PHOSPHORAMIDATE DERIVATIVES OF NUCLEOSIDE COMPOUNDS OF FORMULA 1 DERIVED FROM BASES SUCH AS ADENINE AND GUANINE HAVE ENHANCED THERAPEUTIC POTENCY IN PARTICULAR, ENHANCED POTENCY WITH RESPECT TO THE PROPHYLAXIS OR TREATMENT OF A VIRAL INFECTION SUCH AS HEPATITIS C VIRUS. THE GLYCOSIDE MOIETY OF THE NUCLEOSIDE COMPOUND IS SUITABLY SUBSTITUTED AT THE ß2 POSITION WITH METHYL AND THE PHOSPHORAMIDATE GROUP, SUITABLY COMPRISES 1-NAPHTHYL LINKED BY -O- TO THE P ATOM.