Under nitrogen, a solution of 5-bromopyrimidine (1 g, 6.3 mmol) in 60 mL anhydrous THF was added BuLi (2.5 M, 2.6 mL, 6.5 mmol) at -78° C. The resulting yellow solution was stirred for 20 min, after which ethyl formate (0.55 mL, 6.7 mmol) was added dropwise over 5 min. After 20 min, the reaction was quenched with 1.5 M THF/HCl solution (4.5 mL, 6.7 mmol). The cold bath was removed, and the reaction mixture was stirred for 1 h. THF was removed in vacco, 10 mL of water was then added. The mixture was extracted with CHCl3 (2*10 mL), and the combined organics were dried (MgSO4) and concentrated. The crude product was purified via flash column chromatography (5 per cent MeOH/CHCl3) to give 0.35 g (51 per cent) of the titled Pyrimidine-5-carboxaldehyde.
