Reaktion #4984

Reaktionsgleichung

Dideoxyuridine

iodine monochloride

→

iodide

Ausbeute 66.0%

5-iodo-2', 3'-dideoxyuridine

Ausbeute 66.0%

Lösungsmittel

methanol

methanol

Reaktionsbedingungen

Aufarbeitung

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

Vorschrift

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'-hydroxyl 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.

Quelle