Water → 5-formyl-2,4-dimethyl-1H-pyrrole-3-carboxylic Acid

HRID 50003Notes

Reaction equation

C([O:3][C:4]([C:6]1[C:10]([CH3:11])=[C:9]([CH:12]=[O:13])[NH:8][C:7]=1[CH3:14])=[O:5])C.[OH-].[K+].O>CO>[CH:12]([C:9]1[NH:8][C:7]([CH3:14])=[C:6]([C:4]([OH:5])=[O:3])[C:10]=1[CH3:11])=[O:13]

Participants

Conditions

Temperature: 8 °C

Procedure

5-Formyl-2,4-dimethyl-1H-pyrrole-3-carboxylic acid ethyl ester (806 g), potassium hydroxide (548 g), water (2400 mL) and methanol (300 mL) were refluxed for two hours with stirring and then cooled to 8° C. The mixture was extracted twice with dichloromethane. The aqueous layer was adjusted to pH 4 with 1000 mL of 10 N hydrochloric acid keeping the temperature under 15° C. Water was added to facilitate stirring. The solid was collected by vacuum filtration, washed three times with water and dried under vacuum at 50° C. to give 5-formyl-2,4-dimethyl-1H-pyrrole-3-carboxylic (645 g, 93.5% yield) acid as a yellow solid. NMR (DMSO-d6) δ2.40, 2.43 (2×s, 2×3H, 2×CH3), 9.57 (s, 1H, CHO), 12.07 (br s, 2H, NH+COOH). MS m/z 168 [M+1].

Workup

extractionThe mixture was extracted twice with dichloromethane
customunder 15° C
additionWater was added
stirringto facilitate stirring
filtrationThe solid was collected by vacuum filtration
washwashed three times with water
customdried under vacuum at 50° C.

Sources & evidence

ORD record: ord-f1deff7774114072976ffeda820bbfe9
Source dataset: uspto-grants-2004_03
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06710067B2

Reaction notes

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