d4TMP Delivery from 7-Substituted<i>cyclo</i>Sal-d4TMPs

Benzyl-substituted cycloSal-d4T monophosphates were prepared and evaluated for their ability to release d4TMP selectively. In contrast to previously reported derivatives, two of the new compounds release d4TMP as the sole product while two others gave the expected benzyl phosphate diesters. However, these diesters were surprisingly stable against degradation to release d4TMP.