2,5-Dimethoxytetrahydrofuran → HCID 18975396, compound

Participants

Reaction Conditions

Reaction Steps

To a suspension of 1.4 g of 10-amino-5H,10H-imidazo[1,2-a]indeno[1,2-e]pyrazin-4-one hydrochloride in 25 ml of acetic acid are added 0.41 g of anhydrous sodium acetate and 0.66 g of 2,5-dimethoxytetrahydrofuran. The mixture is stirred at boiling for 1 hour 30 minutes and, after cooling to 20° C., the solid formed is isolated by filtration, washed twice with 30 ml in total of distilled water and air-dried. The product obtained (2.45 g) is chromatographed on 25 g of neutral silica gel (0.06-0.20 mm) contained in a column 2.4 cm in diameter, eluting with a dichloromethane/methanol mixture (90/10 by volume) and collecting an 18 ml fraction and a 540 ml fraction. After addition of decolorizing charcoal, the latter fraction is filtered and the filtrate is concentrated to dryness under reduced pressure (15 mmHg; 2 kPa) at 40° C. The product obtained is suspended for 10 minutes in 5 ml of methanol and then isolated by filtration, washed with 1 ml of methanol and dried under reduced pressure (1 mmHg; 0.13 kPa) at 100° C. 0.6 g of 10-(1-pyrrolyl)-5H,10H-imidazo[1,2-a]indeno[1,2-e]pyrazin-4-one is thus obtained, decomposing without melting above 260° C. (NMR spectrum: [200 MHz; (CD3)2SO-d6 ; δ in ppm]: 6.12 (t, J=2 Hz, 2H: --H 3 and --H 4 of the pyrrole); 6.61 (s, 1H: --CH-- 10); 6.91 (t, J=2 Hz, 2H: --H 2 and --H 5 of the pyrrole); 7.08 and 7.34 (2 broad s, 1H each: --H of the imidazole); from 7.30 to 7.55 and 7.93 [mt and d respectively (J=7.5 Hz), 3H and 1H: --H 6, --H 7, --H 8 and --H 9]; 12.60 (broad s, 1H: --CONH--)).

Provenance & Evidence