Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 89
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Environ Sci Process Impacts ; 21(12): 2080-2092, 2019 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-31599916

RESUMO

The oxidation mechanism of 4-hydroxy-3-hexanone (CH3CH2C(O)CH(OH)CH2CH3) initiated by NO3 radicals in the nighttime is investigated systematically by applying quantum theoretical methods. According to thermodynamic research, the process of H-abstraction on the -CH- group adjacent to the hydroxyl group is the most dominant pathway with the lowest activation energy. The analysis of Mulliken charge charts and molecular electrostatic potential maps illustrate that C-H bonds are the active sites of the reaction, and the calculated C-H bond dissociation energy of the CH3CH2C(O)CH(OH)CH2CH3 molecule further confirms that α-CH is the most easily activated. Individual rate constants for five H-abstraction pathways are calculated by canonical variational theory coupled with small curvature tunneling method over the temperature range of 260-330 K, and the branching ratios are also evaluated. A total rate constant of 1.18 × 10-15 cm3 per molecule per s is obtained at 298 K, which is in good agreement with the reported experimental value. A negative temperature dependence is observed in the titular reaction. The subsequent degradation processes of the advantageous product alkyl radical (CH3CH2C˙(OH)COCH2CH3) are carried out in a NO-rich environment, and propionic acid, NO2 and ozone are obtained as the major final products. The nighttime atmospheric lifetime of 4-hydroxy-3-hexanone is estimated to be around 19 days, indicating that it has impact at night. The titular reaction rate constants are fitted to a three-parameter Arrhenius formula.


Assuntos
Hexanonas/análise , Modelos Teóricos , Nitratos/química , Hexanonas/química , Ligação de Hidrogênio , Cinética , Dióxido de Nitrogênio/análise , Oxirredução , Ozônio/análise , Propionatos/análise , Teoria Quântica , Termodinâmica
2.
Genes (Basel) ; 10(7)2019 07 18.
Artigo em Inglês | MEDLINE | ID: mdl-31323901

RESUMO

2-Methylketones are involved in plant defense and fragrance and have industrial applications as flavor additives and for biofuel production. We isolated three genes from the crop plant Solanum melongena (eggplant) and investigated these as candidates for methylketone production. The wild tomato methylketone synthase 2 (ShMKS2), which hydrolyzes ß-ketoacyl-acyl carrier proteins (ACP) to release ß-ketoacids in the penultimate step of methylketone synthesis, was used as a query to identify three homologs from S. melongena: SmMKS2-1, SmMKS2-2, and SmMKS2-3. Expression and functional characterization of SmMKS2s in E. coli showed that SmMKS2-1 and SmMKS2-2 exhibited the thioesterase activity against different ß-ketoacyl-ACP substrates to generate the corresponding saturated and unsaturated ß-ketoacids, which can undergo decarboxylation to form their respective 2-methylketone products, whereas SmMKS2-3 showed no activity. SmMKS2-1 was expressed at high level in leaves, stems, roots, flowers, and fruits, whereas expression of SmMKS2-2 and SmMKS2-3 was mainly in flowers and fruits, respectively. Expression of SmMKS2-1 was induced in leaves by mechanical wounding, and by methyl jasmonate or methyl salicylate, but SmMKS2-2 and SmMKS2-3 genes were not induced. SmMKS2-1 is a candidate for methylketone-based defense in eggplant, and both SmMKS2-1 and SmMKS2-2 are novel MKS2 enzymes for biosynthesis of methylketones as feedstocks to biofuel production.


Assuntos
Hexanonas/metabolismo , Lycopersicon esculentum/enzimologia , Solanum melongena/metabolismo , Tioléster Hidrolases/metabolismo , Sequência de Aminoácidos , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Genoma de Planta , Hexanonas/química , Filogenia , Proteínas de Plantas/química , Proteínas de Plantas/genética , Solanum melongena/classificação , Solanum melongena/genética , Tioléster Hidrolases/química , Tioléster Hidrolases/genética
3.
ACS Chem Biol ; 14(7): 1490-1497, 2019 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-31243958

