Kinetics and mechanism of the addition of benzylamines to β-nitrostilbenes and β-cyano-4′-nitrostilbenes
作者:Hyuck Keun Oh、Tae Soo Kim、Hai Whang Lee、Ikchoon Lee
DOI:10.1039/b108021k
日期:2002.1.23
addition in acetonitrile is the direct resonance effect (σ− or R−) while that in aqueous solution is the polar electron-withdrawing effect (σ) of the activating groups. Due to stericinhibition the β-phenyl rings in NSB and CNS are prevented from π-overlap with the anionic center in the TS so that the reduced resonance effect leads to unduly low addition rates. The kinetic isotope effects and activation
Catalyst-free chemoselective reduction of the carbon–carbon double bond in conjugated alkenes with Hantzsch esters in water
作者:Qi He、Zhihong Xu、Dehong Jiang、Wensi Ai、Ronghua Shi、Shan Qian、Zhouyu Wang
DOI:10.1039/c3ra48072k
日期:——
A simple, efficient and green protocol for chemoselective reduction of carbon–carbon doublebond in conjugated alkenes with Hantzsch esters is described. Without any additional catalysts, a series of conjugated alkenes with strong electron-withdrawing groups were reduced in water with excellent yield. Functional groups such as nitrile, ester, nitro, fluoro, chloro, bromo, furanyl and benzyl are all
Synthesis of Novel Highly Conjugated α-Cyanostilbene and Dibenzoxanthene Derivatives
作者:Z. M. Al-Amshany、Z. Kaabi、R. M. El-Shishtawy、N. Tashkandi
DOI:10.1134/s107036322311021x
日期:2023.11
were synthesized in good yields. A one-pot reaction between 2-naphthol and furan-2,5-dicarbaldehyde led to the formation of the corresponding dibenzoxanthenederivative. The latter underwent Knoevenagel condensation with a variety of methylene active derivatives to afford the corresponding 5-(14H-dibenzo[a,j]xanthen-14-yl)furan-2-carbaldehydes. Knoevenagel condensation was also applied to synthesize