Potassium Hydroxide → Allyl 2-amino-5-(trifluoromethyl)pyrazolo[1,5-a]pyrimidine-3-carboxylate

Participants

Reaction Steps

3-(1,3-Dioxolan-2-yl)-1,1,1-trifluoro-propan-2-one (55.58 g, 301.9 mmol) and allyl 3,5-diamino-1H-pyrazole-4-carboxylate 3 (55 g, 301.9 mmol) were dissolved in 1,4-dioxane (330 mL). KOH (1.694 g, 30.19 mmol) was added and the yellow suspension was stirred at room temperature for 4 h30 min. The reaction mixture was heated at 90° C. for 16 h. The mixture was cooled down to room temperature. The reaction mixture was concentrated and purified by column chromatography (CombiFlash Companion XL, 1.5 kg column, 0.5 to 40% EtOAc in DCM) to afford allyl 2-amino-5-(trifluoromethyl)pyrazolo[1,5-a]pyrimidine-3-carboxylate 4a as a bright yellow solid (68 g, 79% yield). LC-MS (M+H)+ 287.2; 1H NMR (500 MHz, DMSO-d6) δ 9.18 (m, 1H), 7.46 (m, 1H), 6.77 (s, 2H), 6.05 (m, 1H), 5.62 (m, 1H), 5.26 (m, 1H), 4.78 (m, 2H).

Provenance & Evidence