119285-07-3

193902-78-2

119285-07-3

Example 197b Synthesis of tert-butyl 4-(5-aminopyridin-2-yl)piperazine-1-carboxylate 197b: To a 250-mL round-bottomed flask under nitrogen protection was added 1-tert-butylcarbonyl-4-(5-nitro-2-piperidinyl)piperazine 197a (4.0 g, 13.0 mmol), 10% palladium-carbon (wetted, 500 mg) and methanol (130 mL). The reaction system was evacuated and filled with hydrogen and the reaction was stirred at room temperature for 15 hours. Upon completion of the reaction, the hydrogen was removed by evacuation and filled with nitrogen. The reaction mixture was filtered through a diatomaceous earth pad to remove the catalyst and the filtrate was concentrated under reduced pressure to afford the target compound 197b (3.3 g, 91% yield). Mass spectral data (MS-ESI): [M + H]+ 279.