RESUMO

Metabolic profiling and genome mining revealed that anaerobic bacteria have the potential to produce acyloin natural products. In addition to sattazolin A and B, three new sattazolin congeners and a novel acyloin named clostrocyloin were isolated from three strains of Clostridium beijerinckii, a bacterium used for industrial solvent production. Bioactivity profiling showed that the sattazolin derivatives possess antimicrobial activities against mycobacteria and pseudomonads with only low cytotoxicity. Clostrocyloin was found to be mainly active against fungi. The thiamine diphosphate (ThDP)-dependent sattazolin-producing synthase was identified in silico and characterized both in vivo and in in vitro enzyme assays. A related acyloin synthase from the clostrocyloin producer was shown to be responsible for the production of the acyloin core of clostrocyloin. The biotransformation experiments provided first insights into the substrate scope of the clostrocyloin synthase and revealed biosynthetic intermediates.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Antifúngicos/química , Antifúngicos/farmacologia , Álcoois Graxos/química , Álcoois Graxos/farmacologia , Bactérias Anaeróbias/química , Vias Biossintéticas , Clostridium/química , Hexanonas/química , Hexanonas/farmacologia , Humanos , Indóis/química , Indóis/farmacologia , Mycobacterium/efeitos dos fármacos , Infecções por Mycobacterium/tratamento farmacológico , Micoses/tratamento farmacológico , Pseudomonas/efeitos dos fármacos , Infecções por Pseudomonas/tratamento farmacológico
4.
Biomolecules ; 9(5)2019 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-31035614

RESUMO

At the end of its life cycle, the cellular slime mold Dictyostelium discoideum forms a fruiting body consisting of spores and a multicellular stalk. Originally, the chlorinated alkylphenone differentiation-inducing factors (DIFs) -1 and -3 were isolated as stalk cell inducers in D. discoideum. Later, DIFs and their derivatives were shown to possess several biologic activities including antitumor and anti-Trypanosoma properties. In this study, we examined the antibacterial activities of approximately 30 DIF derivatives by using several bacterial species. Several of the DIF derivatives strongly suppressed the growth of the Gram-positive bacteria Staphylococcus aureus, Bacillus subtilis, and Enterococcus faecalis and Enterococcus faecium, at minimum inhibitory concentrations (MICs) in the sub-micromolar to low-micromolar range. In contrast, none of the DIF derivatives evaluated had any noteworthy effect on the growth of the Gram-negative bacterium Escherichia coli (MIC, >100 µM). Most importantly, several of the DIF derivatives strongly inhibited the growth of methicillin-resistant S. aureus and vancomycin-resistant E. faecalis and E. faecium. Transmission electron microscopy revealed that treatment with DIF derivatives led to the formation of distinct multilayered structures consisting of cell wall or plasma membrane in S. aureus. The present results suggest that DIF derivatives are good lead compounds for developing novel antimicrobials.


Assuntos
Antibacterianos/farmacologia , Diferenciação Celular/efeitos dos fármacos , Dictyostelium/citologia , Hexanonas/farmacologia , Antibacterianos/química , Bactérias/efeitos dos fármacos , Bactérias/ultraestrutura , Dibenzofuranos/química , Dibenzofuranos/farmacologia , Dictyostelium/efeitos dos fármacos , Hexanonas/química , Testes de Sensibilidade Microbiana
5.
Chem Biol Interact ; 305: 156-162, 2019 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-30849340

