Chlorotrimethylsilane → 4-(10-methyl-4,5-dihydro-4-oxo-10H-imidazo[1,2-a]indeno[1,2-e]pyrazin-10-yl)-butyronitrile

Participants

Reaction Steps

The process is performed as in Example 50 for the preparation of ethyl 5-(10-methyl-4,5-dihydro-4-oxo-10H-imidazo[1,2-a]indeno[1,2-e]pyrazin-10-yl)-valerate but starting with 1.42 g of 10-methyl-5H,10H-imidazo[1,2-a]indeno[1,2-e]pyrazin-4-one, 75 ml of dimethylformamide, 1 g of sodium hydride, 0.84 ml of trimethylsilyl chloride and 0.76 ml of 4-bromo-butyronitrile. The product is first purified by crystallization from acetonitrile, then by heating of the crystals to reflux in an ethyl acetate/methanol mixture (9/1 by volume). After allowing to stand for 2 hours at a temperature in the region of 20° C., the suspension is filtered and the solid is washed with ethyl acetate and dried at 60° C. under vacuum (1 mmHg; 0.13 kPa). 0.83 g of 4-(10-methyl-4,5-dihydro-4-oxo-10H-imidazo[1,2-a]indeno[1,2-e]pyrazin-10-yl)-butyronitrile is obtained in the form of an off-white solid melting above 260° C. (Analysis, % calculated C: 71.04, H: 5.30, N: 18.41, O: 5.26, % found C: 70.7, H: 5.5, N: 18.6).

Provenance & Evidence