This compound can be prepared by several different ways: 1) The reaction of 5-fluorouridine (I) with 2,2-dimethoxypropane (A) by means of p-toluenesulfonic acid gives 2',3'-isopropylidene-5-fluorouridine (III), which is treated with triphenylphosphite methiodide in DMF to afford 5'-deoxy-5'-iodo-2',3'-isopropylidene-5-fluorouridine (IV). The reduction of (IV) with H2 over Pd/C in methanol-triethyl-amine yields 5'-deoxy-2',3'-isopropylidene-5-fluorouridine (V), which is finally hydrolyzed with aqueous trifluoroacetic acid. 2) The hydrolysis of compound (IV) with aqueous trifluoroacetic acid as before gives 5'-deoxy-5'-iodouridine (II), which is finally reduced with H2 over Pd/C as before. 3) Compound (II) can also be obtained by reaction of (I) with triphenyl phosphite methiodide as before. 4) It can also be prepared via reduction of the 5'-chloro intermediate with tributyltin hydride.
The condensation of bis(trimethylsilyl)fluorouracil (I) with 5-deoxy-1,2,3-tri-O-acetyl-D-ribofuranose (II) in the presence of trimethylsilyl trifluoromethanesulfonate (III) gives the fully protected compound (IV), which is finally deprotected by the usual methods.