B. Baragaña et al. / Bioorg. Med. Chem. 19 (2011) 2378–2391
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4 days at room temperature and then heated at 100 °C for 30 min
under microwave irradiation. Ethanol was removed under vacuum,
the resulting residue was dissolved in acetonitrile (10 ml) and PL-
MIA (5 g, 2.58 mmol/g, 12.9 mmol) was added. The mixture was
gently stirred for 18 h and then filtered to remove the scavenger.
The compound was further purified by column chromatography
on a Redisep 12 g disposable flash column using CH2Cl2/MeOH
40:1 as eluent. After removing solvents the title compound was ob-
tained as a white solid (210 mg, 35%). Purity by LC–MS (UV chro-
matogram, 190–450 nm): 96%; Rf = 0.4 (10% MeOH in CH2Cl2); 1H
NMR (500 MHz; CDCl3): d 7.65–7.62 (m, 4H, H-Ar), 7.54 (br s, 1H,
NH), 7.41–7.34 (m, 6H, H-Ar), 7.19 (d, J = 7.7 Hz, 1H, CHN), 5.43–
5.42 (m, 1H, CHCO), 3.97 (dd, 1H, J = 13.3 Hz, J = 3.7 Hz, CHCHHN),
3.78–3.55 (m, 6H, CHCHHN, SiO-CH2–CH2, CH2CHCH2, CH2OH),
3.27–3.17 (m, 2H, CH2CH2N), 1.84–1.79 (m, 1H, CH2CHHCH),
1.74–1.69 (m, 1H, CH2CHHCH), 1.02 (s, 9H, CH3); 13C NMR
(125 MHz; CDCl3): d 172.9 (C), 151.1 (C), 146.0 (CH), 135.6 (C),
133.3 (C), 129.8 (C), 127.7 (C), 101.5 (CH), 62.6 (CH2), 59.6 (CH2),
51.6 (CH2), 41.9 (CH), 41.8 (CH2), 32.8 (CH2), 26.9 (CH3), 19.2 (C);
LRMS (ES+) m/z 510.25 [(M+H)+, 100%].
5.1.7. 1-[2-(Methoxyethylamido)-4-hydroxybutyl]uracil (2g)
Lactone 1 (100 mg, 0.48 mmol) was dissolved in anhydrous eth-
anol (2.5 ml) and 2-methoxyethylamine (410 l, 4.76 mmol) was
l
added. The reaction was heated at 90 °C overnight. Ethanol was re-
moved under vacuum, the resulting residue was dissolved in ace-
tonitrile (15 ml) and PL-MIA (2.76 g, 2.58 mmol/g, 7.12 mmol)
was added. The suspension was heated at 55 °C under microwave
irradiation for 15 min and then filtered to remove the scavenger.
Solvents were removed and the compound was further purified
by column chromatography using a Silicyle 12 g disposable flash
column and the following gradient: 1 min hold CH2Cl2, 15 min
ramp to 20% MeOH in CH2Cl2, 5 min hold at 20% MeOH in CH2Cl2.
After removing solvents the title compound was obtained as a
white solid (13 mg, 10%). Purity by LC–MS (UV chromatogram,
190–450 nm): 99%; 1H NMR (300 MHz; MeOD-d3): d 7.30 (d, 1H,
J = 7.9 Hz, CHN), 5.49 (d, 1H, J = 7.8 Hz, CHCO), 3.90 (dd, 1H,
J = 13.5 Hz, J = 4.8 Hz, CH2CHHN), 3.61 (dd, 1H, J = 13.5 Hz,
J = 10.3 Hz, CH2CHHN), 3.52–3.38 (m, 2H, CH2CH2OCH3), 3.30–
3.13 (m, 7H, CH2CH2OH, CH2CH2N, CH3), 2.82 (qd, 1H, J = 14.5 Hz,
J = 4.8 Hz, CH2CHCH2), 1.77–1.51 (m, 2H, CH2CH2CH); 13C NMR
(75 MHz; MeOD-d3): d 173.8 (C), 166.8 (C), 152.7 (C), 147.8 (CH),
101.9 (CH), 71.9 (CH2), 60.3 (CH2), 58.9 (CH3), 52.2 (CH2), 43.8
(CH), 40.3 (CH2), 34.0 (CH2); LRMS (ES+) m/z 286.14.14 [(M+H)+,
100%].
