Sodium Hydroxide → 1,5-dimethyl-3-phenyl-1H-pyrrole-2,4-dicarboxylic acid

HRID 880431Notes

Reaction equation

[OH-].[Na+].[CH3:3][N:4]1[C:8]([CH3:9])=[C:7]([C:10]([O:12]CC)=[O:11])[C:6]([C:15]2[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=2)=[C:5]1[C:21]([O:23]CC)=[O:22]>O.C(O)C>[CH3:3][N:4]1[C:8]([CH3:9])=[C:7]([C:10]([OH:12])=[O:11])[C:6]([C:15]2[CH:16]=[CH:17][CH:18]=[CH:19][CH:20]=2)=[C:5]1[C:21]([OH:23])=[O:22]

Participants

Conditions

Temperature: 0 °C

Procedure

A solution of sodium hydroxide (101 g, 2.53 mol) in water (340 mL) was added to a solution of diethyl 1,5-dimethyl-3-phenyl-pyrrole-2,4-dicarboxylate (80 g, 0.25 mol) in ethanol (340 mL) and heated at reflux for 15 h. Ethanol was removed under reduced pressure and the residue diluted with water (200 mL) and chilled to 0° C. Concentrated hydrochloric acid (˜150 mL) was slowly added to adjust pH to ˜2, while maintaining temperature below 10° C. and the mixture was stirred for 30 min. The precipitated solid was filtered, washed with water (100 mL) and petroleum ether (200 mL) and dried under vacuum at 60° C. to afford 1,5-dimethyl-3-phenyl-pyrrole-2,4-dicarboxylic acid (60 g, 91%) as a white solid.

Workup

temperatureheated
temperatureat reflux for 15 h
customEthanol was removed under reduced pressure
additionthe residue diluted with water (200 mL)
additionConcentrated hydrochloric acid (˜150 mL) was slowly added
temperaturewhile maintaining temperature below 10° C.
filtrationThe precipitated solid was filtered
washwashed with water (100 mL) and petroleum ether (200 mL)
customdried under vacuum at 60° C.

Sources & evidence

ORD record: ord-2c26ab272bea46c2bfe9044c3b81abb6
Source dataset: uspto-grants-2015_03
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08993574B2

Reaction notes

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