Search results for " Synthesis"
showing 10 items of 1625 documents
Enantioselective Synthesis of (−)-Dihydrocodeine and Formal Synthesis of (−)-Thebaine, (−)-Codeine, and (−)-Morphine from a Deprotonated α-Aminonitri…
2014
The α-benzylation of a deprotonated bicyclic α-aminonitrile, followed by Noyori's asymmetric transfer hydrogenation combined with the Grewe cyclization onto a symmetrical A-ring precursor, are the key steps of a short and high-yielding enantioselective synthesis of the morphinan (-)-dihydrocodeine. This compound can be converted to (-)-thebaine in high yield by known transformations, while (-)-codeine and (-)-morphine are available from an advanced intermediate.
Synthesis and characterization of indium oxide at high pressures
2018
Introducción: La naturaleza es sorprendente pero a la vez limitada. A mi entender, nada tiene más potencial que aplicar el ingenio humano para modificar lo que nos rodea y crear algo completamente nuevo. La Física de la Materia Condensada es un campo que actualmente está ganando importancia en la Física moderna. En virtud de los éxitos logrados en Física de la Materia Condensada se han producido enormes avances en el campo de la electrónica cuántica, de los semiconductores y de la ciencia de materiales, teniendo como resultado numerosas aplicaciones tecnológicas que han cambiado nuestras vidas drásticamente en los últimos 50 años. Una de las ramas de la Física de la Materia Condensada es el…
Hydrolase–like catalysis and structural resolution of natural products by a metal–organic framework
2020
[EN] The exact chemical structure of non-crystallising natural products is still one of the main challenges in Natural Sciences. Despite tremendous advances in total synthesis, the absolute structural determination of a myriad of natural products with very sensitive chemical functionalities remains undone. Here, we show that a metal-organic framework (MOF) with alcohol-containing arms and adsorbed water, enables selective hydrolysis of glycosyl bonds, supramolecular order with the so-formed chiral fragments and absolute determination of the organic structure by single-crystal X-ray crystallography in a single operation. This combined strategy based on a biomimetic, cheap, robust and multigr…
Application of molecular topology for the prediction of the reaction times and yields under solvent-free conditions
2010
Ball milling and conventional magnetic stirring can be used to support different laboratory techniques with a highly efficient mixing of reagents under solvent-free conditions. By using multilinear regression and linear discriminant analysis, topological-mathematical models have been built to predict the yield and the reaction time for organocatalytic reactions, Suzuki reactions and reactions of synthesis of heterocyclic compounds. The results from the in silico predictions confirm the usefulness of the approach followed.
A Web-Oriented Java3D Talking Head
2009
Facial animation denotes all those systems performing speech synchro- nization with an animated face model. These kinds of systems are named Talking Heads or Talking Faces. At the same time simple dialogue systems called chatbots have been developed. Chatbots are software agents able to interact with users through pattern-matching based rules. In this paper a Talking Head oriented to the creation of a Chatbot is presented. An answer is generated in form of text trig- gered by an input query. The answer is converted into a facial animation using a 3D face model whose lips movements are synchronized with the sound produced by a speech synthesis module. Our Talking Head exploits the naturalnes…
A Java 3D Talking Head for a Chatbot
2008
Facial animation is referred to all those systems per- forming the speech synchronization with an animated face model. This kind of systems are called ”Talking Head” or ”Talking Face”. In this paper a Talking Head oriented to the creation of a Chatbot is presented. It requires an in- put query and an answer is generated in form of text. The answer is transduced into a facial animation using a 3D face model whose lips movements are synchronized with the sound produced by a speech synthesis module. Our ”Talk- ing Head” explores the naturalness of the facial animation and provides a real-time interactive interface to the user. The WEB infrastructure has been realized using the Client- Server m…
Virtual conversation with a real talking head
2008
A talking head is system performing an animated face model synchronized with a speech synthesis module. It is used as a presentation layer of a conversational Agent which provide an answer. It provides an answer when a query is written as an input by the user. The textual answer is converted into facial movements of a 3D face model whose lips and tongue movements are synchronized with the sound of the synthetic voice. The Client-Server paradigm has been used for the WEB infrastructure delegating the animation and synchronization to the client, so that the server can satisfy multiple requests from clients; while the Chatbot, the Digital Signal Processing and the Natural language Processing a…
Organocatalytic enantioselective synthesis of quinolizidine alkaloids (+)-myrtine, (-)-lupinine, and (+)-epiepiquinamide
2011
The organocatalytic synthesis of quinolizidine alkaloids (+)-myrtine, (-)-lupinine, and (+)-epiepiquinamide is described. It involved, as the key step, an enantioselective intramolecular aza-Michael reaction (IMAMR) catalyzed by Jorgensen catalyst I, affording the common precursor with high enantioselectivity. This compound was subsequently transformed into the three alkaloids in a highly diastereoselective manner. (C) 2011 Elsevier Ltd. All rights reserved.
One-pot synthesis of PbS NP/sulfur-oleylamine copolymer nanocomposites via the copolymerization of elemental sulfur with oleylamine
2014
A novel synthetic and processing strategy for converting elemental sulfur into polymeric and nanocomposite materials is reported. We describe a facile one-pot reaction using elemental sulfur and oleylamine as comonomers to prepare high sulfur content copolymers and lead sulfide nanoparticle (PbS NP) nanocomposites. This process enables the preparation of solution processable copolymers and nanocomposites, where the loading and dispersion of PbS NP inclusions could be precisely controlled. We demonstrate the dual roles of oleylamine with sulfur for both the copolymerization of sulfur copolymers as well as the in situ synthesis of PbS NPs in a one-pot fashion.
Shape-dependency activity of nanostructured CeO2 in the total oxidation of polycyclic aromatic hydrocarbons
2013
11 figures, 2 tables.-- © 2012. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/