Search results for "craft"
showing 10 items of 369 documents
ChemInform Abstract: Indirect Regioselective Heteroarylation of Indoles Through a Friedel-Crafts Reaction with (E)-1,4-Diaryl-2-buten-1,4-diones.
2010
Abstract A two-step synthesis of 3-heteroaryl indoles has been developed. The first step of the sequence involves a Friedel–Crafts alkylation of indoles with 1,4-diaryl-2-buten-1,4-diones to give the corresponding indoles bearing a 1,4-dicarbonyl moiety. The reaction is catalyzed by InCl 3 and takes place with good yields. Cyclization of the diones under different Paal–Knorr conditions allows to prepare indoles substituted at the C3 position with 3-furanyl, 3-pyrrolyl- and 3-thienyl moieties.
Indirect regioselective heteroarylation of indoles through a Friedel–Crafts reaction with (E)-1,4-diaryl-2-buten-1,4-diones
2009
Abstract A two-step synthesis of 3-heteroaryl indoles has been developed. The first step of the sequence involves a Friedel–Crafts alkylation of indoles with 1,4-diaryl-2-buten-1,4-diones to give the corresponding indoles bearing a 1,4-dicarbonyl moiety. The reaction is catalyzed by InCl 3 and takes place with good yields. Cyclization of the diones under different Paal–Knorr conditions allows to prepare indoles substituted at the C3 position with 3-furanyl, 3-pyrrolyl- and 3-thienyl moieties.
Organocatalytic asymmetric addition of naphthols and electron-rich phenols to isatin-derived ketimines: highly enantioselective construction of tetra…
2015
A quinine-derived thiourea organocatalyst promoted the highly enantioselective addition of naphthols and activated phenols to ketimines derived from isatins. The reaction afforded chiral 3-amino-2-oxindoles with a quaternary stereocenter in high yields (up to 99%) with excellent enantioselectivity (up to 99% ee). To the best of our knowledge, this transformation is the first highly enantioselective addition of naphthols to ketimines
Chlorine partitioning in the lowermost Arctic vortex during the cold winter 2015/2016
2019
Activated chlorine compounds in the polar winter stratosphere drive catalytic cycles that deplete ozone and methane, whose abundances are highly relevant to the evolution of global climate. The present work introduces a novel dataset of in situ measurements of relevant chlorine species in the lowermost Arctic stratosphere from the aircraft mission POLSTRACC–GW-LCYCLE–SALSA during winter 2015/2016. The major stages of chemical evolution of the lower polar vortex are presented in a consistent series of high-resolution mass spectrometric observations of HCl and ClONO2. Simultaneous measurements of CFC-12 are used to derive total inorganic chlorine (Cly) and active chlorine (ClOx). The new data…
Evaluation of Sentinel-2 Red-Edge Bands for Empirical Estimation of Green LAI and Chlorophyll Content
2011
ESA’s upcoming satellite Sentinel-2 will provide Earth images of high spatial, spectral and temporal resolution and aims to ensure continuity for Landsat and SPOT observations. In comparison to the latter sensors, Sentinel-2 incorporates three new spectral bands in the red-edge region, which are centered at 705, 740 and 783 nm. This study addresses the importance of these new bands for the retrieval and monitoring of two important biophysical parameters: green leaf area index (LAI) and chlorophyll content (Ch). With data from several ESA field campaigns over agricultural sites (SPARC, AgriSAR, CEFLES2) we have evaluated the efficacy of two empirical methods that specifically make use of the…
Fuzzy-logic-based approach for identifying objects of interest in the PRIDE framework
2008
On-road autonomous vehicle navigation requires real-time motion planning in the presence of static and moving objects. Based on sensed data of the environment and the current traffic situation, an autonomous vehicle has to plan a path by predicting the future location of objects of interest. In this context, an object of interest is a moving or stationary object in the environment that has a reasonable probability of intersecting the path of the autonomous vehicle within a predetermined time frame. This paper investigates the identification of objects of interest within the PRIDE (PRediction In Dynamic Environments) framework. PRIDE is a multi-resolutional, hierarchical framework that predi…
Arte Textil y tradición en la Provincia de Catamarca, Noroeste Argentino
2019
espanolLas tradiciones textiles en la Provincia de Catamarca, constituyen parte de una identidad cultural conformada a partir de elementos muy pujantes provenientes de distinto origen. Estos se traslucen tanto en estilos y tecnicas de piezas de exquisita estetica y calidad. Evidencian ademas, la historia de las industrias y manufacturas textiles que aportaron al desarrollo de esta actividad, considerada por sus habitantes como parte de su idiosincracia que -lamentablemente- con los anos tiende a desaparecer. EnglishThe textile traditions in the province of Catamarca, are part of a cultural identity formed from very vigorous elements from different origins. These are permeated both styles an…
Reducing False Node Failure Predictions in HPC
2019
Future HPC applications must be able to scale to thousands of compute nodes, while running for several days. The increased runtime and node count inconveniently raises the probability of hardware failures that may interrupt computations. Scientists must therefore protect their simulations against hardware failures. This is typically done using frequent checkpoint& restart, which may have significant overheads. Consequently, the frequency in which checkpoints are taken should be minimized. Predicting hardware failures ahead of time is a promising approach to address this problem, but has remaining issues like false alarms at large scales. In this paper, we introduce the probability of unnece…
Aalto-1, multi-payload CubeSat: Design, integration and launch
2021
The design, integration, testing, and launch of the first Finnish satellite Aalto-1 is briefly presented in this paper. Aalto-1, a three-unit CubeSat, launched into Sun-synchronous polar orbit at an altitude of approximately 500 km, is operational since June 2017. It carries three experimental payloads: Aalto Spectral Imager (AaSI), Radiation Monitor (RADMON), and Electrostatic Plasma Brake (EPB). AaSI is a hyperspectral imager in visible and near-infrared (NIR) wavelength bands, RADMON is an energetic particle detector and EPB is a de-orbiting technology demonstration payload. The platform was designed to accommodate multiple payloads while ensuring sufficient data, power, radio, mechanica…
Optimal Starting Conditions for the Rendezvous Maneuver, Part 1: Optimal Control Approach
2008
We consider the three-dimensional rendezvous between two spacecraft: a target spacecraft on a circular orbit around the Earth and a chaser spacecraft initially on some elliptical orbit yet to be determined. The chaser spacecraft has variable mass, limited thrust, and its trajectory is governed by three controls, one determining the thrust magnitude and two determining the thrust direction. We seek the time history of the controls in such a way that the propellant mass required to execute the rendezvous maneuver is minimized. Two cases are considered: (i) time-to-rendezvous free and (ii) time-to-rendezvous given, respectively equivalent to (i) free angular travel and (ii) fixed angular trave…