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The general procedure for the synthesis of 5-chloro-3-iodopyrazolo[1,5-a]pyrimidines from 5-chloropyrazolo[1,5-a]pyrimidines was as follows: 5-chloropyrazolo[1,5-a]pyrimidines (200 mg, 1.30 mmol) were dissolved in N,N-dimethylformamide (DMF, 2 mL), followed by the addition of N-iodosuccinimides (NIS, 322 mg. 1.86 mmol). The reaction mixture was stirred at room temperature overnight. After completion of the reaction, the reaction solution was diluted with ethyl acetate (EtOAc, 100 mL) and washed sequentially with water (50 mL), saturated aqueous sodium thiosulfate (Na2S2O3) (50 mL) and saturated saline (50 mL). The organic phase was separated, dried with anhydrous sodium sulfate (Na2SO4) and concentrated under reduced pressure to remove the solvent. The crude product was purified by silica gel column chromatography with the eluent ethyl acetate/petroleum ether (v/v = 1/4) to afford 5-chloro-3-iodopyrazolo[1,5-a]pyrimidine as a light yellow solid (390 mg, 100% yield). Mass spectrum (ESI, positive ion mode) m/z: 279.9 [M + H]+. 1H NMR (400 MHz, CDCl3) δ (ppm): 8.57 (d, J = 7.2 Hz, 1H), 8.16 (s, 1H), 6.86 (d, J = 7.2 Hz, 1H).

[1] Patent: US2014/234254, 2014, A1. Location in patent: Paragraph 0308; 0309; 0310
[2] Patent: US2016/168156, 2016, A1. Location in patent: Paragraph 0439; 0441; 0442
[3] Bioorganic and Medicinal Chemistry, 2015, vol. 23, # 19, p. 6280 - 6296
[4] Patent: WO2007/13673, 2007, A1. Location in patent: Page/Page column 31