RESUMO

In terms of drug disposal and metabolism SDR21C1 (carbonyl reductase 1; CBR1) exerts an assorted substrate spectrum among a large variety of clinically relevant substances. Additionally, this short-chain dehydrogenase/reductase is extensively expressed in most tissues of the human body, thus underpinning its role in xenobiotic metabolism. Reduction of the chemotherapeutic daunorubicin (DAUN) to daunorubicinol (DAUNol) is a prominent example of its metabolic properties in terms of chemoresistance and cardiotoxicity. The hop-derived prenylated chalcone xanthohumol (XN) and its physiological metabolites isoxanthohumol (IX) and 8-prenylnaringenin (8-PN) have previously been reported to inhibit other DAUN reducing reductases and dehydrogenases including AKR1B1 and AKR1B10. Also with regard to their effects by means of interacting with cancer-related molecular pathways, XN and related prenylated flavonoids in particular have been in the focus of recent studies. In this study, inhibitory properties of these substances were examined with CBR1-mediated 2,3-hexanedione and DAUN reduction. All substances tested in this study turned out to efficiently inhibit recombinant human CBR1 within a low micromolar to submicromolar range. Among the substances tested, 8-PN turned out to be the most effective inhibitor when using 2,3-hexanedione as a substrate (Ki(app) = 180 ±â€¯20 nM). Inhibition rates of recombinant CBR1-mediated DAUN reduction were somewhat weaker with IC50-values ranging from 11 to 20 µM. XN, IX and 8-PN also efficiently inhibited DAUN reduction by SW480 colon adenocarcinoma cytosol (IC50 = 3.71 ±â€¯0.26 µM with 8-PN as inhibitor). This study identifies prenylated inhibitors, which might potentially interact with endogenous CBR1-driven (de-)toxication systems.


Assuntos
Oxirredutases do Álcool/metabolismo , Flavanonas/química , Flavonoides/química , Propiofenonas/química , Xantonas/química , Oxirredutases do Álcool/antagonistas & inibidores , Oxirredutases do Álcool/genética , Linhagem Celular Tumoral , Chalconas/química , Daunorrubicina/química , Daunorrubicina/metabolismo , Flavanonas/metabolismo , Flavonoides/metabolismo , Hexanonas/química , Hexanonas/metabolismo , Humanos , Concentração Inibidora 50 , Cinética , Oxirredução , Propiofenonas/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Especificidade por Substrato , Xantonas/metabolismo
6.
Biol Pharm Bull ; 40(11): 1941-1947, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29093342

RESUMO

Differentiation-inducing factor-3 (DIF-3; 1-(3-chloro-2,6-dihydroxy-4-methoxyphenyl)hexan-1-one), which is found in the cellular slime mold Dictyostelium discoideum, is a potential candidate compound for the development of new medicines; DIF-3 and its derivatives possess several beneficial biological activities, including anti-tumor, anti-Trypanosoma cruzi, and immunoregulatory effects. To assess the relationship between the biological activities of DIF-3 and its chemical structure, particularly in regard to its alkoxy group and the length of the alkyl chains at the acyl group, we synthesized two derivatives of DIF-3, 1-(3-chloro-2,6-dihydroxy-4-methoxyphenyl)octan-1-one (DIF-3(+3)) and 1-(3-chloro-2,6-dihydroxy-4-butoxyphenyl)-hexan-1-one (Hex-DIF-3), and investigated their biological activities in vitro. At micro-molar levels, DIF-3(+3) and Hex-DIF-3 exhibited strong anti-proliferative effects in tumor cell cultures, but their anti-T. cruzi activities at 1 µM in vitro were not as strong as those of other known DIF derivatives. In addition, Hex-DIF-3 at 5 µM significantly suppressed mitogen-induced interleukin-2 production in vitro in Jurkat T cells. These results suggest that DIF-3(+3) and Hex-DIF-3 are promising leads for the development of anti-cancer and immunosuppressive agents.


Assuntos
Antineoplásicos/farmacologia , Proliferação de Células/efeitos dos fármacos , Dictyostelium/metabolismo , Hexanonas/farmacologia , Imunossupressores/farmacologia , Células 3T3 , Animais , Química Farmacêutica , Relação Dose-Resposta a Droga , Células HeLa , Hexanonas/química , Humanos , Concentração Inibidora 50 , Interleucina-2/metabolismo , Células Jurkat , Camundongos , Relação Estrutura-Atividade , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos
7.
J Chem Ecol ; 43(8): 739-744, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28780719

