2-Amino-4, 6-bis [(phosphonomethoxy) alkoxy] pyrimidines bearing two equal or different achiral or chiral phosphonoalkoxy chains have been prepared either by aromatic nucleophilic substitution of 2-amino-4, 6-dichloropyrimidine or by alkylation of 4, 6-dihydroxy- 2-(methylsulfanyl) pyrimidine with appropriate phosphonate-bearing building block. Alkylation of 4, 6-dihydroxy-2-(methylsulfanyl) pyrimidine proved to be the method of ...