N,N-Diethylaniline → 4-Chloroimidazo[1,2-a]quinoxaline

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Reaction Steps

Compound 11 (1.4 g, 6.4 mmol) is solubilized in phosphorus oxychloride (24 ml), and N,N-diethylaniline (3.6 ml). The reaction mixture obtained is carried to reflux for approximately 2 h. The product is insoluble in POCl3 even after heating. The reaction is monitored by TLC, eluent: CH2Cl2/MeOH (95/5). TLC shows the presence of the end product, but also the appearance of breakdown products. The reaction mixture is dark brown in colour. The POCl3 is evaporated under vacuum. The residue is cooled in an ice bath before adding a little water and, dropwise, a saturated sodium bicarbonate solution to neutralize POCl3. A light yellow foam and a brown precipitate appear. The solid is isolated by filtration and is recrystallized in methanol. A beige solid (0.97 g, 75%) is obtained; 1H NMR (300 MHz, DMSO-d6) δ: 8.5 (s, 1H, N—CH—C), 8.06 (d, 1H, ArH), 7.56 (s, 1H, C—CH—N), 7.35 (m, 1H, ArH), 7.25 (m, 2H, ArH). Analysis calculated for C10H6N3C1: C, 58.98; H, 2.97; N, 20.64. Experimental: C, 59.12; H, 2.76; N, 20.45.

Provenance & Evidence