反应详情

A solution of 5-bromo-2-chloropyrimidine (4.03 g, 20.8 mmol), ethyl acrylate (9.06 mL, 83.3 mmol), palladium diacetate (187 mg, 0.830 mmol) and tri(o-tolyl)phosphine (762 mg, 2.50 mmol) in dimethylformamide (22 mL) and diisopropylethylamine (11 mL) was heated at reflux for 3.5 h, then cooled to room temperature and diluted with brine. The suspension was extracted with ethyl acetate. The extract was washed (brine) and dried. After solvent removal at reduced pressure, the residue was chromatographed (silica gel, 11% ethyl acetate/hexane) to give 3.26 g (73%) of ethyl(E)-3-(2-chloro-5-pyrimidinyl)-2-propenoate as a yellow solid, mp 125-127° C. IR 2905, 1698, 1542, 1405, 1160 cm−1; 1H NMR (CDCl3) δ 1.38 (t, J=7.2 Hz, 3H, OCH2CH3), 4.32 (q, J=7.2 Hz, 2H, OCH2CH3), 6.60 (d, J=16.2 Hz, 1H, CH═CHCO), 7.61 (d, J=16.2 Hz, 1H, CH═CHCO), 8.79 (s, 2H, 4-PyrH, 6-PyrH). HRMS calcd C9H9ClN2O2 [M+H]+ 213.0425. found 213.0428.

1. temperatureat reflux for 3.5 h
2. extractionThe suspension was extracted with ethyl acetate
3. washThe extract was washed (brine)
4. customdried
5. customAfter solvent removal at reduced pressure
6. customthe residue was chromatographed (silica gel, 11% ethyl acetate/hexane)