6-Bromopyrido[2,3-d]pyrimidin-2-amine was synthesized as follows: 5-bromo-2-fluoro-3-formylpyridine (3.0 g, 14.78 mmol), guanidine hydrochloride (1.69 g, 17.74 mmol) and triethylamine (4.48 g, 44.35 mmol) were dissolved in 1-methyl-2-pyrrolidinone (15 mL). The reaction mixture was stirred in a microwave reactor at 180 °C for 15 min. Upon completion of the reaction, the mixture was cooled to room temperature and the reaction was quenched with deionized water (200 mL) followed by extraction with ethyl acetate (2 x 300 mL). The organic phases were combined, washed sequentially with deionized water (3 × 50 mL) and saturated saline (3 × 50 mL), dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure to give the crude product. The crude product was purified by silica gel column chromatography with the eluent ratio of ethyl acetate:petroleum ether=3:1, and the final product was 6-bromopyrido[2,3-d]pyrimidin-2-amine (2.0 g, 60% yield) as yellow solid. Mass spectrometry (electrospray positive ion mode) analysis results: C7H5BrN4 theoretical value [M] is 224,226, measured value [M + H] is 225,227.
![6-bromopyrido[2,3-d]pyrimidin-2-amine](/CAS2/GIF/882670-89-5.gif)