Hydrochloric Acid → 2,4,5,6-Tetrachloropyrimidine

関与物質

反応手順

242 g of molten 4,5,6-trichloro-2-trichloromethylpyrimidine are metered into a mixture, warmed to 75°-80° C., of 1,200 ml of water, 600 ml of 50% strength sodium hydroxide solution and 15 ml of an emulsifier solution over a heated dropping funnel in the course of 1.5 hours. A rise in temperature to 95° C. is to be observed as a result of exothermic heat of reaction. A clear amber-coloured solution results. After a further hour at 90°-95° C., the reaction solution is cooled and brought to pH 6 with hydrochloric acid. The product which has crystallised out is filtered off with suction, rinsed with about 70 ml of water and dried. 119 g (82% of theory) of a sand-coloured crystalline substance of melting point 302°-303° C. (decomposition) are obtained. The substance proves to be identical, by comparison of the IR and melting point, to 5,6-dichloro-2,4-dihydroxypyrimidine, which was obtained by hydrolysis of 2,4,5,6-tetrachloropyrimidine according to German Offenlegungsschrift 2,153,511. A small amount of 5,6-dichloro-4-hydroxy-2-pyrimidinecarboxylic acid is detectable in the filtrate.

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