6-CHLORO-4-HYDROXYQUINOLINE

off White powder

Add 6-chloro-4-oxo-2, 3-dihydroquinoline (0.01 mol) to a 25 ml reaction flask, add 15 ml of acetonitrile, acetic acid (0.01 mol), stir for 20 minutes, and slowly add hydrogen peroxide (0.03). Mol), the reaction was stirred at 65 ° C, the progress of the reaction was monitored by TLC, and the reaction was stopped after 7 hours. After the reaction liquid is cooled to room temperature, it is poured into 50 ml of water, stirred and filtered to obtain a crude product of 5-dichloro-4-hydroxyquinoline, which is separated by silica gel column chromatography (column chromatography silica gel 100-200 mesh, eluent) Petroleum ether: ethyl acetate = 1:4), and the eluent was concentrated to give the product. The yield was 88percent, and the purity was 96percent;A mixture of 2, 2-dimethyl-1, 3-dioxane-4, 6-dione (Meldrum's acid, 21.62 g, 0.15 mol) and trimethyl orthoformate (150 mL) was heated to a gentle reflux under nitrogen for 1 hour. The resulting red solution was cooled (80° C.) and 4-chloroaniline (19.14 g, 0.15 mol) was added portionwise resulting in the formation of a yellow solid. The reaction mixture was heated to reflux, stirred vigorously for an additional hour, and then cooled to 25° C. (see Ryan et al. (2006) Org. Lett. 8:2779-2782; Madrid et al. (2005) Bioorg. Med. Chem. Lett. 15:1015-1018). The resulting solid was filtered and washed with cold acetone to afford the ene-amine compound (29.58 g, 70percent, mp. 214-214.5° C. (dec.)) as yellow solid which was characterized by