Ethanol → 3-Bromo-6-chloropyrazolo[1,5-a]pyrimidine

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A 5 L 4-neck round bottom flask equipped with mechanical stirrer, thermocouple, condenser and N2 bubbler was charged with 3-amino-4-bromopyrazole (40.0 g, 240 mmol), 2-Chloro-1,3-bis(dimethylamino)trimethinium hexafluorophosphate (77.0 g, 252 mmol) in acetic acid (390 ml)/ethanol (580 ml). The reaction mixture was heated to 70° C. for 8 hrs. Cool to 0° C. Filter off solids. Wash solids with 500 ml water then 500 ml MeOH and dried under high vac to afford the title compound (45.1 g, 194 mmol). LRMS (APCI) calc'd for (C6H3BrClN3) [M+H]+, 231.9; found 231.9. 1H NMR (CDCl3, 500 MHz) δ 8.74 (s, 1H), 8.52 (s, 1H), 8.14 (s, 1H).

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