17537-64-3Relevant articles and documents
Convenient procedure for dethioketalisation in nitrogen heterocycles
Giri,Sankar
, p. 1795 - 1800 (1993)
Regeneration of carbonyl compounds from the corresponding thioketals in nitrogen heterocycles have been effected using Dowex 50W acidic catalyst in reasonable yields.
Microwave-assisted Friedel-Crafts acylation of indole with acetic anhydride over tungstophosphoric acid modified Hβ zeolite
Bai, Guoyi,Li, Tianyu,Yang, Yonghui,Zhang, Huanhuan,Lan, Xingwang,Li, Fei,Han, Jie,Ma, Zheng,Chen, Qingzhi,Chen, Guofeng
, p. 114 - 117 (2012)
Friedel-Crafts acylation of indole with acetic anhydride has been carried out over zeolites under microwave and conventional heating, respectively. A tungstophosphoric acid modified Hβ (PW-Hβ) zeolite showed better catalytic performance than parent Hβ zeolite due to its higher amount of strongly acidic sites and lower amount of Lewis acid sites, confirmed from NH3 temperature-programmed desorption (NH3-TPD) and Fourier Transform Infrared Spectrometer after adsorption of pyridine (Py-IR). Particularly, microwave radiation was found to make this transformation not only more efficient but also selective to 3-acetylindole compared with conventional heating. Furthermore, PW-Hβ has shown good stability in this reaction.
Overcoming Electron-Withdrawing and Product-Inhibition Effects by Organocatalytic Aerobic Oxidation of Alkylpyridines and Related Alkylheteroarenes to Ketones
Wang, Hua,Liu, Jie,Qu, Jian-Ping,Kang, Yan-Biao
, p. 3942 - 3948 (2020/03/23)
An organocatalyzed aerobic benzylic C-H oxidation of alkyl and aryl heterocycles has been developed. This transition metal-free method is able to overcome the electron-withdrawing effect as well as product-inhibition effects in heterobenzylic radical oxidation. A variety of ketones bearing N-heterocyclic groups could be prepared under relatively mild conditions with moderate to high yields.
Cobalt-Catalyzed Regioselective Direct C-4 Alkenylation of 3-Acetylindole with Michael Acceptors Using a Weakly Coordinating Functional Group
Banjare, Shyam Kumar,Nanda, Tanmayee,Ravikumar
supporting information, p. 8138 - 8143 (2019/10/14)
Herein, we disclosed the first report on the selective C(4)-H functionalization of 3-acetylindole derivatives using first-row transition metal cobalt where an acetyl group is acting as a weakly coordinating directing group. Selective C(4)-H functionalization has been achieved using diverse Michael acceptors (acrylate and maleimide) simply by switching the additive from copper acetate to silver carbonate. Further the formation of a cobaltacycle intermediate was also detected through HRMS for mechanistic insight.
Na 2 CO 3-Catalyzed N-Acylation of Indoles with Alkenyl Carboxylates
Zhou, Xiao-Yu,Chen, Xia
supporting information, p. 516 - 521 (2019/01/10)
The N-acylation of indoles has been accomplished via inorganic base catalysis. It provided an efficient and simple catalysis system for the preparation of N-acylindoles with alkenyl carboxylates as acylating agents. A broad variety of indoles undergo the smooth N-acylation using Na 2 CO 3 as catalyst in MeCN at 120? °C to give the corresponding N-acylindoles in good to excellent yields.
Hydrogen bond donor solvents enabled metal and halogen-free Friedel–Crafts acylations with virtually no waste stream
Liu, Guangchang,Xu, Bo
supporting information, p. 869 - 872 (2018/02/09)
We have developed a metal and halogen-free Friedel–Crafts acylation protocol with virtually no waste stream generation. We propose a hydrogen bonding donor solvent will form a hydrogen bonding network and may provide significant rate enhancement for Friedel–Crafts reactions. Trifluoroacetic acid is one of the strongest H-bond donor solvents, which is also volatile and can be easily recovered by distillation without need for reaction workup. Our protocol is a ‘green’ Friedel–Crafts acylation process: 1) the catalyst can be recovered and reused; 2) using halogen free starting material (carboxylic acids anhydride or carboxylic acids); 3) no need for aqueous reaction work-up; 4) minimum or no waste steam generation.
