Patent ID: 6180790
Filing Date: 2001-01-30
Classification: C07F

Abstract:
A method of preparing a compound represented by the following structural formula: ##STR14##wherein:Y' is, together with a hydroxy group, a nucleoside analog; andA is a substituted benzyl group with one or more protected hydroxy or protected amine groups in the ortho or para positions, relative to the phosphate ester which can be converted in vivo to a hydroxy or amino group;comprising the steps of:a) reacting Y'--OH, a weak anhydrous organic and (A--O).sub.2 --P(NR.sub.21 R.sub.22)in an aprotic polar organic solvent, wherein R21 and R.sub.22 are each independently a lower alkyl, substituted lower alkyl group, an aryl group, a substituted aryl group or, taken together with the phosphoramide nitrogen, are a substituted or unsubstituted five, six or seven membered nitrogen-containing heterocyclic ring,thereby producing an intermediate represented by the following structural formula: ##STR15##b) reacting the intermediate with a phosphite oxidizing agent, thereby forming the prodrug.