Diethyl 2,4-dimethylpyrrole-3,5-dicarboxylate → 2-Carboxyethyl-3,5-dimethyl-1H-pyrrole-4-carboxylic acid

HRID 1828690Notes

Reaction equation

HRID 1828690 reaction equation
[CH3:1][C:2]1[C:6]([C:7]([O:9]CC)=[O:8])=[C:5]([CH3:12])[NH:4][C:3]=1C(OCC)=O>S(=O)(=O)(O)O>[C:7]([CH2:6][CH2:5][N:4]1[C:5]([CH3:12])=[C:6]([C:7]([OH:9])=[O:8])[C:2]([CH3:1])=[CH:3]1)([OH:9])=[O:8]

Participants

3

Reactant 1

HCID 75526Diethyl 2,4-dimethylpyrrole-3,5-dicarboxylate

Product 1

HCID 220580172-Carboxyethyl-3,5-dimethyl-1H-pyrrole-4-carboxylic acidYield 157.7%

Reagents, catalysts & solvents 1

HCID 1118Sulfuric AcidSolvent

Procedure

3,5-Dimethyl-2,4-pyrrole dicarboxylic acid, diethyl ester (200 g, 836 mmol) was placed in a 1 L beaker and treated with 400 mL concentrated sulfuric acid (H2SO4). The mixture was stirred, heated to 45 C with the aid of a heat gun and then maintained at 36–42 C for 25 minutes. The reaction mixture was poured into 3 L crushed ice and stirred for 30 minutes. The yellow solid was recovered by filtration and washed with 200 mL water. The solid was transferred to a 4 L Erlenmeyer flask and treated with 2 L 1 N sodium hydroxide solution (NaOH) followed by 100 mL 10 N NaOH. The basic mixture was filtered and the yellow solid residue was discarded. The filtrate was acidified with H2SO4. The resulting solid was recovered by suction filtration and washed with 2×500 mL water. After suction drying, the material was transferred to a 6 L Erlenmeyer flask and digested briefly in 4 L acetone. After standing overnight at room temperature (RT), the solid was collected by filtration and dried in a vacuum dessicator to afford 139 g, 659 mmol, 79% of the title compound. 1H NMR (DMSO-d6) δ 4.22 (q, 2H), 2.44 (s, 3H), 2.38 (s, 3H), 1.27 (t, 3H).

Workup

  1. temperatureheated to 45 C with the aid of a heat gun
  2. temperaturemaintained at 36–42 C for 25 minutes
  3. additionThe reaction mixture was poured into 3 L
  4. customcrushed ice
  5. stirringstirred for 30 minutes
  6. filtrationThe yellow solid was recovered by filtration
  7. washwashed with 200 mL water
  8. additiontreated with 2 L 1 N sodium hydroxide solution (NaOH)
  9. filtrationThe basic mixture was filtered
  10. filtrationThe resulting solid was recovered by suction filtration
  11. washwashed with 2×500 mL water
  12. customAfter suction drying
  13. filtration(RT), the solid was collected by filtration
  14. customdried in a vacuum dessicator

Sources & evidence

ORD record
ord-8546147d1f9946c5b335b3623a92579b
Source dataset
uspto-grants-2006_06
Patent number
US07060703B2

Reaction notes

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