RESUMO

The compound 1-(1H-pyrrol-2-yl)-1,2-propanedione ("pyrrole") is an important pheromone component of several Asian and South American species of longhorned beetles in the subfamily Cerambycinae. Here, we report the first confirmed identification of this compound as a pheromone component of a cerambycine species native to North America, the rare beetle Dryobius sexnotatus Linsley. Headspace volatiles from males contained (R)-3-hydroxyhexan-2-one and pyrrole (ratio 1:0.13), neither of which were detected in samples from a female. A field bioassay confirmed that adults of both sexes were attracted only to the binary blend of racemic 3-hydroxyhexan-2-one plus pyrrole, and not by either compound alone. Adults of another cerambycine, Xylotrechus colonus (F.), were attracted by 3-hydroxyhexan-2-one, consistent with this compound being the primary component of the pheromone of this species; attraction was not influenced by the presence of pyrrole. This study attests to the effectiveness of pheromone-baited traps in capturing rarely encountered species of cerambycids. It also provides further evidence that pyrrole represents another conserved pheromone motif within the Cerambycinae, now having been found in representatives of five cerambycid tribes from three continents.


Assuntos
Besouros/fisiologia , Atrativos Sexuais/farmacologia , Animais , Ásia , Feminino , Hexanonas/química , Hexanonas/farmacologia , Espécies Introduzidas , Masculino , Espectrometria de Massas , América do Norte , Pirróis/química , Pirróis/farmacologia , Atrativos Sexuais/química , Comportamento Sexual Animal/efeitos dos fármacos , América do Sul
8.
Mar Drugs ; 15(5)2017 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-28505073

RESUMO

Bioactivity-guided isolation of a crude extract from a culture broth of Bacillus sp. has led to the isolation of (-)-4-hydroxysattabacin (1). The inhibitory effect of (-)-4-hydroxysattabacin (1) was investigated on melanogenesis in the murine melanoma cell line, B16F10, and human melanoma cell line, MNT-1, as well as a pigmented 3D-human skin model. (-)-4-Hydroxysattabacin treatment decreased melanin contents in a dose-dependent manner in α-melanocyte stimulating hormone (α-MSH)-stimulated B16F10 cells. Quantitative real time PCR (qRT-PCR) demonstrated that treatment with (-)-4-hydroxysattabacin down-regulated several melanogenic genes, including tyrosinase, tyrosinase-related protein 1 (TRP-1), and tyrosinase-related protein 2 (TRP-2) while their enzymatic activities were unaffected. The anti-melanogenic effects of (-)-4-hydroxysattabacin were further demonstrated in a pigmented 3D human epidermal skin model, MelanodermTM, and manifested as whitening and regression of melanocyte activation in the tissue.


Assuntos
Organismos Aquáticos , Bacillus/metabolismo , Hexanonas/farmacologia , Animais , Linhagem Celular Tumoral , Sobrevivência Celular , Relação Dose-Resposta a Droga , Epiderme/efeitos dos fármacos , Hexanonas/química , Hexanonas/metabolismo , Humanos , Levodopa/administração & dosagem , Levodopa/farmacologia , Melaninas/metabolismo , Melanoma/metabolismo , Camundongos , Estrutura Molecular , Pigmentação/efeitos dos fármacos
9.
J Photochem Photobiol B ; 173: 1-11, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28554071

RESUMO

An osazone based ligand, hexane-3,4-dione-bis(2'-phenylhydrazone) (LH2), was synthesized by 1:2M Schiff base condensation of 3,4-hexanedione and phenylhydrazine in dehydrated methanol. Its palladium(II) complex (1) has also been synthesized. LH2 and 1 have thoroughly been characterized by several spectroscopic and analytical means. DFT optimized structure of 1 shows that it is a monomeric Pd(II) complex having 'N2Cl2' coordination chromophore. Our BVS analysis also satisfactorily reproduces the oxidation number of the palladium center. 1 shows irreversible Pd(II)/Pd(I) reduction in its CV in methanol. 1 is three-fold more emissive than LH2. This enhanced emission has also been supported by time correlated single photon counting (TCSPC) measurements at room temperature. Human serum albumin (HSA) binding aspects of both LH2 and 1 have been investigated through various biophysical techniques. The binding constants as determined from Benesi-Hilderbrand plot using the absorbance spectral analyses were found respectively to be 1.18×105 and 4.38×104M-1 for LH2 and 1. The experimental findings confirm that both are good HSA binders. The thermodynamic parameters (∆G°, ∆H° and ∆S°) have also been evaluated by isothermal titration calorimetric (ITC) experiments. These parameters indicate that the binding processes are spontaneous both for LH2 and 1. Molecular docking analyses reveal that both LH2 and 1 reside in domain-I of HSA.


