中文版 | English

在结果中检索

GSTDTAP

浏览/检索结果: 共13条，第1-10条 帮助

已选(0)清除 条数/页：   排序方式：
Coronavirus: everyone wins when patents are pooled 期刊论文
NATURE, 2020, 581 (7808) : 240-240
作者:  Gariglio, Stefano
收藏  |  浏览/下载：1/0  |  提交时间：2020/07/03

It took a collaborative global effort to reveal the structures of key coronavirus proteins. That spirit is being tested as vaccine development gets under way.


It took a collaborative global effort to reveal the structures of key coronavirus proteins. That spirit is being tested as vaccine development gets under way.


  
Late-stage oxidative C(sp(3))-H methylation 期刊论文
NATURE, 2020, 580 (7805) : 621-+
作者:  Fessler, Evelyn;  Eckl, Eva-Maria;  Schmitt, Sabine;  Mancilla, Igor Alves;  Meyer-Bender, Matthias F.;  Hanf, Monika;  Philippou-Massier, Julia;  Krebs, Stefan;  Zischka, Hans;  Jae, Lucas T.
收藏  |  浏览/下载：70/0  |  提交时间：2020/07/03

Frequently referred to as the '  magic methyl effect'  , the installation of methyl groups-especially adjacent (alpha) to heteroatoms-has been shown to dramatically increase the potency of biologically active molecules(1-3). However, existing methylation methods show limited scope and have not been demonstrated in complex settings(1). Here we report a regioselective and chemoselective oxidative C(sp(3))-H methylation method that is compatible with late-stage functionalization of drug scaffolds and natural products. This combines a highly site-selective and chemoselective C-H hydroxylation with a mild, functional-group-tolerant methylation. Using a small-molecule manganese catalyst, Mn(CF3PDP), at low loading (at a substrate/catalyst ratio of 200) affords targeted C-H hydroxylation on heterocyclic cores, while preserving electron-neutral and electron-rich aryls. Fluorine- or Lewis-acid-assisted formation of reactive iminium or oxonium intermediates enables the use of a mildly nucleophilic organoaluminium methylating reagent that preserves other electrophilic functionalities on the substrate. We show this late-stage C(sp(3))-H methylation on 41 substrates housing 16 different medicinally important cores that include electron-rich aryls, heterocycles, carbonyls and amines. Eighteen pharmacologically relevant molecules with competing sites-including drugs (for example, tedizolid) and natural products-are methylated site-selectively at the most electron rich, least sterically hindered position. We demonstrate the syntheses of two magic methyl substrates-an inverse agonist for the nuclear receptor RORc and an antagonist of the sphingosine-1-phosphate receptor-1-via late-stage methylation from the drug or its advanced precursor. We also show a remote methylation of the B-ring carbocycle of an abiraterone analogue. The ability to methylate such complex molecules at late stages will reduce synthetic effort and thereby expedite broader exploration of the magic methyl effect in pursuit of new small-molecule therapeutics and chemical probes.


A manganese-catalysed oxidative C(sp(3))-H methylation method allows a methyl group to be selectively installed into medicinally important heterocycles, providing a way to improve pharmaceuticals and better understand the '  magic methyl effect'  .


