Phenylacetyl chloride → 10-phenylacetamido-5H,10H-imidazo[1,2-a]indeno[1,2-e]-pyrazin-4-one

Participants

Reaction Steps

To a suspension of 0.55 g of 10-amino-5H,10H-imidazo[1,2-a]indeno[1,2-e]pyrazin-4-one hydrochloride in 30 ml of anhydrous dimethylformamide are added successively, at a temperature in the region of 5° C., 0.63 g of phenylacetyl chloride and, over 5 minutes, a solution of 0.4 g of triethylamine in 2 ml of anhydrous dimethylformamide. After stirring for 1 hour at the same temperature and then for 30 minutes at 20° C., the insoluble product formed is isolated by filtration and washed twice with 3 ml in total of dimethylformamide. The filtrate and the washing are combined, 80 ml of distilled water are added and the insoluble product formed is isolated by filtration, washed twice with 2 ml in total of distilled water and then air-dried. The product obtained (0.27 g) is suspended for 5 minutes in 3 ml of boiling methanol and, after cooling and storing for 1 hour at 5° C., the solid formed is isolated by filtration, washed twice with 1 ml in total of methanol and dried under reduced pressure (5 mmHg; 0.65 kPa) at 60° C. 0.16 g of 10-phenylacetamido-5H,10H-imidazo[1,2-a]indeno[1,2-e]-pyrazin-4-one is thus obtained, decomposing without melting above 260° C. (NMR spectrum: [300 MHz; (CD3)2SO-d6 ; δ in ppm): 3.56 (s, 2H: Ar--CH2 --CO--); 6.12 (d, J=8.5 Hz, 1H: --CH-- 10); from 7.25 to 7.60 (mt, 7H: --H of the phenyl --H 7 and --H 8); 7.38 and 7.48 (2s, 1H each: --H of the imidazole); 7.45 and 7.86 (2 broad d, J=8 Hz, 1H each: --H 6 and --H 9); 8.83 (d, J=8.5 Hz, 1H: --NHCO-- at 10); 12.50 (broad s, 1H: --CONH-- of the ring)).

Provenance & Evidence