Perchloric Acid → Methyl 1,4-Dimethyl-5-[(methylimino)(4-methylphenyl)methyl]-1H-pyrrole-2-acetate Perchlorate

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Reaction Steps

N-Methyl 4-methylbenzimidoyl chloride (5.44 g, 32.5 mmole) was placed in a dry 50 ml round bottom flask and treated with alcohol free chloroform (13 ml) and chlorosulfonic acid (0.38 g, 3.2 mmole). The reaction was placed under a nitrogen atmosphere and stirred at room temperature. Methyl 1,4-dimethyl-1H-pyrrole-2-acetate (5.39 g, 32.3 mmole) was added and the reaction was stirred overnight. The reaction was quenched with saturated aqueous sodium bicarbonate. The phases were separated, and the organic phase was extracted with saturated aqueous sodium bicarbonate and water, then dried over sodium sulfate. The mixture was filtered and the filtrate was concentrated under reduced pressure. The resulting red-brown viscous liquid was dissolved in absolute ethanol and treated with 70% perchloric acid (5.1 g, 35.5 mmole). The solution was cooled and treated with ether to induce crystallization. The solid was isolated by filtration, washed with cold ethanol, and air dried to yield 7.86 g (61%) of the title compound, m.p. 119°-124° C. (dec).

Provenance & Evidence