Disclosed are preferred processes for preparing a 2-halo-5-halomethylpyridine compound. The preferred processes involve cyclocondensing a 2-halo-2-halomethyl aldehyde or ketone of the formula (II) ##STR1## to form a 2-halo-2-halomethylpyridine compound of the formula (III) ##STR2## wherein X is Cl or Br, Y is a cyano group or an aminocarbonyl group, and R, R.sup.1, R.sup.2 and R.sup.3 are, independently, H or an organic radical which does not interfere with the cyclocondensation.
本发明公开了制备2-卤代-5-卤
甲基吡啶化合物的优选过程。该优选过程涉及将式(II)的2-卤代-2-卤甲基醛或酮环缩合,形成式(III)的2-卤代-2-卤
甲基吡啶化合物,其中X为Cl或Br,Y为
氰基或
氨基甲酰基,而R、R.sup.1、R.sup.2和R.sup.3独立地为H或不干扰环缩合的有机基团。