5.1.5. 1-[2-(N,N-dimethylaminoethylamido)-4-
hydroxybutyl)uracil (2e)
Lactone 1 (133 mg, 0.63 mmol) was dissolved in anhydrous eth-
anol (2 ml) and N,N-dimethylethylenediamine (689 ll, 6.33 mmol)
was added. The reaction was heated at 100 °C overnight. Ethanol
was removed under vacuum and the compound was purified by
column chromatography on a Combiflash Companion using a Red-
isep 12 g disposable flash column and the following gradient:
1 min hold at 100% CH2Cl2, 15 min ramp to 20% MeOH–NH3 in
CH2Cl2, 5 min hold at 20% MeOH–NH3 in CH2Cl2. After removing
solvents the title compound was obtained as a white solid
(86 mg, 46%). Purity by LC–MS (UV chromatogram, 190–450 nm):
99%; Rf = 0.4 (20% MeOH–NH3 in CH2Cl2); 1H NMR (500 MHz;
CDCl3): d 8.31 (br s, 1H, NH), 7.25 (d, 1H, J = 7.9 Hz, CHN), 5.67
(d, 1H, J = 7.9 Hz, CHCO), 4.00 (dd, 1H, J = 13.4 Hz, J = 4.3 Hz,
CHCHHN), 3.78–3.68 (m, 2H, CHCHHN and CH2CHHN), 3.64–3.59
(m, 1H, CH2CHHN), 3.49–3.46 (m, 1H, CH2CHHO), 3.33–3.39 (m,
1H, CH2CHHO), 3.13 (dt, 1H, J = 14.9 Hz, J = 5.0 Hz, CH2CHCH2),
2.64–2.60 (m, 1H, CH2CHHNMe2), 2.50–2.45 (m, 1H,
CH2CHHNMe2), 2.30 (s, 6H, CH3), 1.81–1.76 (m, 2H, CH2CH2CH);
13C NMR (125 MHz; CDCl3): d 173.0 (C), 164.0 (C), 153.0 (C),
145.3 (CH), 102.8 (CH), 59.1 (CH2), 58.7 (CH2), 51.6 (CH2), 44.3
(CH), 41.9 (CH2), 36.5 (CH3), 33.1 (CH2); LRMS (ES+) m/z 299.17
[(M+H)+, 100%].
5.1.8. 1-(2-Amido-4-trityloxybutyl)uracil (3a)
The alcohol 2a (186 mg, 0.82 mmol) was dissolved in pyridine
(3 ml) and tritylchloride (343 mg, 1.23 mmol) and DMAP (0.3%
w/w) were added. The reaction was irradiated in the microwave
for 30 min at 100 °C. The solvents were removed under vacuum.
The product was purified by column chromatography on a Combi-
flash Companion using a Redisep 12 g disposable flash column and
the following gradient: 3 min hold at 100% CH2Cl2, 15 min ramp to
10% MeOH in CH2Cl2, 3 min hold at 10% MeOH in CH2Cl2. After
removing solvents the title compound was obtained as white solid
(112 mg, 29%). Purity by LC–MS (UV chromatogram, 190–450 nm)
>99%; Rf = 0.9 (20% MeOH in CH2Cl2); 1H NMR (500 MHz; CDCl3): d
10.57 (br s, 1H, NH), 7.46–7.21 (m, 15H, H-Ar and CHN), 6.30 (br s,
1H, NH), 6.08 (br s, 1H, NH), 5.53 (d, 1H, J = 7.9 Hz, CHCO), 3.99 (dd,
1H, J = 13.4 Hz, J = 4.3 Hz, CHHN), 3.59 (dd, 1H, J = 13.4 Hz,
J = 10.7 Hz, CHHN), 3.29–3.25 (m, 1H, CHHO), 3.15–3.05 (m, 2H,
CHHO and CH2CHCH2), 1.91–1.84 (m, 1H, CH2CHHCH), 1.78–1.71
(m, 1H, CH2CHHCH); 13C NMR (125 MHz; CDCl3): d 175.6 (C),
164.9 (C), 151.2 (C), 146.4 (CH), 143.9 (C), 128.6 (C), 127.9 (C),
127.1 (C), 101.4 (CH), 87.0 (C), 60.9 (CH2), 51.4 (CH2), 42.3 (CH),
30.7 (CH2); LRMS (ESꢀ) m/z 468.2 [(MꢀH)ꢀ, 100%]; HRMS (ESꢀ)
found 468.1948 [MꢀH]ꢀ, C28H26N3O4 requires 468.1929.
