Pegylated imidazoquinolines as TLR7 and TLR8 agonists

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

• wherein
• R1 is selected from H, C1-6alkyl, C1-6alkylamino, C1-6alkoxy, C3-6cycloalkylC1-6alkyl, C3-6cycloalkylC1-6alkylamino, C3-6cycloalkylC1-6alkoxy, C1-6alkoxyC1-6alkyl, C1-6alkoxyC1-6alkylamino and C1-6alkoxyC1-6alkoxy;
• wherein the C1-6alkyl, C1-6alkylamino, C1-6alkoxy, C3-6cycloalkylC1-6alkyl, C3-6cycloalkylC1-6alkylamino, C3-6cycloalkylC1-6alkoxy, C1-6alkoxyC1-6alkyl, C1-6alkoxyC1-6alkylamino or C1-6alkoxyC1-6alkoxy is branched or unbranched and optionally terminally substituted with a hydroxyl, amino, thio, hydrazino, hydrazido, azido, acetylenyl, carboxyl, or maleimido group;
• Z is selected from C2-C6 alkyl and C2-C6 alkenyl, wherein the C2-C6 alkyl or C2-C6 alkenyl is unsubstituted or terminally substituted by —(O—C2-C6alkyl)1-6-;
• X is O or S;
• n is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20;
• R2 is H or a straight or branched, optionally unsaturated, C4-C24 alkyl, or a straight or branched, optionally unsaturated, C4-C24, acyl;
• R3 is a straight or branched, optionally unsaturated, C4-C24 alkyl or a straight or branched, optionally unsaturated, C4-C24 acyl.