Based on carboxylic acid allyl ester as the acylation reagent N - acyl indoles preparation method (by machine translation)
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Paragraph 0041-0043, (2018/12/02)
Based on carboxylic acid allyl ester as the acylation reagent N - acyl indoles preparation method, which belongs to the medical and chemical intermediates and related chemical technical field. This method uses the indole compounds and carboxylic acid allyl ester as the raw material, in the catalysis of alkali, realizes the N - acyl indoles of green, efficient synthesis. The method has high selectivity, mild reaction conditions, functional group compatibility is good, wide substrate range, environment-friendly and the like. Because the N - acyl indoles is an important organic synthetic intermediates, in organic synthesis and in the field of pharmacy has very wide application, therefore, the invention has great application value and social and economic benefits. (by machine translation)
Three-Component Coupling-Oxidative Amidation-Heterocycloannulation: Synthesis of the Indole Alkaloids Hamacanthin A and trans -2,5-Bis(3′-Indolyl)piperazine
Srinivasan, A. Kaliyaperumal,Banerjee, Shyamapada,Pachore, Sharad S.,Syam Kumar
, p. 1057 - 1064 (2017/05/19)
Concise and highly convergent syntheses of antifungal marine bis(indole) alkaloids, hamacanthin A and trans-2,5-bis(3′-indolyl)piperazine is described. The total synthesis of hamacanthin A is accomplished via the oxidative amidation-chemoselective heterocycloannulation of 2,2-dibromo-1-(1H-indol-3-yl)ethanone with 1-(1H-indol-3-yl)ethane-1,2-diamine. The reduction of desbromo hamacanthin with aluminum borohydride afforded the alkaloid trans-2,5-bis(3′-indolyl)piperazine. Two novel and convenient protocols for the synthesis of indolyl-1,2-diaminoethane are also developed in moderate to good yields.
One-Step Dual Template Mediated Synthesis of Nanocrystalline Zeolites of Different Framework Structures
Rani, Poonam,Srivastava, Rajendra,Satpati, Biswarup
, p. 3323 - 3333 (2016/06/14)
A novel, dual template mediated, one-step direct synthesis route is reported here for the preparation of nanocrystalline zeolites of different framework structures (such as ZSM-5, mordenite, and sodalite). In this synthesis strategy, a suitably designed dicationic/tetra-cationic soft template was used along with a conventional zeolite structure director to obtain nanocrystalline zeolites with nanosheet morphology. Nanocrystalline zeolites exhibited large surface area, pore volume, and intercrystalline mesopores. The long hydrophobic chain containing a multiammonium template cooperatively participates in the zeolite crystallization process along with a conventional microporous zeolite structure director to form the ultrathin microporous zeolite framework, while the hydrophobic interaction between the long chains restricted the excessive growth of zeolites and induced the formation of intercrystalline mesopores. Nanocrystalline zeolites exhibited exceptionally high activity in the acid-catalyzed reactions involving large molecules when compared with conventional zeolites. This synthesis strategy can be extended for the preparation of zeolites of different framework structures or other porous materials in the future.
Synthesis of industrially important aromatic and heterocyclic ketones using hierarchical ZSM-5 and Beta zeolites
Kore, Rajkumar,Srivastava, Rajendra,Satpati, Biswarup
, p. 129 - 141 (2015/09/28)
Hierarchical ZSM-5 and Beta zeolites were investigated in the synthesis of wide range of industrially important aromatic/heterocyclic ketones by Friedel-Crafts acylation and benzoylation reactions. For comparative study, conventional ZSM-5 and Beta, and amorphous mesoporous Al-MCM-41 were investigated. Hierarchical zeolites were prepared by multi-ammonium structure directing agents whereas conventional zeolites were prepared by mono-ammonium structure directing agents. Among the catalysts investigated in this study, hierarchical Beta exhibited the highest reactant conversion in the acylation and benzoylation reactions. In this study, the systematic assessment of the catalytic activity of acid catalysts for wide range of aromatic and heterocyclic compounds is shown under one umbrella. To the best of our knowledge, these reactions over hierarchical zeolites (ZSM-5 and Beta) are reported here for the first time. Structure activity relationship is explained based on the physico-chemical properties, molecular size, reactivity of reactants, and reaction mechanism. Catalysts can be easily recovered and reused with negligible loss in the catalytic activity.
