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1.
J Chem Ecol ; 45(9): 741-754, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31456059

RESUMO

A vital trait in insects is their cuticular hydrocarbon (CHC) profile, which protects the insect against desiccation and serves in chemical communication. Due to these functions, CHC profiles are shaped by both climatic conditions and biotic interactions. Here, we investigated CHC differentiation in the neotropical parabiotic ant species Crematogaster levior and Camponotus femoratus, which mutualistically share a nest. Both consist of two cryptic species each (Cr. levior A and B and Ca. femoratus PAT and PS) that differ genetically and possess strongly different CHC profiles. We characterized and compared CHC profiles of the four cryptic species in detail. Our results suggest that Cr. levior A, Ca. femoratus PAT and Ca. femoratus PS adapted their CHC profiles to the parabiotic lifestyle by producing longer-chain CHCs. At the same time, they changed their major CHC classes, and produce more alkadienes and methyl-branched alkenes compared to Cr. levior B or non-parabiotic species. The CHC profiles of Cr. levior B were more similar to related, non-parabiotic species of the Orthocrema clade than Cr. levior A, and the chain lengths of B were similar to the reconstructed ancestral state. Signals of both the parabiotic partner (biotic conditions) and climate (abiotic conditions) were found in the CHC profiles of all four cryptic species. Our data suggest that mutualisms shaped the CHC profiles of the studied species, in particular chain length and CHC class composition. Beside this, signals of the parabiotic partners indicate potential impacts of biotic interactions, via chemical mimicry or chemical camouflage.


Assuntos
Escamas de Animais/química , Hidrocarbonetos/química , Hidrocarbonetos/metabolismo , Simbiose/fisiologia , Alcadienos/química , Animais , Formigas , Estilo de Vida , Especificidade da Espécie
2.
Chem Pharm Bull (Tokyo) ; 67(5): 397-403, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31061363

RESUMO

Cyano (CN) groups are equivalent to carbonyl as well as amino- and hydroxymethyl groups. Therefore, their catalytic introduction under metal catalysis is an important issue in synthetic organic chemistry. Ni-catalyzed hydrocyanation is one of the most well-investigated, powerful tools for installing a CN group. However, it is still difficult to control chemo- and regioselectivity. In this review, the author uses allenes to enable regio-, stereo-, and face-selective transformations to natural product synthesis and axial chirality transfer.


Assuntos
Alcadienos/síntese química , Produtos Biológicos/síntese química , Técnicas de Química Sintética/métodos , Níquel/química , Nitrilos/síntese química , Alcadienos/química , Produtos Biológicos/química , Catálise , Modelos Moleculares , Nitrilos/química , Estereoisomerismo
3.
Macromol Rapid Commun ; 40(13): e1900087, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31058385

RESUMO

The synthesis of diblock and triblock linear polyolefins via ring opening metathesis polymerization (ROMP) in an aqueous nanoparticle dispersion is presented. The different block polyolefins are synthesized from the cyclic olefins 1,5-cyclooctadiene and norbornene (NB), using a water-soluble TEGylated ruthenium alkylidene catalyst, yielding the structures PCOD-b-PNB, PNB-b-PCOD, and PCOD-b-PNB-b-PCOD. High monomer conversion (>90%), monitored by NMR, is achieved in relatively short times (≈1 h) for the polymerization of each block. The livingness of the system, essential to obtain block copolymers, is confirmed by gel permeation chromatography. Latex particles' size during the multiple steps range between 90 and 150 nm. The results demonstrate that it is possible to obtain nanoparticle latexes from ROMP-based monomers with block copolymer architectures, creating the opportunity to copolymerize olefins bearing different functional groups for the synthesis of new materials.


Assuntos
Alcadienos/química , Norbornanos/química , Polímeros/síntese química , Rutênio/química , Catálise , Emulsões , Estrutura Molecular
4.
Molecules ; 24(9)2019 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-31064088

RESUMO

Flavonoids are well-characterized polyphenolic compounds with pharmacological and therapeutic activities. However, most flavonoids have not been developed into clinical drugs, due to poor bioavailability. Herein, we report a strategy to increase the drugability of flavonoids by constructing C(sp2)-O bonds and stereo- as well as regioselective alkenylation of hydroxyl groups of flavonoids with ethyl-2,3-butadienoate allenes. Twenty-three modified flavonoid derivatives were designed, synthesized, and evaluated for their anti-cancer activities. The results showed that compounds 4b, 4c, 4e, 5e, and 6b exhibited better in vitro inhibitory activity against several cancer cell lines than their precursors. Preliminary structure-activity relationship studies indicated that, in most of the cancer cell lines evaluated, the substitution on position 7 was essential for increasing cytotoxicity. The results of this study might facilitate the preparation or late-stage modification of complex flavonoids as anti-cancer drug candidates.


