-Tritylamino-2′,5′-dideoxyuridine (2j). The amine 2k
(0.200 g, 0.88 mmol) was taken up in dry pyridine (5 mL), and
the mixture was sonicated for a few minutes. Trityl chloride
(0.278 g, 1.00 mmol) was added, and the reaction mixture was
stirred at 50 °C overnight. The reaction was quenched with
H2O (20 mL), and the crude mixture was extracted with
dichloromethane (DCM) (3 × 10 mL). The combined organic
layers were washed with H2O (10 mL), dried over MgSO4, and
concentrated in vacuo. The crude oil was purified by flash
column chromatography (ISOLUTE SI column) eluting with
0 f 10% CH3OH in CHCl3. The fractions with Rf ) 0.28 (10%
CH3OH/CHCl3) yielded compound 2j as a white solid (0.202
1
g, 49%). mp 132-134 °C; H NMR (300 MHz, CDCl3) δ 2.07
1
(2H, m, 2′-H), 2.28-2.53 (2H, m, 5′-H), 2.73 (1H, dd, J ) 3.5,
12.1 Hz, CH2NH), 2.97 (1H, bs, 3′-OH), 4.19 (1H, m, 4′-H), 4.33
(1H, m, 3′-H), 5.72 (1H, d, J ) 8.1 Hz, 5-H), 6.36 (1H, t, J )
6.4 Hz, 1′-H), 7.14 (1H, d, J ) 8.1 Hz, 6-H), 7.23-7.43 (9H, m,
Ph-H), 7.57 (6H, m, Ph-H), 9.47 (1H, bs, 3-NH); 13C NMR (75
MHz, CDCl3) δ 40.8 (2′-CH2), 46.6 (5′-CH2), 71.1 (Ph3C), 73.0
(3′-CH), 85.4 (1′-CH), 86.7 (4′-CH), 103.2 (5-CH), 127.0
(Ph-CH), 128.4 (Ph-CH), 129.0 (Ph-CH), 139.8 (6-CH), 145.8
(Ph-C), 150.7 (2-C), 163.7 (4-C); MS (ES+) m/z 492 ([M + Na]+,
23%), 243 (Ph3C+, 100%), 470 ([M + H]+, 4%); HRMS (ES+)
°C; H NMR (300 MHz, CDCl3) δ 1.17 [9H, m, C(CH3)3], 2.24
(1H, m, 2′-CHH), 2.78 (1H, m, 2′-CHH), 4.00 (2H, m, 5′-H),
4.38 (1H, d, J ) 26.7 Hz, 4′-H), 5.34 (1H, dd, J ) 4.9, 53.8 Hz,
3′-H), 5.56 (1H, d, J ) 8.1 Hz, 5-H), 6.51 (1H, m, 1′-H), 7.43-
7.60 (6H, m, Ph-H), 7.65-7.74 (4H, m, Ph-H), 7.27 (1H, d, J
) 8.1 Hz, 6-H), 9.11 (1H, bs, 3-NH); 13C NMR (75 MHz, CDCl3)
δ 19.7 [C(CH3)3], 27.4 [C(CH3)3], 39.7 (d, J ) 21.3 Hz, 2′-CH2),
64.1 (d, J ) 10.9 Hz, 5′-CH2), 85.4 (1′-CH), 85.6 (d, J ) 24.7
Hz, 4′-CH), 94.7 (d, J ) 178.7 Hz, 3′-CH), 103.2 (5-CH), 128.5
(Ph-CH), 128.6 (Ph-CH), 130.7 (Ph-CH), 132.2 (Ph-C), 132.8
(Ph-C), 135.7 (Ph-CH), 136.0 (Ph-CH), 140.0 (6-CH), 150.6 (2-
C), 163.5 (4-C); 19F NMR (282 MHz, CDCl3) δ-175.5 (m, 3′-F);
MS (ES-) m/z 467 ([M - H]-, 53%), 75 (100%); HRMS (ES+)
calcd for C25H29N2O4FNaSi+ (M + Na)+ 491.1773, found
491.1764; Anal. (C25H29N2O4F, 0.08 HCl) C, H, N, Cl.
calcd for C28H28N3O4 (M + H)+ 470.2074, found 470.2076;
+
Anal. (C28H27N3O4, 0.3 HCl, 0.1 H2O) C, H, N, Cl.
