Dimethylformamide → Ethyl 4-formyl-2-methyl-1H-pyrrole-3-carboxylate

Participants

Reaction Conditions

Reaction Steps

N,N-dimethylformamide (5.5 mL, 71 mmol) in dichloromethane (126 mL) at 0° C. was treated dropwise with oxalyl dichloride (6 mL, 71 mmol). The mixture was stirred at 0° C. for 30 minutes and then at ambient temperature for 1 hour. The mixture was again cooled to 0° C. and treated with a mixture of Example 1a (20 g, 64.6 mmol) in dichloromethane (126 mL). The reaction mixture was stirred at 0° C. for 2 hours and then at ambient temperature for 48 hours. The reaction mixture was again cooled to 0° C. and slowly quenched with 4 N aqueous sodium hydroxide solution. The mixture was then extracted with ethyl acetate (2×300 mL). The combined organic layers were washed with saturated aqueous sodium chloride, dried over anhydrous magnesium sulfate, filtered and concentrated. The residue was triturated with a mixture of 9:1 hexanes/ethyl acetate, filtered, and dried under high vacuum to give 8.67 g (74%) of the title compound.

Provenance & Evidence