Assuntos
Antineoplásicos/síntese química , Antineoplásicos/uso terapêutico , Éteres/química , Flavonoides/síntese química , Flavonoides/uso terapêutico , Alcadienos/química , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Desenho de Drogas , Humanos , Estrutura Molecular , Estereoisomerismo , Relação Estrutura-Atividade
5.
J Microbiol Biotechnol ; 29(5): 820-826, 2019 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-30982318

RESUMO

This study evaluated the anti-inflammatory potential of a grasshopper ketone (GK) isolated from the brown alga Sargassum fulvellum on lipopolysaccharide (LPS)-induced RAW 264.7 murine macrophage cell line. GK was isolated and purified from the n-hexane fraction and its structure was verified on the basis of NMR spectroscopic data. GK up to 100 µg/ml is not cytotoxic to RAW 264.7, and is an effective inhibitor of LPS-induced NO production in RAW 264.7 cells. The production of pro-inflammatory cytokines, including IL-6, IL-1ß, and TNF-α was found significantly reduced in 0.1-100 µg/ml dose ranges of GK treatment (p < 0.05). We confirmed the dose-dependent and significant inhibition of iNOS and COX-2 proteins expression. In addition, it has been shown that GK induces anti-inflammatory effects by inhibiting MAPKs (ERK, JNK, and p38) and NF-κB p65 phosphorylation. Our results show that the anti-inflammatory properties of GK may be due to the inhibition of the NF-κB and MAPKs pathways, which are associated with the attenuation of cytokine secretion.


Assuntos
Alcadienos/isolamento & purificação , Alcadienos/farmacologia , Anti-Inflamatórios/farmacologia , Cicloexanóis/isolamento & purificação , Cicloexanóis/farmacologia , Lipopolissacarídeos/efeitos adversos , Células RAW 264.7/efeitos dos fármacos , Sargassum/química , Alcadienos/química , Animais , Sobrevivência Celular/efeitos dos fármacos , Cicloexanóis/química , Ciclo-Oxigenase 2/metabolismo , Citocinas/metabolismo , Relação Dose-Resposta a Droga , Etanol , Inflamação/tratamento farmacológico , Interleucina-1beta/metabolismo , Interleucina-6/metabolismo , Camundongos , Proteínas Quinases Ativadas por Mitógeno/metabolismo , NF-kappa B/metabolismo , Óxido Nítrico/metabolismo , Fosforilação , Transdução de Sinais/efeitos dos fármacos , Fator de Transcrição RelA/metabolismo , Fator de Necrose Tumoral alfa/metabolismo
6.
Nature ; 567(7748): 420-424, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30867596

RESUMO

Living systems can generate an enormous range of cellular functions, from mechanical infrastructure and signalling networks to enzymatic catalysis and information storage, using a notably limited set of chemical functional groups. This observation is especially notable when compared to the breadth of functional groups used as the basis for similar functions in synthetically derived small molecules and materials. The relatively small cross-section between biological and synthetic reactivity space forms the foundation for the development of bioorthogonal chemistry, in which the absence of a pair of reactive functional groups within the cell allows for a selective in situ reaction1-4. However, biologically 'rare' functional groups, such as the fluoro5, chloro6,7, bromo7,8, phosphonate9, enediyne10,11, cyano12, diazo13, alkene14 and alkyne15-17 groups, continue to be discovered in natural products made by plants, fungi and microorganisms, which offers a potential route to genetically encode the endogenous biosynthesis of bioorthogonal reagents within living organisms. In particular, the terminal alkyne has found broad utility via the Cu(I)-catalysed azide-alkyne cycloaddition 'click' reaction18. Here we report the discovery and characterization of a unique pathway to produce a terminal alkyne-containing amino acid in the bacterium Streptomyces cattleya. We found that L-lysine undergoes an unexpected reaction sequence that includes halogenation, oxidative C-C bond cleavage and triple bond formation through a putative allene intermediate. This pathway offers the potential for de novo cellular production of halo-, alkene- and alkyne-labelled proteins and natural products from glucose for a variety of downstream applications.


