Ethyl 3,3,3-trifluoro-2-oxopropanoate → Tert-butyl 4-(3-oxo-2-(trifluoromethyl)-3,4-dihydropyrido[2,3-b]pyrazin-8-yloxy)naphthalen-1-ylcarbamate

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Reaction Steps

To tert-butyl 4-(2,3-diaminopyridin-4-yloxy)naphthalen-1-ylcarbamate (1.00 g, 2.73 mmol) dissolved in 20 mL of anhydrous ethanol under argon and at reflux was added the ethyl trifluoropyruvate (697 mg, 0.50 mL, 4.10 mmol). The reaction mixture was stirred at reflux for 3 hours. After cooling at RT, a precipitate was formed, filtered off and rinsed with Et2O. tert-butyl 4-(3-oxo-2-(trifluoromethyl)-3,4-dihydropyrido[2,3-b]pyrazin-8-yloxy)naphthalen-1-ylcarbamate was obtained as a white solid (116 mg, 0.246 mmol, 9%). The filtrate was evaporated under vacuum. The residue was chromatographied (eluent: CH2Cl2/EtOAc: 4/1 towards 0/1) to afford the second isomer as a slightly yellow solid (540 mg, 1.14 mmol, 42%).

Provenance & Evidence