Cytotoxic nucleoside-corticosteroid phosphodiesters

Abstract

Nucleotides of nucleosides or bases having known cytotoxic activity are reacted with steroids, preferably corticosteroids, to form corresponding cytotoxic nucleoside-corticosteroid phosphodiester analogues of the formula: ##STR1## wherein: steroid is the residue formed by removal of a hydroxyl hydrogen atom from a natural or synthetic adrenal corticosteroid containing the characteristic cyclopentanophenanthrene nucleus which is esterified to the phosphate moiety at the 21-position; sugar is a naturally occurring pentose or deoxypentose in the furanose form, preferably ribose, deoxyribose, lyxose, xylose or arabinose and especially ribose, deoxyribose or arabinose, which is esterified to the phosphate moiety at the 5'-position and covalently bonded to the heterocycle moiety at the 1'-position to form a nucleoside; and heterocycle is a purine, pyrimidine, hydrogenated pyrimidine, triazolopurine or similar nucleoside base. The conjugates exhibit an enhanced therapeutic index as compared to the parent nucleoside or base compounds, and are thus useful cytotoxic, antiviral and antineoplastic agents.

Dependencies are inferred from the claim text.