1,1,1,4,4,4-Hexafluoro-2,3-butanedione → Ethyl 3-amino-5,6-bis(trifluoromethyl)pyrazine-2-carboxylate

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Reaction Steps

To a solution of amino-carbamimidoyl-acetic acid ethyl ester (Int E2)(1.25 g, 8.61 mmol) in DMF (5 ml) was added 1,1,1,4,4,4-hexafluorobutane-2,3-dione (5 g, 25.8 mmol) and the mixture was stirred at RT for 25 days. The yellow suspension was partitioned between EtOAc (50 ml) and water (50 ml) and the organic portion was washed with brine (30 ml), dried (MgSO4) and concentrated in vacuo. The crude product was purified by mass directed LC-MS eluting with MeCN/Water/0.1% TFA. The clean fractions were poured into EtOAc (50 ml) and washed with saturated NaHCO3 (50 ml), dried (MgSO4) and concentrated in vacuo to afford the title compound; 19F NMR (400 MHz, DMSO-d6): Peak 1 at −62 ppm, peak 2 at −64.6 ppm

Provenance & Evidence