A mixture of 2,5-dibromopyridine (1.19 g), N-Boc-propargylamine (781 mg), Pd(PPh3)2Cl2 (73 mg), and CuI (10 mg) in diisopropylamine (20 mL) was stirred at room temperature overnight under nitrogen atmosphere. To the mixture was added N-Cbz-propargylamine (1.14 g) and the mixture was heated under reflux temperature for 5 hours under nitrogen atmosphere. The mixture was cooled to room temperature. To the mixture was added ethyl acetate (50 mL). The precipitates were filtered and washed with ethyl acetate. The filtrate and washings were combined and purified by silica gel column to give 6-1 (250 mg) as a crystalline compound.
