Imidazopyridine derivatives and aza-imidazopyridine derivatives as Janus kinase 2 inhibitors and uses thereof

A compound of Formula (I′):

• or a pharmaceutically acceptable salt, solvate, hydrate, polymorph, co-crystal, tautomer, or stereoisomer thereof, wherein:
• each instance of RA is independently halogen or substituted or unsubstituted alkyl;
• each instance of R1 is independently hydrogen or substituted or unsubstituted alkyl;
• k is 0, 1, or 2;
• is
• RE is hydrogen;
• RJ is hydrogen;
• YA is N or CRB;
• YB is N or CRB;
• YC is N or CRB;
• YD is N or CRB;
• provided that no more than one of YA, YB, YC, and YD is N;
• each instance of RB is independently hydrogen, halogen, substituted or unsubstituted alkyl, —OR1, or —CN;
• is
• XA is N or CRH,
• XB is N or CRH,
• XC is N or CRH;
• XD is N or CRH;
• provided that no more than one of XA, XB, XC and XD is N;
• each instance of RH is independently hydrogen;
• RK is hydrogen or substituted or unsubstituted alkyl;
• RC is hydrogen;
• RG is
• or hydrogen;
• and
• each instance of RD is independently substituted or unsubstituted carbocyclyl;
• or two instances of RD are joined together to form a substituted or unsubstituted;
• carbocyclic ring;
• provided that the compound is not of the formula: