Nucleoside phosphoramidate prodrugs

A compound of formula I-6:

• wherein:
• (a) R1 is H, —CH3, phenyl, p-bromo-phenyl, p-chloro-phenyl or p-fluoro-phenyl;
• (b) R2 is H;
• (c) R3a is H and R3b is H, —CH3, —CH(CH3)2, —CH2CH(CH3)2, —CH(CH3)CH2CH3, —CH2Ph or lower cycloalkyl;
• (d) R4 is hydrogen, —CH3, ethyl, n-propyl, i-propyl, n-butyl, 2-butyl, t-butyl, benzyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, N-methyl-aziridin-2-yl, N-methyl-azetidin-3-yl, N-methyl-pyrrolidin-3-yl, N-methyl-pyrrolidin-4-yl, N-methyl-piperidin-4-yl, lower haloalkyl or di(C1-6 alkyl)amino-C1-6 alkyl;
• (e) R5 is H;
• (f) R is H, —CH3, —CH2F, —CHF2, —CF3 or —F;
• (g) X is H, —OH, —OCH3, —F, —NH2 or —N3;
• with the proviso that X cannot be OH when R6 is —CH3 or —CH2F;
• (h) Y is —OH, —NH2, —OCH3 or —OC(O)CH3;
• (i) R10 and R11 are independently H, —F, —Br, —I, —OH, —OR′, —NH2, —NHR′, —NR′2, —CO2R′, —CONH2, —CONHR′, —CONR′2, —CH═CHCO2H or —CH═CHCO2R′,
• with the proviso that when R10 is —OH, R11 is not —NH2;
• (j) Z is N or —CR12;
• wherein R12 is H, halogen, —OR′, —NH2, —NHR′, —NR′2, —NO2, C1-6 alkyl, —CO2R′, —CONH2, —CONHR′, —CONR′2, —CH═CHCO2H or —CH═CHCO2R′;
• (k) R′ is C1-6 alkyl, a lower cycloalkyl or —C(O)(C1-6 alkyl) or alternatively, in the instance of —NR′2, each R′ comprise at least one C atom that are joined to form a heterocycle comprising at least two carbon atoms;
• and
• (l) P* is a chiral phosphorus atom;
• or a pharmaceutically acceptable salt thereof.