Inhibitors of Plasmodium falciparum dUTPase
Journal of Medicinal Chemistry, 2006, Vol. 49, No. 14 4193
d, J ) 6.2 Hz, 4′-H), 4.28 (2H, d, J ) 7.4 Hz, 1′-H), 5.69-5.98
(2H, m, 5-H and 3′-H), 6.01-6.09 (1H, m, 2′-H), 7.16 (1H, d, J )
8.0 Hz, 6-H), 7.29-7.41 (9H, m, Ph-H), 7.49-7.52 (6H,m, Ph-H),
8.21 (1H, bs, 3-NH); 13C NMR (75 MHz, CDCl3) δ 44.9 (1′-CH2),
59.9 (4′-CH2), 87.8 (Ph3C), 102.1 (5-CH), 126.1 (3′-CH), 127.7
(Ph-CH), 128.4 (Ph-CH), 129.0 (Ph-CH), 132.5 (2′-CH), 144.1 (Ph-
C), 144.2 (6-CH), 151.2 (2-C), 164.0 (4-C); LRMS (ES+) m/z 447
([M + Na]+, 100%); HRMS (ES+) calcd for C27H24N2O3Na (M +
Na)+ 447.1679, found 447.1680; Anal. (C27H24N2O3, 0.4 H2O) C,
H, N.
1-[(E)-4-trityloxy-2-butenyl]uracil (8a). Compound 8a was
prepared following general procedure B, from the N3-benzoyluracil
38 (0.05 mg, 0.09 mmol) treated with 0.2 M CH3ONa in CH3OH
(5 mL, 1.0 mmol). After removal of the Dowex resin and
concentration of the filtrate in vacuo, the residue was purified by
flash column chromatography, eluting the silica gel column with
0f5% CH3OH in CHCl3. White solid (38 mg, 90%). Rf ) 0.51
(10% CH3OH/CHCl3); mp 70-72 °C; 1H NMR (300 MHz, CDCl3)
δ 3.74 (2H, d, J ) 3.9 Hz, 1′-H), 4.42 (2H, d, J ) 5.6 Hz, 4′-H),
5.77 (1H, d, J ) 7.9 Hz, 5-H), 5.83-5.98- (2H, m, 2′-H and 3′-H),
7.19 (1H, d, J ) 7.9 Hz, 6-H), 7.27-7.39 (9H, m, Ph-H), 7.49
(6H, d, J ) 7.8 Hz, Ph-H), 9.04 (1H, bs, 3-NH); 13C NMR (75
MHz, CDCl3) δ 49.6 (1′-CH2), 64.0 (4′-CH2),87.5 (Ph3C), 102.9
(5-CH), 124.1 (3′-CH), 124.1 (Ph-CH), 128.3 (Ph-CH), 129.0 (Ph-
CH), 133.3 (2′-CH), 144.1 (6-CH), 144.3 (Ph-C), 151.1 (2-C), 163.9
(4-C); LRMS (ES+) m/z 447 ([M + Na]+, 100%); HRMS (ES+)
calcd for C27H28N3O3 (M + NH4)+ 442.2125, found 442.2128; Anal.
(C27H24N2O3, 0.2 H2O) C, H, N.
