Methanol → 5-Formyl-2-methyl-4-phenyl-1H-pyrrole-3-carboxylic Acid

HRID 481060Notes

Reaction equation

HRID 481060 reaction equation
C([O:3][C:4]([C:6]1[C:10]([C:11]2[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=2)=[C:9]([CH:17]=[O:18])[NH:8][C:7]=1[CH3:19])=[O:5])C.CO.[OH-].[K+]>O>[CH:17]([C:9]1[NH:8][C:7]([CH3:19])=[C:6]([C:4]([OH:5])=[O:3])[C:10]=1[C:11]1[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=1)=[O:18]

Participants

5

Reactant 3

HCID 887MethanolHCID 14797Potassium HydroxideHCID 206047795-formyl-2-methyl-4-phenyl-1H-pyrrole-3-carboxylic acid ethyl ester

Product 1

HCID 219156195-Formyl-2-methyl-4-phenyl-1H-pyrrole-3-carboxylic AcidYield 52%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

5-Formyl-2-methyl-4-phenyl-1H-pyrrole-3-carboxylic acid ethyl ester was dissolved in water (100 mL) and methanol (45 mL) with stirring. Added KOH (2 eq. 1.9 g) and heated in 100° C. After 2.5 h, cooled to room temperature and the remaining ester was removed by extracting into ethyl acetate (200 mL), dried and concentrated. The water layer was acidified to pH=3 using 2N HCl. The white solid was removed by filtration, rinsing with water. The solid was re-concentrated from toluene, triturated with hexanes and dried to afford 2 g (52%) of an off-white solid.1H NMR (360 MHz, DMSO-d6) δ12.46 (br s, 1H, CO2H), 11.95 (s, 1H, NH), 9.08 (s, 1H, CHO), 7.36 (s, 5H, ArH), 2.49 (s, 3H, CH3). MS m/z (relative intensity %, ion) found 229 (100, M+); calc. 229.2.

Workup

  1. customthe remaining ester was removed
  2. extractionby extracting into ethyl acetate (200 mL)
  3. customdried
  4. concentrationconcentrated
  5. customThe white solid was removed by filtration
  6. washrinsing with water
  7. concentrationThe solid was re-concentrated from toluene
  8. customtriturated with hexanes
  9. customdried

Sources & evidence

ORD record
ord-83e225ca86cf49edbbe16de4828e43da
Source dataset
uspto-grants-2003_11
Patent number
US06653308B2

Reaction notes

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