GSTDTAP

浏览/检索结果: 共16条,第1-10条 帮助

限定条件    
已选(0)清除 条数/页:   排序方式:
A general carbonyl alkylative amination for tertiary amine synthesis 期刊论文
NATURE, 2020
作者:  Ouyang, David;  He, Bryan;  Ghorbani, Amirata;  Yuan, Neal;  Ebinger, Joseph;  Langlotz, Curtis P.;  Heidenreich, Paul A.;  Harrington, Robert A.;  Liang, David H.;  Ashley, Euan A.;  Zou, James Y.
收藏  |  浏览/下载:12/0  |  提交时间:2020/07/03

The ubiquity of tertiary alkylamines in pharmaceutical and agrochemical agents, natural products and small-molecule biological probes(1,2) has stimulated efforts towards their streamlined synthesis(3-9). Arguably the most robust method for the synthesis of tertiary alkylamines is carbonyl reductive amination(3), which comprises two elementary steps: the condensation of a secondary alkylamine with an aliphatic aldehyde to form an all-alkyl-iminium ion, which is subsequently reduced by a hydride reagent. Direct strategies have been sought for a '  higher order'  variant of this reaction via the coupling of an alkyl fragment with an alkyl-iminium ion that is generated in situ(10-14). However, despite extensive efforts, the successful realization of a '  carbonyl alkylative amination'  has not yet been achieved. Here we present a practical and general synthesis of tertiary alkylamines through the addition of alkyl radicals to all-alkyl-iminium ions. The process is facilitated by visible light and a silane reducing agent, which trigger a distinct radical initiation step to establish a chain process. This operationally straightforward, metal-free and modular transformation forms tertiary amines, without structural constraint, via the coupling of aldehydes and secondary amines with alkyl halides. The structural and functional diversity of these readily available precursors provides a versatile and flexible strategy for the streamlined synthesis of complex tertiary amines.


The synthesis of tertiary amines is achieved through a carbonyl alkylative amination reaction facilitated by visible light, in which an aldehyde and an amine condense to form an iminium ion that subsequently reacts with alkyl radical.


  
A mycobacterial ABC transporter mediates the uptake of hydrophilic compounds 期刊论文
NATURE, 2020, 580 (7803) : 409-+
作者:  Al-Shayeb, Basem;  Sachdeva, Rohan;  Chen, Lin-Xing;  Ward, Fred;  Munk, Patrick;  Devoto, Audra;  Castelle, Cindy J.;  Olm, Matthew R.;  Bouma-Gregson, Keith;  Amano, Yuki;  He, Christine;  Meheust, Raphael;  Brooks, Brandon;  Thomas, Alex;  Levy, Adi;  Matheus-Carnevali, Paula;  Sun, Christine;  Goltsman, Daniela S. A.;  Borton, Mikayla A.;  Sharrar, Allison;  Jaffe, Alexander L.;  Nelson, Tara C.;  Kantor, Rose;  Keren, Ray;  Lane, Katherine R.;  Farag, Ibrahim F.;  Lei, Shufei;  Finstad, Kari;  Amundson, Ronald;  Anantharaman, Karthik;  Zhou, Jinglie;  Probst, Alexander J.;  Power, Mary E.;  Tringe, Susannah G.;  Li, Wen-Jun;  Wrighton, Kelly;  Harrison, Sue;  Morowitz, Michael;  Relman, David A.;  Doudna, Jennifer A.;  Lehours, Anne-Catherine;  Warren, Lesley;  Cate, Jamie H. D.;  Santini, Joanne M.;  Banfield, Jillian F.
收藏  |  浏览/下载:34/0  |  提交时间:2020/07/03

Mycobacterium tuberculosis (Mtb) is an obligate human pathogen and the causative agent of tuberculosis(1-3). Although Mtb can synthesize vitamin B-12 (cobalamin) de novo, uptake of cobalamin has been linked to pathogenesis of tuberculosis2. Mtb does not encode any characterized cobalamin transporter(4-6)  however, the gene rv1819c was found to be essential for uptake of cobalamin(1). This result is difficult to reconcile with the original annotation of Rv1819c as a protein implicated in the transport of antimicrobial peptides such as bleomycin(7). In addition, uptake of cobalamin seems inconsistent with the amino acid sequence, which suggests that Rv1819c has a bacterial ATP-binding cassette (ABC)-exporter fold1. Here, we present structures of Rv1819c, which reveal that the protein indeed contains the ABC-exporter fold, as well as a large water-filled cavity of about 7,700 angstrom(3), which enables the protein to transport the unrelated hydrophilic compounds bleomycin and cobalamin. On the basis of these structures, we propose that Rv1819c is a multi-solute transporter for hydrophilic molecules, analogous to the multidrug exporters of the ABC transporter family, which pump out structurally diverse hydrophobic compounds from cells(8-11).


