反应详情

0.27 g (0.0010 mol) of 4-azidomethyl-2-hydroxy-quinoline-3-carboxylate was dissolved in 20 ml of hot dimethylformamide and treated with 14 mg of 10% Pd/C. A stream of hydrogen was introduced slowly during 11/2 hrs. The suspension was filtered under argon and the filtrate was partially concentrated under a high vacuum. The residue was treated with 25 ml of de-gassed ethanol, filtered off, dried in a vacuum and there were obtained ~60 mg (30%) of 4-hydroxy-2,3-dihydro-1 H-pyrrolo[3,4-c]quinolin-3-one as an air-sensitive, grey solid. The mother liquor was concentrated totally. The residue was dissolved in 75 ml of methanol and a stream of oxygen was conducted in slowly during 21/2 hrs. The mixture was filtered, concentrated, chromatographed over silica gel with ethyl acetate/methanol 9:1 as the eluent and the product was recrystallized from hot ethyl acetate. Yield: 0.033 g (15%) of 4-hydroxy-2,3-dihydro-1H-pyrrolo[3,4-c]-quinoline-1,3-dione as yellow crystals; m.p. 340°-350° C. (dec., subl.).

1. filtrationThe suspension was filtered under argon
2. concentrationthe filtrate was partially concentrated under a high vacuum
3. additionThe residue was treated with 25 ml of de-gassed ethanol
4. filtrationfiltered off
5. customdried in a vacuum