Compounds for treating diseases associated with hyaluronan overproduction

A compound of Formula Ia:

• [hyaluronan production inhibitor]-[labile linker]-X (Ia),
• or a pharmaceutically acceptable salt thereof,
• wherein the hyaluronan production inhibitor fragment is of:
• formula A
• wherein Y is a group selected from the group consisting of:
• RA1, RA2, and RA4 are each independently selected from the group consisting of —OH, —ORA5, halo, C1-6 alkyl, C2-6 alkenyl, C2-6 alkynyl, which C1-6 alkyl, C2-6 alkenyl and C2-6 alkynyl groups are optionally substituted by one or more groups selected from halo, —OH and —OMe;
• and one RA1, RA2 or RA4 group is
• n is 0 to 5;
• m is 0 to 5;
• and
• RA5 is C1-6 alkyl, C2-6 alkenyl, C2-6 alkynyl, which three groups are optionally substituted by one or more groups selected from halo, —OH and —OMe;
• formula B
• wherein RB1, RB2, and RB3 are each independently selected from the group consisting of —OH, —ORB4, halo, C1-6 alkyl, C2-6 alkenyl, and C2-6 alkynyl, which C1-6 alkyl, C2-6 alkenyl and C2-6 alkynyl groups are optionally substituted with one or more groups selected from halo, —OH and —OMe;
• and one RB2 or RB3 group is
• n is 0 to 4;
• m is 0 to 5;
• RB4 is C1-6 alkyl, C2-6 alkenyl, C2-6 alkynyl, which three groups are optionally substituted by one or more groups selected from halo, —OH and —OMe;
• formula C
• wherein the wavy line represents the point of attachment to the labile linker fragment;
• formula D
• wherein the wavy line represents the point of attachment to the labile linker fragment;
• or
• formula E
• wherein the wavy line represents the point of attachment to the labile linker fragment;
• the labile linker fragment is —OC(O)RL1—;
• wherein RL1 is selected from C1-6 alkylene, C2-6 alkenylene, C2-6 alkynylene, arylene, or heteroarylene, which five groups are optionally substituted with one or more groups independently selected from halo, —ORL2 or ═O;
• RL2 represents H or C1-6 alkyl;
• X is selected from the group consisting of quaternary ammonium, quaternary phosphonium, pyridinium and thiazolium salts;
• or
• X is
• wherein R5 is C1-6 alkyl.