  
Relationship between the molecular composition, visible light absorption, and health-related properties of smoldering woodsmoke aerosols 期刊论文
ATMOSPHERIC CHEMISTRY AND PHYSICS, 2020, 20 (1) : 539-559
作者:  Chan, Lam Kam;  Nguyen, Khanh Q.;  Karim, Noreen;  Yang, Yatian;  Rice, Robert H.;  He, Guochun;  Denison, Michael S.;  Nguyen, Tran B.
收藏  |  浏览/下载:12/0  |  提交时间:2020/07/02
Torsional refrigeration by twisted, coiled, and supercoiled fibers 期刊论文
SCIENCE, 2019, 366 (6462) : 216-+
作者:  Wang, Run;  Fang, Shaoli;  Xiao, Yicheng;  Gao, Enlai;  Jiang, Nan;  Li, Yaowang;  Mou, Linlin;  Shen, Yanan;  Zhao, Wubin;  Li, Sitong;  Fonseca, Alexandre F.;  Galvao, Douglas S.;  Chen, Mengmeng;  He, Wenqian;  Yu, Kaiqing;  Lu, Hongbing;  Wang, Xuemin;  Qian, Dong;  Aliev, Ali E.;  Li, Na;  Haines, Carter S.;  Liu, Zhongsheng;  Mu, Jiuke;  Wang, Zhong;  Yin, Shougen;  Lima, Marcio D.;  An, Baigang;  Zhou, Xiang;  Liu, Zunfeng;  Baughman, Ray H.
收藏  |  浏览/下载:8/0  |  提交时间:2019/11/27
Ammonia emission control in China would mitigate haze pollution and nitrogen deposition, but worsen acid rain 期刊论文
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2019, 116 (16) : 7760-7765
作者:  Liu, Mingxu;  Huang, Xin;  Song, Yu;  Tang, Jie;  Cao, Junji;  Zhang, Xiaoye;  Zhang, Qiang;  Wang, Shuxiao;  Xu, Tingting;  Kang, Ling;  Cai, Xuhui;  Zhang, Hongsheng;  Yang, Fumo;  Wang, Huanbo;  Yu, Jian Zhen;  Lau, Alexis K. H.;  He, Lingyan;  Huang, Xiaofeng;  Duan, Lei;  Ding, Aijun;  Xue, Likun;  Gao, Jian;  Liu, Bin;  Zhu, Tong
收藏  |  浏览/下载:12/0  |  提交时间:2019/11/27
ammonia emission  China  PM2.5  acid rain  nitrogen deposition  
The earliest human occupation of the high-altitude Tibetan Plateau 40 thousand to 30 thousand years ago 期刊论文
SCIENCE, 2018, 362 (6418) : 1049-+
作者:  Zhang, X. L.;  Ha, B. B.;  Wang, S. J.;  Chen, Z. J.;  Ge, J. Y.;  Long, H.;  He, W.;  Da, W.;  Nian, X. M.;  Yi, M. J.;  Zhou, X. Y.;  Zhang, P. Q.;  Jin, Y. S.;  Bar-Yosef, O.;  Olsen, J. W.;  Gao, X.
收藏  |  浏览/下载:20/0  |  提交时间:2019/11/27
Rapid change of superconductivity and electron-phonon coupling through critical doping in Bi-2212 期刊论文
SCIENCE, 2018, 362 (6410) : 62-+
作者:  He, Y.;  Hashimoto, M.;  Song, D.;  Chen, S. -D.;  He, J.;  Vishik, I. M.;  Moritz, B.;  Lee, D. -H.;  Nagaosa, N.;  Zaanen, J.;  Devereaux, T. P.;  Yoshida, Y.;  Eisaki, H.;  Lu, D. H.;  Shen, Z. -X.
收藏  |  浏览/下载:10/0  |  提交时间:2019/11/27
Aerosol-induced changes in the vertical structure of precipitation: a perspective of TRMM precipitation radar 期刊论文
ATMOSPHERIC CHEMISTRY AND PHYSICS, 2018, 18 (18) : 13329-13343
作者:  Guo, Jianping;  Liu, Huan;  Li, Zhanqing;  Rosenfeld, Daniel;  Jiang, Mengjiao;  Xu, Weixin;  Jiang, Jonathan H.;  He, Jing;  Chen, Dandan;  Min, Min;  Zhai, Panmao
收藏  |  浏览/下载:17/0  |  提交时间:2019/04/09
Exploration of PM2.5 sources on the regional scale in the Pearl River Delta based on ME-2 modeling 期刊论文
ATMOSPHERIC CHEMISTRY AND PHYSICS, 2018, 18 (16) : 11563-11580
作者:  Huang, Xiao-Feng;  Zou, Bei-Bing;  He, Ling-Yan;  Hu, Min;  Prevot, Andre S. H.;  Zhang, Yuan-Hang
收藏  |  浏览/下载:7/0  |  提交时间:2019/04/09
Near-infrared deep brain stimulation via upconversion nanoparticle-mediated optogenetics 期刊论文
SCIENCE, 2018, 359 (6376) : 679-683
作者:  Chen, Shuo;  Weitemier, Adam Z.;  Zeng, Xiao;  He, Linmeng;  Wang, Xiyu;  Tao, Yanqiu;  Huang, Arthur J. Y.;  Hashimotodani, Yuki;  Kano, Masanobu;  Iwasaki, Hirohide;  Parajuli, Laxmi Kumar;  Okabe, Shigeo;  Teh, Daniel B. Loong;  All, Angelo H.;  Tsutsui-Kimura, Iku;  Tanaka, Kenji F.;  Liu, Xiaogang;  McHugh, Thomas J.
收藏  |  浏览/下载:13/0  |  提交时间:2019/11/27