Piperidine → 4-Acetyl-1-[3-[[2-[n-[6-(1-piperidinyl)pyridin-2-yl]amino]thiazol-5-yl]thio]benzoyl]piperazine

A solution of Example 4 (30 mg, 0.058 mmol), piperidine (86 μL, 0.87 mmol), 4-dimethylaminopyridine (7.1 mg, 0.058 mmol) in pyridine (300 μL) was heated to 134° C. in a sealed vial under nitrogen for 8.75 h. Most of pyridine was removed on a speed-vac at 40° C. The residue was purified using reversed phase automated preparative HPLC (conditions: YMC S5 ODS A 20×100 mm column, 15 min gradient starting from 10% solvent B (90% MeOH, 10% H2O, 0.1% TFA) and 90% solvent A (10% MeOH, 90% H2O, 0.1% TFA ) to 90% solvent B and 10% solvent A, flow rate 20 mL/min, λ=220 nM) to obtain the titled compound (25.2 mg, 68%) as a light tan solid.