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.
Synthesis and antioxidant activity of hydroxylated phenanthrenes as cis-restricted resveratrol analogues
摘要:
Five hydroxylated phenanthrenes as "cis-configuration-fixed" resveratrol analogues differing in the number and position of the hydroxyl groups were designed and synthesized. Their antioxidant activity was studied by ferric reducing antioxidant power, 2,2-diphenyl-1-picrylhydrazyl free radical-scavenging, and DNA strand breakage-inhibiting assays, corresponding to their electron-donating, hydrogen-transfer and DNA-protecting abilities, respectively. In the above assays, their activity depends significantly on the number and position of the hydroxyl groups, and most of them are more effective than resveratrol. Noticeably, compound 9b (2,4,6-trihydroxyl phenanthrene) with the same hydroxyl group substitutions as resveratrol, is superior to the reference compound, highlighting the importance of extension of the conjugation over multiple aromatic-rings. Similar activity sequences were obtained in different experimental models, but the appreciable differences could contribute detailed insights into antioxidant mechanisms. Based on these results, the hydroxylated phenanthrenes may be considered as a novel type of resveratrol-directed antioxidants. (C) 2012 Elsevier Ltd. All rights reserved.
Divergent Reactivity in Cu<sup>II</sup>-Catalyzed Oxidative Coupling between Indole/Tryptamine Derivatives and β-Arylacrylic Acids
作者:Wei Cao、Jinbao Fan、Linyang Yan、Guangyao Zeng、Jinjin Ma、Yajing Wang、Yingjun Zhou、Xu Deng
DOI:10.1021/acs.orglett.9b03697
日期:2019.12.6
Condition-controlled divergent oxidativecoupling reactions between indole/tryptamine derivatives and β-arylacrylic acids with the catalysis of copper(II) have been developed. Specifically, a formal Michael addition/dehydration sequence between indoles and β-arylacrylic acids occurred in the presence of catalytic CuBr2 in CH3CN under air, thus affording highly functionalized 2,3-dihydro-1H-pyrrolo[1
已经开发出条件控制的吲哚/色胺衍生物与β-芳基丙烯酸之间的氧化偶联反应,其催化铜(II)。具体而言,在空气中CH 3 CN中存在催化CuBr 2时,吲哚与β-芳基丙烯酸之间存在正式的迈克尔加成/脱水序列,从而提供了高度官能化的2,3-二氢-1 H-吡咯并[1,2- a ]吲哚。相反,在将氧化剂改变为t BuOOH,将溶剂改变为DCM时,反应过程切换到空前的氧化偶合/环化级联反应,从而选择性地得到四环吡咯并[2,3- b ]二氢吲哚。
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.
Microwave induced one pot process for the preparation of arylethenes
申请人:Council of Scientific & Industrial Research
公开号:US07759527B2
公开(公告)日:2010-07-20
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.