392-13-2Relevant academic research and scientific papers
Annulative π-Extension (APEX) of Indoles to Pyrido[1,2- a]indoles Using 4-Oxo Peroxides as C4 Units
Wang, Xin,Lou, Chenhao,Lv, Leiyang,Li, Zhiping
, p. 5978 - 5982 (2021/08/03)
Annulative π-extension (APEX) of 3-substituted indoles to pyrido[1,2-a]indoles is developed by using 4-oxo peroxides as π-extending reagents, which are employed as versatile C4 building blocks. This transformation is initiated by Br?nsted acid-mediated Hock rearrangement of the peroxyl group. Notably, the pyrido[1,2-a]indole products are obtained by elimination of the indole moiety from the corresponding dihydropyrido[1,2-a]indoles, which could be selectively formed at room temperature.
Synthesis of Pyrido[2,3-b]indole Derivatives via Rhodium-Catalyzed Cyclization of Indoles and 1-Sulfonyl-1,2,3-triazoles
An, Yuehui,Chen, Yidian,Duan, Shengguo,Li, Chuan-Ying,Xu, Ze-Feng,Xue, Bing,Zhang, Wan
, (2020/04/22)
Acyloxy-substituted α,β-unsaturated imines generated in situ from triazoles can act as aza-[4 C] synthons and be trapped by indoles in a stepwise [4 + 2] cycloaddition reaction, thus providing rapid access to valuable pyrido[2,3-b]indoles in high yields. Attractive features of this reaction system include operational simplicity, readily available substrates, construction of sterically demanding quaternary centers, and convenient derivatization using triflate. (Figure presented.).
Selective Oxidative Cleavage of 3-Methylindoles with Primary Amines Affording Quinazolinones
He, Junhui,Dong, Jianyu,Su, Lebin,Wu, Shaofeng,Liu, Lixin,Yin, Shuang-Feng,Zhou, Yongbo
supporting information, p. 2522 - 2526 (2020/04/09)
A selective functionalization of C-C-C bonds toward N-C-O bonds is realized by an n-Bu4NI-catalyzed reaction of 3-methylindoles with primary amines using TBHP as the unique oxidant. The systematic process involves oxygenation, nitrogenation, ring-opening, and recyclization, affording a broad range of quinazolinones in good to excellent yields.
Exploring the influence of designer surfactant hydrophobicity in key C–C/C–N bond forming reactions
Reddy, Singarajanahalli Mundarinti Krishna,Kothandapani, Jagatheeswaran,Sengan, Megarajan,Veerappan, Anbazhagan,Selva Ganesan, Subramaniapillai
, p. 80 - 86 (2019/01/14)
Designer micellar medium was explored for the transformation of diverse anilines to the corresponding densely substituted biologically relevant skatole derivatives in an aqueous medium via 5-exo-trig cyclization reaction. The scope of the reaction was extended to intermolecular Csp2-Csp2 and Csp2-N bond forming reactions in water. Systematic investigations revealed that altering hydrophobicity of surfactant influences the yield of both C–C and C–N bond forming reactions in water.
N-Alkylation-Initiated Redox-Neutral [5 + 2] Annulation of 3-Alkylindoles with o-Aminobenzaldehydes: Access to Indole-1,2-Fused 1,4-Benzodiazepines
Wang, Shuai,Shen, Yao-Bin,Li, Long-Fei,Qiu, Bin,Yu, Liping,Liu, Qing,Xiao, Jian
, p. 8904 - 8908 (2019/11/19)
Described herein is an unprecedented N-Alkylation-initiated redox-neutral [5 + 2] annulation of 3-Alkylindoles with o-Aminobenzaldehydes via a cascade N-Alkylation/dehydration/[1,5]-hydride transfer/Friedel-Crafts alkylation sequence. A series of indole-1,2-fused 1,4-benzodiazepines are facilely constructed in moderate to good yields in one step. This protocol features excellent regioselectivity, metal-free conditions, high step economy, and wide substrate scope.