3′-O-tert-Butyldimethylsilyl-5′-O-sulfamoyl-2′-deoxyuri-
dine (3e). A solution of sulfamoyl chloride (1.55 g, 13.47 mmol)
in dry DMA (10 mL) was added dropwise at 0 °C to a stirred
solution of 3f (2.30 g, 6.73 mmol) in dry DMA (10 mL). After
being stirred for 3 h, the reaction mixture was poured into
cold brine (40 mL) and extracted with CHCl3 (3 × 100 mL).
The combined organic layers were washed with H2O (2 × 100
mL), dried over Na2SO4, and reduced in vacuo. The resulting
crude product was purified by flash column chromatography
eluting with 3 f 10% CH3OH in CHCl3. The fractions with Rf
) 0.33 (10% CH3OH/CHCl3) yielded compound 3e as a white
solid (2.02 g, 71%). mp 163-165 °C; 1H NMR (300 MHz, CD3-
OD) δ 0.05 [6H, s, Si(CH3)2], 0.86 [9H, s, C(CH3)3], 2.05-2.13
(1H, m, 2′-CHH), 2.17-2.27 (1H, m, 2′-CHH), 3.95 (1H, m, 3′-
H), 4.12 (2H, m, 5′-H), 4.36 (1H, m, 4′-H), 5.62 (1H, d, J ) 8.1
Hz, 5-H), 6.13 (1H, t, J ) 6.8 Hz, 1′-H), 7.56 (1H, d, J ) 8.1
Hz, 6-H); 13C NMR (75 MHz, CD3OD) δ -4.6 (SiCH3), -4.5
(SiCH3), 18.0 [C(CH3)3], 26.0 [C(CH3)3], 39.2 (2′-CH2), 68.3 (5′-
CH2), 72.2 (3′-CH), 84.0 (1′-CH), 84.7 (4′-CH), 102.5 (5-CH),
140.9 (6-CH), 150.7 (2-C), 163.4 (4-C); IR (KBr) 1712, 1694,
1650, 1378, 1142 cm-1; MS (CI) m/z 439 ([M + NH4]+, 100%),
422 ([M + H]+, 80%); HRMS (ES+) calcd for C15H28N3O7SSi+
(M + H)+ 422.1412, found 422.1421.
5′-O-Triphenylsilyl-2′,3′-dideoxy-3′-fluorouridine (4c).
A procedure identical to the one used for 1m was employed.
Compound 4c was obtained as a white solid (0.274 g, 60%)
from the reaction of 3′-fluoro-2′,3′-dideoxyuridine (0.214 g, 0.93
mmol) with TPSCl (0.332 g, 1.12 mmol) in dry pyridine (7 mL).
Flash column chromatography (ISOLUTE SI column) was
carried out using 0 f 10% CH3OH in CHCl3. Rf (10% CH3-
OH/CHCl3) 0.66; mp 171-172 °C; 1H NMR (300 MHz, CDCl3)
δ 2.19 (1H, m, 2′-CHH), 2.67 (1H, m, 2′-CHH), 4.11 (2H, m,
5′-H), 4.36 (1H, d, J ) 27.1 Hz, 3′-H), 5.20-5.45 (2H, m, 4′-H
and 5-H), 6.50 (1H, dd, J ) 5.4, 9.1 Hz, 1′-H), 7.41-7.75 (16H,
m, 6-H and Ph-H), 9.04 (1H, bs, 3-NH); 13C NMR (75 MHz,
CDCl3) δ 39.5 (d, J ) 20.7 Hz, 2′-CH2), 64.3 (d, J ) 11.5 Hz,
5′-CH2), 85.2 (1′-CH), 85.4 (d, J ) 24.7 Hz, 4′-CH), 94.9 (d, J
) 178.7 Hz, 3′-CH), 103.1 (5-CH), 128.8 (Ph-CH), 131.2 (Ph-
CH), 133.0 (Ph-C), 135.7 (Ph-CH), 140.1 (6-CH), 150.7 (2-C),
163.5 (4-C); 19F NMR (282 MHz, CDCl3) δ -175.1 (m, 3′-F);
MS (ES-) m/z 487 ([M - H]-, 31%), 75 (100%); HRMS (ES+)
calcd for C27H25N2O4FNaSi+ (M + Na)+ 511.1460, found
511.1448; Anal. (C27H25N2O4FSi, 0.15 HCl) C, H, N, Cl.
