Iodine chloride → 5-Iodo-2',3'-dideoxyuridine

Beteiligte Stoffe

Reaktionsschritte

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.

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