| abstract |
Compounds of the following formulas which have anti-tumor and anti-viral activity and are especially useful in treating viral infections, their compositions and use. A phosphonomethoxymethyoxymethyl purine/pyrimidine derivative of the formula (See formula I) wherein X and X' are the same or different and are hydrogen or alkyl. R and R' axe the same or different and are hydrogen, alkyl,hydroxyalkyl or R"CO-where R" is an alkyl and B is a purine or pyrimidine base. |