antiviral agents for hepatitis B

A compound of formula IV: ** ** Formula or pharmaceutically acceptable salts thereof; wherein R4 is H or C1-C6 alkyl; each R5 is independently selected at each occurrence from the group consisting of CH3, C1-C6 alkoxy, halo, -CN, -NO2, C1-C6 haloalkyl, C1-C6 -dihaloalquilo -trihaloalquilo and C1-C6; R10 is OH, halo, C1-C6 alkyl, (C1-C6) -OH, C1-C6 -cloroalquilo, -diclororalquilo C1-C6, C1-C6 -tricloroalquilo, C1-C6 fluoroalkyl, C1-C6 -difluoroalquilo, -trifluoroalquilo C1-C6, C1-C6 heteroalkyl, C3-C10 cycloalkyl, C3-C10 heterocycloalkyl, aryl, heteroaryl, - (C1-C4) - (C3-C10), - (C1-C4) - (heterocycloalkyl C3- C10), - (C1-C4 alkyl) - (aryl) or - (C1-C4) - (heteroaryl), and wherein the alkyl, heteroalkyl, cycloalkyl, heterocycloalkyl, aryl ring or heteroaryl is optionally substituted with 1-5 substituents selected from R2; R11 is a bond or C1-C3 alkyl, wherein C1-C3 is optionally substituted with 1-3 substituents selected from R2; R2 is independently selected at each occurrence from the group consisting of halo, -CN, -NO2, -C1-C6 alkyl, - C1-C6 alkoxy, C1-C6 fluoroalkyl, C1-C6 -heteroalquilo, C (O) - ( C1-C6) and C (O) alkyl - (C1-C6); w is 0, 1 or 2; each occurrence of x is independently selected from the group consisting of 0, 1, 2, 3 and 4; each occurrence and is independently selected from the group consisting of 1, 2, and 3; and each occurrence of Z is independently selected from the group consisting of 0, 1, 2, and 3.