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

Participants

Reaction Conditions

Reaction Steps

A suspension of 5.75 g of 5H,10H-imidazo-[1,2-a]indeno[1,2-e]pyrazin-4-one, 10 g of sodium hydroxide pellets and 125 mg of tetrabutylammonium bromide in 200 ml of dimethyl sulphoxide is stirred at a temperature in the region of 20° C. 3.18 g of benzaldehyde are then added and the stirring is continued for 18 hours at a temperature in the region of 20° C. The reaction mixture is poured into a mixture of water and ice (250 ml) and acidified with 100 ml of acetic acid. The solid formed is filtered off and the crude product is purified by two successive chromatographies on a column of silica with a mixture of dichloromethane and methanol (90/10 by volume). 0.13 g of 10-benzylidene-5H,10H-imidazo[1,2-a]indeno-[1,2-e]pyrazin-4-one is thus obtained, in the form of a yellow solid melting above 260° C. (Analysis % calculated C: 77.16, H: 4.21, N: 13.50, O: 5.14, % found C: 76.7, H: 3.7, N: 13.2).

Provenance & Evidence