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

Participants

Reaction Conditions

Reaction Steps

To a suspension of 0.6 g of 10-amino-5H,10H-imidazo[1,2-a]indeno[1,2-e]pyrazin-4-one hydrochloride in 30 ml of anhydrous dimethylformamide, maintained under a nitrogen atmosphere at a temperature in the region of 0° C., are successively added 0.22 g of propionyl chloride and 0.4 g of triethylamine. The mixture is stirred for 3 hours 30 minutes and 0.22 g of propionyl chloride is added. The mixture is stirred for 1 hour at the same temperature and for 16 hours at a temperature in the region of 20° C. The insoluble material formed is removed by filtration and the filtrate is concentrated to dryness under reduced pressure (10 mmHg; 1.3 kPa) at 100° C. The product obtained (1.14 g) is dissolved at 40° C. in 10 ml of acetic acid and, after addition of 50 ml of distilled water, the solution is stirred for 1 hour at a temperature in the region of 20° C. The insoluble material formed is separated out by filtration, washed twice with 4 ml in total of distilled water and dried under reduced pressure (1 mmHg; 0.13 kPa) at 100° C. 0.26 g of 10-propionamido-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: [200 MHz; (CD3)2SO d6 ; δ in ppm]: 1.14 (t, J=7.5 Hz, 3H: --CH3 ethyl); 2.28 (q, J=7.5 Hz, 2H: --COCH2 -ethyl); 6.18 (d, J=8.5 Hz, 1H: --CH-- 10); 7.38 and 7.48 (2t broad, J=8 Hz, 1H each: --H7 and --H8); 7.52 and 7.88 (2d broad, J=8 Hz, 1H each: --H6 and --H9); 7.60 and 7.62 (2s, 1H each: --H of the imidazole); 8.48 (d, J=8.5 Hz, 1H: --NHCO-- at 10); 12.43 (broad a, 1H: --CONH-- of the ring)].

Provenance & Evidence