Metabolically Stable Alkoxyalkyl Esters of Antiviral or Antiproliferative Phosphonates, Nucleoside Phosphonates and Nucleoside Phosphates

A nucleoside phosphate selected from the group of compounds having the following structures:

• wherein
• R is selected from the group consisting of —R1—O—R2, wherein R1 is selected from the group consisting of an optionally substituted C1 to C11 alkyl group and R2 is selected from the group consisting of a C6 to C17 alkyl group or a C6 to C17 alkenyl group;
• wherein
• said C6 to C17 alkyl group is substituted with one or more alkyl groups selected from the group consisting of methyl, ethyl, propyl, or cycloalkyl, including cyclopropyl and/or one or more halogens selected from the group consisting of F, Cl, Br and I;
• and further wherein said C6 to C17 alkyl group includes one or more substituents at or near the terminal position of the alkyl group;
• and
• wherein
• said C6 to C17 alkenyl group is optionally-substituted with an alkyl group selected from the group consisting of methyl, ethyl, propyl, a cycloalkyl group including, cyclopropyl and/or one or more halogens selected from the group consisting of F, Cl, Br and I;
• and further wherein the said C6 to C17 alkenyl group contains one or more double bonds, including a terminal double bond;
• B is selected from a purine or pyrimidine base;
• and
• A is a counterion selected from the group consisting of H+, Li+, Na+, K+, NH4+, tetraalkyl ammonium and other tertiary amine salts including triethylamine.