Nitric Acid → Methyl-4-nitropyrrole-2-carboxylic acid

HRID 908138Notes

Reaction equation

HRID 908138 reaction equation
[N+:1]([O-:4])(O)=[O:2].C[N:6]1[CH:10]=[CH:9][CH:8]=[C:7]1[C:11]([OH:13])=[O:12].[CH3:14]C(OC(C)=O)=O>>[CH3:14][C:8]1[C:9]([N+:1]([O-:4])=[O:2])=[CH:10][NH:6][C:7]=1[C:11]([OH:13])=[O:12]

Participants

4

Reactant 3

HCID 944Nitric AcidHCID 7918Acetic Anhydride2×HCID 814531-Methyl-2-pyrrolecarboxylic acid

Product 1

HCID 53700357Methyl-4-nitropyrrole-2-carboxylic acid

Conditions

Temperature
50 °C

Procedure

Acetic anhydride (8 mL) was treated with 70% nitric acid (1.6 mL) and the mixture heated to 50° C. for 15 minutes, then cooled to room temperature, and slowly added to a suspension of 1-methyl-2-pyrrolecarboxylic acid (2 g) in Ac2O (12 mL) and cooled to −25° C. The mixture was stirred at −15° C. for 0.5 hr, then the temperature was allowed to rise to ambient, and stirring was continued for 20 min. The mixture was again cooled to −25° C. and the resulting precipitate was collected in a funnel cooled on dry ice. The solid was washed with a small amount of cold Ac2O (−25° C.), and then dissolved in 1M NaOH solution. Acidification with 1M HCl precipitated the compound. Yield (0.77 g, 28%). 1H NMR (DMSO): δ 8.19 (d, 1H, J=1.8 Hz); 7.23 (d, 1H, J=2.0 Hz); 3.90 (s, 3H).

Workup

  1. temperaturecooled to room temperature
  2. temperaturecooled to −25° C
  3. stirringstirring
  4. waitwas continued for 20 min
  5. temperatureThe mixture was again cooled to −25° C.
  6. customthe resulting precipitate was collected in a funnel
  7. temperaturecooled on dry ice
  8. washThe solid was washed with a small amount of cold Ac2O (−25° C.)
  9. dissolutiondissolved in 1M NaOH solution
  10. customAcidification with 1M HCl precipitated the compound
  11. customYield (0.77 g, 28%)

Sources & evidence

ORD record
ord-7c9d868017804b47a9fe50eb48ab3b82
Source dataset
uspto-grants-2011_09
Patent number
US08017599B2

Reaction notes

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