4-Pyridinecarboxaldehyde → 10-(4-pyridylmethylene)-5H,10H-imidazo[1,2-a]indeno[1,2-e]pyrazin-4-one

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Reaction Steps

The procedure is performed as in Example 17 for the preparation of 10-(2-furylmethylene)-5H,10H-imidazo[l,2-a]indeno[1,2-e]pyrazin-4-one, but starting with 2 g of 5H,10H-imidazo[1,2-a]indeno[1,2-e]pyrazin-4-one, 40 ml of dimethyl sulphoxide, 0.64 g of sodium hydride and 1.07 g of 4-pyridinecarboxaldehyde. The crude product (1.5 g) is purified by crystallization in 100 ml of dimethylformamide and 50 ml of methanol to give 1.06 g of 10-(4-pyridylmethylene)-5H,10H-imidazo-[1,2-a]indeno[1,2-e]pyrazin-4-one, in the form of an orange solid melting above 260° C. (Analysis % calculated C: 73.07, H: 3.87, N: 17.94, O: 5.12, % found C: 72.9, H: 3.7, N: 18.2).

Provenance & Evidence