Asymmetric Synthesis
Mostrando 1-12 de 161 artigos, teses e dissertações.
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1. RECENT ADVANCES IN CYANATION REACTIONS
Transformations involving structurally complex molecules, natural products and representative molecules are extremely important to obtain key reaction intermediates, in addition to accessing molecules with bioactive properties. The development of cyanation methodologies in those molecules becomes important, because nitriles are versatile and important buildi
Química Nova. Publicado em: 2022
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2. A New Energetic Complex: Synthesis, Structure, and Combustion Catalysis Performance
The potential of tetrazole-based ligands for forming energetic complexes applied in pyrotechnics and propellants is demonstrated with the use of 5,5’-(1,3-phenylene)bis(1H-tetrazole) (H2BTB) to generate an energetic complex with high energy. A new energetic complex of PbII-tetrazolate, [Pb2(BTB)2(H2O)8]·5H2O (1), was synthesized and structurally character
J. Braz. Chem. Soc.. Publicado em: 2020-08
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3. SYNTHESIS, CHARACTERIZATION, ADSORPTION AND THERMODYNAMIC STUDIES OF PURE AND BINARY CO2-N2 MIXTURES ON OXYGEN ENRICHED NANOSTRUCTURED CARBON ADSORBENTS
Abstract Oxygen enriched porous carbons have been synthesized by a nanocasting technique using mesoporous zeolite as template and epoxy resin as precursor. Characterization results show the effect of the nanocasting technique on the development of heterogeneous surface, high basicity, and high surface area of 686.37 m2g-1, beneficial for CO2 adsorption. Pure
Braz. J. Chem. Eng.. Publicado em: 09/12/2019
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4. Synthesis of the C(7)-C(20) Fragment of Spirotoamides A, B and C
This work describes the preparation of the C(7)-C(20) fragment of spirotoamides A to C in a very elegant fashion, achievement very high levels of stereocontrol. The synthesis has been accomplished by a sequence involving 14 steps (0.36% overall yield, average of 81% for each step) in high diastereo and enantioselectivity, employing, as determining steps, asy
J. Braz. Chem. Soc.. Publicado em: 12/08/2019
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5. When Serendipity Knocks on the Door: Synthesis and Physicochemical Characterization of 7-Chloro-2,3-dihydro-5H-thiazolo[3,2-a ]pyrimidin-5-one
Herein, we present the serendipitous obtaining of 7-chloro-2,3-dihydro-5H-thiazolo [3,2-a]pyrimidin-5-one in 40% yield by using POCl3 and a thiobarbituric acid derivative. The thiazolopyrimidine derivative was characterized by 1H nuclear magnetic resonance (NMR), UV-Vis, and Fourier transform infrared (FTIR) spectroscopy. Additionally, the structure was conf
J. Braz. Chem. Soc.. Publicado em: 04/07/2019
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6. New Approach for the Stereoselective Synthesis of (+)-epi-Cytoxazone
The stereoselective total synthesis of (+)-epi-cytoxazone was performed satisfactorily in 8 steps, in 17% overall yield, via a novel route from 2,3-O-(3-pentylidene)-(R)-glyceraldehyde. The bulky group alkene-ketal allowed intramolecular control of the target molecule's asymmetric centers in the dihydroxylation step by promoting the approach of OsO4 to the f
J. Braz. Chem. Soc.. Publicado em: 2019-03
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7. AVANÇOS RECENTES NA HIDROAMINAÇÃO DE COMPOSTOS INSATURADOS
This review presents thermodynamics and kinetics aspects of the hydroamination reaction, recent advancements on this field for non-activated alkenes, alkynes and allenes, employing transition metal catalysis or organocatalysis, including activation by hydrogen bonding or Brønsted acids. Selected syntheses that contain a strategic hydroamination step will be
Quím. Nova. Publicado em: 2017-09
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8. Synthesis, Characterization and Dielectric Properties of New 5-(4-Hydroxyphenyl)- 10,15,20-tri-4-[2-(3-pentadecylphenoxy)ethoxy]phenyl porphyrin and Their Ni, Co and Cu Complexes
New asymmetric cardanol-based porphyrins, free-base and coordinated with Ni, Co and Cu, were synthesized and completely characterized as A3B type. Such porphyrins were obtained aiming improved solubility in polar solvents due insertion of an -OH phenolic group. Their thermal and dielectric properties were also evaluated. Changes in the synthetic route reduce
J. Braz. Chem. Soc.. Publicado em: 2017-06
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9. Nitric oxide and asymmetric dimethyl arginine (ADMA) levels in an experimental hydronephrotic kidney caused by unilateral partial ureteral obstruction
ABSTRACT Aim Our aim is to measure asymmetric dimethyl arginine and nitric oxide levels in rats with induced unilateral acute ureteral obstruction to research the effects on the kidney. Material and Methods The study included 21 adolescent (average age 6 weeks) Sprague-Dawley male rats weighing between 240-290g divided at random into 3 groups. Group-1: C
Int. braz j urol.. Publicado em: 2016-06
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10. Asymmetric Synthesis of Highly Functionalized Cyclohexa-1,3-dienes via Organocatalyzed One-Pot Three-Component Domino Reaction of Malononitrile with α,β-Unsaturated Imines
The enantioselective synthesis of highly functionalized cyclohexa-1,3-dienes was achieved via an organocatalytic one-pot three-component domino reaction. In addition, a possible mechanism accounting for the reaction was proposed.
J. Braz. Chem. Soc.. Publicado em: 2015-03
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11. Ultrafiltration membranes from waste polyethylene terephthalate and additives: synthesis and characterization
The synthesis and characterization of asymmetric ultrafiltration membranes from recycled polyethylene terephthalate (PET) and polyvinylpyrrolidone (PVP) is reported. PET is currently used in many applications, including the manufacture of bottles and tableware. Monomer extraction from waste PET is expensive, and this process has not yet been successfully dem
Quím. Nova. Publicado em: 2014
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12. Asymmetric synthesis of propranolol, naftopidil and (R)-monobutyrin using a glycerol desymmetrization strategy
Este trabalho descreve uma abordagem para dessimetrização de glicerol utilizando canforsulfonamida disponível como material de partida. A estratégia para síntese assimétrica de (R)/(S)-propranolol, (R)/(S)-naftopidila e (R)-monobutirina com formação de espirocetal por dessimetrização foi empregada e a reação de Mitsunobu foi utilizada para a form
J. Braz. Chem. Soc.. Publicado em: 2013-03