Provided herein are improved processes for the preparation of a compound of Formula IX (AG-10). Also provided herein are pharmaceutically acceptable salts of Formula I and Formula Ib as well as crystalline types of Formula IX (AG-10). The processes described herein provide improved yields and efficiency, while the pharmaceutically acceptable salts and crystalline forms provide unexpected pharmacokinetic properties. Other features and aspects of the present disclosure will be apparent to a person of skill in the art upon reading the remainder of the specification.