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

Participants

Reaction Conditions

Reaction Steps

(E)-4-Oxo-but-2-enoic acid ethyl ester (2.7 mL, 22.99 mmol), 2-nitro benzoic acid (0.648 g, 3.83 mmol), and pyrrolidine (0.31 mL, 3.83 mmol) were added simultaneously to a solution of commercially available 3-chloro-2-hydroxy-benzaldehyde (5.0 g, 19.16 mmol) in dimethysulfoxide (20 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 (1:1.2) as eluents, yielded 5-chloro-3-formyl-2H-chromene-2-carboxylic acid ethyl ester as a solid (2.10 g, 50.1%).

Provenance & Evidence