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ChemicalBook CAS DataBase List 2,4-Dimethylpyrrole
625-82-1

2,4-Dimethylpyrrole synthesis

10synthesis methods
420 g (2.0 mol) of 2,4-dimethyl-3,5-bismethoxycarbonylpyrrole were suspended in 1200 g of 20% strength sodium hydroxide solution, and the mixture was heated. The solid gradually passed into solution during this process. At 92° C. gas had started to evolve vigorously; some of the dicarboxylic acid was decarboxylated in the process. The methanol formed during the hydrolysis was distilled off continuously until essentially only water was passing over. The mixture which remained was then neutralized with 250 g of 50% strength sulfuric acid (pH about 7.5) and heated to boiling at the reflux condenser with water separator. The 2,4-dimethylpyrrole separated out as a yellow upper phase over the course of a few hours. The aqueous phase was continuously recycled into the boiling mixture. A total of 152.5 g of organic phase was obtained. This comprised 8.1% of water, the remainder consisted of 99.1% of 2,4-dimethylpyrrole, determined as area percentages by gas chromatography using a flame ionization detector. This corresponded to 138.9 g of 2,4-dimethylpyrrole (73% of theory).
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Yield:-

Reaction Conditions:

in tetrahydrofuran

Steps:

47 Starting compound II: 2,4-dimethylpyrrole (0.21 mL, 2.0 mmol)
Starting compound II: 2,4-dimethylpyrrole (0.21 mL, 2.0 mmol) Starting compound III: 2-chloro-4-nitrobenzoyl chloride (0.48 g, 2.2 mmol) in THF (1 mL)

References:

Havez, Sophie Elisabeth US2003/73832, 2003, A1

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