Nitric Acid → HCID 10333535, compound

Participants

Reaction Conditions

Reaction Steps

20 g of 5,6-dihydro-2-methyl-4H-pyrrolo[3,2,1-ij]-quinoline-1-acetic acid (prepared by hydrolysis of its ethyl ester obtained by Example 1C)) were cautiously added to 50 ml of sulfuric acid cooled to 0° C. The nitrating acid (=mixture of 5.56 ml of concentrated sulfuric acid and 4.04 ml of concentrated nitric acid) was then added cautiously. The reaction mixture was allowed to react at a temperature of 0° C. for 1 hour and at room temperature for 2 hours. To work up the reaction mixture, it was added to 200 g of ice, and a precipitate formed. The reaction mixture was extracted with dichloromethane, and a part of the precipitate which formed dissolved in the dichloromethane phase. The dichloromethane phase was separated, and the residual precipitate which remained in the aqueous phase was filtered out, washed with water and dried. 7.54 g of 5,6-dihydro-2-methyl-8-nitro-4H-pyrrolo-[3,2,1-ij]quinoline-1-acetic acid were obtained as a greenish-yellow powder. The dichloromethane phase was washed with water, dried and concentrated. The residue which remained, which further contained acid in addition to oily impurities, was treated with about 25 ml of ethanol to remove the oily impurities and filtered. A further 3.23 g of the acid were thus obtained, so that the total yield was 10.8 g.

Provenance & Evidence