Lithium Hydroxide → 5-Formyl-3-methyl-1H-pyrrole-2-carboxylic acid

HRID 397414Notes

Reaction equation

HRID 397414 reaction equation
[OH-].[Li+].C([O:5][C:6]([C:8]1[NH:9][C:10]([CH:14]=[O:15])=[CH:11][C:12]=1[CH3:13])=[O:7])C>CO.O>[CH:14]([C:10]1[NH:9][C:8]([C:6]([OH:7])=[O:5])=[C:12]([CH3:13])[CH:11]=1)=[O:15]

Participants

5

Reactant 2

HCID 3939Lithium HydroxideHCID 1113514ethyl 5-formyl-3-methyl-1H-pyrrole-2-carboxylate

Product 1

HCID 156940785-Formyl-3-methyl-1H-pyrrole-2-carboxylic acidYield 88%

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 962WaterSolvent2×

Procedure

Lithium hydroxide (8.73 g, 36.44 mmol) was added to the 5-formyl-3-methyl-1H-pyrrole-2-carboxylic acid ethyl ester (1.32 g, 7.27 mmol) in methanol (27 mL) and water (9 mL). The mixture was stirred at room temperature for over the weekend. The reaction was diluted with water (10 mL), evaporated most of the methanol and washed with ether. The aqueous layer was acidified with 1N HCl (37 mL) to pH=2, extracted with ethyl acetate. Washed with brine, dried and concentrated. The residue was washed with dichloromethane and filtered to give 0.98 g (88%) of 5-formyl-3-methyl-1H-pyrrole-2-carboxylic acid as a tan solid. 1H NMR (360 MHz, DMSO-d6) δ 12.87 (br s, 1H, COOH), 12.41 (br s, 1H, NH), 9.63 (s, 1H, CHO), 6.74 (s, 1H), 2.26 (s, 3H, CH3).

Workup

  1. customevaporated most of the methanol
  2. washwashed with ether
  3. extractionextracted with ethyl acetate
  4. washWashed with brine
  5. customdried
  6. concentrationconcentrated
  7. washThe residue was washed with dichloromethane
  8. filtrationfiltered

Sources & evidence

ORD record
ord-a9f054f4bf484d6e925d22356e482069
Source dataset
uspto-grants-2003_08
Patent number
US06610688B2

Reaction notes

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