Treatment of 6-alkoxy-1,4,5,6-tetrahydropyridines with neutral alumina (activity grade I) suspended in refluxing acetonitrile, afforded 1,4-dihydropyridines in excellent yields. This method allowed the efficient synthesis of 5,6-unsubstituted dihydropyridines, which are difficult to prepare by traditional methods, from acyclic and readily available precursors.
                                    用悬浮在回流
乙腈中的中性氧化铝(活性等级I)处理6-烷氧基-
1,4,5,6-四氢吡啶,可获得高收率的1,4-
二氢吡啶。这种方法可以从无环且容易获得的前体中高效合成5,6-未取代
二氢吡啶,而传统方法很难制备这种化合物。