Dimethylformamide → Methyl 3-formyl-4,5-dimethyl-1H-pyrrole-2-carboxylate

Participants

Reaction Steps

15.0 g (0.0979 mole) of phosphorus oxychloride were dropwise added to a solution of 13.7 g (0.0898 mole) of methyl 4,5-dimethylpyrrole-2-carboxylate in 13 ml (0.17 mole) of dimethylformamide over a period of 1.3 hours with ice-cooling, and the resulting mixture was stirred at room temperature for 0.5 hour and then at 90-100° C. for 0.5 hour. The hot reaction mixture thus obtained was poured into ice-water and dissolved. The solution was adjusted to pH 5-6 with a 10% aqueous solution of sodium hydroxide. The solids precipitated were collected by filtration and then dissolved in 600 ml of ethyl acetate. The filtrate was extracted twice with 200 ml each of ethyl acetate. The combined extracts were washed with water and dried over anhydrous sodium sulfate, and the solvent was distilled off. The residue was washed with a mixture of hexane and ethyl acetate and collected by filtration to give 10.6 g (0.0583 mole) of methyl 3-formyl-4,5-dimethylpyrrole-2-carboxylate as a brown powder.

Provenance & Evidence