Pyridyl derivatives as CFTR modulators

A compound of formula I:

• or a pharmaceutically acceptable salt thereof, wherein:
• RN is H, or alkyl;
• A is an optionally substituted 3 membered monocyclic ring;
• B is optionally fused to a 5-7 membered ring selected from the group consisting of cycloaliphatic, aryl, heterocyclic, and heteroaryl;
• R1 is halo, alkyl, OH, alkoxy, thioalkyl, trifluoromethoxy;
• or
• two R1 on adjacent atoms, taken together, form
• wherein J is selected from the group consisting of CH2, CF2, or C(CH3)2;
• W is independently a (C1-C6) alkylidene chain wherein up to two methylene units of W are independently replaced by —O—, —S—, SO2—, or —NR′—;
• R′ is independently H, alkyl, aryl, heteroaryl, aralkyl, cycloalkyl, or heterocyclic;
• RW is independently H, halo, CN, NO2, N(R)2, CF3, OCF3, OH, OR, C(O)R, CO2R, C(O)N(R)2, —O(C1-C6)alkylidene-OR, —O(C1-C6)alkylidene-N(R)2, —O(C1-C6)alkylidene-heterocyclic, or an optionally substituted aliphatic, cycloaliphatic, aryl, aryloxy, heterocyclic, or heteroaryl, wherein, when substituted, RW is substituted with up to two R2;
• R2 is halo, CN, NO2, CF3, OCF3, OR, OC(O)R, OC(O)N(R)2, SR, S(O)R, SO2R, SO2N(R)2, SO3R, C(O)R, CO2R, C(O)N(R)2, N(R)2, NRC(O)R, NRCO2R, NRC(O)N(R)2, NRSO2R, B(OR)2, or NRSO2N(R)2;
• R is independently H, alkyl, cycloalkyl, heterocyclic, aryl, or heteroaryl;
• n is 1 or 2;
• w is an integer from 1 to 4 inclusive;
• and
• x is an integer from 1 to 5 inclusive.