Remarkable synergism in methylimidazole-promoted decarboxylation of substituted cinnamic acid derivatives in basic water medium under microwave irradiation: a clean synthesis of hydroxylated (E)-stilbenes
摘要:
A metal-free protocol for decarboxylation of substituted alpha-phenylcinnamic acid derivatives in aqueous media is developed, wherein a remarkable synergism between methylimidazole and aq NaHCO3 in polyethylene glycol under microwave furnished the corresponding para/ortho hydroxylated (E)-stilbenes in a mild and efficient manner. The critical role of water in facilitating the decarboxylation imparts an interesting facet to the synthetic utility of water mediated organic transformations. The developed protocol provides a clean alternative to the hitherto indispensable multistep approaches involving toxic quinoline and a copper salt combination as the common decarboxylating agent. (C) 2007 Elsevier Ltd. All rights reserved.
Efficient synthesis of functionalized olefins by Wittig reaction using Amberlite resin as a mild base
作者:Tushar R. Valkute、Eswar K. Aratikatla、Asish K. Bhattacharya
DOI:10.1080/00397911.2016.1276191
日期:2017.3.19
convenient procedure for the synthesis of olefins by the reaction of stabilized, semistabilized, and nonstabilized phosphorous ylides with various aldehydes or ketone using Amberlite resin as a mild base is described. Our developed method offers facile and racemization-free synthesis of α,β-unsaturated amino esters and chiral allylic amine. The developed methodology offers mild reaction conditions, high efficiency
Iron in the Service of Chromium: The <i>ortho</i>-Benzannulation of <i>trans</i>,<i>trans</i>-Dienyl Fischer Carbene Complexes
作者:Yiqian Lian、William D. Wulff
DOI:10.1021/ja0540268
日期:2005.12.1
from dienyl chromium carbene complexes is a known process (ortho-benzannulation) that only occurs with certain cis,trans-dienyl complexes. Control experiments show that trans,trans-dienyl chromium carbene complexes do not undergo conversion to 2-alkoxyphenols in the absence of an iron source. The process most likely occurs either via coordination of the dienyl unit in the chromium carbene complex to
(omega- aminoalkoxy )stilbene derivatives has been synthesized and screened for anticonvulsantactivity. The effect of structural modification of these molecules on the activities has been systematically examined. Potent anticonvulsantactivity was displayed by 2-[4-(4-methyl-1 piperazinyl)butoxy]stilbene (20) and some2-[4-(3-alkoxy-1-piperidino)butoxy]stilbene derivatives (21, 37, 38, and 40), as determined
An unusual, mild and convenient one-pot two-step access to (E)-stilbenes from hydroxy-substituted benzaldehydes and phenylacetic acids under microwave activation: a new facet of the classical Perkin reaction
作者:Arun K. Sinha、Vinod Kumar、Abhishek Sharma、Anuj Sharma、Rakesh Kumar
DOI:10.1016/j.tet.2007.08.034
日期:2007.11
selectivity has been developed through a modified Perkin reaction between benzaldehydes and phenylacetic acids bearing 4- or 2-hydroxy substitution at the aromatic ring, in the presence of piperidine–methylimidazole and polyethylene glycol under microwave irradiation. The observation of a simultaneous condensation–decarboxylation leading to the unusual formation of hydroxystilbenes in lieu of α-phenylcinnamic
Microwave Induced One Pot Process For The Preparation Of Arylethenes
申请人:Sinha Kumar Arun
公开号:US20080045752A1
公开(公告)日:2008-02-21
The invention entitled “A Microwave Induced One Pot Process for The Preparation of Arylethenes” provides a method for the preparation of commercially important 2- or 4-hydroxy substituted arylethenes like styrenes or stilbenes in one pot utilizing cheaper substrates in the form of 2- or 4-hydroxy substituted cinnamic acids and their derivatives as well as reagents in the form of base such as sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium bicarbonate, sodium carbonate, potassium bicarbonate, potassium carbonate, ammonium acetate, imidazole, methylimidazole and the combination thereof, with or without solvent such as dimethylformamide, dimethylsulfoxide, ethylene glycol, diethylene glycol, acetonitrile, acetone, methyl imidazoles, ionic liquid, water and the like. The reaction time vary from 1 min-12 hrs and yield of the products from 49-76% depending upon the base, acid, substrate source of heating monomode or multimode microwave or conventional. It is important to mention that the presence of 2- or 4-hydroxy substitution at phenyl ring of cinnamic acids and their derivatives is essential requirements towards formation of corresponding arylethenes in one step.