By transphosphatidylation between 1-(2-C-cyano-2-deoxy-beta-D-arabinofuranosyl)cytosine (I) and the 3-phosphatidylcholine (II) catalyzed by phospholypase D from Streptomyces sp. AA 586 in a two phase system of choroform and acetate buffer (pH 4.5) at 40 C.