GENERAL METHODS: 2-substituted 5-halopyridine or 5-halopyrimidine substrate (0.5 mmol), N-heterocyclic amine (1.0 mmol), Cu(NO3)2 (0.1 mmol), and Cs2CO3 (1.0 mmol) were sequentially added to a 25 mL Schlenk tube, followed by DMF (2 mL). The reaction mixture was stirred at 130 °C or 140 °C for 24 h under air atmosphere (refer to the scheme and table for specific temperatures). Upon completion of the reaction, the mixture was poured into brine (15 mL) and extracted with dichloromethane (3 x 15 mL). The organic phases were combined, concentrated under reduced pressure and finally purified by silica gel (200-300 mesh) column chromatography to obtain the target product 5-bromo-2-pyrazol-1-yl-pyrimidine.
