Reaction #83995

Reaction equation

Dideoxyuridine

iodine monochloride

→

iodide

Yield 66.0%

5-IODO-2',3'-DIDEOXYURIDINE

Yield 66.0%

Solvents

methanol

methanol

Conditions

Workup

1. 1
   Temperatureafter cooling to 25°
2. 2
   TemperatureThe dark purple reaction mixture was heated in a 50° bath under nitrogen for 20 minutes
3. 3
   Temperatureimmediately cooled in an ice-water bath
4. 4
   Filtrationthe resulting precipitate was collected by filtration
5. 5
   Washwashed with cold methanol (2×10 mL)
6. 6
   OtherVacuum-drying overnight

Procedure

Dideoxyuridine (2.122 g, 10.0 mmol) was dissolved in 30 mL of warm methanol and, after cooling to 25°, iodine monochloride (4.06 g, 25 mmol, 2.5 eq. Fisher) in methanol (20 mL) was added over 5 minutes. The dark purple reaction mixture was heated in a 50° bath under nitrogen for 20 minutes and then immediately cooled in an ice-water bath. After standing without stirring for 165 minutes, the resulting precipitate was collected by filtration and washed with cold methanol (2×10 mL). Vacuum-drying overnight afforded 2.232 g (66%) of iodide 21 as off-white microcrystals. This material was used without further purification in the next reaction, but other preparations were purified by chromatography or recrystallization from boiling methanol (30 mL/g) to give white needles (mp d 160°-164°). NMR indicated that the crude precipitate was homogeneous, but also that the 5'-hydroxy proton was very broad due to exchange catalyzed by trace impurities. Chromatographed or recrystallized materials afforded spectra in which this proton was, as usual, a sharp triplet.

Source