Nitric Acid → Methyl-4-nitropyrrole-2-carboxylic acid
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
Procedure
Acetic anhydride (8 ml) and nitric acid (70%, 1.6 mL) were heated to 50° C. for 15 minutes and cooled to room temperature. The solution was then slowly added to a suspension of 1-methyl-2-pyrrolecarboxylic acid (2.0 g, 0.02 mol) in Ac2O (12 ml) cooled to −25° C. The mixture was stirred for 30 min at −15° C., warmed to room temperature and stirred for another 20 min. The mixture was again cooled to −25° C. and the resulting precipitate collected in a funnel cooled with dry ice. The solid was washed with cold Ac2O (−25° C.), followed by Ac2O:CCl4 (1:1, −25° C.), and then CCl4 and hexane. The yellow solid was dissolved in NaOH (1M) and acidified with HCl to yield the product as a light cream solid which was collected and air-dried. Yield 0.98 g (36%). 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
- temperaturecooled to −25° C
- temperaturewarmed to room temperature
- stirringstirred for another 20 min
- temperatureThe mixture was again cooled to −25° C.
- customthe resulting precipitate collected in a funnel
- temperaturecooled with dry ice
- washThe solid was washed with cold Ac2O (−25° C.)
- customfollowed by Ac2O:CCl4 (1:1, −25° C.)
- dissolutionThe yellow solid was dissolved in NaOH (1M)
Sources & evidence
- ORD record
- ord-805acd1d087d4f88a4eaf091789c5ce3
- Source dataset
- uspto-grants-2011_09
- Patent number
- US08017599B2
Reaction notes
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