1969-72-8Relevant academic research and scientific papers
A Photolabile Carboxyl Protecting Group for Solid Phase Peptide Synthesis
Yang, Hongpeng,Peng, Tao,Wen, Xiaoxue,Chen, Tingting,Sun, Yunbo,Liu, Shuchen,Wang, Gang,Zhang, Shouguo,Wang, Lin
, p. 497 - 502 (2021/05/04)
A new kind of photolabile protecting group (PLPG) for carboxyl moieties was designed and synthesized as the linker between resin and peptide. This group can be used for the protection of amino acid carboxyl groups. The peptide was synthesized on Nph (2-hy
PIII/PV=O Catalyzed Cascade Synthesis of N-Functionalized Azaheterocycles
Li, Gen,Luzung, Michael R.,Nykaza, Trevor V.,Radosevich, Alexander T.,Yang, Junyu
supporting information, p. 4505 - 4510 (2020/02/05)
An organocatalytic method for the modular synthesis of diverse N-aryl and N-alkyl azaheterocycles (indoles, oxindoles, benzimidazoles, and quinoxalinediones) is reported. The method employs a small-ring organophosphorus-based catalyst (1,2,2,3,4,4-hexamethylphosphetane P-oxide) and a hydrosilane reductant to drive the conversion of ortho-functionalized nitroarenes into azaheterocycles through sequential intermolecular reductive C?N cross coupling with boronic acids, followed by intramolecular cyclization. This method enables the rapid construction of azaheterocycles from readily available building blocks, including a regiospecific approach to N-substituted benzimidazoles and quinoxalinediones.
UiO-66 microcrystals catalyzed direct arylation of enol acetates and heteroarenes with aryl diazonium salts in water
Sun, Zhong-Hua,Chen, Wang,Qian, Bing-Bing,Wang, Liang,Yu, Binxun,Chen, Qun,He, Ming-Yang,Zhang, Zhi-Hui
, (2020/01/25)
UiO-66 is a classic Metal–organic framework (MOF) that constructed by zirconium cations and terephthalate with high chemical and thermal stability. Using pristine UiO-66 nanocrystals as the catalysts, the carbon–carbon bond formation based on denitrogenat
Atroposelective Arene Formation by Carbene-Catalyzed Formal [4+2] Cycloaddition
Xu, Ke,Li, Wenchang,Zhu, Shaoheng,Zhu, Tingshun
supporting information, p. 17625 - 17630 (2019/11/29)
Atroposelective arene formation is an efficient method to build axially chiral molecules with multi-substituted arenes. Reported here is an organocatalyzed atroposelective arene formation reaction by an N-heterocyclic carbene (NHC) catalyzed formal [4+2] cycloaddition of conjugated dienals and α-aryl ketones. This study expands the synthetic potential of NHC organocatalysis and provides a competitive pathway for the synthesis of axially chiral ligands, catalysts, and other functional molecules.
Synthesis method of parecoxib sodium isomeric impurities
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Paragraph 0041-0048, (2019/01/23)
The invention provides a synthesis method of parecoxib sodium isomeric impurities. Structures of the parecoxib sodium isomeric impurities are shown in formulae I and II in the description. The synthesis method comprises the following steps: the compound as shown in the formula I is subjected to reaction with the compound as shown in formula II or the compound as shown in formula III under the action of alkali, and a compound as shown in formula IV is generated; the corresponding parecoxib sodium isomeric impurities are generated by reduction reaction, diazotization, sulfonylation, amino substitution reaction and acylation reaction; the total reaction yield is higher than 22%, and purity of a target product is higher than 99%.
Porphyrins as Photoredox Catalysts in Csp2-H Arylations: Batch and Continuous Flow Approaches
De Souza, Aline A. N.,Silva, Nathalia S.,Müller, Andressa V.,Polo, André S.,Brocksom, Timothy J.,De Oliveira, Kleber T.
, p. 15077 - 15086 (2019/01/03)
We have investigated both batch and continuous flow photoarylations of enol-acetates to yield different α-arylated aldehyde and ketone building blocks by using diazonium salts as the aryl-radical source. Different porphyrins were used as SET photocatalysts, and photophysical as well as electrochemical studies were performed to rationalize the photoredox properties and suggest mechanistic insights. Notably, the most electron-deficient porphyrin (meso-tetra(pentafluorophenyl)porphyrin) shows the best photoactivity as an electron donor in the triplet excited state, which was rationalized by the redox potentials of excited states and the turnover of the porphyrins in the photocatalytic cycle. A two-step continuous protocol and multigram-scale reactions are also presented revealing a robust, cost-competitive, and easy methodology, highlighting the significant potential of porphyrins as SET photocatalysts.