Assuntos
Complexos de Coordenação/metabolismo , Simulação de Acoplamento Molecular , Paládio/química , Albumina Sérica/metabolismo , Sítios de Ligação , Calorimetria , Dicroísmo Circular , Complexos de Coordenação/síntese química , Complexos de Coordenação/química , Polarização de Fluorescência , Hexanonas/química , Humanos , Ligantes , Conformação Molecular , Fenil-Hidrazinas/química , Ligação Proteica , Estrutura Terciária de Proteína , Bases de Schiff/química , Albumina Sérica/química , Termodinâmica
10.
J Microbiol Biotechnol ; 27(6): 1065-1070, 2017 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-28297749

RESUMO

This study aimed to examine the anti-candidal efficacy of a novel ketone derivative isolated from Diaporthe sp. ED2, an endophytic fungus residing in medicinal herb Orthosiphon stamieus Benth. The ethyl acetate extract of the fungal culture was separated by open column and reverse phase high-performance liquid chromatography (HPLC). The eluent at retention time 5.64 min in the HPLC system was the only compound that exhibited anti-candidal activity on Kirby-Bauer assay. The structure of the compound was also elucidated by nuclear magnetic resonance and spectroscopy techniques. The purified anti-candidal compound was obtainedas a colorless solid and characterized as 3-hydroxy-5-methoxyhex-5-ene-2,4-dione. On broth microdilution assay, the compound also exhibited fungicidal activity on a clinical strain of Candida albicans at a minimal inhibitory concentration of 3.1 µg/ml. The killing kinetic analysis also revealed that the compound was fungicidal against C. albicans in a concentration- and time-dependent manner. The compound was heat-stable up to 70°C, but its anti-candidal activity was affected at pH 2.


Assuntos
Antifúngicos/farmacologia , Ascomicetos/química , Candida/efeitos dos fármacos , Endófitos/química , Hexanonas/farmacologia , Cetonas/metabolismo , Cetonas/farmacologia , Antifúngicos/química , Antifúngicos/metabolismo , Ascomicetos/metabolismo , Candida albicans/efeitos dos fármacos , Candidíase/tratamento farmacológico , Candidíase/microbiologia , Cromatografia Líquida de Alta Pressão , Endófitos/metabolismo , Hexanonas/química , Hexanonas/isolamento & purificação , Hexanonas/metabolismo , Concentração de Íons de Hidrogênio , Cetonas/química , Cetonas/isolamento & purificação , Lamiaceae/microbiologia , Testes de Sensibilidade Microbiana , Temperatura
11.
J Proteome Res ; 16(2): 889-897, 2017 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-28088865

RESUMO

Protein precipitation in acetone is frequently employed ahead of mass spectrometry for sample preconcentration and purification. Unfortunately, acetone is not chemically inert; mass artifacts have previously been observed on glycine-containing peptides when exposed to acetone under acidic conditions. We herein report a distinct chemical modification occurring at the level of intact proteins when incubated in acetone. This artifact manifests as one or more satellite peaks in the MS spectrum of intact protein, spaced 98 u above the mass of the unmodified protein. Other artifacts (+84, +112 u) also appear upon incubation of proteins or peptides in acetone. The reaction is pH-sensitive, being suppressed when proteins are exposed to acetone under acidic conditions. The +98 u artifact is speculated to originate through an intermediate product of aldol condensation of acetone to form diacetone alcohol and mesityl oxide. A +98 u product could originate from nucleophilic attack on mesityl oxide or through condensation with diacetone alcohol. Given the extent of modification possible upon exposure of proteins to acetone, particularly following overnight solvent exposure or incubation at room temperature, an awareness of the variables influencing this novel modification is valued by proteomics researchers who employ acetone precipitation for protein purification.


