1,1,3,3-四甲基二硅氧烷(TMDS)和聚甲基氢硅氧烷(PMHS)与异丙醇钛(IV)结合使用时,提供了两个方便的系统,可将腈还原为相应的伯胺。通过1 H NMR研究了这两个系统的动力学,结果表明,用PMHS进行还原的速度比用TMDS进行还原的速度更快。在存在Br,CC,NO 2的情况下,这两个钛基体系同时还原芳族和脂肪族腈,OH和环丙基环。在环丙基腈的情况下,观察到由于分子间还原性烷基化反应而形成的仲胺。该结果被用于还原二腈,其通过分子内还原性烷基化反应一步一步导致了氮杂环庚烷,哌啶,吡咯烷和氮杂环丁烷衍生物。
Practical Way to Imidazo[4,5-b] and [4,5-c]Pyridine-2-ones via Cascade Ureidation/Palladium-Catalyzed Cyclization
作者:Franck Lach、Patrice Koza
DOI:10.1021/co300078f
日期:2012.9.10
We developed an efficient one-pot tandem carbamoyl chloride amination and palladium-catalyzed intramolecular urea cyclization, which furnished high-throughput access to imidazo[4,5-b]pyridine-2-one and related imidazo[4,5-c]pyridine-2-one ring systems. Moderate to excellent yields were reported.
GARIGIPATI, RAVI S., TETRAHEDRON LETT., 31,(1990) N4, C. 1969-1972