Fluoropyridine compounds having a fluoro substituent in at least one of the 2-, 4-, and 6-positions are prepared by treatment of an appropriate 2-, 4-, or 6-chloropyridine compound with excess hydrogen fluoride in a dipolar, aprotic solvent at an elevated temperature and super-atmospheric pressure. Thus, 3,5-dichloro-2,4,6-trifluoropyridine is prepared by heating a mixture of pentachloropyridine, N-methyl-2-pyrrolidinone, and hydrogen fluoride at about 220°C and about 900 kiloPascals of pressure.
在 2、4 和 6 位中至少一个位置上具有
氟取代基的
氟吡啶化合物,是通过在双极性、无相溶剂中,在高温和超大气压下,用过量
氟化氢处理适当的 2、4 或 6-
氯吡啶化合物制备的。因此,3,5-二
氯-2,4,6-三
氟吡啶是通过在约 220°C 和约 900 千帕斯卡压力下加热五
氯吡啶、N-甲基-
2-吡咯烷酮和
氟化氢的混合物制备的。