butyl]uracil 39 (0.05 g, 0.15 mmol), trityl chloride (0.05 mg, 0.19
mmol), and dry pyridine (2 mL) were irradiated with microwaves
to reach the temperature of 160 °C for 5 min. The irradiating cycle
was repeated three times. The solvent was removed in vacuo, and
the crude product was purified by flash column chromatography
using 40% hexane in EtOAc. Compound 9c was obtained as a white
foam (70 mg, 79%). Rf ) 0.27 (40% hexane/EtOAc); mp 86-88
1
°C; H NMR (300 MHz, CDCl3) δ 1.47 (9H, s, C[CH3]3), 1.53-
1.62 (1H, m, 3′-H), 1.67-1.85 (2H, m, 2′-H), 3.05-3.10 (1H, m,
4′-CHH), 3.23-3.31 (3H, m, 1′-H and 4′-CHH), 3.76-3.84 (2H,
m, 3′-H), 4.58 (1H, t, J ) 6.1 Hz, NHBoc), 5.67 (1H, dd, J ) 2.4,
7.9 Hz, 5-H), 7.27-7.40 (10H, m, 6-H and Ph-H), 7.48 (6H, d, J
) 7.0 Hz, Ph-H), 8.08 (1H, bs, 3-NH); 13C NMR (75 MHz, CDCl3)
δ 28.4 (C[CH3]3), 29.7 (2′-CH2), 36.9 (3′-CH2), 40.8 (4′-CH2), 46.8
(1′-CH2), 64.3 (CH2OTr), 79.2 (C[CH3]3), 86.8 (Ph3C), 101.9 (5-
CH), 126.9 (Ph-CH), 127.8 (Ph-CH), 128.6 (Ph-CH), 143.7 (Ph-
C), 145.0 (6-CH), 150.8 (2-C), 156.5 (NHCO2), 163.8 (4-C); HRMS
(ES+) calcd for C33H38N3O5 (M + H)+ 498.2387, found 498.2384;
Anal. (C33H37N3O5, 0.30 H2O) C, H; Calcd N, 7.49; found N, 6.98.
1-[2-(Hydroxymethyl)-4-(trityloxy)butyl]uracil (10a). The in-
termediate 46 (0.14 g, 0.28 mmol) was deacetylated according to
general procedure B using 0.2 M CH3ONa in CH3OH (5 mL, 1.0
mmol). Compound 10a was obtained as a white solid (73 mg, 57%).
1
Rf ) 0.51 (10% CH3OH/CH2Cl2); mp 83-85 °C; H NMR (500
MHz, CDCl3) δ 1.64-1.77 (2H, m, 3′-H), 3.21-3.28 (2H, m, 4′-
H), 2.03-2.10 (1H, m, 2′-H), 3.44 (1H, dd, J ) 4.4, 12.0 Hz,
CHHOH), 3.49 (1H, dd, J ) 3.4 Hz, 12.0 Hz, CHHOH), 3.63 (1H,
dd, J ) 4.9, 14.0 Hz, 1′-CHH), 3.78 (1H, dd, J ) 9.0, 14.0 Hz,
1′-CHH), 5.69 (1H, d, J ) 7.9 Hz, 5-H), 7.12 (1H, d, J ) 7.9 Hz,
6- H), 7.27 (3H, m, Ph-H), 7.33 (6H, d, J ) 7.5 Hz, Ph-H), 7.45
(6H, d, J ) 7.4 Hz, Ph-H), 9.67 (1H, bs, 3-NH); 13C NMR (125
MHz, CDCl3) δ 29.1 (3′-CH2), 38.3 (2′-CH), 49.0 (1′-CH2), 61.0
(CH2OH), 61.1 (4′-CH2), 87.0 (Ph3C), 102.4 (5-CH), 127.3 (Ph-
CH), 127.9 (Ph-CH), 128.7 (Ph-CH), 143.9 (Ph-C), 145.6 (6-CH),
151.9 (2-C), 163.8 (4-C); LRMS (ES+) m/z 479 ([M + Na]+,
100%); HRMS (ES+) calcd for C28H28N2NaO4 (M + Na)+
479.1941, found 479.1946; Anal. (C28H28N2O4, 1.20 H2O) C, H,
N.
