Reacción #6365

Ecuación de reacción

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

Rendimiento 88.6%

Disolventes

THF

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.ADDITIONwas added
2. 2
   workup.WAITleft
3. 3
   OtroThe solvent was evaporated under reduced pressure
4. 4
   Otrothe residue obtained
5. 5
   Otrochromatographed on silica gel

Procedimiento

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%).

Fuente