Convenient one-step synthesis of 4-unsubstituted 2-amino-4H-chromene-2-carbonitriles and 5-unsubstituted 5H-chromeno[2,3-b]pyridine-3-carbonitriles from quaternary ammonium salts
作者:Vitaly A. Osyanin、Dmitry V. Osipov、Yuri N. Klimochkin
DOI:10.1016/j.tet.2012.04.065
日期:2012.7
We have reported DBU catalyzed synthesis of 4-unsubstituted 2-amino-4H-chromene-2-carbonitriles in water under reflux. The attractive features of this process are mild reaction conditions, short reaction times, easy isolation of products and good yields. 5H-chromeno[2,3-b]pyridine-3-carbonitriles were obtained by refluxing excess of malononitrile and quaternary ammonium salts in ethanol in the presence
我们已经报道了DBU在回流下在水中催化4-未取代的2-氨基-4 H-亚甲基-2-腈的合成。该方法的吸引人的特征是反应条件温和,反应时间短,产物易于分离和产率高。在NaOH为催化剂的情况下,通过将过量的丙二腈和季铵盐在乙醇中回流,得到5 H -chromeno [2,3 - b ]吡啶-3-腈。据信这些反应的机理涉及邻醌甲基化物中间体的形成。