1H-pyrazolo[3,4-b]pyridines and therapeutic uses thereof

A method of treating a bone or cartilage disease in a subject, the method comprising administering to the subject a therapeutically effective amount of a compound of Formula Ib, or a pharmaceutically acceptable salt thereof:

• wherein:
• R1, R3, R6, and R8 are H;
• R2 is pyridylR12;
• R5 is selected from the group consisting of -arylR12 and -heteroarylR12;
• each R9 is independently selected from the group consisting of H, C1-6 alkyl, —CF3, —(C1-9 alkyl)ncarbocyclyl, and —(C1-9 alkyl)naryl;
• alternatively, two adjacent R9, may be taken together to form a fused ring with the nitrogen;
• each R12 is 1-5 substituents each selected from the group consisting of H, C1-6 alkyl, halide, —CF3, —CN, —NHC(═O)R9, and —NHC(═O)N(R9)2;
• Y1, Y2, and Y4 are carbon;
• Y3 is nitrogen and R7 is absent;
• and
• each n is 0 or 1.