C -Methylation of Alcohols, Ketones, and Indoles with Methanol Using Heterogeneous Platinum Catalysts
Siddiki, S. M. A. Hakim,Touchy, Abeda S.,Jamil, Md. A. R.,Toyao, Takashi,Shimizu, Ken-Ichi
, p. 3091 - 3103 (2018/04/14)
A versatile, selective, and recyclable heterogeneous catalytic method for the methylation of C-H bonds in alcohols, ketones, and indoles with methanol under oxidant-free conditions using a Pt-loaded carbon (Pt/C) catalyst in the presence of NaOH is reported. This catalytic system is effective for various methylation reactions: (1) the β-methylation of primary alcohols, including aryl, aliphatic, and heterocyclic alcohols, (2) the α-methylation of ketones, and (3) the selective C3-methylation of indoles. The reactions are driven by a borrowing-hydrogen mechanism. The reaction begins with the dehydrogenation of the alcohol(s) to afford aldehydes, which subsequently undergo a condensation reaction with the nucleophile (aldehyde, ketone, or indole), followed by hydrogenation of the condensation product by Pt-H species to yield the desired product. In all of the methylation reactions explored in this study, the Pt/C catalyst exhibits a significantly higher turnover number than other previously reported homogeneous catalytic systems. Moreover, it is demonstrated that the high catalytic activity of Pt can be rationalized in terms of the adsorption energy of hydrogen on the metal surface, as revealed by density functional theory calculations on different metal surfaces.
Iron-Catalyzed Methylation Using the Borrowing Hydrogen Approach
Polidano, Kurt,Allen, Benjamin D. W.,Williams, Jonathan M. J.,Morrill, Louis C.
, p. 6440 - 6445 (2018/07/25)
A general iron-catalyzed methylation has been developed using methanol as a C1 building block. This borrowing hydrogen approach employs a Kn?lker-type (cyclopentadienone)iron carbonyl complex as catalyst (2 mol %) and exhibits a broad reaction scope. A variety of ketones, indoles, oxindoles, amines, and sulfonamides undergo mono- or dimethylation in excellent isolated yields (>60 examples, 79% average yield).
Preparation method of 3-substituted oxidized indole and derivative
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Paragraph 0037; 0039; 0194, (2018/06/26)
The invention belongs to the technical field of organic chemistry and pharmaceutical chemistry and particularly relates to a method of preparing 3-substituted oxidized indole and a derivative. In themethod, with a 3-substituted indole derivative as a raw material and one or more of a tetrabutyl ammonium halide compound/sodium chloride/sodium iodide/potassium iodide as additives, and one or more of dichloromethane/1,2-dichloroethane/tetrahydrofurane/methylbenzene/1,4-dioxane/ethyl acetate/methanol are added as solvents; then one or more of [bis(trifluoroacetoxyl)iodine]benzene/iodosobenzene diacetate are added as oxidants in order to carry out a reaction with reaction temperature being controlled, thus producing the 3-substituted oxidized indole derivative. The method has gentle reaction conditions, simple operations, short reaction time and high yield, and is free of a metal catalyst and is environment-friendly.
Methylation of C(sp3)-H/C(sp2)-H bonds with methanol catalyzed by cobalt system
Liu, Zhenghui,Yang, Zhenzhen,Yu, Xiaoxiao,Zhang, Hongye,Yu, Bo,Zhao, Yanfei,Liu, Zhimin
supporting information, p. 5228 - 5231 (2017/11/06)
A highly efficient Co-based catalytic system, composed of a commercially available Co salt, a tetradentate phosphine ligand P-(CH2CH2PPh2)3(PP3), and a base (denoted as [Co]/PP3/base), is developed for the methylation of C(sp3)-H and C(sp2)-H bonds using methanol as a methylating reagent. The Co(BF4)2.6H2O/PP3/K2CO3 catalytic system showed high catalytic activity for the methylation of C-H bonds in aryl alkyl ketones, aryl acetonitriles, and indoles, with wide substrate scope and good functional group tolerance, and methylsubstituted products were obtained in good to excellent yields at 100 °C. This cheap, readily available, and highly efficient Co-based catalytic system may have promising applications in methylation reaction using methanol.
Synthesis of Enantioenriched Indolines by a Conjugate Addition/Asymmetric Protonation/Aza-Prins Cascade Reaction
Daniels, Blake E.,Ni, Jane,Reisman, Sarah E.
supporting information, p. 3398 - 3402 (2016/03/22)
A conjugate addition/asymmetric protonation/aza-Prins cascade reaction has been developed for the enantioselective synthesis of fused polycyclic indolines. A catalyst system generated from ZrCl4 and 3,3′-dibromo-BINOL enables the synthesis of a range of polycyclic indolines in good yields and with high enantioselectivity. A key finding is the use of TMSCl and 2,6-dibromophenol as a stoichiometric source of HCl to facilitate catalyst turnover. This transformation is the first in which a ZrCl4BINOL complex serves as a chiral Lewis-acid-assisted Br?nsted acid.
