16096-32-5Relevant academic research and scientific papers
Diaryliodonium Salt-Based Synthesis of N-Alkoxyindolines and Further Insights into the Ishikawa Indole Synthesis
Ogura, Akihiro,Shibata, Kouhei,Takao, Ken-Ichi
, p. 10067 - 10087 (2021/07/26)
A diaryliodonium salt-based strategy enabled the first systematic synthesis of rarely accessible N-alkoxyindolines. Mechanistic analyses suggested that the reaction likely involves reductive elimination of iodobenzene from iodaoxazepine via a four-membered transition state, followed by Meisenheimer rearrangement. Substrates with N-carbamate protection afforded indole in a manner similar to that of the Ishikawa indole synthesis. Preinstallation of a stannyl group as an iodonium salt precursor greatly expanded the substrate scope, and further mechanistic insights are discussed.
Covalent Organic Frameworks toward Diverse Photocatalytic Aerobic Oxidations
Liu, Shuyang,Tian, Miao,Bu, Xiubin,Tian, Hua,Yang, Xiaobo
supporting information, p. 7738 - 7744 (2021/05/07)
Photoactive two-dimensional covalent organic frameworks (2D-COFs) have become promising heterogenous photocatalysts in visible-light-driven organic transformations. Herein, a visible-light-driven selective aerobic oxidation of various small organic molecules by using 2D-COFs as the photocatalyst was developed. In this protocol, due to the remarkable photocatalytic capability of hydrazone-based 2D-COF-1 on molecular oxygen activation, a wide range of amides, quinolones, heterocyclic compounds, and sulfoxides were obtained with high efficiency and excellent functional group tolerance under very mild reaction conditions. Furthermore, benefiting from the inherent advantage of heterogenous photocatalysis, prominent sustainability and easy photocatalyst recyclability, a drug molecule (modafinil) and an oxidized mustard gas simulant (2-chloroethyl ethyl sulfoxide) were selectively and easily obtained in scale-up reactions. Mechanistic investigations were conducted using radical quenching experiments and in situ ESR spectroscopy, all corroborating the proposed role of 2D-COF-1 in photocatalytic cycle.
Electron Transfer Photoredox Catalysis: Development of a Photoactivated Reductive Desulfonylation of an Aza-Heteroaromatic Ring
Qiang-Liu,Liu, Yu-Xiu,Song, Hong-Jian,Wang, Qing-Min
supporting information, p. 3110 - 3115 (2020/07/04)
Herein, we report a protocol for desulfonylation of aza-heteroaromatic rings via photoinduced electron transfer and hydrogen atom transfer. This general protocol has a wide substrate range and moderate to good yields. The utility of the method was demonstrated by the chemoselective desulfonylation of a molecule containing both an aliphatic and an aromatic sulfonamide. (Figure presented.).
Regioselective Formation of Substituted Indoles: Formal Synthesis of Lysergic Acid
Beaudry, Christopher M.,Points, Gary L.,Stout, Kenneth T.
supporting information, p. 16655 - 16658 (2020/12/01)
A Diels–Alder reaction-based strategy for the synthesis of indoles and related heterocycles is reported. An intramolecular cycloaddition of alkyne-tethered 3-aminopyrones gives 4-substituted indolines in good yield and with complete regioselectivity. Additional substitution is readily tolerated in the transformation, allowing synthesis of complex and non-canonical substitution patterns. Oxidative conditions give the corresponding indoles. The strategy also allows the synthesis of carbazoles. The method was showcased in a formal synthesis of lysergic acid.
DMSO/t-BuONa/O2-Mediated Aerobic Dehydrogenation of Saturated N-Heterocycles
Cai, Hu,Tan, Wei,Xie, Yongfa,Yang, Ruchun,Yue, Shusheng
, p. 7501 - 7509 (2020/07/07)
Aromatic N-heterocycles such as quinolines, isoquinolines, and indolines are synthesized via sodium tert-butoxide-promoted oxidative dehydrogenation of the saturated heterocycles in DMSO solution. This reaction proceeds under mild reaction conditions and has a good functional group tolerance. Mechanistic studies suggest a radical pathway involving hydrogen abstraction of dimsyl radicals from the N-H bond or α-C-H of the substrates and subsequent oxidation of the nitrogen or α-aminoalkyl radicals.
