Ethanol → HCID 19610839, compound

Participants

Reaction Steps

2.72 g (28.88 mmol, 2.4 eq) of 2-aminopyridine are added twice to a suspension of 4.00 g (12.12 mmol, 1 eq) of 2,3-dibromo-1,4-dihydro-1,4-dioxo-5-methylnaphthalene in 500 mL of ethanol. This mixture is brought to reflux for 48 h. After cooling to ambient temperature, the ethanol is eliminated by evaporation under reduced pressure. The 2,3-dibromo-1,4-dihydro-1,4-dioxo-5-methylnaphthalene that did not react is eliminated by precipitation in a CH2Cl2 /heptane, 80/20 mixture. The raw product is purified by chromatography on a preparation plate (support: silica SIL G-200 UV254 2 mm; eluant: CH2Cl2 /EtOH, 97/3) to produce 6,11-dihydro-6,11-dioxo-7-methylnaphtho[2',3':4,5] imidazo-[1,2-a]pyridine or 6,11-dihydro-6,11-dioxo-10-methylnaphtho[2',3':4,5]imidazo[1,2-a]pyridine or 5,6-dihydro-5,6-dioxo-4-methylnaphtho[1',2':4,5]-imidazo[1,2-a]pyridine in the form of yellowish-orange crystals.

Provenance & Evidence