Hydrochloric Acid → 4-Isobutylamino-3-nitroquinoline

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Reaction Steps

To 50.0 g (0.269 mole) of 4-hydroxy-3-nitroquinoline in 300 ml of N,N-dimethylformamide in a 500 ml erlenmeyer flask was added, gradually, 44.3 g (0.2892 mole) of phosphorus oxychloride. The resulting mixture was heated on a steam bath for about 15 minutes, and was then poured onto ice with stirring. After neutralization with saturated sodium bicarbonate solution, the resulting light-colored solid was separated by filtration and washed sequentially with a saturated sodium bicarbonate solution and water. The solid was dissolved in methylene chloride and the solution obtained was dried over sodium chloride, filtered and transferred to a 2 l erlenmeyer flask. Triethylamine (159.6 g, 1.577 moles) was added at one time, followed by the slow addition of 21.2 g (0.2892 mole) of isobutylamine. After the isobutylamine had been added, the mixture was heated on a steam bath for about 30 minutes. The methylene chloride was removed by rotary evaporation. Water was added to the residue obtained, and concentrated hydrochloric acid was subsequently added to dissolve the residue. The solution was filtered, and the filtrate was brought to pH 8-9 with concentrated ammonium hydroxide. The resulting yellow solid was filtered, washed with water, and dried to provide 73.4 g of crude 4-isobutylamino-3-nitroquinoline, m.p. 114°-118° C. The product was further purified by recrystallization from ethanol.

Provenance & Evidence