Bicyclic heteroaryl derivatives as CFTR potentiators

A compound of the Formula III

• or a pharmaceutically acceptable salt thereof;
• wherein
• W is selected from the group consisting of phenyl and a five to six membered heteroaryl comprising one to three heteroatoms each of which is independently selected from the group consisting of N, O and S(O)n;
• wherein the phenyl and heteroaryl are optionally substituted with one to three R3;
• Y is a five membered heteroaryl comprising one to four heteroatoms each of which is independently selected from the group consisting of N, O and S(O)n;
• wherein the heteroaryl is optionally substituted with one to three substituents each of which is independently selected from the group consisting of halo, C1-C6 alkyl and C1-C6haloalkyl;
• Z is C1-C6 alkyl or phenyl;
• wherein the phenyl is optionally substituted with one to three halo;
• R1a and R1b are each independently selected from the group consisting of —H, —OH, halo,
• C1-C6alkyl optionally substituted with one to three substituents each of which is independently selected from the group consisting of halo, —OH, C1-C3alkyoxy, C3-C7 cycloalkyl and a four to seven membered heterocycloalkyl comprising one to three heteroatoms each of which is independently selected from the group consisting of N, O and S(O)n,
• C3-C7 cycloalkyl optionally substituted with one to three substituents each of which is independently selected from the group consisting of —OH, halo and C1-C6 alkyl, and
• four to seven membered heterocycloalkyl optionally substituted with one to three substituents each of which is independently selected from the group consisting of —OH, halo and C1-C6 alkyl;
• or R1a and R1b taken together with the carbon to which they are attached form a C3-C7 cycloalkyl or a four to seven membered heterocycloalkyl comprising one to three heteroatoms each of which is independently selected from the group consisting of N, O and S(O)n;
• and wherein the C3-C7 cycloalkyl or four to seven membered heterocycloalkyl are optionally substituted with one to three substituents each of which is independently selected from the group consisting of —OH, halo and C1-C6 alkyl;
• R3 at each occurrence is independently selected from the group consisting of C1-C6 alkyl, C1-C6alkoxy, halo and C1-C6 haloalkyl;
• and
• n at each occurrence is independently 0, 1 or 2.