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

Participants

Reaction Conditions

Reaction Steps

Into a 5-L four necked round-bottomed flask equipped with a mechanical stirrer, a thermometer pocket, addition funnel, air condenser and a nitrogen bubbler was charged dimethyl formamide (1.05 L). The solvent was cooled to 0° C. To this chilled solvent, phosphorous oxychloride (0.434 L) was charged at below 5° C. After addition, the temperature of the reaction mixture was slowly brought to 25-30° C. Then a solution of 2,4-dimethyl-1H-pyrrole-3-carboxylic acid ethyl ester (III) (0.7 Kg; 4.2 mole) dissolved in dimethyl formamide (1.05 L) was added drop-wise into the flask at 25-30° C. After addition, the temperature of the reaction mixture was brought to 50° C. and maintained for 2-3 hours. The reaction was monitored by TLC. After maintenance, the reaction mixture was cooled to 25-30° C. and quenched in a carboy containing ice-water. The pH of the solution was then adjusted to 12-13 using aq. KOH solution. After pH adjustment, the solution was stirred at 25-30° C. and filtered and washed with water. The product was dried in a hot air oven at 60° C.

Provenance & Evidence