Assuntos
Acetona/química , Artefatos , Citocromos c/análise , Proteínas de Escherichia coli/análise , Espectrometria de Massas/normas , Peptídeos/análise , Animais , Precipitação Química , Citocromos c/química , Escherichia coli/química , Proteínas de Escherichia coli/química , Hemoglobinas/análise , Hemoglobinas/química , Hexanonas/química , Concentração de Íons de Hidrogênio , Mioglobina/análise , Mioglobina/química , Pentanóis/química , Pentanonas/química , Peptídeos/química , Proteômica/métodos , Espectrometria de Massas por Ionização por Electrospray/normas , Ubiquitina/análise , Ubiquitina/química
12.
Molecules ; 22(1)2017 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-28085079

RESUMO

The synthesis of 4-styryl-substituted 2,3,8-trioxabicyclo[3.3.1]nonanes, peroxides with the core structure of the bioactive 1,2,4-trioxane ring, was conducted by a multistep route starting from the aryl methyl ketones 1a-1c. Condensation and reduction/oxidation delivered enals 4a-4c that were coupled with ethyl acetate and reduced to the 1,3-diol substrates 6a-6c. Highly diastereoselective photooxygenation delivered the hydroperoxides 7a-7c and subsequent PPTS (pyridinium-p-toluenesulfonic acid)-catalyzed peroxyacetalization with alkyl triorthoacetates gave the cyclic peroxides 8a-8e. These compounds in general show only moderate antimalarial activities. In order to extend the repertoire of cyclic peroxide structure, we aimed for the synthesis of spiro-perorthocarbonates from orthoester condensation of ß-hydroxy hydroperoxide 9 but could only realize the monocyclic perorthocarbonate 10. That the central peroxide moiety is the key structural motif in anticancer active GST (glutathione S-transferase)-inhibitors was elucidated by the synthesis of a 1,3-dioxane 15-with a similar substitution pattern as the pharmacologically active peroxide 11-via a singlet oxygen ene route from the homoallylic alcohol 12.


Assuntos
Antimaláricos/síntese química , Antineoplásicos/síntese química , Artemisininas/síntese química , Ésteres/síntese química , Compostos Heterocíclicos/química , Peróxidos/síntese química , Acetatos/química , Benzenossulfonatos/química , Compostos Bicíclicos Heterocíclicos com Pontes/química , Hexanonas/química , Oxirredução , Oxigênio Singlete/química , Compostos de Espiro/química , Estereoisomerismo
13.
Sci Rep ; 6: 32379, 2016 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-27582417

RESUMO

Jet fuel range branched cycloalkanes with high density (0.82 g mL(-1)) and low freezing point (217-219 K) was first prepared by the solvent-free intramolecular aldol condensation of the trione from the hydrolysis of the alkylation product of mesityl oxide and 2-methylfuran (or the one-pot reaction of mesityl oxide, 2-methylfuran and water), followed by hydrodeoxygenation (HDO).


Assuntos
Cicloparafinas/química , Cicloparafinas/síntese química , Furanos/química , Hexanonas/química , Lignina/química , Aldeídos/química , Catálise , Hidrogenação , Hidrólise , Ácidos de Lewis/química , Solventes
14.
ChemSusChem ; 9(10): 1209-15, 2016 05 23.
Artigo em Inglês | MEDLINE | ID: mdl-27075722

RESUMO

The highly selective hydrogenation/hydrolytic ring-opening reaction of 5-hydroxymethylfuraldehyde (5-HMF) was catalyzed by homogeneous Cp*Ir(III) half-sandwich complexes to produce 1-hydroxy-2,5-hexanedione (HHD). Adjustment of pH was found to regulate the distribution of products and reaction selectivity, and full conversion of 5-HMF to HHD with 99 % selectivity was achieved at pH 2.5. A mechanistic study revealed that the hydrolysis/ring-opening reaction of 2,5-bis-(hydroxymethyl)furan is the important intermediate reaction step. In addition, an isolated yield of 85 % for HHD was obtained in a 10 g-scale experiment, and the reaction with fructose as the starting material also led to a 98 % GC yield (71.9 % to fructose) of HHD owing to the excellent tolerance of the catalyst under acidic conditions.