Assuntos
Alquinos/química , Alquinos/metabolismo , Aminoácidos/biossíntese , Aminoácidos/química , Vias Biossintéticas , Streptomyces/metabolismo , Alcadienos/química , Alcadienos/metabolismo , Alcenos/química , Alcenos/metabolismo , Proteínas de Bactérias/metabolismo , Vias Biossintéticas/genética , Carbono/química , Carbono/metabolismo , Glucose/química , Glucose/metabolismo , Halogenação , Lisina/química , Lisina/metabolismo , Família Multigênica/genética , Serina/análogos & derivados , Serina/biossíntese , Serina/química , Streptomyces/genética
8.
Macromol Rapid Commun ; 40(2): e1800326, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30040146

RESUMO

Ring opening metathesis polymerization (ROMP) is a technique that allows the synthesis of well-defined linear polyolefins. Polymerization-induced self-assembly (PISA) involves the synthesis of amphiphilic block copolymers: a hydrophilic block is first polymerized homogeneously in solution (usually water) followed by polymerization of a second hydrophobic block, resulting in a diblock copolymer that self-assembles. In this communication, preliminary results of the development of PISA for the synthesis of amphiphilic block linear polyolefins via ROMP using a water-soluble PEGylated ruthenium alkylidene catalyst are presented. In the first step, a water-soluble modified-norbornene monomer was polymerized in water, then 1,5-cyclooctadiene was added to the system to produce amphiphilic block polyolefins. By varying the concentrations of hydrophilic versus hydrophobic monomer, stable latexes with final particles of ≈200 nm diameter were prepared.


Assuntos
Alcadienos/química , Técnicas de Química Sintética/métodos , Polimerização , Polímeros/química , Alcadienos/síntese química , Catálise , Interações Hidrofóbicas e Hidrofílicas , Microscopia Eletrônica de Transmissão , Modelos Químicos , Estrutura Molecular , Norbornanos/química , Polienos/síntese química , Polienos/química , Polietilenoglicóis/química , Polímeros/síntese química , Rutênio/química , Água/química
9.
J Phys Chem B ; 122(51): 12322-12330, 2018 12 27.
Artigo em Inglês | MEDLINE | ID: mdl-30512958

RESUMO

To protect themselves, insects cover their bodies with what is called cuticular lipid. The cuticular lipid of an American cockroach has a unique lipid content; the most abundant is a cis-alkadiene, cis, cis-6,9-heptacosadiene, amounting to about 70%, which is followed by a branched alkane 3-methylpentacosane. In order to clarify the structural features of the unique lipid composition below the critical temperature, the cuticular lipid was studied by Fourier transform infrared (FTIR) spectroscopy in combination with an attenuated total reflection (ATR) sampling technique. The infrared spectra measured on an extracted lipid sample at 20 °C suggested that the lipid keeps an appreciable level of conformational and lateral packing regularity, in spite of a high cis-unsaturated lipid content, and also a highly disordered condition around the methyl terminals and cis-olefin groups. The CH2 scissoring and the CH2 rocking regions showed the characteristics of the O⊥ subcell. The same characteristics were observed also by in situ measurements on a forewing of the American cockroach. Combining the spectral features of these bands and the physicochemical properties of each component, it can be inferred that saturated lipids form highly ordered domains within the liquid containing the cis, cis-diene as the main component. For comparison, the cuticular lipid of a male cricket, which consisted of many different hydrocarbons, including 15% of unsaturated hydrocarbons, showed a lower regularity both in the conformation and in the lateral packing of hydrocarbon chains. These results imply that not only the degree of cis-unsaturation but also the chemical structure diversity of hydrocarbons are the important factors to determine the physicochemical properties of cuticular lipid.


