The reaction of 6-chloro-9-[2-(hydroxymethyl)cyclopropylidenemethyl]purine-2-amine (I) with methanol and K2CO3 gives of 9-[2-(hydroxymethyl)cyclopropylidenemethyl]-6-methoxypurine-2-amine (II) which is then condensed with the phosphorylated L-alanine ester (III) by means of N-methylimidazole (NMI) in pyridine/THF. The intermediate the phosphorylated L-alanine ester (III) has been obtained by condensation of L-alanine methyl ester (IV) with phenyl dichlorophosphate (V) by means of TEA in dichloromethane.