Pyridines useful as modulators of ion channels

A compound of formula IA-ii, formula IB-ii formula IC-ii, or formula ID-ii:

• or a pharmaceutically acceptable salt thereof,
• wherein:
• R1 and R2, taken together with the nitrogen atom to which they are bound, form an optionally substituted 3-8-membered, monocyclic saturated or partially unsaturated ring having 0-3 additional heteroatoms independently selected from nitrogen, sulfur, or oxygen;
• wherein the ring formed by R1 and R2 taken together, are each optionally and independently substituted at one or more substitutable carbon, nitrogen, or sulfur atoms with z independent occurrences of —R4,
• wherein z is 0-5;
• y is 0-5;
• each occurrence of R3b, R3c, R4, and R5 is independently Q—RX;
• wherein Q is a bond or is a C1-C6 alkylidene chain wherein up to two non-adjacent methylene units of Q are optionally and independently replaced by —NR—, —S—, —O—, —CS—, —CO2—, —OCO—, —CO—, —COCO—, —CONR—, —NRCO—, —NRCO2—, —SO2NR—, —NRSO2—, —CONRNR—, —NRCONR—, —OCONR—, —NRNR—, —NRSO2NR—, —SO—, —SO2—, —PO—, —PO2—, —OP(O)(OR)—, or —POR—;
• and each occurrence of RX is independently selected from —R′, halogen, —NO2, —CN, —OR′, —SR′, —N(R′)2, —NR′COR′, —NR′CON(R′)2, —NR′CO2R′, —COR′, —CO2R′, —OCOR′, —CON(R′)2, —OCON(R′)2, —SOR′, —SO2R′, —SO2N(R′)2, —NR′SO2R′, —NR′SO2N(R′)2, —COCOR′, —COCH2COR′, —OP(O)(OR′)2, P(O)(OR′)2, —OP(O)2OR′, —P(O)2OR′, —PO(R′)2, or OPO(R′)2;
• each occurrence of R is independently hydrogen or an optionally substituted C1-6 aliphatic group;
• each occurrence of R′ is independently hydrogen or an optionally substituted C1-6 aliphatic group, provided that:
• iii) in formula I-B, when y is 0, R3a and R3b are both hydrogen, R1 and R2 taken together form 4-hydroxy-2-hydroxymethyl-pyrrolidin-1-yl, then R3C is not —NRCO—RX or —NRCOR′.