The present disclosure is directed to compounds (I′) and to their use in methods for the treatment of disorders associated with fluid retention or salt overload, such as heart failure (in particular, congestive heart failure), chronic kidney disease, end-stage renal disease, liver disease, and peroxisome proliferator-activated receptor (PPAR) gamma agonist-induced fluid retention. The present disclosure is also directed to compounds (I′) and their use in methods for the treatment of hypertension. The present disclosure is also directed to compounds (I′) and to their use in methods for the treatment of gastrointestinal tract disorders, including the treatment or reduction of pain associated with gastrointestinal tract disorders.