A Ag/P-stereogenic phosphine-complex-catalyzed 1,3-dipolarcycloaddition of azomethine ylides with electron-deficientolefins is reported. In this reaction, highly functionalized pyrrolines with a spiro-quaternary stereogenic center were obtained in good yields (up to 99%) with excellent levels of diastereo- (up to >20:1 dr) and enantioselectivities (up to >99% ee). The chirality of adducts was controlled
Anti-melanogenesis screening of 47 synthesized curcumin-like diarylpentanoid analogues was performed to show that some had a potent inhibitory effect on the melanogenesis in B16 melanoma cells. Their actions were considered to be mostly due to tyrosinase inhibition, tyrosinase expression inhibition, and melanin pigment degradation. The structure–activity relationships of those curcumin-like diarylpentanoid analogues which inhibited the melanogenesis and tyrosinase activity were also discussed. Of those compounds assayed, (2E,6E)-2,6-bis(2,5-dimethoxybenzylidene)cyclohexanone showed the most potent anti-melanogenesis effect, the mechanism of which is considered to be the degradation of the melanin pigment in B16 melanoma cells, affecting neither the tyrosinase activity nor tyrosinase expression.
Solvent-Free Crossed Aldol Condensation of Cyclic Ketones with Aromatic Aldehydes Assisted by Microwave Irradiation
作者:Abbas A. Esmaeili、Mehri Salimi Tabas、Mohammad A. Nasseri、Foad Kazemi
DOI:10.1007/s00706-004-0256-9
日期:2005.4
A fast alumina-promoted crossed aldol-condensation reaction of aldehydes and cyclic ketones under microwave irradiation is described. This process is simple, efficient, and environmentally benign and proceeds in fairly high yield without any self-condensation.
Synthesis of SrCO<sub>3</sub> Nanoparticles Supported on Montmorillonite as
Efficient Catalyst in the Preparation of α, ά-bis(substituted benzylidene)
cycloalkanones
作者:Enayatollah Sheikhhosseini、Azim Mohammadpour
DOI:10.2174/1570178619666220314145346
日期:2022.11
analysis (XRD), scanning electron microscopy (SEM), and pore size distribution analysis. Crossed-aldol condensation of an aromatic aldehyde with cycloalkanone in the presence of these nanoparticles produced α, ά-bis(substituted-benzylidene) cycloalkanones in good yields without using any solvent. The present method is operationally simple and dosed not use organic solvent, which makes the process environmentally
摘要:本研究采用可控、简便的微波法将Sr(NO3)2负载于天然膨润土上合成了SrCO3@蒙脱土纳米复合材料。SrCO3@蒙脱石纳米粒子的特性通过红外光谱 (IR)、能量色散 X 射线分析 (EDX)、X 射线衍射分析 (XRD)、扫描电子显微镜 (SEM) 和孔径分布等先进技术进行鉴定分析。在这些纳米颗粒的存在下,芳香醛与环烷酮的交叉醛醇缩合以良好的收率产生α,α-双(取代的亚苄基)环烷酮,而无需使用任何溶剂。本方法操作简单,不使用有机溶剂,对环境无害。
A facile synthesis of α,α′-bis(substituted-benzylidene)-cycloalkanones and substituted-benzylidene heteroaromatics: utility of NaOAc as a catalyst for aldol-type reaction
Utility of NaOAc in glacial HOAc as a catalyst for aldol-type condensation reactions was examined. Reactions of cycloalkanones and selected heteroaromatics with various aldehydes in the presence of NaOAc in glacial HOAc provided alpha,alpha-bis(substituted-benzylidene)cycloalkanones and substituted-benzylidene heteroaromatics, respectively, in good yields. (c) 2007 Elsevier Ltd. All rights reserved.