16732-81-3Relevant articles and documents
Synthesis method for preparing 2-substituted indole derivative
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Paragraph 0155-0158, (2019/05/28)
The invention relates to a synthesis method for preparing a 2-substituted indole derivative. The method includes the following steps: mixing aromatic amine compounds (I), ketone compounds (II) and a drying agent in an organic solvent; adding a palladium catalyst; and reacting in an aerobic weak acid environment to prepare the indole compounds (III). (I), (II) and (III) are as shown in the specification, wherein R1 is selected from hydrogen, C1-C6 alkyl, C1-C6 alkoxy, C1-C6 alkanoyl, C2-C6 alkenyl, C2-C6 alkynyl, halogen, hydroxyl, substituted or unsubstituted amino, substituted or unsubstituted phenyl, pyridyl and heterocyclic aryl; (I) can be pyridylamine, pyrimidylamine, pyridazinam or pyrazinamide which may further be substituted or unsubstituted; and the substituents are selected fromone or more C1-C6 alkyl, C1-C6 alkoxy, C1-C6 alkanoyl, C2-C6 alkenyl, C2-C6 alkynyl, halogen, hydroxyl, amino; and R2 is selected from C1-C6 alkyl, formate groups or C1-C6 alkylamide groups.
Carboxylic Acid-Promoted Single-Step Indole Construction from Simple Anilines and Ketones via Aerobic Cross-Dehydrogenative Coupling
Ren, Long,Nan, Guanglei,Wang, Yongcheng,Xiao, Zhiyan
, p. 14472 - 14488 (2018/11/23)
The cross-dehydrogenative coupling (CDC) reaction is an efficient strategy for indole synthesis. However, most CDC methods require special substrates, and the presence of inherent groups limits the versatility for further transformation. A carboxylic acid-promoted aerobic catalytic system is developed herein for a single-step synthesis of indoles from simple anilines and ketones. This versatile system is featured by the broad substrate scope and the use of ambient oxygen as an oxidant and is convenient and economical for both laboratory and industry applications. The existence of the labile hydrogen at C-3 and the highly transformable carbonyl at C-2 makes the indoles versatile building blocks for organic synthesis in different contexts. Computational studies based on the density functional theory (DFT) suggest that the rate-determining step is carboxylic acid-assisted condensation of the substrates, rather than the functionalization of aryl C-H. Accordingly, a pathway via imine intermediates is deemed to be the preferred mechanism. In contrast to the general deduction, the in situ formed imine, instead of its enamine isomer, is believed to be involved in the first ligand exchange and later carbopalladation of the α-Me, which shed new light on this indolization mechanism.
OBO-Protected Pyruvates as Reagents for the Synthesis of Functionalized Heteroaromatic Compounds
Alves Esteves, C. Henrique,Koyioni, Maria,Christensen, Kirsten E.,Smith, Peter D.,Donohoe, Timothy J.
supporting information, p. 4048 - 4051 (2018/07/15)
Pd-catalyzed α-arylation of methyl-OBO-ketone (OBO = 4-methyl-2,6,7-trioxabicyclo[2.2.2]octan-1-yl) gives rise to arylated OBO-protected pyruvates. By appropriate prefunctionalization of the aryl ring or by subsequent functionalization at the α-carbonyl p
Tripodal S-Ligand Complexes of Copper(I) as Catalysts for Alkene Aziridination, Sulfide Sulfimidation, and C-H Amination
Lam, Tsz Lung,Tso, Ken Chi-Hang,Cao, Bei,Yang, Chen,Chen, Daqing,Chang, Xiao-Yong,Huang, Jie-Sheng,Che, Chi-Ming
, p. 4253 - 4257 (2017/04/26)
Copper(I) complexes of tris(thioimidazolyl)borates (R′TmR), including [Cu(TmPh)(PR″3)] (R″ = Ph, Cu1; Cy, Cu2) and [Cu(R′TmPh)(PR″3)]+ (R′ = N-methylimidazole; R″ = Ph, Cy) were prepared an
Synthesis of Indole-2-carboxylate Derivatives via Palladium-Catalyzed Aerobic Amination of Aryl C-H Bonds
Clagg, Kyle,Hou, Haiyun,Weinstein, Adam B.,Russell, David,Stahl, Shannon S.,Koenig, Stefan G.
, p. 3586 - 3589 (2016/08/16)
A direct oxidative C-H amination affording 1-acetyl indolecarboxylates starting from 2-acetamido-3-arylacrylates has been achieved. Indole-2-carboxylates can be targeted with a straightforward deacetylation of the initial reaction products. The C-H amination reaction is carried out using a catalytic Pd(II) source with oxygen as the terminal oxidant. The scope and application of this chemistry is demonstrated with good to high yields for numerous electron-rich and electron-poor substrates. Further reaction of selected products via Suzuki arylation and deacetylation provides access to highly functionalized indole structures.
