Cyclic nucleotide analogs

A compound of Formula (I), or a pharmaceutically acceptable salt thereof:

• wherein:
• B1 is selected from the group consisting of
• RG2 is an unsubstituted C1-6 alkyl;
• RH2 is hydrogen or NH2;
• X1 is S (sulfur);
• R1 is selected from the group consisting of —Z1—R9, an optionally substituted N-linked amino acid and an optionally substituted N-linked amino acid ester derivative;
• Z1 is selected from the group consisting of O (oxygen), S (sulfur) and)N(R10);
• R2 and R3 are hydrogen;
• R4 is hydrogen or azido;
• R5 is hydrogen;
• R6 is selected from the group consisting of hydrogen, halogen, —OR11 and —OC(═O)R12;
• R7 is halogen or an optionally substituted C1-6 alkyl;
• R8 is hydrogen;
• R9 is selected from the group consisting of an optionally substituted alkyl, an optionally substituted alkenyl, an optionally substituted alkynyl, an optionally substituted cycloalkyl, an optionally substituted cycloalkenyl, an optionally substituted aryl, an optionally substituted heteroaryl, an optionally substituted heterocyclyl, an optionally substituted aryl(C1-6 alkyl), an optionally substituted heteroaryl(C1-6 alkyl) and an optionally substituted heterocyclyl(C1-6 alkyl);
• R10 is hydrogen;
• R11 is hydrogen or an optionally substituted C1-6 alkyl;
• and
• R12 is an optionally substituted C1-6 alkyl or an optionally substituted C3-6 cycloalkyl.