Imidazoquinoline derivatives and their use in therapy

A compound of formula (I):

• wherein:
• R1 represents —O—Z—(P(═O)—OH)—O—Y-A
• R2 represents H, C1-C6 alkyl, C1-C6 alkylamino, C1-C6 alkoxy, C3-C6 cycloalkylC1-C6 alkyl, C3-C6 cycloalkylC1-C6 alkylamino, C3-C6 cycloalkylC1-C6 alkoxy, C1-C6 alkoxyC1-C6 alkyl, C1-C6 alkoxyC1-C6 alkylamino, C1-C6 alkoxyC1-C6 alkoxy;
• and optionally terminally substituted with a hydroxyl, amino, —NHNH2, N3, —CΞCH, —COOH, or maleimido group;
• Z represents (C2-C6 alkyleneO)q;
• Y represents (C2-C6 alkyleneO)r;
• q represents an integer 1 to 6;
• r represents 0 or an integer 1 to 20;
• R3 represents C2-C6 alkylene-OH, C2-C6 alkylene-NH2, C2-C5 alkenyl-CH2—OH or C2-C5 alkenyl-CH2—NH2;
• A represents
• wherein:
• R4 represents H, C4-C24 alkyl, C4-C24 alkenyl, —CO—C3-C23 alkyl, or —CO—C3-C23 alkenyl;
• R5 represents C4-C24 alkyl, C4-C24 alkenyl, —CO—C3-C23 alkyl, or —CO—C3-C23 alkenyl;
• p represents 0 or an integer 1 to 6;
• or a pharmaceutically acceptable salt thereof.