2-Nitrobenzoic acid → 5-methoxy-3-formyl-2H-chromene-2-carboxylic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

(E)-4-oxo-but-2-enoic acid ethyl ester (7.63 mL, 63.09 mmol), 2-nitro benzoic acid (1.77 g, 10.52 mmol), and pyrrolidine (0.87 mL, 10.52 mmol) were added simultaneously to a solution of commercially available 2-hydroxy-6-methoxy-benzaldehyde (8.0 g, 52.58 mmol) in dimethysulfoxide (50 mL) at 25° C. and the solution was stirred for 78 hours at 25° C. The reaction was quenched by the addition of water. The reaction mixture was then partitioned between water and ethyl acetate. The combined organics were washed with a saturated brine solution, dried over anhydrous sodium sulfate, filtered, rinsed and concentrated in vacuo. The residue obtained was purified on a silica gel flash column chromatography using ethyl acetate-hexanes as eluants, yielding 5-methoxy-3-formyl-2H-chromene-2-carboxylic acid ethyl ester as a solid (1.80 g, 51.9%).

Provenance & Evidence