1-[4-Acetyloxy-3-(tritylaminomethyl)butyl]uracil (9a). Trityl
chloride (0.13 g, 0.46 mmol) was added to a solution of compound
41 (0.10 g, 0.43 mmol) and triethylamine (0.64 mL, 0.46 mmol)
in dry CH2Cl2 (5 mL). The reaction mixture was stirred at room
temperature for 6 h. Further trityl chloride (0.06 g, 0.23 mmol)
and triethylamine (0.32 mL, 0.23 mmol.) were added, and the
reaction was left stirring overnight. Water (5 mL) was added. The
organic layer was extracted and washed with 0.1M HCl (5 mL),
dried over MgSO4, concentrated in vacuo, and purified by flash
column chromatography eluting with 0 f 5% CH3OH in CH2Cl2.
The title compound was obtained as a white foam (150 mg, 70%).
1-[4-Hydroxy-2-(trityloxymethyl)butyl]uracil (10b). The TB-
DMS protected intermediate 43 (0.13 g, 0.23 mmol) was dissolved
in THF (3 mL). Tetrabutylammonium fluoride (0.07 g, 0.27 mmol)
was added, and the reaction mixture was stirred at room temperature
until complete disappearance of the starting material was observed
by TLC. The solvent was removed in vacuo, and the crude product
was purified by flash column chromatography eluting with 5 f
10% CH3OH in CHCl3. The title compound was obtained as a white
solid (49 mg, 47%). Rf ) 0.57 (10% CH3OH/CHCl3); mp 85-88
°C; 1H NMR (500 MHz, CDCl3) δ 1.69-1.77 (2H, m, 3′-H), 2.14
(1H, bs, 4′-OH), 2.21 (1H, m, 2′-H), 3.14-3.19 (2H, m, 4′-H),
3.71-3.76 (2H, m, 1′-CHH and CHHOTr), 3.79-3.84 (1H, m,
CHHOTr), 3.99 (1H, dd, J ) 4.1, 13.8 Hz, 1′-CHH), 5.32 (1H, d,
J ) 7.9 Hz, 5-H), 6.69 (1H, d, J ) 7.9 Hz, 6-H), 7.27-7.30 (6H,
m, Ph-H), 7.34 (3H, t, J ) 7.5 Hz, Ph-H), 7.43 (6H, d, J ) 7.6 Hz,
Ph-H), 8.23 (1H, bs, 3-NH); 13C NMR (125 MHz, CDCl3) δ 32.3
(3′-CH2), 36.1 (2′-CH), 49.4 (1′-CH2), 60.2 (CH2OTr), 62.5 (4′-
CH2), 86.7 (Ph3C), 101.5 (5-CH), 127.3 (Ph-CH), 128.0 (Ph-CH),
128.6 (Ph-CH), 143.4 (Ph-C), 145.3 (6-CH), 151.1 (2-C), 163.7
(4-C); LRMS (ES+) m/z 479 ([M + Na]+, 100%); HRMS (ES+)
calcd for C28H28N2O4Na (M + Na)+ 479.1941, found 479.1935;
Anal. (C28H28N2O4, 1.40 H2O) C, H, N.
