果糖催化合成四氢苯并[b]吡喃衍生物:动力学和机理研究(英文)

Fructose was used as an efficient catalyst for three-component condensation reactions of aryl aldehydes,malononitrile,and dimedone in a mixture of EtOH and H_2O as green solvents.The advantages of this method are a short reaction time,high yields,low cost,easy accesses,and simple work-up.The mechanism of the synthesis of a derivative of 4H-tetrahydrobenzo[b]pyran was clarified using spectroscopic kinetic methods.The activation energy(Ea=65.34 kJ/mol)and related kinetic parameters(ΔG=69.14 kJ/mol,ΔS=20.99 J/(mol·K),andΔH=62.89 kJ/mol)were calculated,based on the effects of temperature,concentration,and solvent.The first step in the proposed mechanism was identified as the rate-determining step(k1),based on the steady-state approximation.

An efficient synthesis of 2,2′-arylmethylene bis-(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) and 1,8-dioxooctahydroxanthenes using ZnO and ZnO-acetyl chloride

2,2'-Arylmethylene bis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) 4l-s produced from reaction between dimedone with various aldehydes in acetonitrile using ZnO as a catalyst;whereas in the presence of ZnO-acetyl chloride catalysts the reaction is limited to give only 1,8-dioxo-octahydroxanthenes 3a-k in very good yields.

One-pot five-component synthesis of highly functionalized piperidines using oxalic acid dihydrate as a homogenous catalyst

一个有效绿协议为准备被描述高度经由一个一个壶的 functionalized 哌啶在面对象在在周围的温度的乙醇的催化剂的草酸酸二水合物的芳香的醛，苯胺和 -ketoesters 之间的五部件的反应。结构以及这些混合物的相对立体化学被单个 X 光检查结晶的分析证实。

Entirely green protocol for the synthesis of β-aminoketones using saccharose as a homogenous catalyst

Saccharose was applied as an efficient and homogenous catalyst for a one-pot,three-component Mannich reaction for the formation ofβ-aminoketones from aromatic aldehydes,anilines,and acetophenone at ambient temperature in excellent yields.This protocol has the following advantages： mild conditions,high yields,clean reaction profiles,operational simplicity,and environmentally benign and simple work-up procedures.

An effcient one-pot multi-component synthesis of 3,4,5-substituted furan-2(5H)-ones catalyzed by tetra-n-butylammonium bisulfate

A facile one-pot synthesis of 3,4,5-substituted furan-2（5H）-one derivatives from a three-component reaction of aniline derivatives, dialkylacetylenedicarboxylates and aromatic aldehydes under mild conditions using tetra-n-butylammonium bisulfate as a catalyst has been developed.