Potassium Hydroxide → 9-chloro-6-imino-4-oxo-3-phenyl-6H-pyrido[2,1-a]isoindole-1-carboxylic acid

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Reaction Steps

3.5 g of 10-chloro-4-oxo-3-phenyl-4H-pyrido[2,1-a]-phthalazine-1-carboxylic acid were added to a solution of 5.6 g of potassium hydroxide in 60 ml of methanol, whereupon the mixture was heated to boiling under reflux for 25 hours. The solvent was then removed in a vacuum and the residue was taken up in 60 ml of water. The product was precipitated by the addition of 2N hydrochloric acid. The crystals were filtered off under suction, washed with water and dried in a vacuum. There was obtained 3.32 g of 9-chloro-6-imino-4-oxo-3-phenyl-6H-pyrido[2,1-a]isoindole-1-carboxylic acid as yellowish crystals with a m.p. of 266°-268° (decomposition).

Provenance & Evidence