Described are preferred processes for preparing alkenyl-substituted nitrogenous heterocycles such as vinylpyridines, which comprise reacting a corresponding methyl-substituted heterocycle with a C
1
compound such as formadehyde in the vapor phase over a zeolite catalyst having acidic and basic catalytic sites. The preferred zeolite is a medium-pore zeolite, for example having a constraint index of about 0.5 to about 12. Processes of the invention can be conducted as facile, one-step syntheses utilizing relatively low ratios of alkyl-substituted starting heterocycle (e.g. &agr;-picoline or &ggr;-picoline) to formaldehyde while nonetheless achieving high selectivities and yields of the corresponding alkenyl compound.
本文描述了制备烯基取代的含氮
杂环化合物,如
乙烯吡啶的首选方法,包括将相应的甲基取代的杂环与C1化合物(如
甲醛)在具有酸性和碱性催化位点的
沸石催化剂上在气相中反应。首选
沸石是中孔
沸石,例如具有约0.5至约12的约束指数。本发明的方法可以作为简便的一步合成进行,使用相对较低的烷基取代起始杂环(例如α-苯基
吡啶或γ-苯基
吡啶)与
甲醛的比例,同时实现相应烯基化合物的高选择性和产率。