Nitrogen → ethyl 2-[(E)-2-phenylethenyl]-1,3-oxazole-4-carboxylate

関与物質

反応手順

In a flame dried round-bottomed flask equipped with a magnetic stir bar and under inert atmosphere (N2), a suspension of 3-phenyl-acrylamide (10.31 g, 67.95 mmol) and NaHCO3 (28.47 g, 339.73 mmol) in THF (260 mL) was treated with 3-bromo-2-oxo-propionic acid ethyl ester (13.04 mL, 88.33 mmol) and the reaction mixture was heated at reflux for 15 h. 3-Bromo-2-oxo-propionic acid ethyl ester (13.04 mL, 88.33 mmol) was added again and the reaction mixture was stirred at reflux for 15 h. The reaction mixture was then filtered over celite and the solvents were evaporated under reduced pressure. The residue was dissolved in THF (30 mL) and treated at 0° C., dropwise, with trifluoroacetic anhydride (30.0 mL, 215.83 mmol). The reaction mixture was then stirred at rt overnight. Sat. aq. Na2CO3 was added and the mixture was extracted with EA (3×150 mL), dried over MgSO4, filtered, and the solvent was removed under reduced pressure. Purification of the residue by FC (1:9 EA-Hept) gave the title compound as a yellow solid. TLC:rf (1:9 EA-Hept)=0.1. LC-MS-conditions 02: tR=1.01 min; [M+H]+=244.48.

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