Abstract: | The crystal structure of 5‐fluoro‐1‐octanoyluracil 5‐fluoro‐1‐octanoylpyrimidine‐2,4(1H,3H)‐dione, C12H17FN2O3], a lipophilic prodrug of 5‐fluorouracil, is described. The 5‐fluoropyrimidine‐2,4(1H,3H)‐dione moiety is similar to the known structure of 1‐acetyl‐5‐fluorouracil. The 1‐octanoyl group and the 5‐fluorouracil moiety are essentially coplanar, with the octanoyl carbonyl group oriented towards the the ring C—H group and away from the nearer ring carbonyl group. The torsion angle C—N—C—O (from the ring CH group to the octanoyl carbonyl group) of 9.2 (2)° is similar to the corresponding torsion angles reported for 1‐acetyl‐5‐fluorouracil (17.3 and 1.6°) and 1,3‐diacetyl‐5‐fluorouracil (8.8°). |