Potassium tert-Butoxide-Promoted Acceptorless Dehydrogenation of N-Heterocycles
Liu, Tingting,Wu, Kaikai,Wang, Liandi,Yu, Zhengkun
supporting information, p. 3958 - 3964 (2019/08/01)
Potassium tert-butoxide-promoted acceptorless dehydrogenation of N-heterocycles was efficiently realized for the generation of N-heteroarenes and hydrogen gas under transition-metal-free conditions. In the presence of KOtBu base, a variety of six- and five-membered N-heterocyclic compounds efficiently underwent acceptorless dehydrogenation to afford the corresponding N-heteroarenes and H2 gas in o-xylene at 140 °C. The present protocol provides a convenient route to aromatic nitrogen-containing compounds and H2 gas. (Figure presented.).
Dehydrogenation of N-Heterocycles by Superoxide Ion Generated through Single-Electron Transfer
Huang, Yuan-Qiong,Song, Hong-Jian,Liu, Yu-Xiu,Wang, Qing-Min
supporting information, p. 2065 - 2069 (2018/01/27)
Nitrogen-containing heteroarene motifs are found in numerous pharmaceuticals, natural products, and synthetic materials. Although several elegant methods for synthesis of these compounds through dehydrogenation of the corresponding saturated heterocycles have been reported, some of the methods are hampered by long reaction times, harsh conditions, and the need for catalysts that are not readily available. This work reports a novel method for dehydrogenation of N-heterocycles. Specifically, O2.? generated in situ acts as the oxidant for N-heterocycle substrates that are susceptible to oxidation through a hydrogen atom transfer mechanism. This method provides a general, green route to N-heteroarenes.
A indole compound and its preparation method and application (by machine translation)
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Paragraph 0130; 0131, (2018/10/02)
The invention discloses a indole compound and its preparation method and application. The indole compounds of the structural formula such as formula (I) is shown. The indoles, rice galenical demonstrate the excellent inhibitory activity, the effect of most of the compound is obviously better than the positive control drug validamycin; especially compound I - 43, I - 44, I - 54, I - 73, II - 7 and II - 17, its galenical very good living body protection and treating effect, effect is better than the positive control; more specifically, compound I - 43 of the rice sheath blight bacteriostatic activity than validamycin activity is improved by nearly 300 times. The indole compounds in the prevention and/or treatment of rice sheath blight has great application prospects. In addition the compound of the invention is simple in construction, the preparation method is simple, and is suitable for large-scale industrial production. (I). (by machine translation)
β-Amino alcohols from anilines and ethylene glycol through heterogeneous Borrowing Hydrogen reaction
Llabres-Campaner, Pedro J.,Ballesteros-Garrido, Rafael,Ballesteros, Rafael,Abarca, Belén
supporting information, p. 5552 - 5561 (2017/08/22)
Borrowing Hydrogen (BH), also called Hydrogen Autotransfer (HA), reaction with neat ethylene glycol represents a key step in the preparation of β-amino alcohols. However, due to the stability of ethylene glycol, mono-activation has rarely been achieved. Herein, a combination of Pd/C and ZnO is reported as heterogeneous catalyst for this BH/HA reaction. This system results in an extremely air and moisture stable, and economic catalyst able to mono-functionalize ethylene glycol in water, without further activation of the diol. In this work, different diols and aromatic amines have been explored affording a new approach towards amino alcohols. This study reveals how the combination of two solid species can afford interesting catalytic properties in heterogeneous phase. ZnO activates ethylene glycol while Pd/C is the responsible of the BH/HA cycle. This catalytic system has also been found useful to dehydrogenate indoles affording indolines that undergo in situ BH/HA cycle prior to re-aromatization, representing a tandem heterogeneous process.
Nickel-catalyzed methylation of aryl halides/tosylates with methyl tosylate
Wang, Jiawang,Zhao, Jianhong,Gong, Hegui
supporting information, p. 10180 - 10183 (2017/09/23)
This work describes the cross-electrophile methylation of aryl bromides and aryl tosylates with methyl tosylate. The mild reaction conditions allow effective methylation of a wide set of heteroaryl electrophiles and dimethylation of dibromoarenes.
