1-[5-[2(R)-(2,4-dichloro-5-methoxyphenoxy)-propionamido]-2,5-dideoxy-2-fluoro-β-D-arabinofuranosyl]-5-ethyluracil 、
N-Boc-L-缬氨酸 以gave 1-[3-O-[N-(tert-butoxycarbonyl)-L-valyl]-5-[2(R)-(2,4-dichloro-5-methoxyphenoxy)-propionamido]-2,5-dideoxy-2-fluoro-β-D-arabinofuranosyl]-5-ethyluracil as a white solid, m.p. 110° C. (dec)的产率得到1-[3-O-[N-(tert-butoxycarbonyl)-L-valyl]-5-[2(R)-(2,4-dichloro-5-methoxyphenoxy)-propionamido]-2,5-dideoxy-2-fluoro-β-D-arabinofuranosyl]-5-ethyluracil