Shared posts

10 Oct 00:27

Palladium-Catalyzed Aerobic Oxygenation of Allylarenes

by Chunsheng Li, Meng Li, Jianxiao Li, Jianhua Liao, Wanqing Wu and Huanfeng Jiang

TOC Graphic

The Journal of Organic Chemistry
DOI: 10.1021/acs.joc.7b01729
28 Aug 07:09

A 31-residue peptide induces aggregation of tau's microtubule-binding region in cells

by Jan Stöhr

Nature Chemistry 9, 874 (2017). doi:10.1038/nchem.2754

Authors: Jan Stöhr, Haifan Wu, Mimi Nick, Yibing Wu, Manasi Bhate, Carlo Condello, Noah Johnson, Jeffrey Rodgers, Thomas Lemmin, Srabasti Acharya, Julia Becker, Kathleen Robinson, Mark J. S. Kelly, Feng Gai, Gerald Stubbs, Stanley B. Prusiner & William F. DeGrado

The self-propagation of misfolded conformations of tau occurs in neurodegenerative diseases, including Alzheimer's disease. The microtubule-binding region, tau244-372, reproduces much of the aggregation behaviour of tau in cells and animal models. Now, it has been shown that a 31-residue peptide from tau's R3 domain forms a cross-β conformation that efficiently seeds aggregation of tau244-372 in cells.

02 May 14:11

Anthranil: An Aminating Reagent Leading to Bifunctionality for Both C(sp3)−H and C(sp2)−H under Rhodium(III) Catalysis

by Songjie Yu, Guodong Tang, Yingzi Li, Xukai Zhou, Yu Lan, Xingwei Li

Abstract

Previous direct C−H nitrogenation suffered from simple amidation/amination with limited atom-economy and is mostly limited to C(sp2)−H substrates. In this work, anthranil was designed as a novel bifunctional aminating reagent for both C(sp2)−H and C(sp3)−H bonds under rhodium(III) catalysis, thus affording a nucleophilic aniline tethered to an electrophilic carbonyl. A tridendate rhodium(III) complex has been isolated as the resting state of the catalyst, and DFT studies established the intermediacy of a nitrene species.

Thumbnail image of graphical abstract

Double agent: Anthranil was designed as a novel bifunctional aminating reagent for both C(sp2)−H and C(sp3)−H bonds under rhodium(III) catalysis, thus affording a nucleophilic aniline tethered to an electrophilic carbonyl. A tridendate rhodium(III) complex was isolated as the resting state of the catalyst, and DFT studies established the intermediacy of a nitrene species.

11 Jan 14:38

‘On water synthesis’ of oxindoles bearing quaternary carbon center through C–H (sp3) functionalization of methyl azaarenes

yangchi

TL?///

Publication date: 3 February 2016
Source:Tetrahedron Letters, Volume 57, Issue 5
Author(s): Srinivasarao Yaragorla, Garima Singh, Ravikrishna Dada
A catalyst-free and green approach of sp3 C–H functionalization of methyl azaarenes with malononitrile and isatins for the synthesis of oxindole derivatives bearing quaternary carbon center has been described in water. This one-pot three component synthesis endures the key features like first ‘on water synthesis’, short reaction times, moderate to good yields, and large substrate scope.

Graphical abstract

image
07 Jan 03:20

Skeletally Diverse Synthesis of Indole-Fused Diazocine and Diazepine Frameworks by One-Pot, Two-Component Cascade Reaction

by Tushar Ulhas Thikekar, Manikandan Selvaraju and Chung-Ming Sun

TOC Graphic

Organic Letters
DOI: 10.1021/acs.orglett.5b03481
02 Jan 16:21

Synthesis of fully substituted naphthyridines: a novel domino four-component reaction in a deep eutectic solvent system based on choline chloride/urea

yangchi

多米诺

Publication date: 20 January 2016
Source:Tetrahedron Letters, Volume 57, Issue 3
Author(s): Ahmad Shaabani, Seyyed Emad Hooshmand, Azadeh Tavousi Tabatabaei
The diversity-oriented synthesis of a naphthyridine scaffold has been demonstrated via a novel domino four-component reaction. The syntheses were achieved by reacting a diamine, 1,1-bis(methylthio)-2-nitroethylene, 2-aminoprop-1-ene-1,1,3-tricarbonitrile, and various carbonyl compounds using a deep eutectic solvent (DES), based on choline chloride/urea, thus providing a new class of poly-functionalized fused naphthyridine derivatives with the concomitant formation of three new rings and six σ bonds. The reaction conditions were mild and did not require additional base catalysts. Given the inexpensive, nontoxic, and recyclable nature of the DES, these reaction conditions are simple and highly environmentally friendly.

Graphical abstract

image
26 Nov 13:31

Rh(III)-Catalyzed Redox-Neutral Annulation of Azo and Diazo Compounds: One-step Access to Cinnolines

Org. Chem. Front., 2015, Accepted Manuscript
DOI: 10.1039/C5QO00331H, Research Article
Hequan Yao, Peng Sun, Youzhi Wu, Yue Huang, Xiaoming Wu, Jinyi Xu, Aijun Lin
Reported herein is a Rh-catalyzed redox-neutral annulation reaction between azo and diazo compounds, thus leading to the direct synthesis of cinnolines under mild conditions. The procedure exhibited broad substrate scope,...
The content of this RSS Feed (c) The Royal Society of Chemistry
21 Aug 08:39

Curcumin-inspired cytotoxic 3,5-bis(arylmethylene)-1-(N-(ortho-substituted aryl)maleamoyl)-4-piperidones: A novel group of topoisomerase II alpha inhibitors

Publication date: 1 October 2015
Source:Bioorganic & Medicinal Chemistry, Volume 23, Issue 19
Author(s): Amitabh Jha, Katherine M. Duffield, Matthew R. Ness, Sujatha Ravoori, Gabrielle Andrews, Khushwant S. Bhullar, H.P. Vasantha Rupasinghe, Jan Balzarini
Three series of novel 3,5-bis(arylmethylene)-1-(N-(ortho-substituted aryl)maleamoyl)-4-piperidones, designed as simplified analogs of curcumin with maleic diamide tether, were synthesized and bioevaluated. These compounds displayed potent cytotoxicity towards human Molt 4/C8 and CEM T-lymphocytes as well as murine L1210 leukemic cells. In contrast, the related N-arylmaleamic acids possessed little or no cytotoxicity in these three screens. Design of these compounds was based on molecular modeling studies performed on a related series of molecule in a previous study. Representative title compounds were found to be significantly potent in inhibiting the activity of topoisomerase II alpha indicating the possible mode of action of these compounds. These compounds were also potent antioxidants in vitro and attenuated the AAPH triggered peroxyl radical production in human fibroblasts. Various members of these series were also well tolerated in both in vitro and in vivo toxicity analysis.

Graphical abstract

image