Assuntos
Formiatos/química , Furaldeído/análogos & derivados , Irídio/química , Compostos Organometálicos/química , Água/química , Tampões (Química) , Catálise , Furaldeído/química , Hexanonas/química , Concentração de Íons de Hidrogênio , Soluções
15.
J Econ Entomol ; 108(4): 1860-8, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26470328

RESUMO

Many species of cerambycid beetles in the subfamily Cerambycinae are known to use male-produced pheromones composed of one or a few components such as 3-hydroxyalkan-2-ones and the related 2,3-alkanediols. Here, we show that this pheromone structure is characteristic of the cerambycine genus Neoclytus Thomson, based on laboratory and field studies of 10 species and subspecies. Males of seven taxa produced pheromones composed of (R)-3-hydroxyhexan-2-one as a single component, and the synthetic pheromone attracted adults of both sexes in field bioassays, including the eastern North American taxa Neoclytus caprea (Say), Neoclytus mucronatus mucronatus (F.), and Neoclytus scutellaris (Olivier), and the western taxa Neoclytus conjunctus (LeConte), Neoclytus irroratus (LeConte), and Neoclytus modestus modestus Fall. Males of the eastern Neoclytus acuminatus acuminatus (F.) and the western Neoclytus tenuiscriptus Fall produced (2S,3S)-2,3-hexanediol as their dominant or sole pheromone component. Preliminary data also revealed that males of the western Neoclytus balteatus LeConte produced a blend of (R)-3-hydroxyhexan-2-one and (2S,3S)-2,3-hexanediol but also (2S,3S)-2,3-octanediol as a minor component. The fact that the hydroxyketone-hexanediol structural motif is consistent among these North American species provides further evidence of the high degree of conservation of pheromone structures among species in the subfamily Cerambycinae.


Assuntos
Besouros/química , Glicóis/química , Hexanonas/química , Feromônios/química , Animais , Masculino , Especificidade da Espécie , Estados Unidos
16.
Bioorg Med Chem ; 23(15): 4311-5, 2015 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-26122773

RESUMO

The multiple pharmacological activities of differentiation-inducing factor-1 (DIF-1) of the cellular slime mold Dictyostelium discoideum led us to examine the use of DIF-1 as a 'drug template' to develop promising seed compounds for drug discovery. DIF-1 and its derivatives were synthesized and evaluated for their regulatory activities in innate immune responses. We found two new derivatives (4d and 5e) with highly selective inhibitory activities against production of the antimicrobial peptide attacin in Drosophila S2 cells and against production of interleukin-2 in Jurkat cells.


Assuntos
Hexanonas/química , Imunidade Inata/efeitos dos fármacos , Imunossupressores/química , Imunossupressores/farmacologia , Animais , Animais Geneticamente Modificados , Benzeno/química , Técnicas de Química Sintética , Dictyostelium , Drosophila/citologia , Drosophila/imunologia , Descoberta de Drogas , Avaliação Pré-Clínica de Medicamentos/métodos , Hexanonas/farmacologia , Humanos , Proteínas de Insetos/metabolismo , Interleucina-2/metabolismo , Células Jurkat/efeitos dos fármacos , Células Jurkat/metabolismo
17.
Mater Sci Eng C Mater Biol Appl ; 45: 573-7, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25491866

RESUMO

In this study, a novel simple method was developed to prepare functional hyaluronic acid (HA) hydrogels simultaneously containing hydrazone and disulfide bonds in their crossbridges. The HA hydrogels were formed by directly reacting 2,5-hexanedione and 3,3'-dithiodipropionate hydrazide-modified HA, and were characterized by FT-IR, SEM, TGA and mechanical tests. The results showed that the formation of HA hydrogels was a result of the reaction between ketone and hydrazide groups. The resultant HA hydrogels exhibited a porous morphology with a pore size range of 50 µm to 400 µm, and their compressive modulus and G″/G' ratio were 18.8±0.6 kPa and 0.002, respectively. Both swelling and degradation ratios gradually decreased with the increasing degree of crosslinking. However, the degree of crosslinking had a slight effect on the decomposition temperature of the HA hydrogels. It can be concluded that the simple method presented in this study is feasible to prepare HA hydrogels through hydrazone bond crosslinking by reacting diketone molecules and hydrazide-modified HA, and the HA hydrogels have potential in biomedical applications.


