Abstract Knoevenagelcondensation of various aromatic and heteroaromatic aldehydes with active methylene compounds like methyl and ethyl cyanoacetate, malononitrile, and cyanoacetamide proceeds smoothly with stirring in water in the presence of 4 mol% of diammonium hydrogen phosphate. The reactions were carried out at room temperature in short periods with very simple workup procedure and good to high
<i>aza</i>-Wittig Reaction with Nitriles: How Carbonyl Function Switches from Reacting to Activating
作者:Hamidulla B. Tukhtaev、Konstantin L. Ivanov、Stanislav I. Bezzubov、Dmitry A. Cheshkov、Mikhail Ya. Melnikov、Ekaterina M. Budynina
DOI:10.1021/acs.orglett.8b04135
日期:2019.2.15
ketone) in aza-Wittig reactions. To demonstrate the synthetic utility of the obtained iminophosphazenes as N,N-binucleophiles, their transformations into pyrrole-fused systems, pyrrolo[1,2-a]imidazoles and pyrrolo[1,2-a][1,3]diazepines, were carried out.
通过在磷腈和腈官能团之间发生不寻常的氮杂-维蒂希反应并提供吡咯衍生的亚氨基磷腈,进行了α-EWG取代(吸电子基团,EWG)γ-叠氮基丁腈的转化。发现α-EWGs控制化学选择性,并取决于其性质,在氮杂-Wittig反应中充当CN基团活化剂(例如,酯,酰胺或腈)或竞争剂(例如,酮)。为了证明所得亚氨基磷腈作为N,N-双亲核试剂的合成效用,将其转化为吡咯稠合体系,即吡咯并[1,2- a ]咪唑和吡咯并[1,2- a ] [1,3]二氮杂s。执行。
Knoevenagel condensation catalyzed by novel Nmm-based ionic liquids in water
A series of novel N-methyl morpholine (Nmm) based ionic liquids with 1,2-propanediol group were synthesized and used as catalysts for Knoevenagel condensation at roomtemperature in water. Under the effect of the catalyst, various aldehydes or aliphatic ketones could react with a wide range of activated methylene compounds well, including malononitrile, alkyl cyanoacetate, cyanoacetamide, β-diketone
t-butoxide catalyses the title reaction between aromatic aldehydes and malononitrile or alkyl cyanoacetates. At ambient temperatures, this procedure specifically gives high yields of E olefinic Knoevenagel products.
Knoevenagel and Wittig-Horner reactions in solid-liquid systems, with magnesium oxide or zinc oxide as catalyst. When Wittig-Horner reaction is competitive with Knoevenagel reaction, the catalyst can be modified to give a highly selective reaction ; the addition of dimethylsulfoxide on MgO or heiamethylphosphoric triamide on ZnO gives more efficient catalysts for the Wittig-Homer reaction. The addition of a small