Triethylamine → 5'-O-[N-{(N-benzyloxycarbonylphenylalanyl)alanyl}isoleucyl]-5-fluorouridine

Participants

Reaction Steps

0.46 Gram of 5'-O-(N-alanylisoleucyl)-5-fluorouridine hydrochloride obtained in Example 4 was dissolved in dimethylformamide (20 ml), and 1.51 g (5.30 mmol) of N-benzyloxycarbonylphenylalanine and 1.10 g (6.74 mmol) of diethylphosphoryl cyanide were then added. To this solution was added dropwise under ice-cooling a solution of 2.40 g (23.8 mmol) of triethylamine in diethylformamide (3 mmol), and the reaction liquid was kept for 17 hours at -20° C. and then concentrated under reduced pressure. The residue was dissolved in chloroform (200 ml) and the solution was washed with a 3% aqueous solution of potassium hydrogen carbonate (100 ml). The aqueous layer was further extracted with chloroform (100 ml). These organic layers were dried (over Na2SO4) and then concentrated under reduced pressure, and the residue was subjected to separation/purification by way of silica gel column chromatography (first time: a linear gradient of chloroform containing 3%→6% methanol; second time: a linear gradient of chloroform containing 3%→6% methanol) whereby 1.25 g (35%) of 5'-O-[N-{(N-benzyloxycarbonylphenylalanyl)alanyl}isoleucyl]-5-fluorouridine was obtained as a colorless powdery solid.

Provenance & Evidence