(i) converting a compound of formula 682-1 into a compound of formula 682-2 (ii) converting said compound of formula 682-2 into a compound of formula 682-3 and (iii) converting said compound of formula 682-3 into a compound of formula 682-4. Further aspects of the invention relate to the use of the above process in the preparation of 2-cyano-2-deoxy-N4 -palmi-toyl-1-p-D-arabmofuranosylcytosine, a pyrimidine nucleoside which is therapeutically useful in the treatment and/or prevention of cancer.