反応手順
Uridine 5 (7, 50 g, 0.21 mol) together with 4 (70 g, 0.23 mol) was dissolved in DMF (150 mL). p-Toluenesulfonic acid monohydrate (3.8 g, 20 mmol) was added, the mixture was placed on a Buechi R-134 rotavapor and agitated under reduced pressure (70 mbar) at 50° C. for 15 h. The mixture was then neutralized with triethylamine (2.8 ml, 20 mmol) and subsequently concentrated in vacuo. The resulting residue was suspended in EtOAc (400 mL), filtered and washed with 1:1 EtOAc/H2O (400 mL), H2O (2×200 mL), 1:1 H2O/Et2O (200 mL) and Et2O (2×200 mL) to give a colorless solid as a mixture of 2 diastereomers (6, 77 g, 0.16 mol, 76%). Upon recrystallisation from EtOH/EtOAc one of the diastereomers exclusively crystallized: M.p.: 176-178° C.; 1H-NMR (400 MHz, (CD3)2SO3) δ=11.38 (s, 1H), 7.82 (d, J=8.1, 1H), 7.42 (d, J8.6, 2H), 6.95 (d, J=8.6, 2H), 5.94 (s, 1H), 5.90 (s, 1H), 5.64 (d, J=8.1, 1H), 5.10 (t, J=5.2, 1H), 4.99 (m, 1H), 4.82 (m, 1H), 4.23 (m, 1H), 4.04 (q, J=7.1, 2H), 3.97 (t, J=6.3, 2H), 3.60 (m, 2H), 2.30 (t, J=7.4, 2H), 1.71 (m, 2H), 1.58 (m, 2H), 1.41 (m, 2H), 1.16 (t, J=7.1, 3H); 13C-NMR (400 MHz, (CD3)2SO) δ=172.8, 163.2, 159.7, 150.3, 142.1, 128.4 (2C), 128.0, 114.2 (2C), 106.5, 101.7, 91.3, 86.4, 84.2, 81.6, 67.4, 61.3, 59.6, 33.4, 28.3, 25.0, 24.2, 14.1; IR (film) ν=3467, 2933, 1692, 1677, 1248, 1116, 1077, 828; HRMS (MALDI-FTMS) m/z 513.1851 (513.1849 calculated for C24H30N2O9Na (M+Na)+).
