Tropolone derivatives and tautomers thereof for iron regulation in animals

A compound or a tautomer thereof, or a pharmaceutically acceptable salt of either, represented by Formula Ia:

• wherein:
• X represents oxygen or sulfur;
• Ra represents hydrogen, halo, alkyl, substituted alkyl, heteroalkyl, alkoxy, substituted alkoxy, alkoxyalkyl, substituted alkoxyalkyl, cycloalkyl, substituted cycloalkyl, heterocycloalkyl, substituted heterocycloalkyl, alkenyl, substituted alkenyl, heteroalkenyl, cycloalkenyl, substituted cycloalkenyl, heterocycloalkenyl, substituted heterocycloalkenyl, alkynyl, substituted alkynyl, or heteroalkynyl;
• Ra′ represents hydrogen, halo, alkyl, or substituted alkyl;
• and Rb, Rc, and Rd are independently selected from the group consisting of hydrogen, halo, alkyl, substituted alkyl, heteroalkyl, alkyl cycloalkyl, alkylheterocycloalkyl, alkoxy, substituted alkoxy, alkoxyalkyl, substituted alkoxyalkyl, cycloalkyloxy, substituted cycloalkyloxy, heterocycloalkyloxy, substituted heterocycloalkyloxy, cycloalkyl, substituted cycloalkyl, heterocycloalkyl, substituted heterocycloalkyl, alkenyl, substituted alkenyl, heteroalkenyl, cycloalkenyl, substituted cycloalkenyl, heterocycloalkenyl, substituted heterocycloalkenyl, alkynyl, substituted alkynyl, and heteroalkynyl;
• provided that Ra, Rb, Rc, and Rd are not all hydrogen.