Ethanol → HCID 19610833, compound

Participants

Reaction Steps

2.72 g (28.88 mol, 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-6-methylnaphthalene (No. CAS 72364-92-2) 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-6-methylnaphthalene that had not reacted is eliminated by precipitation in a CH2Cl2 /heptane, 70/30 mixture. The raw product is purified by two successive chromatographies on a preparation plate (support: silica SIL G-200 UV254 2 mm; eluant first plate: CH2Cl2 /MeOH, 97/3, and eluant second plate: heptane/AcOEt, 50/60) to produce 6,11-dihydro-6,11-dioxo-8-methylnaphtho[2,,3':4,5]imidazo[1,2-a]pyridine, 6,11-dihydro-6,11-dioxo-9-methylnaphtho[2',3':4,5]imidazo[1,2-a] pyridine, 5,6-dihydro-5,6-dioxo-2-methylnaphtho[1',2':4,5] imidazo[1,2-a]pyridine or 5,6-dihydro-5,6-dioxo-3-methylnaphth [1',2':4,5]imidazo[1,2-a]pyridine in the form of orange crystals.

Provenance & Evidence