Triphenylphosphine-Carbon Tetrabromide-Lithium Azide

Ph3P-CBr4-LiN3
(PPh3)

[603-53-0]  · C18H15P  · Triphenylphosphine-Carbon Tetrabromide-Lithium Azide  · (MW 262.30) (CBr4)

[558-13-4]  · CBr4  · Triphenylphosphine-Carbon Tetrabromide-Lithium Azide  · (MW 331.61) (LiN3)

[19597-69-4]  · LiN3  · Triphenylphosphine-Carbon Tetrabromide-Lithium Azide  · (MW 48.97)

(reagent combination for the conversion of alcohols to azides)

Physical Data: Ph3P: mp 79-81 °C; bp 377 °C; d 1.0749 g cm-3. CBr4: mp 90-91 °C; bp 190 °C; d 3.273 g cm-3. LiN3: mp 115-298 °C (dec).

Solubility: sol DMF.

Preparative Method: reactive intermediates are generated in situ by reaction of Ph3P, CBr4, and LiN3.

Handling, Storage, and Precautions: Ph3P is an irritant; CCl4 is toxic and a cancer suspect agent; use in a fume hood. All solvents used must be carefully dried because the intermediates are all susceptible to hydrolysis. All azides are potentially explosive; workup with halogenated solvents is not recommended.

5-Azido Nucleosides.

Introducing the azido group selectively to the 5-position of various nucleosides can be accomplished with a combination of Triphenylphosphine, Carbon Tetrabromide, and lithium azide. This works well for uridine (eq 1) and thymidine. The yields are somewhat lower for N4-benzoylcytidine (eq 2) and N6-benzoyladenosine. The method is unsuccessful at introducing the azido group into the 5-position of N2-benzoylguanosine.1


1. Hata, T.; Yamamoto, I.; Sekine, M. CL 1975, 977.

Michael J. Taschner

The University of Akron, OH, USA



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