IAP BIR domain binding compounds

A compound of Formula 1:

• or a salt thereof, wherein
• R1 is H or alkyl;
• R2 is methyl or ethyl;
• R3 is alkyl, cycloalkyl, heterocyclyl, heteroaryl, or aryl, any of which can be optionally further substituted with an amino, alkylamino, or alkoxy;
• R4 and R5 are each, independently, H or alkyl;
• R6 is H, halogen, or alkoxy;
• X is O, S, CH2, —(CH2)2— or CH—R7, wherein R7 is NR8, OR8, NC(O)OR8, NHC(O)R8 or NHSO2R8, wherein R8 is alkyl, cycloalkyl, heterocyclyl, aryl, arylalkyl, or heteroaryl, any of which can be optionally further substituted with an alkyl, alkoxy, haloalkyl, or halogen;
• or X is
• and G is
• wherein R9 is substituted or unsubstituted alkyl, cycloalkyl, heterocyclyl, aryl or heteroaryl;
• or
• (2) a substituted or unsubstituted azole or pyrrole ring, optionally fused to a substituted or unsubstituted aryl, heteroaryl, cycloalkyl or heterocyclyl.