4,4'-Dimethoxytrityl Chloride [Hydroxyl Protecting Agent]

• 2'-Deoxyuridine [D0060]
• 4,4'-Dimethoxytrityl Chloride (= DMT-Cl) [D1612]
• Pyridine

DMT-Cl (0.41 g, 1.2 mmol) was added to a solution of 2’-deoxyuridine (0.23 g, 1.00 mmol) in pyridine (4.1 mL) under N₂ atmosphere and the mixture was stirred for 4.5 h at room temperature. The mixture was diluted with EtOAc (10 mL) and washed with saturated NaHCO₃ aq. (10 mL) and brine (10 mL x 2), dried over Na₂SO₄ (10 g) and concentrated in vacuo. The residue was purified by silica gel column chromatography (2% Et₃N in hexane:2% Et₃N in EtOAc = 1:10) to give 1 as a white amorphous (0.46 g, 0.85 mmol, 85% yield).

The reaction solution was monitored by TLC (dichloromethane: methanol = 10:1) and UPLC.
2'-Deoxyuridine was coevaporated with pyridine (2.0 mL x 2) and dried in vacuo for 30 min before use.
In silica gel column chromatography, 2% of triethylamine was added to the solvents to prevent degradation of the compound.

Compound 1

¹H NMR (400 MHz, DNSO-d₆); δ 11.35 (s, 1H), 7.64 (d, J = 8.2 Hz, 1H), 7.37 (d, J = 8.2 Hz, 2H), 7.31 (t, J = 7.3 Hz, 2H), 7.24 (dd, J = 8.5 Hz, 2.1 Hz, 5H), 6.90 (d, J = 8.7 Hz, 4H), 6.14 (t, J = 6.4 Hz, 1H), 5.37 (dd, J = 8.5 Hz, 1.6 Hz, 1H), 5.35 (d, J = 4.6 Hz, 1H), 4.30-4.25 (m, 1H), 3.87 (q, J = 4.0 Hz, 1H), 3.74 (s, 6H), 3.25-3.15 (m, 2H), 2.18 (t, J = 6.2 Hz, 2H).

• Stereospecific Syntheses of 3’-Deuterated Pyrimidine Nucleosides and Their Site-Specific Incorporation into DNA
  • P. Chirakul, S. T. Sigurdsson, Org. Lett. 2003, 5, 917.