þ
5.1.6. 1-[2-Morpholinamido-4-hydroxybutyl)uracil (2f)
Lactone 1 (150 mg, 0.71 mmol) was dissolved in anhydrous eth-
anol (2.5 ml) and morpholine (622
l
l, 7.14 mmol) was added. The
5.1.9. 1-(2-Dimethylamido-4-trityloxybutyl)uracil (3b)
reaction was heated at 90 °C for 48 h. Ethanol was removed under
vacuum and the compound was purified by column chromatogra-
phy on a Combiflash Companion using a Silicyle 12 g disposable
flash column and the following gradient: 1 min hold CH2Cl2,
15 min ramp to 20% MeOH in CH2Cl2, 5 min hold 20% MeOH in
CH2Cl2. After removing solvents the title compound was obtained
as a white solid (59 mg, 28%). Purity by LC–MS (UV chromatogram,
190–450 nm): 95%; Rf = 0.2 (10% MeOH in CH2Cl2); 1H NMR
(500 MHz; CD3OD-d3): d 7.47 (d, 1H, J = 7.8 Hz, CHN), 5.63 (d, 1H,
J = 7.8 Hz, CHCO), 4.01 (dd, 1H, J = 13.4 Hz, J = 5.4 Hz, CH2CHHN),
3.79 (dd, 1H, J = 13.4 Hz, J = 9.1 Hz, CH2CHHN), 3.71–3.48 (m,
11H, CH2CHCH2, CH2CH2OCPh3, CHCH2N and CH2CH2O), 1.90–
1.84 (m, 1H, CH2CHHCH), 1.74–1.68 (m, 1H, CH2CHHCH); 13C
NMR (75 MHz; CD3OD-d3): d 173.8 (C), 166.7 (C), 152.8 (C), 148.2
(CH), 101.9 (CH), 68.0 (CH2), 67.9 (CH2), 60.1 (CH2), 52.9 (CH2),
47.7 (CH2), 43.8 (CH2), 37.7 (CH), 34.2 (CH2); LRMS (ES+) m/z
298.14 [(M+H)+, 100%].
Alcohol 2b (140 mg, 0.55 mmol) was dissolved in pyridine
(1.5 ml) and tritylchloride (229 mg, 0.82 mmol) and DMAP (0.3%
w/w) were added. The reaction was irradiated in the microwave
for 3 ꢁ 15 min at 100 °C. The solvents were removed under vac-
uum. The white solid reaction crude was purified by column chro-
matography on a Redisep 12 g disposable flash column using
CH2Cl2/MeOH 40:1 and then CH2Cl2/MeOH 20:1 as eluent. After
removing solvents the title compound was obtained as a white so-
lid (107 mg, 39%). Purity by LC–MS (UV chromatogram, 190–
450 nm) >99%; Rf = 0.5 (10% MeOH in CH2Cl2); 1H NMR
(500 MHz; DMSO-d6): d 11.34 (br s, 1H, NH), 7.43 (d, J = 7.9 Hz,
1H, CHN), 7.40–7.24 (m, 15H, H-Ar), 5.50 (d, J = 7.9 Hz, 1H, CHCO),
3.81 (dd, J = 13.3 Hz, J = 6.4 Hz, 1H, CHHN), 3.60 (dd, J = 13.3 Hz,
J = 8.1 Hz, 1H, CHHN), 3.52–3.50 (m, 1H, CH2CHCH2), 3.03–2.99
(m, 1H, CHHO), 2.85 (s, 3H, CH3), 2.82–2.77 (m, 1H, CHHO), 2.69
(s, 3H, CH3), 1.83–1.79 (m, 1H, CH2CHHCH), 1.67–1.63 (m, 1H,
CH2CHHCH); 13C NMR (125 MHz; CDCl3): d 172.8 (C), 163.5 (C),