Assuntos
Ácido Hialurônico/química , Hidrogéis/química , Força Compressiva , Módulo de Elasticidade , Hexanonas/química , Hidrogéis/síntese química , Microscopia Eletrônica de Varredura , Porosidade , Reologia , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , Termogravimetria
18.
Spectrochim Acta A Mol Biomol Spectrosc ; 129: 307-13, 2014 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-24747853

RESUMO

The reaction between 2,5-hexanedione and salicylic acid hydrazide produced two compounds: 2,5-hexanedione bis(salicyloylhydrazone) [HDSH] (ethanol insoluble) and N-(2,5-dimethyl-1H-pyrrol-1-yl)-2-hydroxybenzamide [DPH] (ethanol soluble). HDSH formed complexes with Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Hg(II) and Pd(II) which are characterized by elemental analyses, spectra (IR, (1)H NMR, ESR and MS), thermal and magnetic measurements. The crystals of [Ni(HDSH-2H)(EtOH)(H2O)] and [Cu(HDSH-2H)] were solved having octahedral and square-planar geometries, respectively. The other complexes have the formulae [Co(HDSH-2H)(H2O)2], [Cu(HDSH-H)2], [Zn(HDSH-2H)(H2O)2], [Cd2(HDSH-4H)(H2O)4], [Cd2(HDSH-2H)(H2O)4Cl2]; [Hg(HDSH-2H)] and [Pd2(HDSH-4H)(H2O)4]. The obtained complexes are stable in air and non-hygroscopic. The magnetic moments and electronic spectra of the complexes provide different geometries. The ESR spectra support the mononuclear geometry for [Cu(HDSH-2H)] and [Cu(HDSH-H)2]. The thermal decomposition of the complexes revealed the coordinated waters as well as the end product which is in most cases the metal oxide. The crystal structure of N-(2,5-dimethyl-1H-pyrrol-1-yl)-2-hydroxybenzamide is solved by X-ray technique.


Assuntos
Benzamidas/química , Complexos de Coordenação/química , Cobre/química , Hexanonas/química , Hidrazonas/química , Níquel/química , Benzamidas/síntese química , Complexos de Coordenação/síntese química , Cristalografia por Raios X , Hexanonas/síntese química , Hidrazonas/síntese química , Modelos Moleculares , Análise Espectral
19.
Chembiochem ; 15(4): 527-32, 2014 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-24474719

RESUMO

Two new acyloin compounds were isolated from the thermophilic bacterium Thermosporothrix hazakensis SK20-1(T) . Genome sequencing of the bacterium and biochemical studies identified the thiamine diphosphate (TPP)-dependent enzyme Thzk0150, which is involved in the formation of acyloin. Through extensive analysis of the Thzk0150-catalyzed reaction products, we propose a putative reaction mechanism involving two substrates: 4-methyl-2-oxovalerate as an acyl donor and phenyl pyruvate as an acyl acceptor.


Assuntos
Chloroflexi/química , Álcoois Graxos/metabolismo , Proteínas de Bactérias/metabolismo , Biocatálise , Candida albicans/efeitos dos fármacos , Chloroflexi/metabolismo , Álcoois Graxos/química , Álcoois Graxos/farmacologia , Hexanonas/química , Hexanonas/metabolismo , Hexanonas/farmacologia , Cetoácidos/química , Cetoácidos/metabolismo , Ácidos Fenilpirúvicos/química , Ácidos Fenilpirúvicos/metabolismo
20.
Org Lett ; 15(24): 6230-3, 2013 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-24295220

RESUMO

An unexpected transformation of 1,6-diarylhexa-1,5-diene-3,4-diones (cinnamils) to 2,3,8-triaryl vinyl fulvenes via N-Heterocyclic Carbene (NHC) catalysis is reported. Mechanistic as well as synthetic novelty is the hallmark of this reaction.


Assuntos
Alcadienos/química , Ciclopentanos/síntese química , Compostos Heterocíclicos/química , Hexanonas/química , Metano/análogos & derivados , Catálise , Ciclopentanos/química , Metano/química , Estrutura Molecular
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA