Water → 10-benzenesulphonamido-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 -10° C., are successively added 0.29 g of benzenesulphonyl chloride and a solution of 0.4 g of triethylamine in 2 ml of anhydrous dimethylformamide and the mixture is stirred for 1 hour 30 minutes at the same temperature. 0.29 g of benzenesulphonyl chloride is added and the mixture is stirred for 2 hours 30 minutes, while allowing the temperature to rise gradually to 10° 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 (1.72 g) is dissolved in 6 ml of acetic acid at 40° C. and, after addition of 40 ml of distilled water, the solution is stirred for 1 hour. 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. 0.19 g of 10-benzenesulphonamido-5H,10H-imidazo[1,2-a]indeno-[1,2-e]pyrazin-4-one is thus obtained, melting at 216° C. [N.M.R. spectrum: [300 MHz; (CD3)2SO d6 ; δ in ppm]: 5.71 (d, J=8.5 Hz, 1H: --CH-- 10); 6.34 and 7.77 (2d broad, J=8 Hz, 1H each: --H6 and --H9); 7.08 and 7.36 (2t broad, J=8 Hz, 1H each: --H7 and --H8); 7.56 and 7.74 (2s, 1H each: --H of the imidazole); 7.68 (t, J=7.5 Hz, 2H: --H at 3 and --H at 5 of the phenylsulphonyl); 7.78 (t, J=7.5 Hz, 1H: --H at 4 of the phenylsulphonyl); 7.95 (d, J=7.5 Hz, 2H: --H at 2 and --H at 6 of the phenylsulphonyl); 8.62 (d, J=8.5 Hz, 1H: --NHCO-- at 10); 12.46 (broad s, 1H: --CONH-- of the ring)].

Provenance & Evidence