Nitric Acid → 1-Methyl-4-nitropyrrole-2-carboxylic acid

Temperature

50 °C

Acetic anhydride (20 mL) was treated with nitric acid (4.0 mL, 70%) and the mixture heated to 50° C. for 15 min then cooled to room temperature, and slowly added to a suspension of 1-methyl-2-pyrrolecarboxylic acid (4 g, 15.98 mmol) in of Ac2O (12 mL) 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 precipitate collected in a funnel cooled with dry ice, the solid was washed with a small quantity of cold Ac2O (−25° C.). The crystalline solid was taken up in water containing NaOH (1 g). Acidification with the HCl precipitated the pure compound. NMR as previously reported.

1. temperaturethen cooled 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 precipitate collected in a funnel
7. temperaturecooled with dry ice
8. washthe solid was washed with a small quantity of cold Ac2O (−25° C.)
9. additioncontaining NaOH (1 g)
10. customAcidification with the HCl precipitated the pure compound

ORD record

ord-5abe4b5c60314b9781ad892dd1f06b1c

Source dataset

uspto-grants-2011_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08017599B2