Assuntos
Alcadienos/análise , Exoesqueleto/química , Lipídeos/análise , Asas de Animais/química , Alcadienos/química , Animais , Gryllidae/química , Lipídeos/química , Masculino , Periplaneta/química , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Estereoisomerismo
10.
Org Biomol Chem ; 17(1): 122-134, 2018 12 19.
Artigo em Inglês | MEDLINE | ID: mdl-30520931

RESUMO

Short syntheses of oxa-preussin, racemic preussin and (-)-preussin are reported. Starting from a racemic 3-nonyl-substituted methoxyallene derivative, its lithiation and addition to phenylethanal provided the corresponding allenyl alcohol that was converted into two diastereomeric dihydrofuran derivatives by silver nitrate-catalyzed 5-endo-trig cyclization. The acid hydrolysis of the enol ether moiety gave heterocyclic ketones and subsequent highly stereoselective reductions with l-selectride furnished 2-benzyl-5-nonylfuran-3-ol derivatives in good overall yield. The major all-cis-diastereomer has the skeleton and relative configuration of preussin and is hence called oxa-preussin. An analogous sequence with the same allene, but an N-sulfonyl imine as the electrophile, finally led to racemic preussin. The stereoselectivities of the individual steps are discussed in detail. With an enantiopure 2-benzyl-5-nonylpyrrolidin-3-one intermediate the preparation of (-)-preussin with an enantiomeric ratio of >95 : 5 could be accomplished in a few steps. The sign of the optical rotation of this product finally proved the absolute configurations of its precursors and demonstrated that our chiral auxiliary-based route led to the antipode of the natural product. The cytotoxicity of several of the prepared heterocycles against MCF-7 tumor cells was investigated and five compounds, including racemic and enantiopure (-)-preussin, were identified as highly cytotoxic with IC50 values in the range of 3-6 µM.


Assuntos
Alcadienos/química , Anisomicina/análogos & derivados , Álcoois , Anisomicina/síntese química , Anisomicina/toxicidade , Catálise , Citotoxinas/síntese química , Humanos , Hidrólise , Concentração Inibidora 50 , Cetonas , Células MCF-7 , Estereoisomerismo
11.
Molecules ; 23(11)2018 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-30463230

RESUMO

In recent years, there have been extraordinary developments of organophosphine-catalyzed reactions. This includes progress in the area of [4C+X] annulations, which are of particular interest due to their potential for the rapid construction of 5⁻8-membered cyclic products. In this short overview, we summarize the remarkable progress, emphasizing reaction mechanisms and key intermediates involved in the processes. The discussion is classified according to the type of electrophilic reactants that acted as C4 synthons in the annulation process, in the order of α-alkyl allenoates, γ-alkyl allenoates, α-methyl allene ketones, ß'-OAc allenoate, δ-OAc allenoate, activated dienes and cyclobutenones.


Assuntos
Fosfinas/química , Alcadienos/química , Catálise , Ciclização , Cetonas/química , Naftalenos/química
12.
J Am Chem Soc ; 140(48): 16450-16454, 2018 12 05.
Artigo em Inglês | MEDLINE | ID: mdl-30451496

RESUMO

We report a Pd-catalyzed intermolecular hydrophosphinylation of 1,3-dienes to afford chiral allylic phosphine oxides. Commodity dienes and air stable phosphine oxides couple to generate organophosphorus building blocks with high enantio- and regiocontrol. This method constitutes the first asymmetric hydrophosphinylation of dienes.


Assuntos
Alcadienos/química , Compostos Alílicos/síntese química , Fosfinas/química , Catálise , Técnicas de Química Sintética/métodos , Complexos de Coordenação/química , Paládio/química , Fosfinas/síntese química , Estereoisomerismo
13.
Org Lett ; 20(20): 6336-6339, 2018 10 19.
Artigo em Inglês | MEDLINE | ID: mdl-30272985

RESUMO

An efficient, unified approach for the synthesis of ß-carbolines, γ-carbolines, and other fused azaheteroaromatics has been realized under metal-free conditions, from propargylic amines and (hetero)aromatic aldehydes. This unified strategy provides ß- and γ-carbolines as well as a range of fused azaheteroaromatics with a broad substrate scope and excellent functional group compatibility. The formal synthesis of oxopropalines D and G has been achieved on gram scale (3a), in a one-pot reaction from commercially available materials (previous shortest reported route to 3a was 5 steps). NMR studies of the conversion of imine intermediate 3aa to ß-carboline 3a were conducted and revealed that the reaction proceeded through an allene intermediate.


Assuntos
Carbolinas/síntese química , Aldeídos/química , Alcadienos/química , Aminas/química , Piridinas/química , Estereoisomerismo
14.
Bioorg Med Chem ; 26(16): 4751-4760, 2018 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-30121214

RESUMO

Our earlier studies indicate that (1E,4E)-1,5-bis(1-alkyl-1H-imidazol-2-yl)penta-1,4-diene-3-ones and (1E,4E)-1,5-bis(1-alkyl-1H-benzo[d]imidazol-2-yl)penta-1,4-diene-3-ones exhibit up to 121-fold greater antiproliferative potency than curcumin in human prostate cancer cell models, but only 2-10 fold increase in mouse plasma concentrations. The present study aims to further optimize them as anti-prostate cancer agents with both good potency and bioavailability. (1E,4E)-1,5-Bis(1H-imidazol-2-yl)penta-1,4-diene-3-one, the potential metabolic product of (1E,4E)-1,5-bis(1-alkyl-1H-imidazol-2-yl)penta-1,4-diene-3-ones, was synthesized and evaluated for its anti-proliferative activity. The promising potency of 1,5-bis(1-alkyl-1H-imidazol-2-yl)penta-1,4-diene-3-ones was completely abolished by removing the 1-alkyl group, suggesting the critical role of an appropriate group on the N1 position. We then envisioned that N-aryl substitution to exclude the C-H bond on the carbon adjacent to the N1 position (α-H) may increase the metabolic stability. Consequently, seven (1E,4E)-1,5-bis(1-aryl-1H-imidazol-2-yl)penta-1,4-dien-3-ones and three (1E,4E)-1,5-bis(1-aryl-1H-benzo[d]imidazol-2-yl)penta-1,4-dien-3-ones, as well as three (1E,4E)-1,5-bis(1-aryl-1H-pyrrolo[3,2-b]pyridine-2-yl)penta-1,4-dien-3-ones, were synthesized through a three-step transformation, including N-arylation via Ullmann condensation, formylation, and Horner-Wadsworth-Emmons reaction. Six optimal (1E,4E)-1,5-bis(1-aryl-1H-imidazol-2-yl)penta-1,4-dien-3-ones exhibit 24- to 375-fold improved potency as compared with curcumin. Replacement of the imidazole with bulkier benzoimidazole and 4-azaindole results in a substantial decrease in the potency. (1E,4E)-1,5-Bis(1-(2-methoxyphenyl)-1H-imidazol-2-yl)penta-1,4-dien-3-one (17d) was established as an optimal compound with both superior potency and good bioavailability that is sufficient to provide the therapeutic efficacy necessary to suppress in vivo tumor growth.


Assuntos
Alcadienos/química , Antineoplásicos/química , Curcumina/química , Alcadienos/farmacocinética , Alcadienos/farmacologia , Animais , Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Curcumina/farmacocinética , Curcumina/farmacologia , Desenho de Drogas , Ensaios de Seleção de Medicamentos Antitumorais , Estabilidade de Medicamentos , Meia-Vida , Humanos , Masculino , Microssomos Hepáticos/metabolismo , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/patologia , Ratos , Ratos Sprague-Dawley , Estereoisomerismo , Relação Estrutura-Atividade
15.
Nat Chem ; 10(9): 953-960, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30061614

RESUMO

For over a century, the structures and reactivities of strained organic compounds have captivated the chemical community. Whereas triple-bond-containing strained intermediates have been well studied, cyclic allenes have received far less attention. Additionally, studies of cyclic allenes that bear heteroatoms in the ring are scarce. We report an experimental and computational study of azacyclic allenes, which features syntheses of stable allene precursors, the mild generation and Diels-Alder trapping of the desired cyclic allenes, and explanations of the observed regio- and diastereoselectivities. Furthermore, we show that stereochemical information can be transferred from an enantioenriched silyl triflate starting material to a Diels-Alder cycloadduct by way of a stereochemically defined azacyclic allene intermediate. These studies demonstrate that heteroatom-containing cyclic allenes, despite previously being overlooked as valuable synthetic intermediates, may be harnessed for the construction of complex molecular scaffolds bearing multiple stereogenic centres.


Assuntos
Alcadienos/química , Compostos Aza/química , Reação de Cicloadição , Teoria da Densidade Funcional , Conformação Molecular , Estereoisomerismo
16.
Org Lett ; 20(15): 4425-4429, 2018 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-29999326

RESUMO

Thermal isomerizations of various propargyl 3-acylpropiolates are described. Many result in the formation of 3-acylbutenolides. These reactions appear to proceed through intermediate 2,3-dehydropyrans (strained cyclic allenes), which then isomerize in a previously unobserved fashion. Competitive processes that provide additional mechanistic insights are also described.


Assuntos
Alcadienos/química , Alquinos/química , Catálise , Ciclização , Dimerização , Isomerismo , Estrutura Molecular , Oxirredução , Termodinâmica
17.
Org Lett ; 20(15): 4566-4570, 2018 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-30009612

RESUMO

A modular and practical route to versatile cyano-1,3-dienes by a sequence involving deconjugative alkylation and "Tsuji-Saegusa-Ito oxidation" is reported. In this letter, the versatility of the products is also explored, including a route to benzochromene scaffolds common to many natural products.


Assuntos
Benzopiranos/síntese química , Alcadienos/química , Alquilação , Catálise , Isomerismo , Estrutura Molecular , Nitrilos/química , Compostos Organometálicos/química , Oxirredução , Paládio/química
18.
J Am Chem Soc ; 140(27): 8434-8438, 2018 07 11.
Artigo em Inglês | MEDLINE | ID: mdl-29936839

RESUMO

Conjugated dienes and polyenes are typically synthesized by sequential introduction of C═C bonds. Here, we report a practical and scalable, catalytic dienylation that is highly regio- and stereoselective for both C═C bonds. The reaction is enabled by a stereoselective palladium-catalyzed cross-coupling that is preceded by a regioselective base-induced ring opening of readily available sulfolenes. The dienylation reaction is particularly useful for the synthesis of synthetically challenging dienes containing cis double bonds. We also show that the reaction can serve as a synthetic platform for the construction of conjugated polyenes.


Assuntos
Alcadienos/síntese química , Polienos/síntese química , Alcadienos/química , Catálise , Técnicas de Química Sintética/métodos , Paládio/química , Polienos/química , Estereoisomerismo
19.
Carbohydr Res ; 465: 29-34, 2018 07 30.
Artigo em Inglês | MEDLINE | ID: mdl-29929049

RESUMO

Synthesis of 1,2-annulated-C-aryl glycosides has been achieved in a stereoselective manner through the Diels-Alder reaction between carbohydrate-derived terminally unsubstituted dienes and in situ generated arynes. In these reactions, formation of sugar-fused (or branched) naphthalenes was also observed and found to be temperature dependent and thus constituting one of the salient features of this work. The synthetic importance of 1,2-annulated-C-aryl glycosides has been explored by transforming them into densely oxygenated products by functionalizing the unsubstituted exo-double bond. Further, 1,2-annulated-C-aryl glycosides give rapid access to C-aryl glycosides in four steps.


Assuntos
Alcadienos/química , Alquinos/química , Carboidratos/química , Glicosídeos/síntese química , Naftalenos/síntese química , Açúcares/síntese química , Glicosídeos/química , Estrutura Molecular , Naftalenos/química , Estereoisomerismo , Açúcares/química
20.
Food Chem ; 263: 89-95, 2018 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-29784333

RESUMO

Phenolics can trap lipid-derived reactive carbonyls as a protective function that diminishes the broadcasting of the lipid oxidative damage to food macromolecules. In an attempt to clarify the trapping of 2,4-alkadienals by phenolics, this study analyzes the reactions of 2,4-hexadienal, 2,4-heptadienal, and 2,4-decadienal with 2-methylresorcinol. These reactions produced (E)-4-(alk-1-en-1-yl)-8-methyl-2,7-bis(prop-1-en-2-yloxy)chromanes, which were isolated and characterized by 1D and 2D NMR and MS. Carbonyl-phenol adduct formation was favored at pH > 7 and moderate temperatures (25-80 °C). Adducts were quantified and shown to be produced as a mixture of diastereomers. Diastereomers 2R,4S plus 2S,4R were formed to a higher extent than diastereomers 2R,4R plus 2S,4S under the different conditions assayed, although activation energies (Ea) for the formation of all of them was mostly the same (∼62 kJ·mol-1). These results show that phenolics can trap 2,4-alkadienals and provide the basis for the later detection of the formed adducts in food pro[ducts.


Assuntos
Alcadienos/química , Lipídeos/química , Resorcinóis/química , Aldeídos/química , Concentração de Íons de Hidrogênio , Espectroscopia de Ressonância Magnética , Oxirredução , Fenóis/química , Estereoisomerismo
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