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1.
Chemistry ; 27(62): 15276, 2021 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-34709677

RESUMO

Invited for the cover of this issue are Oleksandr Grygorenko and co-workers at Enamine Ltd., Institute of Organic Chemistry NAS Ukraine, and Taras Shevchenko National University of Kyiv. The image depicts a musical allegory for chemical synthesis: a guitar player in a flask, creating notes that become an orgoboron compound. Read the full text of the article at 10.1002/chem.202102108.


Assuntos
Ácidos Borônicos , Química Orgânica , Química Farmacêutica , Humanos
2.
Chemistry ; 27(64): 15829-15841, 2021 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-34647364

RESUMO

The name of Menshutkin is most frequently associated with his eponymous reaction (the quaternization of tertiary amines with alkyl halides). However, he made encyclopedic contributions to the field of reaction kinetics, where he carried out extensive studies of the effects of reactant structure on the rates of esterification of monohydric, dihydric and trihydric alcohols with monocarboxylic acids, and monobasic and dibasic carboxylic acids and anhydrides with monohydric alcohols. In these studies, he deduced an order of reactivity of alcohols in esterification on the basis of their reactions with acetic acid, and the effects of acid structure on the rates of esterification based on the reaction of the carboxylic acid with isobutyl alcohol. When his attention later turned to the substitution chemistry of amines, he defined the parameters that affected their reactions: anilines were less reactive than alkylamines, secondary more reactive than primary amines, and the reaction was accelerated by replacing benzene as a solvent with alcohols. The wide-ranging work of Menshutkin, the physical organic chemist, is discussed.


Assuntos
Anidridos , Química Orgânica , Álcoois , Ácidos Carboxílicos , Esterificação
4.
J Org Chem ; 86(15): 10672-10698, 2021 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-34314187

RESUMO

We report our efforts toward achieving C(sp2)-C(sp3) coupling reactions with 2,2-difluorobicyclo[1.1.1]pentane (BCP-F2) building blocks. By comparing the reactivities of matching pairs of bicyclo[1.1.1]pentane (BCP) and BCP-F2 analogues, we discovered that the Barluenga coupling reaction was the only cross-coupling protocol that translated well between the two structural motifs in contrast to other reported protocols. In this chemistry, a BCP-F2 bearing a tosylhydrazone functional group is cross-coupled with an arylboronic acid. These results further expanded the scope of BCP-F2 building blocks for potential applications in organic chemistry as well as medicinal chemistry.


Assuntos
Química Orgânica , Química Farmacêutica
5.
J Org Chem ; 86(20): 14192-14198, 2021 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-34235919

RESUMO

We combine random sampling and active machine learning (ML) to optimize the synthesis of isomacroin, executing only 3% of all possible Friedländer reactions. Employing kinetic modeling, we augment machine intuition by extracting mechanistic knowledge and verify that a global optimum was obtained with ML. Our study contributes evidence on the potential of multiscale approaches to expedite the access to chemical matter, further democratizing organic chemistry in a data-motivated fashion.


Assuntos
Química Orgânica , Aprendizado de Máquina , Cinética
6.
Molecules ; 26(11)2021 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-34071640

RESUMO

A facile solid-phase synthetic method for incorporating the imidazoline ring motif, a surrogate for a trans peptide bond, into bioactive peptides is reported. The example described is the synthesis of an imidazoline peptidomimetic analog of an insect pyrokinin neuropeptide via a cyclization reaction of an iminium salt generated from the preceding amino acid and 2,4-diaminopropanoic acid (Dap).


Assuntos
Imidazolinas/química , Neuropeptídeos/química , Peptídeos/química , beta-Alanina/análogos & derivados , Animais , Química Orgânica/métodos , Éteres/química , Hormônios de Inseto/química , Insetos , Espectroscopia de Ressonância Magnética , Polímeros/química , Propionatos/química , Técnicas de Síntese em Fase Sólida , Solventes/química , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , beta-Alanina/química
7.
Chemistry ; 27(41): 10488, 2021 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-34180093

RESUMO

Invited for the cover of this issue is Kamil Parkan and co-workers at University of Chemistry and Technology and Institute of Organic Chemistry and Biochemistry, Prague. The cover graphic depicts a schematic representation of the assembly of aryl-C-glycosides based on a protecting-group-free Hiyama reaction. Read the full text of the article at 10.1002/chem.202101052.


Assuntos
Compostos Benzidrílicos , Glucosídeos , Química Orgânica , Glicosídeos , Humanos
8.
Molecules ; 26(9)2021 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-34066597

RESUMO

Thirty-three alkyl and aryl isothiocyanates, as well as isothiocyanate derivatives from esters of coded amino acids and from esters of unnatural amino acids (6-aminocaproic, 4-(aminomethyl)benzoic, and tranexamic acids), were synthesized with satisfactory or very good yields (25-97%). Synthesis was performed in a "one-pot", two-step procedure, in the presence of organic base (Et3N, DBU or NMM), and carbon disulfide via dithiocarbamates, with 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium toluene-4-sulfonate (DMT/NMM/TsO-) as a desulfurization reagent. For the synthesis of aliphatic and aromatic isothiocyanates, reactions were carried out in a microwave reactor, and selected alkyl isothiocyanates were also synthesized in aqueous medium with high yields (72-96%). Isothiocyanate derivatives of L- and D-amino acid methyl esters were synthesized, under conditions without microwave radiation assistance, with low racemization (er 99 > 1), and their absolute configuration was confirmed by circular dichroism. Isothiocyanate derivatives of natural and unnatural amino acids were evaluated for antibacterial activity on E. coli and S. aureus bacterial strains, where the most active was ITC 9e.


Assuntos
Química Orgânica/métodos , Isotiocianatos/síntese química , Morfolinas/química , Tolueno/química , Triazinas/química , Aminas/química , Antibacterianos/química , Técnicas de Química Sintética , Cromatografia , Dicroísmo Circular , Escherichia coli/efeitos dos fármacos , Indicadores e Reagentes , Isotiocianatos/análise , Isotiocianatos/química , Espectroscopia de Ressonância Magnética , Micro-Ondas , Solventes , Staphylococcus aureus/efeitos dos fármacos , Enxofre/química , Temperatura
9.
Molecules ; 26(11)2021 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-34067307

RESUMO

Green pepper fruit is often consumed before it is completely ripe. However, the influence of the phenological stage in which the green pepper is consumed as a potential influencing factor in its bioactive compounds content and antioxidant capacity remains unknown. In addition, no literature is available concerning the bioactive compounds changes in 'Lamuyo' green peppers along its developmental and growth cycle. For this, two different approaches have been carried out, one using twelve different phenological stages (S1 to S12), and in the other, seven different harvest dates (from 27 February to 20 April). Moreover, bioactive compounds changes during 21 days of postharvest storage at 8 °C were investigated. In this study, bioactive compounds (ascorbic acid, dehydroascorbic acid, and total phenolic content) and the total hydrophilic and lipophilic (TAA-H and TAA-L) antioxidant activity were analysed. In addition, total soluble solids, total acidity, individual sugars, and organic acids were determined. Vitamin C levels increased along the phenological stages and harvest dates due to significant increases in ascorbic and dehydroascorbic acid levels. Our results show that the total phenol content decreases as vegetables develop and subsequently increases both as ripening begins and by the last harvest date. Furthermore, TAA-H was also greater by the phenological stage S12 and the 20 April harvest date. In conclusion, the phenological stage and harvest date are key factors that significantly influence the bioactive compounds of green peppers, and those that appear by S12 and 20 April could be more beneficial to health.


Assuntos
Antioxidantes/análise , Capsicum/química , Capsicum/crescimento & desenvolvimento , Ácido Ascórbico/análise , Ácido Ascórbico/química , Química Orgânica , Ácido Desidroascórbico/química , Análise de Alimentos , Conservação de Alimentos/métodos , Frutas/química , Concentração de Íons de Hidrogênio , Fenol , Fenóis/análise , Fenóis/química , Compostos Fitoquímicos/análise , Açúcares/química , Temperatura , Fatores de Tempo
10.
Molecules ; 26(8)2021 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-33920588

RESUMO

The synthesis of glycosides and modified nucleosides represents a wide research field in organic chemistry. The classical methodology is based on coupling reactions between a glycosyl donor and an acceptor. An alternative strategy for new C-nucleosides is used in this approach, which consists of modifying a pre-existent furyl aglycone. This approach is applied to obtain novel pyridazine C-nucleosides starting with 2- and 3-(ribofuranosyl)furans. It is based on singlet oxygen [4+2] cycloaddition followed by reduction and hydrazine cyclization under neutral conditions. The mild three-step one-pot procedure leads stereoselectively to novel pyridazine C-nucleosides of pharmacological interest. The use of acetyls as protecting groups provides an elegant direct route to a deprotected new pyridazine C-nucleoside.


Assuntos
Furanos/química , Nucleosídeos/química , Piridazinas/química , Terpenos/química , Química Orgânica/tendências , Glicosídeos/síntese química , Glicosídeos/química , Nucleosídeos/síntese química , Piridazinas/síntese química , Terpenos/síntese química
11.
Chem Rec ; 21(11): 2990-3004, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33566455

RESUMO

Carbohydrates and their conjugates are not only involved in important biological processes but are also regarded as promising therapeutics and prophylactics. Over the last century, several glycosylation methodologies, glycosyl donors, and protecting groups have been developed and some of them have found broad synthetic applications in carbohydrate chemistry. In this Personal Account, we describe how glycosylation and protecting group strategies have been implemented in our as well as in other research groups as to synthesize bioactive glycans, more specifically naturally occurring lupane-type saponins as well as oligosaccharides related to Burkholderia species.


Assuntos
Saponinas , Química Orgânica , Glicosilação , Oligossacarídeos
12.
J Org Chem ; 86(5): 3758-3767, 2021 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-33439649

RESUMO

Rearrangement reactions in organic chemistry are attractive strategies to build efficiently complex scaffolds, in just one step, from simple starting materials. Among them, aryl migrations are certainly one of the most useful and straightforward rearrangement for building attractive carbon-carbon bonds. Of note, anionic aryl migration reactions have been largely described compared to their radical counterparts. Recently, visible-light catalysis has proven its efficiency to generate such radical rearrangements due to the concomitant loss of a particle (often CO2 or SO2), which is the driving-force of the reaction. Here, we disclose a Smiles-type rearrangement, triggered by a phosphorus-containing unit (arylphosphoramidate), therefore called "phospho-Smiles" rearrangement, allowing a Csp2-Csp2 bond formation thanks to a 1,4-aryl migration reaction. In addition, combining this approach with a radical hydroamination/amination reaction produces an amination/phospho-Smiles cascade particularly attractive, for instance, to investigate the synthesis of the phthalazine core, a scarcely described scaffold of interest for medicinal chemistry projects.


Assuntos
Química Orgânica , Luz , Aminação , Carbono , Catálise
13.
Int J Mol Sci ; 22(2)2021 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-33477625

RESUMO

The goal of prebiotic chemistry is the depiction of molecular evolution events preceding the emergence of life on Earth or elsewhere in the cosmos. Plausible experimental models require geochemical scenarios and robust chemistry. Today we know that the chemical and physical conditions for life to flourish on Earth were at work much earlier than thought, i.e., earlier than 4.4 billion years ago. In recent years, a geochemical model for the first five hundred million years of the history of our planet has been devised that would work as a cradle for life. Serpentinization processes in the Hadean eon affording self-assembled structures and vesicles provides the link between the catalytic properties of the inorganic environment and the impressive chemical potential of formamide to produce complete panels of organic molecules relevant in pre-genetic and pre-metabolic processes. Based on an interdisciplinary approach, we propose basic transformations connecting geochemistry to the chemistry of formamide, and we hint at the possible extension of this perspective to other worlds.


Assuntos
Evolução Química , Formamidas/química , Origem da Vida , Prebióticos , Catálise , Química Orgânica , Planeta Terra , Humanos
14.
Molecules ; 26(3)2021 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-33494521

RESUMO

Despite its uniqueness, the Bargellini multicomponent reaction remains barely known by the most part of chemists. This can be ascribed to the fact that this transformation has not been adequately reviewed in the classic books of named reactions in organic chemistry. Nevertheless, several works on this reaction have been carried out over the years, many of them were written in Italian in the period 1929-1966. In this review article we extensively cover, in a chronological order, the most important applications of the Bargellini reaction reported to date, with the hope that this knowledge-sharing will help chemists to properly use this multicomponent transformation and imagine novel reactivities based on it.


Assuntos
Química Orgânica/história , Descoberta de Drogas/história , História do Século XX , Itália
15.
Int J Mol Sci ; 22(2)2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33467549

RESUMO

According to the traditional definition of the concept of "simple substance" adopted in chemistry, it is as a chemical compound, the structural unit of which (molecule, ion, radical, the link of the polymer chain, the unit cell of the crystal lattice, etc [...].


Assuntos
Química Orgânica/métodos , Compostos Orgânicos/química , Polímeros/química , Teoria Quântica , Cristalografia por Raios X , Modelos Moleculares , Estrutura Molecular
16.
Yakugaku Zasshi ; 141(1): 1-13, 2021.
Artigo em Japonês | MEDLINE | ID: mdl-33390437

RESUMO

Chemical biology and structural development studies performed at The University of Tokyo during 1977-2020 are outlined chronologically. The studies are divided into three parts, i.e., (i) chemical biology of chemical carcinogenesis and molecular design of anti-tumor agents, (ii) structural development studies on biological response modifiers, and (iii) studies on so-called dramatype drug discovery focusing on pharmacological chaperones and protein knockdown-inducers. The first part describes analysis of DNA modification by Glu-P-1, which is a typical carcinogenic heterocyclic amine found in cooked foods, as well as molecular design of DNA-cleaving agents with anti-tumor properties. The second part deals with structural development studies of nuclear receptor ligands and various biological response modifiers derived from thalidomide, including the ligand superfamily concept and the multi-template strategy. The third part describes pharmacological chaperones that should be useful for the treatment of protein misfolding diseases, including Niemann-Pick type C disease and retinitis pigmentosa, and a protein knockdown strategy aimed at degradation of neurodegenerative-disease-causing polyglutamic aggregative proteins.


Assuntos
Antineoplásicos , Desenvolvimento de Medicamentos/métodos , Desenvolvimento de Medicamentos/tendências , Descoberta de Drogas/métodos , Descoberta de Drogas/tendências , Fatores Imunológicos , Química Orgânica , Desenho de Fármacos , Técnicas de Silenciamento de Genes , Humanos , Ligantes , Chaperonas Moleculares/uso terapêutico , Ácido Poliglutâmico , Dobramento de Proteína , Deficiências na Proteostase/tratamento farmacológico , Talidomida/química , Fatores de Tempo , Tóquio , Universidades
17.
J Chem Inf Model ; 61(1): 123-133, 2021 01 25.
Artigo em Inglês | MEDLINE | ID: mdl-33410697

RESUMO

Retrosynthesis is an essential task in organic chemistry for identifying the synthesis pathways of newly discovered materials, and with the recent advances in deep learning, there have been growing attempts to solve the retrosynthesis problem through transformer models, which are the state-of-the-art in neural machine translation, by converting the problem into a machine translation problem. However, the pure transformer provides unsatisfactory results that lack grammatical validity, chemical plausibility, and diversity in reactant candidates. In this study, we develop tied two-way transformers with latent modeling to solve those problems using cycle consistency checks, parameter sharing, and multinomial latent variables. Experimental results obtained using public and in-house datasets demonstrate that the proposed model improves the retrosynthesis accuracy, grammatical error, and diversity, and qualitative evaluation results verify its ability to suggest valid and plausible results.


Assuntos
Química Orgânica , Redes Neurais de Computação
18.
J Oleo Sci ; 70(2): 237-245, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33456010

RESUMO

A two-stage enzymatic hydrolysis method, in which phospholipase A1 (PLA1) was added after phospholipase A2 (PLA2) was added for a certain time, was successfully carried out to prepare glycerylphosphorylcholine (GPC) from soybean concentrated phospholipid. Effects of reaction variables on hydrolysis reaction were optimized using response surface methodology, and the optimal conditions were as follows: PLA2 load of 1.25%, PLA1 load of 0.70%, substrate concentration of 13%, reaction temperature of 41°C, and stirring rate of 680 rpm. Under the optimal conditions, the GPC yield reached 83.07%, which is close to the predicted value by the fitted model. This paper not only provides an efficient and low-cost method to prepare GPC, but also improves the high-value utilization of soybean concentrated phospholipid.


Assuntos
Química Orgânica/métodos , Glicerilfosforilcolina/síntese química , Fosfolipases A1/química , Fosfolipases A2/química , Fosfolipídeos/química , Soja/química , Hidrólise , Temperatura
19.
Anal Bioanal Chem ; 413(7): 1851-1859, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33469709

RESUMO

In this work, a liquid-liquid microextraction methodology using solidified floating organic drop (SFODME) was combined with liquid chromatography and UV/Vis detection to determine non-steroidal anti-inflammatory drugs (NSAIDs) naproxen (NPX), diclofenac (DCF), and mefenamic acid (MFN) in tap water, surface water, and seawater samples. Parameters that can influence the efficiency of the process were evaluated, such as the type and volume of the extractor and dispersive solvents, effect of pH, agitation type, and ionic strength. The optimized method showed low detection limits (0.09 to 0.25 µg L-1), satisfactory recovery rates (90 to 116%), and enrichment factors in the range between 149 and 199. SFODME showed simplicity, low cost, speed, and high concentration capacity of the analytes under study. Its use in real samples did not demonstrate a matrix effect that would compromise the effectiveness of the method, being possible to apply it successfully in water samples with different characteristics.


Assuntos
Anti-Inflamatórios não Esteroides/análise , Cromatografia Líquida de Alta Pressão/métodos , Microextração em Fase Líquida/métodos , Química Orgânica/métodos , Diclofenaco/análise , Dodecanol/análise , Concentração de Íons de Hidrogênio , Íons , Limite de Detecção , Modelos Lineares , Ácido Mefenâmico/análise , Metanol , Naproxeno/análise , Concentração Osmolar , Preparações Farmacêuticas/análise , Reprodutibilidade dos Testes , Água do Mar , Solventes , Temperatura , Água/análise , Poluentes Químicos da Água/análise
20.
J Environ Manage ; 279: 111603, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33172705

RESUMO

Heterogeneous catalysis has currently become an emerging tool for the design and development of sustainable manufacturing processes in order to obtain advanced intermediates, fine chemicals, and bioactive molecules. This field has been considered efficient and eco-friendly, as it investigates the utilization of non-hazardous metals for atom-economical reactions. Nanomaterials have created a significant impact on scientific and engineering advancements due to their tunable properties with superior performance over their massive counterparts. Due to the increased demand for heterogeneous catalysts in industries and academia, different transition metal oxides have been made into substantial nanostructures. Among them, titanium dioxide (TiO2) nanomaterials have received more attention on account of their chemical stability, low cost, dual acid-base properties, good oxidation rate and refractive index. Different modifications of TiO2 extend their applications as active catalysts or catalyst supports in diverse catalytic processes, such as photovoltaics, lithium batteries, pigments and others. One-dimensional (1-D) TiO2 nanostructures such as nanotubes, nanowires and nanorods have achieved greater importance owing to the unique properties of improved porosity, decreased inter-crystalline contacts, large surface-to-volume ratio, superior dispersibility, amplified accessibility of hydroxyl (-OH) groups and presence of good concentrations of Brønsted/Lewis acid sites. Since the discovery, 1-D TiO2 nanostructures have served good photocatalytic applications, but were less explored in organic transformations. While many articles and reviews have covered the applications of 0-D and 1-D TiO2 nanostructured materials (NSMs) in photoelectrochemical reactions and solar cells, there are other interesting applications of these as well. In contrast to the conventional multi-step processes that utilise the stepwise formation of individual bonds, one-pot conversions based on multicomponent reactions (MCRs) have acquired much significance in contemporary organic synthesis. This paper presents a critical review on history, classification, design and synthetic utility of titania-based nanostructures, which could be used as robust solid-acid catalysts and catalyst supports for MCRs. Further, to put ideas into perspective, the introduction and applications of MCRs for various organic transformations have been discussed.


Assuntos
Química Orgânica , Nanoestruturas , Catálise , Titânio
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