Dimethylcarbamoyl Chloride → Ethyl (Z)-3-(dimethylcarbamoylamino)-4,4,4-trifluoro-but-2-enoate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

Ethyl 3-amino-4,4,4-trifluorocrotonate (18.4 g, 100 mmol) is added to a stirred solution of sodium hydride (60% in mineral oil, 9.6 g, 250 mmol) in N,N-dimethyl-formamide (60 mL) at 5° C. under nitrogen over a 60 minute period. The reaction mixture is allowed to warm to and held at room temperature for 15 minutes, cooled to 5° C., and treated with dimethylcarbamoylchloride (21.6 g, 200 mmol) over a 60 minute period. The resultant solution is then warmed to and held at room temperature for 2 hours, diluted with water (150 mL), and extracted with ethyl acetate (2×150 mL). The combined organic layers are dried, filtered and concentrated, and the mineral oil layer is removed to obtain a residue. Flash column chromatography of the residue on silica gel using a 85:15 hexanes/ethyl acetate solution gives the title product as a yellow liquid (18.1 g, 71% yield): 1H NMR (DMSO-d6)δ 9.18 (s,1H), 5.85 (s, 1H), 4.20 (q, 2H), 2.89 (s, 6H), 1.18 (t, 3H) ; 19F NMR δ −65.7 (s).

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