The lithiated β-amino-β-substituted acrylonitriles 4a-d generated in situ by reaction of lithioacetonitrile with either acetonitrile or substituted nitriles undergo cyclocondensation with α-oxoketenedithioacetals through 1,4-addition to afford 2,6-substituted and 5,6-annelated-4-(methylthio)-3-cyanopyridines 6a-m, 11a-h and 12a-b in good yields. A few of the 2,6-diheterylpyridines 6n-q were also synthesized
通过
硫代
乙腈与
乙腈或取代的腈反应原位生成的
锂化的β-
氨基-β-取代的
丙烯腈4a-d通过1,4-加成与α-
氧杂环丁二
硫缩醛进行环缩合,得到2,6-取代的和5,6-使4-(甲
硫基)-3-
氰基吡啶6a-m,11a-h和12a-b退火。按照该方法,还合成了一些
2,6-二杂基
吡啶6n-q。另一方面,将相应的α-肉桂酰基12a-c和α-(5-芳基-
2,4-
戊二烯酰基)(12d)
酮二
硫缩醛与4a环合,得到相应的4-芳基-(或4-
苯乙烯基-6- [2-双(甲
硫基)
乙烯基] -3-
氰基吡啶14a-d具有良好的产率。