Aminopyridines useful as inhibitors of protein kinases

A compound of formula I:

• or a pharmaceutically acceptable salt thereof, wherein:
• Ht is I-c:
• wherein any substitutable carbon in ring I-c is optionally substituted with —R10;
• Ring D is phenyl, wherein the phenyl is optionally substituted with 1-5 —R5;
• Z1 is N;
• each RX, RY, and RZ is independently H, halo, or C1-6 aliphatic, wherein the aliphatic is optionally substituted with 1-5 groups selected from halo, —CN, and —OR;
• each R10 is independently selected from haloC1-6alkyl, C1-6 alkyl, halo, OR, C(═O)R, CO2R, COCOR, NO2, CN, S(O)R, SO2R, SR, N(R4)2, CON(R4)2, SO2N(R4)2, OC(═O)R, N(R4)COR, N(R4)CO2R;
• each R4 is independently selected from H, C1-6alkyl, or haloC1-6alkyl;
• each R5 is independently selected from halo, haloC1-6alkyl, C3-6 cycloalkyl, or C1-6alkyl;
• and
• each R is independently selected from H, C1-6alkyl, or haloC1-6alkyl.