反应详情

温度

100 °C

A solution of 2.3 g of 3,7-dimethyl-4-oxo-5H, 10H-imidazo[1,2-a]indeno[1,2-e]pyrazinium bromide in 15 g of imidazole is stirred under a nitrogen atmosphere for 20 hours at 160° C., cooled to 100° C. and then poured over 60 g of a mixture of distilled water and ice. The insoluble matter is separated by filtration, washed twice with a total of 10 ml of distilled water and with 5 ml of ethyl ether and then air dried. The product (1.7 g) is chromatographed on 100 g of neutral silica gel (0.020-0.045 mm) contained in a column 3.2 cm in diameter, eluting under pressure with a dichloromethane-methanol mixture (97-7 by volume) and collecting 10-ml fractions. The fractions 35 to 182 are pooled and concentrated to dryness under reduced pressure (15 mmHg; 2 kPa) at 40° C. The product obtained (0.6 g) is dissolved in a boiling mixture of 64 ml of dimethylformamide and 16 ml of distilled water and the solution, supplemented with decolorizing charcoal, is filtered hot, cooled and kept for 16 hours at 5° C. The crystals are separated by filtration, washed with 3 ml of distilled water and with 3 ml of ethanol and then dried under reduced pressure (1 mmHg; 0.13 kPa) at 60° C. 0.3 g of 7-methyl-5H, 10H-imidazo[1,2-a]indeno[1,2-e]pyrazin-4-one is thus obtained which decomposes without melting above 300° C. [NMR spectrum: (200 MHz; DMSO-d6 ; δ in ppm): 2.40 (s, 3H: Ar--CH3); 3.98 (s, 2H: --CH2-- in position 10); 7.15 (broad d, J=8 Hz 1H: --H8); 7.49 (d, J=8 Hz, 1H: --H9); 7.60 and 7.99 (2s broad, 1H each: --H of imidazole); 7.72 (broad s, 1H: --H6); 12.35 (unresolved complex, 1H: --CONH--)].

1. customThe insoluble matter is separated by filtration
2. washwashed twice with a total of 10 ml of distilled water and with 5 ml of ethyl ether
3. customair dried
4. customThe product (1.7 g) is chromatographed on 100 g of neutral silica gel (0.020-0.045 mm)
5. washeluting under pressure with a dichloromethane-methanol mixture (97-7 by volume)
6. customcollecting 10-ml fractions
7. concentrationconcentrated to dryness under reduced pressure (15 mmHg; 2 kPa) at 40° C
8. customThe product obtained (0.6 g)
9. filtrationis filtered hot
10. temperaturecooled
11. customThe crystals are separated by filtration
12. washwashed with 3 ml of distilled water and with 3 ml of ethanol
13. customdried under reduced pressure (1 mmHg; 0.13 kPa) at 60° C