The synthesis of 5' - deoxynucleoside 5' - phosphonates which contains a 5' - CP
bond in place of the 5' -COP bond of the naturally occuring nucleotides is described.
The preparation of phosphonate derivatives of acyclo - nucleosides and a simple
method for the conversion of 1-? -D-ribofuranosyl pyrimidines to the corresponding
1-? -D-arabinofuranosyl pyrimidines are also explained