作者:Elise Salanouve、Sandrine Guillou、Marine Bizouarne、Frédéric J. Bonhomme、Yves L. Janin
DOI:10.1016/j.tet.2012.02.057
日期:2012.4
β-unsaturated ketones were prepared. Upon addition of hydrazine, followed by iodination, 4-iodinated 3-methoxypyrazoles were obtained. The occurrence of a side compound also provided insights in the scope of this synthesis. In a second part, 1-(4-chlorophenyl)-3,3-dimethoxyprop-2-en-1-one was obtained from 1,1-dimethoxyethene and 4-chlorobenzoylchloride. The subsequent addition of hydrazine or phenylhydrazine
通过1,1-二甲氧基乙烯与酸酐的缩合反应,可制得合成上有用的β,β-二甲氧基-α,β-不饱和酮。加入肼后,进行碘化,得到4-碘化的3-甲氧基吡唑。副化合物的出现也为该合成的范围提供了见识。在第二部分中,从1,1-二甲氧基乙烯和4-氯苯甲酰氯获得1-(4-氯苯基)-3,3-二甲氧基丙-2-烯-1-酮。随后加入肼或苯肼得到5-(4-氯苯基)-3-甲氧基-1 H-吡唑或1-苯基-5-(4-氯苯基)-3-甲氧基吡唑,空前的总收率为64或54%。出乎意料的是,加入2-吡啶肼导致了2-([1,2,4]三唑并[4,3-a]吡啶-3-基)-1-(4-氯苯基)乙酮。这导致我们设计了原始条件,从而以39%的总收率得到了目标1-(2-吡啶基)-5-(4-氯苯基)-3-甲氧基吡唑。从各种羧氯化物开始,提供了另外的实例。