Monocyclic 1,2,3-triazines have been allowed to react with silyl enol ether or ketene silyl acetal in the presence of 1-chloroethyl chloroformate to give 2-(1-chloroethoxycarbonyl)-5-substituted-2,5-dihydrotriazines in good yields. These dihydro adducts are oxidized by ceric ammonium nitrate in CH3CN–H2O to afford 5-substituted 1,2,3-triazines.
单环
1,2,3-三嗪在
氯甲酸 1-chloroethyl chloroformate 的存在下与
硅基
酚醚或酮基
硅基
缩醛反应,可以得到 2-(1-
氯乙氧羰基)-5-取代的-2,5-二氢三嗪,收率很高。这些二氢加合物在 CH3CN-
H2O 中被
硝酸铈铵氧化,得到 5-取代的
1,2,3-三嗪。