Alpha, beta- and beta, gamma-difluoropyridine compounds are prepared by contacting a beta-halo- alpha- or gamma-fluoropyridine compound or suitable precursor thereof with an effective amount of KF or CsF in a polar aprotic solvent (diluent) at an elevated temperature under substantially anhydrous conditions with removal of the difluoropyridine products essentially as they are formed. The starting material may optionally be added as the reaction proceeds to minimize decomposition. The reaction is also optionally conducted in the presence of an acid scavenger and/or a crown ether or other phase-transfer catalyst.
α、β和β、γ-二
氟吡啶化合物的制备方法是:在极性无
水溶剂(稀释剂)中,将β-卤代-α-或γ-
氟吡啶化合物或其适当前体与有效量的 KF 或 CsF 在高温下接触,基本上在形成二
氟吡啶产物时将其除去。 在反应进行过程中可选择加入起始原料,以尽量减少分解。 该反应还可选择在酸清除剂和/或
冠醚或其他相转移催化剂存在下进行。