C-H arylation reactions through aniline activation catalysed by a PANI-g-C3N4-TiO2 composite under visible light in aqueous medium
Wang, Liang,Shen, Jun,Yang, Sen,Liu, Wenjie,Chen, Qun,He, Mingyang
supporting information, p. 1290 - 1296 (2018/03/26)
A PANI (polyaniline)-g-C3N4-TiO2 composite was prepared and found to be efficient for radical C-H arylation reactions. The arylation process involved coupling of in situ generated aryl diazonium salts from aniline with heteroarenes, enol acetates or benzoquinones under visible light in aqueous medium or pure water. A broad range of substrates survived the reaction conditions to provide the desired products in moderate to good yields. Scale-up (10 mmol) synthesis was also achieved. This semiconductor photocatalyst showed good photocatalytic performance and stability. Recycle studies showed that this composite could be readily recovered and a slight decrease in the catalytic activity was observed after ten consecutive runs.
Salicylic Acid-Catalyzed Arylation of Enol Acetates with Anilines
Felipe-Blanco, Diego,Gonzalez-Gomez, Jose C.
supporting information, p. 2773 - 2778 (2018/07/29)
α-Aryl ketones are both structure moieties commonly found in bioactive compounds and versatile synthetic intermediates for the preparation of drug-like molecules. An operationally simple and scalable protocol has been developed to prepare α-aryl ketones from readily available aromatic amines and enol acetates (or silyl enol ethers). This metal-free methodology features the use of salicylic acid as a convenient catalyst to promote the formation of aryl radicals from in-situ generated aryl diazonium salts, without demanding thermal or photochemical activation. The mild reaction conditions used are compatible with anilines substituted with diverse functionalities. Structural elaboration of some prepared α-aryl ketones was accomplished to illustrate their usefulness as building blocks. (Figure presented.).
Method for preparing indole and derivatives thereof
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Paragraph 0022-0023; 0025-0026, (2017/08/24)
The invention discloses a method for preparing indole and derivatives of indole. The method for preparing indole and the derivatives of indole is characterized by comprising the following two steps that (1) a catalyst, a ligand and alkali are added in a reaction tube, under the protection of nitrogen, beta-hydroxy ketone or ester is reacted with a mixed solution of o-nitro aryl halides for 3 to 8h in an oil bath pan at the temperature of 90 to 120 DEG C, and then cooled to room temperature after reaction, and extracted, washed, dried and subjected to chromatography to obtain a product of o-nitro alpha-aryl ketone or ester; (2) o-nitro alpha-aryl ketone or ester obtained in the step (1), a reducing agent system and a solvent are added to the reaction tube, and reacted for 3 to 8h at the temperature of 60 to 100 DEG C, and then extracted, washed, dried and subjected to chromatography after being reacted to obtain a target product of indole and the derivatives of indole. Reaction raw materials, the catalyst, the ligand, the alkali and the solvent used in the invention are all industrial commodities, and simple and readily available, wide in sources, cheap in price, and further very stable in performances, and with no need for special storage conditions; in addition, the method for preparing indole and the derivatives of indole disclosed by the invention has the characteristics of low cost, high yield, simple process, less pollution and the like.
C-C Activation by Retro-Aldol Reaction of Two β-Hydroxy Carbonyl Compounds: Synergy with Pd-Catalyzed Cross-Coupling to Access Mono-α-arylated Ketones and Esters
Zhang, Song-Lin,Yu, Ze-Long
, p. 57 - 65 (2016/01/15)
A retro-aldol reaction of two β-hydroxy compounds in synergy with Pd-catalyzed cross-coupling of aryl halides is reported herein, which produces selectively mono-α-arylated ketones and esters in good yields. This reaction is compatible with a broad range of aryl iodides, bromides, chlorides, and triflates and can tolerate an array of functional groups on the aromatic ring. Ready scale-up of this reaction to gram level is applicable without an appreciable decrease in the reaction yield. Furthermore, concise syntheses of biologically active isocoumarin and indole derivatives have been achieved to greatly demonstrate the synthetic value of this retro-aldol reaction. Finally, the reaction mechanism has been discussed on the basis of experimental observations and DFT computational results. A regulated six-membered-ring transition structure has been located for the key retro-aldol C-C cleavage, which constitutes the rate-determining step of a full catalytic cycle. The concept of C-C activation by retro-aldol reaction may also find applications in other fundamental reactions.