  
Assessing the exploratory potential in Brazil by applying a creaming curve variant 期刊论文
ENERGY POLICY, 2019, 129: 672-683
作者:  Hallack, Larissa Nogueira;  Szklo, Alexandre
收藏  |  浏览/下载：5/0  |  提交时间：2019/11/26
Creaming curve  Exploration effort  Wildcat wells  Yet-to-find discoveries  Recovery factor  
Evolution of global marine fishing fleets and the response of fished resources 期刊论文
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2019, 116 (25) : 12238-12243
作者:  Rousseau, Yannick;  Watson, Reg A.;  Blanchard, Julia L.;  Fulton, Elizabeth A.
收藏  |  浏览/下载：17/0  |  提交时间：2019/11/27
fishing capacity  effort  CPUE  artisanal  industrial  
Predicting tree height from tree diameter and dominant height using mixed-effects and quantile regression models for two species in Turkey 期刊论文
FOREST ECOLOGY AND MANAGEMENT, 2018, 419: 240-248
作者:  Ozcelik, Ramazan;  Cao, Quang V.;  Trincado, Guillermo;  Gocer, Nilsun
收藏  |  浏览/下载：24/0  |  提交时间：2019/04/09
Chapman-Richards  Calibration  Brutian pine  Taurus cedar  Sampling effort  
Conservation of salamanders in managed forests: Methods and costs of monitoring abundance and habitat selection 期刊论文
FOREST ECOLOGY AND MANAGEMENT, 2017, 400: 43817
作者:  Romano, Antonio;  Costa, Andrea;  Basile, Marco;  Raimondi, Ranieri;  Posillico, Mario;  Roger, Daniele Scinti;  Crisci, Aldo;  Piraccini, Riccardo;  Raia, Pasquale;  Matteucci, Giorgio;  De Cinti, Bruno
收藏  |  浏览/下载：14/0  |  提交时间：2019/04/09
Amphibian conservation  Forest management  N-mixture models  Survey effort  Costs analysis  Fine spatial scale  
The effect of sampling effort on estimates of methane ebullition from peat 期刊论文
WATER RESOURCES RESEARCH, 2017, 53 (5)
作者:  Ramirez, Jorge A.;  Baird, Andy J.;  Coulthard, Tom J.
收藏  |  浏览/下载：7/0  |  提交时间：2019/04/09
peatland  methane ebullition  sampling effort  porosity  
China's energy system transformation towards the 2 degrees C goal: Implications of different effort-sharing principles 期刊论文
ENERGY POLICY, 2017, 103
作者:  Pan Xunzhang;  Chen Wenying;  Clarke, Leon E.;  Wang Lining;  Liu Guannan
收藏  |  浏览/下载：18/0  |  提交时间：2019/04/09
China  Energy system transformation  INDC  Carbon budgets  Effort-sharing  
Extinct or still out there? Disentangling influences on extinction and rediscovery helps to clarify the fate of species on the edge 期刊论文
GLOBAL CHANGE BIOLOGY, 2017, 23 (2)
作者:  Lee, Tamsin E.;  Fisher, Diana O.;  Blomberg, Simon P.;  Wintle, Brendan A.
收藏  |  浏览/下载：10/0  |  提交时间：2019/04/09
cure rate model  detectability  Lazarus  mammalia  search effort  
Tonopah Test Range Air Monitoring: CY2013 Meteorological, Radiological, and Airborne Particulate Observations 科技报告
来源：US Department of Energy (DOE). 出版年： 2014
作者:  Mizell, Steve A;  Nikolich, George;  Shadel, Craig;  McCurdy, Greg;  Etyemezian, Vicken;  Miller, Julianne J
收藏  |  浏览/下载：18/0  |  提交时间：2019/04/05
In 1963  the U.S. Department of Energy (DOE) (formerly the Atomic Energy Commission [AEC])  implemented Operation Roller Coaster on the Tonopah Test Range (TTR) and an adjacent area of the Nevada Test and Training Range (NTTR) (formerly the Nellis Air Force Range). This test resulted in radionuclide-contaminated soils at Clean Slate I  II  and III. This report documents observations made during on-going monitoring of radiological  meteorological  and dust conditions at stations installed adjacent to Clean Slate I and Clean Slate III and at the TTR Range Operations Control center. The primary objective of the monitoring effort is to determine if winds blowing across the Clean Slate sites are transporting particles of radionuclide-contaminated soils beyond both the physical and administrative boundaries of the sites. Results for the calendar year (CY) 2013 monitoring include: (1) the gross alpha and gross beta values from the monitoring stations are approximately equivalent to the highest values observed during the CY2012 reporting at the surrounding Community Environmental Monitoring Program (CEMP) stations (this was the latest documented data available at the time of this writing)  (2) only naturally occurring radionuclides were identified in the gamma spectral analyses  (3) the ambient gamma radiation measurements indicate that the average annual gamma exposure is similar at all three monitoring stations and periodic intervals of increased gamma values appear to be associated with storm fronts passing through the area  and (4) the concentrations of both resuspended dust and saltated sand particles generally increase with increasing wind speed. However  differences in the observed dust concentrations are likely due to differences in the soil characteristics immediately adjacent to the monitoring stations. Neither the resuspended particulate radiological analyses nor the ambient gamma radiation measurements suggest wind transport of radionuclide-contaminated soils.