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。
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
The synthesis of a small library of dihydrouracils spiro-fused to pyrrolidines is described. These compounds are synthesized from b-aryl pyrrolidines, providing products with the 2-arylethyl amine moiety, a structural feature often encountered in compounds active in the central nervous system. The b-aryl pyrrolidines are synthesized through a three-step methodology that includes a Knoevenagel condensation reaction, a 1,3-dipolar cycloaddition reaction, and a nitrile reduction.
A catalyst system of Sevelamer, a phosphate-binding drug, has been prepared and used in the Knoevenagel reaction of aromatic aldehydes in water to produce substituted electrophilic alkenes. The products were obtained in excellent yields. Several novel, related catalytic systems showed promising catalytic properties for aromatic and heterocyclic aldehydes. The Sevelamer catalyst can be recovered using simple filtration and reused numerous times (up to 15 times) in the aqueous Knoevenagel reaction without any significant lowering of activity. (C) 2014 Xian-Liang Zhao and Ke-Fang Yang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
Dihydrothiazine derivatives, their preparation, their inclusion in anthelmintic and pesticidal compositions and their use as anthelmintics and pesticides