5-Fluorouracil → Tegafur

Reaction equation

[F:1][C:2]1[C:3](=[O:9])[NH:4][C:5](=[O:8])[NH:6][CH:7]=1.[O:10]1[CH:14]=[CH:13][CH2:12][CH2:11]1.Cl([O-])(=O)(=O)=O.C[S+](C)C1C=CC=CC=1>N1C=CC=CC=1>[O:10]1[CH2:14][CH2:13][CH2:12][CH:11]1[N:6]1[CH:7]=[C:2]([F:1])[C:3](=[O:9])[NH:4][C:5]1=[O:8]

Participants

Procedure

In 10 ml of pyridine were dissolved 0.39 g of 5-fluorouracil and 0.42 g of 2,3-dihydrofuran. To the solution were added 72 mg of dimethylphenylsulfonium perchlorate and the mixture was reacted for 5 hours at 130° C. After the reaction, pyridine was distilled off under reduced pressure and 20 ml of water were added to the residue. The aqueous solution was treated with caustic soda to have a pH value of 10-11 and then washed with 20 ml of chloroform. The aqueous alkaline solution was treated while cold with diluted hydrochloric acid to adjust the pH value of the solution to 3.5 and then extracted three times with 20 ml of chloroform. The chloroform extract was dried and then the chloroform was distilled off. The residue was recrystallized from ethanol to obtain 0.35 g of 1-(2-tetrahydrofuryl)-5-fluorouracil. The yield was 58.3%.