1-[2-(Azidomethyl)-4-(trityloxy)butyl]uracil (10c). Compound
10c was prepared by tritylation of 1-[2-(azidomethyl)-4-(hydroxy)-
butyl]uracil 48 (0.10 g, 0.42 mmol) with trityl chloride (0.16 g,
0.58 mmol) in dry pyridine (5 mL), according to general procedure
C. White solid (163 mg, 82%). Rf ) 0.57 (10% CH3OH/CHCl3);
mp 75-80 °C; 1H NMR (500 MHz, CDCl3) δ 1.42-1.51 (2H, m,
3′-H), 2.03-2.11 (1H, m, 2′-H), 2.96-3.14 (4H, m, 1′-H and 4′-
H), 3.42-3.46 (1H, m, CHHN3), 3.50 (1H, dd, J )6.1, 13.9 Hz,
CHHN3), 5.49 (1H, dd, J ) 2.0, 7.9 Hz, 5-H), 6.90 (1H, d, J ) 7.9
Hz, 6-H), 7.06-7.09 (3H, m, Ph-H), 7.14 (6H, t, J ) 7.6 Hz, Ph-
H), 7.25 (6H, d, J ) 7.3 Hz, Ph-H), 8.52 (1H, bs, 3-NH); 13C NMR
1
Rf ) 0.60 (10% CH3OH/CHCl3); mp 68-72 °C; H NMR (300
MHz, CDCl3) δ 1.65-1.83 (3H, m, 2′-H and 3′-H), 2.03 (3H, s,
CH3CO), 2.17 (2H, d, J ) 6.0 Hz, CH2NHTr), 3.68 (2H, m, 1′-H),
4.27 (2H, d, J ) 5.0 Hz, 4′-H), 5.66 (1H, d, J ) 7.9 Hz, 5-H), 7.02
(1H, d, J ) 7.9 Hz, 6-H), 7.19-7.30 (9H, m, Ph-H), 7.46 (6H, d,
J ) 7.3 Hz, Ph-H), 9.07 (1H, bs, 3-NH); 13C NMR (75 MHz,
CDCl3) δ 21.3 (CH3CO), 29.7 (2′-CH2), 37.0 (3′-CH), 44.6 (CH2-
NHTr), 47.4 (1′-CH2), 65.3 (CH3CO2CH2 or 4′-CH2), 71.3 (Ph3C),
102.7 (5-CH), 126.8 (Ph-CH), 128.3 (Ph-CH), 129.0 (Ph-CH), 144.7
(6-CH), 146.2 (Ph-C), 151.1 (2-C), 164.0 (4-C), 171.5 (CH3CO);
LRMS (CI) m/z 498.3 ([M + H]+, 100%); HRMS (ES+) calcd for
C30H32N3O4 (M + H)+ 498.2387, found 498.2384; Anal. (C30H31-
N3O4,1.5 H2O) C, H, N.
1-[4-Hydroxy-3-(tritylaminomethyl)butyl]uracil (9b). The in-
termediate 9a (0.11 g, 0.22 mmol) was deacetylated according to
general procedure B using 0.2 M CH3ONa in CH3OH (5 mL, 1.0
mmol). Compound 9b was obtained as a white foam (100 mg, 99%).
1
Rf ) 0.66 (10% CH3OH/CHCl3); mp 75-80 °C; H NMR (300
MHz, CDCl3) δ 1.47-1.68 (2H, m, 2′-H), 1.84 (1H, bs, 3′-H),
2.40-2.48 (2H, m, CH2NHTr), 3.57-3.82 (3H, m, 1′-H and 4′-
CHH), 3.90-3.95 (1H, m, 4′-CHH), 5.26 (2H, bs, CH2OH and Ph3-
CNH), 5.65 (1H, d, J ) 7.9 Hz, 5-H), 7.03 (1H, d, J ) 7.9 Hz,
6-H), 7.35-7.23 (9H, m, Ph-H), 7.41-7.48 (6H, m, Ph-H), 8.16
(1H, bs, 3-NH); 13C NMR (75 MHz, CDCl3) δ 29.4 (2′-CH2), 38.3
(3′-CH), 47.5 (1′-CH2), 48.1 (CH2NHTr), 67.0 (4′-CH2), 97.8
(Ph3C), 102.7 (5-CH), 127.2 (Ph-CH), 128.5 (Ph-CH), 128.9 (Ph-
CH), 144.7 (6-CH), 145.1 (Ph-C), 150.9 (2-C), 163.7 (4-C); LRMS
(ES+) m/z 456 ([M + H]+, 100%); HRMS (ES+) calcd for
C28H30N3O3 (M + H)+ 456.2282, found 456.2283; Anal. (C28H29-
N3O3, 0.5 H2O, 1.0 HCl) C, H, N.
1-[4-(tert-Butoxycarbonylamino)-3-(trityloxymethyl)butyl]-
uracil (9c). 1-[4-(tert-Butoxycarbonylamino)-3-(hydroxymethyl)-