Chiral Compounds
Mostrando 1-12 de 68 artigos, teses e dissertações.
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1. Absolute Configuration Reassignment of Natural Products: An Overview of the Last Decade
The assignment of absolute configuration (AC) is a crucial step in the structural characterization of natural products, especially for those subjected to biological assays. Methods such as X-ray crystallography, stereocontrolled organic synthesis, nuclear magnetic resonance (NMR), and chiroptical spectroscopies are commonly used to determine the AC of chiral
J. Braz. Chem. Soc.. Publicado em: 2021-08
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2. Chiral Amino and Imino-Alcohols Based on (R)-Limonene
Derivatives of the natural occurring and inexpensive terpene (R) -limonene were synthetized and completely characterized. Starting from internal olefin epoxidation, followed by epoxide opening with sodium azide and azide reduction with LiAlH4, two chiral amino-alcohols were obtained. The amino-alcohols were reacted with three different aldehydes, generating
J. Braz. Chem. Soc.. Publicado em: 2020-03
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3. ONE-POT DIASTEREOSELECTIVE SYNTHESIS OF CHIRAL TRICYCLIC L-CYSTEINE AND D-PENICILLAMINE DERIVATIVES: A LABORATORY EXPERIMENT
A one-pot diastereoselective synthesis of thiazolidine-ring fused systems derived from enantiomerically pure amino acids, L-cysteine or D-penicillamine, and achiral succindialdehyde is described as an experiment to be carried out by upper-division undergraduate students in a laboratory classroom. Reactions were performed under mild conditions, the products w
Quím. Nova. Publicado em: 2020-01
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4. Biotechnological Properties of Sponges from Northeast Brazil: Cliona varians as a Biocatalyst for Enantioselective Reduction of Carbonyl Compounds
To research the potential ability of whole marine sponges to act as biocatalysts, this paper describes for the first time the employment of whole Cliona varians sponge in the stereoselective reduction of prochiral a-keto esters and isatin to the corresponding chiral alcohols. The addition of D-fructose, D-glucose or sucrose remarkably increased the conversio
J. Braz. Chem. Soc.. Publicado em: 2019-01
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5. Determination of Enantioselectivities by Means of Chiral Stationary Phase HPLC in Order to Identify Effective Proline-Derived Organocatalysts
The pyrrolidine fragment is a privileged scaffold within chiral ligands employed in coordination complexes exhibiting catalytic activity in asymmetric reactions and, more recently, as enantioselective organocatalysts per se. Likewise, the employment of (S)-proline as starting material constitutes the most direct form to synthesize those chiral derivatives. A
J. Braz. Chem. Soc.. Publicado em: 2018-05
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6. Absolute Configuration of Solenopsis Piperidines is a Tool to Classify Fire Ants (Formicidae:Myrmicinae)
Piperidine alkaloids are predominant in ant venom glands of S. invicta and S. saevissima. These ants are broadly sympatric in Southeastern Brazil, and potentially diagnostic compounds could assist in ant identification. We determined the absolute configuration of 2,6-dialkyl-piperidines of S. invicta and S. saevissima workers and used these data to group Sou
J. Braz. Chem. Soc.. Publicado em: 2018-02
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7. Chiral Bistacrine Analogues: Synthesis, Cholinesterase Inhibitory Activity and a Molecular Modeling Approach
Cholinesterase enzymes are important targets for the therapy of Alzheimer’s disease. Tacrine-based dual binding site cholinesterases inhibitors are potential disease-modifying anti-Alzheimer drug candidates. In the present work, we described the synthesis of a series of chiral homo- and heterodimers of bis(7)-tacrine connected by a heptylene chain as a spa
J. Braz. Chem. Soc.. Publicado em: 2017-11
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8. Synthesis, Characterization and in vitro Antioxidant Activity of New Chiral N-boc Organotellurium Compounds, (CH3)3OC(O)NHCH(R)C(O)NHCH2-CH2Te-C6H4-4-OCH3, Containing Carbamate and Peptide Groups
Synthesis, characterization and antioxidant activity of a new series of chiral N-boc oraganotellurium compounds, (CH3)3OC(O)NHCH(R)C(O)NHCH2CH2Te-C6H4-4-OCH3, containing carbamate and peptide groups have been reported in this paper. These chiral peptides were synthesized in good to excellent yields, via acid-amine coupling reaction of N-boc L-amino acids wit
J. Braz. Chem. Soc.. Publicado em: 2016-06
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9. ENZYMATIC RESOLUTION OF ANTIDEPRESSANT DRUG PRECURSORS IN AN UNDERGRADUATE LABORATORY
The use of biocatalysts in synthetic chemistry is a conventional methodology for preparing enantiomerically enriched compounds. Despite this fact, the number of experiments in chemical teaching laboratories that demonstrate the potential of enzymes in synthetic organic chemistry is limited. We describe a laboratory experiment in which students synthesized a
Quím. Nova. Publicado em: 2015-02
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10. Cromatografia gasosa quiral na resolução de enantiômeros envolvidos em flavours de frutas
This work addresses the use of chiral gas chromatography in resolving optically active stereoisomers and racemates found in fruit flavours. It presents the types of chiral selectors applied to terpene-derived metal coordination compounds, polysiloxane-linked α-amino acid and mixed chiral stationary phases, and focuses on derivatized cyclodextrins, the most
Quím. Nova. Publicado em: 2014
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11. Catálise assimétrica no Brasil: desenvolvimento e potencialidades para o avanço da indústria química brasileira
The preparation of enantiomerically pure or enriched substances is of fundamental importance to pharmaceutical, food, agrochemical, and cosmetics industries and involves a growing market of hundreds of billions of dollars. However, most chemical processes used for their production are not environmentally friendly because in most cases, stoichiometric amounts
Quím. Nova. Publicado em: 2013
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12. ReaÃÃes biocatalÃticas usando cÃlulas Ãntegras de Lens culinaris (Lentilha). / REACTIONS USING WHOLE CELL BIOCATALYTIC LENS CULINARIS (LENTIL)
This paper describes the use of seeds of lentil (Lens culinaris) as intact plant system in biocatalytic reactions of reduction and hydrolysis. Initially, some plant sources were evaluated for their action in the biocatalytic reduction of aromatic ketone acetophenone. The plants that showed positive results in the reduction reaction underwent determination of
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 23/10/2012