Hydrochloric Acid → Ethyl 2,4-dimethyl-1H-pyrrole-3-carboxylate

HRID 2101617Notes

Reaction equation

HRID 2101617 reaction equation
[CH2:1]([O:3][C:4]([C:6]1[C:7]([CH3:19])=[C:8](C(OC(C)(C)C)=O)[NH:9][C:10]=1[CH3:11])=[O:5])[CH3:2].C(O)C.Cl>O>[CH2:1]([O:3][C:4]([C:6]1[C:7]([CH3:19])=[CH:8][NH:9][C:10]=1[CH3:11])=[O:5])[CH3:2]

Participants

5

Reactant 3

HCID 313Hydrochloric AcidHCID 702EthanolHCID 43476602-Tert-butyl 4-ethyl 3,5-dimethyl-1h-pyrrole-2,4-dicarboxylate

Product 1

HCID 137481Ethyl 2,4-dimethyl-1H-pyrrole-3-carboxylateYield 87.2%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Conditions

Temperature
54 °C

Procedure

3,5-Dimethyl-1H-pyrrole-2,4-dicarboxylic acid 2-tert-butyl ester 4-ethyl ester (2600 g) and ethanol (7800 mL) were stirred vigorously while 10 N hydrochloric acid (3650 mL) was slowly added. The temperature increased from 25° C. to 35-C and gas evolution began. The mixture was warmed to 54° C. and stirred with further heating for one hour at which time the temperature was 67° C. The mixture was cooled to 5° C. and 32 L of ice and water were slowly added with stirring. The solid was collected by vacuum filtration and washed three times with water. The solid was air dried to constant weight to give of 2,4-dimethyl-1H-pyrrole-3-carboxylic acid ethyl ester (1418 g, 87% yield) as a pinkish solid. 1H-NMR (dimethylsulfoxide-d6) δ 2.10, 2.35 (2×s, 2×3H, 2×CH3), 4.13 (q, 2H, CH2), 6.37 (s, 1H, CH), 10.85 (s, 1H, NH). MS m/z 167 [M+1].

Workup

  1. additionwas slowly added
  2. temperaturewith further heating for one hour at which time the temperature
  3. customwas 67° C
  4. temperatureThe mixture was cooled to 5° C.
  5. stirringwith stirring
  6. filtrationThe solid was collected by vacuum filtration
  7. washwashed three times with water
  8. customdried to constant weight

Sources & evidence

ORD record
ord-73dafd05afce4f719eff3a9cdb08f2d7
Source dataset
uspto-grants-2009_08
Patent number
US07572924B2

Reaction notes

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