反应详情

A suspension of 9-hydroxy-9H-indeno[1,2-b]pyrazine-2,3(1H, 4H)-dione. 1H2O (0.50 g, 2.13 mmol) in benzene (20 ml), 2-methoxyethanol (10 ml) and p-toluensulfonic acid (20 mg) was refluxed with water separation for 20 hours. The reaction mixture was evaporated in vacuo to dryness, the residue was suspended in ethanol (10 ml) and the precipitate was filtered off and washed with ethanol and dried to give 0.48 g of the crude product, which was recrystallized from ethanol to yield 0.35 g (60%) of the title compound. M.p.>300° C. 1 -NMR (DMSO-d6, δ): 3.22 (s, 3H), 3.27-3.51 (m, 4H), 5.24 (s, 1H), 7.18 (t, 1H), 7.33 (t, 1H), 7.42 (d, 1H), 7.5 (d, 1H), 12.06 (s, 1H), 12.29 (s, 1H).

1. customThe reaction mixture was evaporated in vacuo to dryness
2. filtrationthe precipitate was filtered off
3. washwashed with ethanol
4. customdried
5. customto give 0.48 g of the crude product, which
6. customwas recrystallized from ethanol