1245644-42-1

General procedure for the synthesis of 6-bromo-3-iodoimidazo[1,2-a]pyrazines from 2-bromoimidazo[1,2-a]pyrazines: 6-bromoimidazo[1,2-a]pyrazines (500 mg, 2.52 mmol) and N-iodosuccinimide (NIS, 852 mg, 3.79 mmol) were dissolved in N,N-dimethylformamide (DMF, 10 mL) in N,N-dimethylformamide (DMF, 10 mL), and after degassing, the reaction mixture was heated to 60 °C and kept for 10 hours. After completion of the reaction, the mixture was cooled to room temperature and extracted with dichloromethane (DCM). The organic phase was washed sequentially with aqueous sodium thiosulfate (Na2S2O3) and saturated saline and dried over anhydrous sodium sulfate (Na2SO4). After concentration, the crude product was purified by column chromatography (petroleum ether: ethyl acetate = 5:1) to afford 6-bromo-3-iodoimidazo[1,2-a]pyrazine (530 mg, 65% yield). The product was confirmed by 1H-NMR (CDCl3, 400 MHz): δ 8.75 (s, 1H), 8.18 (s, 1H), 7.82 (s, 1H). Mass spectrometry (MS) analysis showed (M+H)+: 324/326.

[1] Patent: WO2013/34048, 2013, A1. Location in patent: Page/Page column 74; 75
[2] Patent: EP2818471, 2014, A1. Location in patent: Paragraph 0191; 0192