Methane → 10-isobutyramido-5H,10H-imidazo[1,2-a]indeno[1,2-e]-pyrazin-4-one

Participants

Reaction Conditions

Reaction Steps

To a suspension of 1 g of 10-amino-5H,10H-imidazo[1,2-a]indeno[1,2-e]pyrazin-4-one hydrochloride in 50 ml of anhydrous dimethylformamide, maintained under an argon atmosphere at a temperature in the region of -10° C., are successively added 0.9 g of isobutyryl chloride and a solution of 0.4 g of triethylamine in 5 ml of anhydrous dimethylformamide. The mixture is stirred for 1 hour at the same temperature and 0.4 g of isobutyryl chloride is added. The mixture is stirred for 30 minutes at the same temperature and for 1 hour while allowing the temperature to return gradually to 20° C. The insoluble material formed is removed by filtration and the filtrate is concentrated to dryness under reduced pressure (15 mmHg; 2 kPa) at 70° C. The product obtained (1.63 g) is dissolved in 30 ml of methanol and, after addition of decolorizing charcoal, the solution is filtered, diluted with 40 ml of distilled water and stored for 45 minutes at a temperature in the region of 20° C. The insoluble material formed is separated out by filtration, washed with 5 ml of distilled water and with 5 ml of acetone and then dried under reduced pressure (1 mmHg; 0.13 kPa) at 100° C. 0.38 g of 10-isobutyramido-5H,10H-imidazo[1,2-a]indeno[1,2-e]-pyrazin-4-one is thus obtained, decomposing without melting above 260° C. [N.M.R. spectrum: [300 MHz; (CD3)2SO d6 ; δ in ppm]: 1.09 and 1.12 [2d, J=7.5 Hz, 6H: --CH(CH3)2 ]; 2.48 [mt, 1H: --CH(CH3)2 ]; 6.15 (d, J=8.5 Hz, 1H: --CH-- 10); 7.35 and 7.45 (2t broad, J=8.5 Hz, 1H each: --H7 and --H8); 7.47 and 7.85 (2d broad, J=8 Hz, 1H each: --H6 and --H9); 7.52 and 7.58 (2s, 1H each: --H of the imidazole); 8.46 (d, J=8.5 Hz, 1H: --NHCO-- at 10); 12.48 (broad s, 1H: --CONH-- of the ring)].

Provenance & Evidence