3′-O-tert-Butyldimethylsilyl-2′,5′-dideoxyuridine 5′-N-
Diphenylphosphoramidate (3i). TBDMSOTf (0.11 mL, 0.48
mmol) was added dropwise at 0 °C to a solution of 2a (0.20 g,
0.44 mmol) in dry DMF (10 mL) and dry pyridine (0.1 mL,
0.96 mmol). The reaction was stirred for 2.5 h, H2O (5 mL)
was added, and the mixture was extracted with CH2Cl2 (3 ×
50 mL). The organic layers were dried over Na2SO4 and
reduced in vacuo. Further purification by flash column chro-
matography, eluting with 5 f 15% CH3OH in CHCl3, yielded
compound 3i as a pale yellow viscous liquid (0.15 g, 60%). Rf
5′-Tritylamino-3′-fluoro-2′,3′,5′-trideoxyuridine (4f). A
procedure identical to the one used for 2j was employed.
Compound 4f was obtained as a pale yellow solid (91 mg, 32%)
from the reaction of 5′-amino-3′-fluoro-2′,3′,5′-trideoxyuridine
(12) (0.137 g, 0.59 mmol) and trityl chloride (0.199 g, 0.66
mmol) in dry pyridine (4 mL). Flash column chromatography
(ISOLUTE SI column) was carried out using 0 f 5% CH3OH
1
in CHCl3. Rf (10% CH3OH/CHCl3) 0.36; H NMR (300 MHz,
CDCl3) δ 1.87-2.13 (2H, m, 2′-H), 2.28 (1H, dd, J ) 8.1, 12.0
Hz, CH2NH), 2.57-2.78 (2H, m, 5′-H), 4.48 (1H, dm, J ≈ 25
Hz, 4′-H), 5.11 (1H, dd, J ) 5.3, 53.7 Hz, 3′-H), 5.71 (1H, d, J
) 8.1 Hz, 5-H), 6.37 (1H, dd, J ) 5.6, 8.7 Hz, 1′-H), 6.98 (1H,
d, J ) 8.1 Hz, 6-H), 7.23-7.43 (9H, m, Ph-H), 7.53 (6H, m,
Ph-H), 9.39 (1H, s, 3-NH); 13C NMR (75 MHz, CDCl3) δ 38.5
(d, J ) 21.8 Hz, 2′-CH2), 46.1 (d, J ) 9.2 Hz, 5′-CH2), 71.1
(Ph3C), 85.2 (d, J ) 25.3 Hz, 4′-CH), 85.5 (1′-CH), 94.4 (d, J )
179.9 Hz, 3′-CH), 103.6 (5-CH), 127.1 (Ph-CH), 128.5 (Ph-CH),
1
(15% CH3OH/CHCl3) 0.61; H NMR (300 MHz, CDCl3) δ 0.00
[6H, s, Si(CH3)2], 0.83 [9H, s, C(CH3)3], 2.00-2.19 (2H, m, 2′-
H), 3.14-3.39 (2H, m, 5′-H), 3.83 (1H, m, 4′-H), 4.26 (1H, m,
3′-H), 5.56 (1H, d, J ) 8.1 Hz, 5-H), 6.03 (1H, t, J ) 6.8 Hz,
1′-H), 7.09-7.21 (6H, m, Ph-H), 7.21-7.36 (4H, m, Ph-H), 7.55
(1H, d, J ) 8.1 Hz, 6-H); 13C NMR (75 MHz, CDCl3) δ -4.5
(SiCH3), -4.3 (SiCH3), 18.3 [C(CH3)3], 26.1 [C(CH3)3], 40.8 (2′-