Dimethylformamide → Ethyl 3-(4-fluorophenyl)-5-methyl-1,2-oxazole-4-carboxylate

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Reaction Steps

To a suspension of 4-fluoro-benzaldehyde oxime (1.39 g, 10.0 mmol) in DMF (10 mL) was added portionwise within 5 minutes at 15 to 20° C. N-chlorosuccinimide (1.36 g, 10.0 mmol) and the resulting mixture was stirred at room temperature for 90 minutes. The yellow solution (containing N-Hydroxy-4-fluoro-benzenecarboximidoyl chloride) was then treated within 2 minutes at room temperature with a solution of ethyl-3-(1-pyrrolidino)crotonate (1.89 g, 10.0 mmol) in 5 mL of DMF and the resulting solution was stirred at room temperature for 28 hours. The mixture was diluted with water (25 mL) and subsequently extracted with ethyl acetate (4×25 mL). The combined organic layers were washed with 1 M HCl (2×25 mL) and water (2×25 mL), dried over Na2SO4 and subsequently concentrated to dryness (45° C./25 mbar) to afford 2.37 g (95%) of the title ester as a brownish solid with a purity of 100% (by GC) and 97% (by HPLC).

Provenance & Evidence