4-乙氧基-2-氧代丁-3-烯酸乙酯

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: Reference: Riley, T. A.; Hennen, W. J.; Dalley, N. K.; Wilson, B. E.; J. Heterocyclic Chem., 1987, 24, 955-964. Heat a mixture of cyclopropylcarbamidine hydrochloride (2.05 g, 17 mmol), (E)-4-ethoxy-2-oxo-but-3-enoic acid ethyl ester (4.39 g, 25.5 mmol), ethanol (12 mL), and sodium ethoxide (1.16 g, 17 mmol) in a microwave at 140° C. for 20 min. Concentrate the reaction mixture under reduced pressure and partition the residue between ethyl acetate and brine. Separate the organic layer and concentrate under reduced pressure. Purify the residue by silica gel chromatography (10-30% ethyl acetate/hexane) to give 2-cyclopropyl-pyrimidine-4-carboxylic acid ethyl ester (1.5 g, 46%) as light yellow oil. MS (m/z): 193.0 (M+H)+. Heat Concentrate the reaction mixture under reduced pressure partition the residue between ethyl acetate and brine Separate the organic layer concentrate under reduced pressure Purify the residue by silica gel chromatography (10-30% ethyl acetate/hexane)

反应条件: temp:55.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: Reference: Dujardin, G; Rossignol, S.; Brown, E. Synthesis, 1998, 763-770. Add ethyl chlorooxoacetate (67 mL, 600 mmol) to a solution of palladium acetate (1.35 g, 6 mmol), ethyl vinyl ether (315 mL, 3.3 mol), and triethylamine (125 mL, 900 mmol) at ambient temperature. Heat to 55° C. for 24 hours, cool to room temperature, then partition the reaction mixture between diethyl ether and water. Concentrate under reduced pressure the organic layer to obtain (E)-4-ethoxy-2-oxo-but-3-enoic acid ethyl ester (72 g, 70%) as a brown oil. 1H NMR (400 MHz, CDCl3): δ 7.84 (d, J=13.2 Hz, 1H), 6.15 (d, J=13.2 Hz, 1H), 4.29 (q, J=7.6 Hz, 2H), 4.03 (q, J=6.8 Hz, 2H), 1.34 (m, 6H). Synthesis, 1998, 763-770 at ambient temperature cool to room temperature partition the reaction mixture between diethyl ether and water Concentrate under reduced pressure the organic layer