Reaktion #6365

Reaktionsgleichung

diethyl azodicarboxylate

diethyl (R)-[2-benzyloxy-1-(hydroxymethyl)ethoxy]methylphosphonate

triphenylphosphine

2-[bis-(t-butoxycarbonyl)amino]-9-hydroxy-6-methoxypurine

→

(S)-2-[bis-(t-butoxycarbonyl)amino]-9-[3-benzyloxy-2-(diethoxyphosphorylmethoxy)propoxy]-6-methoxypurine

Ausbeute 88.6%

Lösungsmittel

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONwas added
2. 2
   workup.WAITleft
3. 3
   SonstigeThe solvent was evaporated under reduced pressure
4. 4
   Sonstigethe residue obtained
5. 5
   Sonstigechromatographed on silica gel

Vorschrift

To a stirred solution of diethyl (R)-[2-benzyloxy-1-(hydroxymethyl)ethoxy]methylphosphonate (1.0 g, 3 mmol), triphenylphosphine (1.18 g, 4.5 mmol) and 2-[bis-(t-butoxycarbonyl)amino]-9-hydroxy-6-methoxypurine (1.15 g, 3 mmol) in dry THF (20 ml), cooled in ice and under a mitrogen atmosphere, was added, dropwise, diethyl azodicarboxylate (0.71 ml, 4.5 mmol). The resulting solution was allowed to warm to ambient temperature and left stirring for 16 hours. The solvent was evaporated under reduced pressure and the residue obtained chromatographed on silica gel using hexane/ethyl acetate 2:1 as eluant. The eluant was changed as follows: hexane/ethyl acetate 1:1, hexane/ethyl acetate 1:2 and finally to ethyl acetate to give (S)-2-[bis-(t-butoxycarbonyl)amino]-9-[3-benzyloxy-2-(diethoxyphosphorylmethoxy)propoxy]-6-methoxypurine as a colourless oil (1.85 g, 88%).

Quelle