A mixture of 6-((trimethylsilyl)ethynyl)-3-(4-piperidin-1-ylmethylphenyl)-9H-dipyrido[2,3-b;4′,3′-d]pyrrole (120 mg, 0.3 mmol) and potassium carbonate (170 mg, 1.2 mmol) in methanol (2 mL) was stirred at ambient temperature for 1 h. The reaction mixture was diluted with DCM (20 mL) and methanol (2 mL) and washed with water (15 mL). The organic phase was separated, dried over sodium sulfate, filtered and evaporated in vacuo to afford a brown residue that was taken to the next step without purification.
