Molecules 2007, 12
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APT (MeOD, 75 MHz) δ 27.4 (CH3), 85.9 (C), 118.5 (CH), 119.5 (CH), 119.6 (CH), 135.2 (CH),
138.4 (C), 146.3 (C), 167.5 (C) ppm; IR (KBr plate) ν 3144, 2979, 2934, 2802, 2668, 2802, 2668,
2544, 1902, 1758, 1703, 1657, 1563, 1492, 1457, 1384, 1336, 1320, 1302, 1255, 1204, 1148, 989, 841,
656 cm-1; ESI-MS (positive mode) 139.0 (M- Boc)+, 182.8 (M- tBu)+, 238.2 (M) +.
2’-[3-(1-tertbutoxycarbonyl-imidazol-4-yl)acryloyl]-amido-5’-O-(4,4’-dimethoxytrityl)-2’-deoxy-
uridine (5)
A solution of 2 (154 mg, 0.65 mmol) in DMF (2 mL) was cooled to 0 °C. 1-(3-Dimethylamino-
propyl)-3-ethylcarbodiimide hydrochloride (125 mg, 0.65 mmol) and N-hydroxysuccinimide (75 mg,
0.65 mmol) were added. The mixture was allowed to warm to rt and was stirred overnight. The
reaction mixture was then cooled to 0 °C and 4 (300 mg, 0.54 mmol) was added. The reaction was
allowed to warm to room temperature and stirred for 7h, then H2O was added and the aqueous layer
was extracted with EtOAc (3 x). The combined organic layers were dried over anhydrous Na2SO4 and
concentrated under reduced pressure. The residue was purified by column chromatography on silica
1
gel (DCM/MeOH, 97:3) to afford 5 (240 mg, 68%): Rf (DCM/MeOH, 9/1): 0.5; H-NMR (300 MHz,
MeOD) δ 8.25 (1 H, s), 7.93 (1 H, d, J = 8.3 Hz), 7.74 (1 H, s), 7.52-7.23 (10 H, m), 6.91 (4 H, d, J =
8.9 Hz), 6.79 (1 H, d, J = 15.4 Hz), 6.17 (1 H, d, J= 8.5 Hz), 5.34 (1 H, d, J = 8.1 Hz), 5.04 (1 H, dd, J
= 5.4, 8.3 Hz), 4.43 (1 H, m), 4.18 (1 H, m), 3.79 (6 H, s), 3.49 (1H, AB dd, J = 2.7, 10.8 Hz), 3.40
(1H, AB dd, J = 2.7, 10.6 Hz), 1.65 (9 H, s) ppm; APT (MeOD, 75 MHz) δ 28.0 (CH3), 49.9 (C) 55.8
(CH3), 57.3 (CH), 65.1 (CH2), 72.6 (CH), 87.4 (CH), 87.8 (CH), 87.8 (C), 88.5 (C), 103.0 (CH), 114.4
(CH), 120.1 (CH), 121.8 (CH), 128.2 (CH), 129.1, 129.5 (CH), 131.4 (CH), 132.7 (CH), 136.6 (C),
136.9 (C), 140.1 (C), 142.5 (CH), 145.8 (C), 147.8 (C), 152.6 (C), 160.3 (C), 165.9 (C), 168.9 (C)
ppm; IR (KBr plate) ν 3306, 2929, 1766, 1722, 1644, 1614, 1462, 1384, 1254, 1091, 988, 836 cm-1;
ESI-MS (positive mode) 303.3 (DMTr) +, 665.6 (M-Boc) +, 766.0 (M) +.
2’-[3-(imidazol-4-yl]acryloyl]-amido-5’-O-(4,4’-dimethoxytrityl)-2’-deoxyuridine (6)
A solution of urocanic acid (1, 152 mg, 1.1 mmol) in DMF (5 mL) was cooled to 0 °C. 1-(3-
Dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (210 mg, 1.1 mmol) and N-hydroxy-
succinimide (127 mg, 1.1 mmol) were added. The mixture was allowed to warm to rt and was stirred
for 5h, then 4 (600 mg, 1.1 mmol) was added and the reaction was stirred overnight at rt. H2O was
added and the aqueous layer was extracted with EtOAc (3 x) and CHCl3 (1 x). The combined organic
layers were dried over anhydrous Na2SO4 and concentrated under reduced pressure. The residue was
purified by column chromatography on silica gel (DCM/MeOH, 9:1) to afford 6 (338 mg, 45%): Rf
(DCM/ MeOH 9/ 1): 0.2; 1H-NMR (300 MHz, MeOD) δ 7.93 (1 H, d, J = 8.1 Hz), 7.77 (1 H, s), 7.51-
7.23 (11 H, m), 6.91 (4 H, d, J = 8.8 Hz), 6.62 (1 H, d, J = 15.6 Hz), 6.17 (1 H, d, J= 8.3 Hz), 5.34 (1
H, d, J = 8.1 Hz), 5.03 (1 H, dd, J = 5.5, 8.3 Hz), 4.42 (1 H, m), 4.18 (1 H, m), 3.79 (6 H, s), 3.49 (1 H,
AB dd, J = 2.7, 10.8 Hz), 3.40 (1 H, AB dd, J = 2.7, 10.7 Hz) ppm; APT (MeOD, 75 MHz) δ 169.5
(C), 165.9 5 (C), 160.4 (C), 152.6 (C), 145.8 (C), 142.5 (CH), 136.9 (C), 136.6 (C), 131.5 (CH), 131.4
(CH), 129.5 (CH), 129.0 (CH), 128.1 (CH), 118.7 (CH), 114.3 (CH), 103.0 (CH), 88.5 (C), 87.9 (CH),
87.4 (CH), 72.6 (CH), 65.1 (CH2), 57.2 (CH), 55.8 (CH3) ppm; IR (KBr plate) ν 3252, 2925, 1760,