Ligand-free copper-catalyzed one-pot synthesis of indole-2-carboxylic esters
Zhu, Zhiqiang,Yuan, Jiangjun,Zhou, Yirong,Qin, Yang,Xu, Jingshi,Peng, Yiyuan
supporting information, p. 511 - 514 (2014/02/14)
A simple, efficient, and facile synthetic route for the preparation of indole-2-carboxylic esters was described. The cascade reactions of 2-bromobenzaldehyde and glycine ester hydrochloride were promoted by Cu 2O and a base to provide the corresponding products in good yields. Commercially available, inexpensive substrates and reagents were employed under mild reaction conditions in this one-pot operation, which is complementary to existing methods for access to 2-substituted indoles. A simple, efficient, and facile synthetic route to indole-2-carboxylic esters through copper-catalyzed one-pot cascade reactions of commercially available, inexpensive 2-bromobenzaldehyde and glycine ester hydrochloride without the use of any external ligand under mild conditions is reported. Copyright
Ligand-Free Copper-Catalyzed One-Pot Synthesis of Indole-2-carboxylic Esters
Zhu, Zhiqiang,Yuan, Jiangjun,Zhou, Yirong,Qin, Yang,Xu, Jingshi,Peng, Yiyuan
supporting information, p. 511 - 514 (2015/10/05)
A simple, efficient, and facile synthetic route for the preparation of indole-2-carboxylic esters was described. The cascade reactions of 2-bromobenzaldehyde and glycine ester hydrochloride were promoted by Cu2O and a base to provide the corresponding products in good yields. Commercially available, inexpensive substrates and reagents were employed under mild reaction conditions in this one-pot operation, which is complementary to existing methods for access to 2-substituted indoles.
Indoles via Knoevenagel-Hemetsberger reaction sequence
Heaner Iv, William L.,Gelbaum, Carol S.,Gelbaum, Leslie,Pollet, Pamela,Richman, Kent W.,Dubay, William,Butler, Jeffrey D.,Wells, Gregory,Liotta, Charles L.
, p. 13232 - 13242 (2013/09/02)
A series of substituted indoles have been synthesized by the sequential reaction of aromatic aldehydes with ethyl azidoacetate in the presence of sodium ethoxide to form the corresponding ethyl α-azido-β-arylacrylates (Knoevenagel process) followed by a solvent mediated thermolysis (Hemetsberger process). The isolated yields of the ethyl α-azido-β-arylacrylates were significantly increased when employing the sacrificial electrophile ethyl trifluoroacetate. 1H NMR and coupled 1H-13C NMR analysis of the ethyl α-azido-β-arylacrylates indicate that the condensation is stereospecific - only the Z-isomer could be detected. Solvent mediated thermal treatment of the meta-substituted ethyl α-azido-β- arylacrylates resulted in the formation of both the 5- and 7- substituted indoles - the 5-regioisomer being slightly favored over the 7-regioisomer. Analogous thermal treatment of (2Z, 2Z′)-diethyl 3,3′-(1,3- phenylene)bis(2-azidoacrylate) and (2Z, 2Z′)-diethyl 3,3′-(1,4- phenylene)bis(2-azidoacrylate) exclusively produced pyrroloindoles, diethyl 1,5-dihydropyrrolo[2,3-f]indole-2,6-dicarboxylate and diethyl 1,5-dihydropyrrolo[2,3-f]indole-2,6-dicarboxylate, respectively. Results are also reported which indicate that the α-azido-β-arylacrylates can be used in the subsequent Hemetsberger indolization process without prior purification.
Design, synthesis and aromatase inhibitory activities of novel indole-imidazole derivatives
Wang, Rui,Shi, Hong-Fan,Zhao, Jing-Feng,He, Yan-Ping,Zhang, Hong-Bin,Liu, Jian-Ping
supporting information, p. 1760 - 1762 (2013/04/10)
A series of novel indole-imidazole derivatives have been prepared and evaluated in vitro on the aromatase inhibitory activities. The results suggested that proton or a small electron-withdrawing group at para-position of the phenyl ring would enhance the inhibitory activities and any bulky group should be avoided in order to keep a relative small volume for this kind of molecules.
A ligand-free, copper-catalyzed cascade sequence to indole-2-carboxylic esters
Koenig, Stefan G.,Dankwardt, John W.,Liu, Yanbing,Zhao, Hang,Singh, Surendra P.
supporting information; experimental part, p. 6549 - 6551 (2011/02/24)
A variety of indole-2-carboxylic esters are accessible in yields up to 61% through a ligand-free, coppercatalyzed reaction of a series of commercially available 2-halo aryl aldehydes with benign glycine amidoesters, including the common reagent ethyl acetamidoacetate. This one-pot, three-reaction format allows ready entry to the desired heterocycles from starting substrates in the reactivity order of iodo > bromo ≥ chloro substituents. An assortment of functional groups is tolerated, adding to the generality of this methodology.
