Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 458
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Molecules ; 24(21)2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31671644

RESUMO

Sesquiterpenoids constitute a marvelously varied group of natural products that feature a vast array of molecular architectures. Among them, the unusual bicyclo [6.3.0] undecane sesquiterpenoids are one of the most representative. To date, only approximately 42 naturally occurring compounds with this unique scaffold, which can be classified into seven different groups, have been reported. As the first-found member of each type, dactylol, asteriscanolide, dumortenol, toxicodenane C, and capillosanane S are characteristic of the four methyl groups on the five-eight-membered ring system. Only 11-hydroxyjasionone and sinuketal decorate the core with an isopropyl group. These natural products exhibit a wide range of bioactivities, including antifouling, anti-inflammatory, immune suppression, cytotoxic, antimutagenic, antiplasmodial, and antiviral activities. It was noted that some total syntheses of precapnellane-sesquiterpenoids (dactylol, poitediol, precapnelladiene), asteriscanolide, and 11-hydroxyjasionone have been achieved, because their cyclooctanoid core represents an important target for the development of synthetic strategies to prepare eight-membered ring-containing compounds. This review focuses on these natural sesquiterpenoids and their biological activities and synthesis, and aims to provide a foundation for further research of these interesting compounds.


Assuntos
Alcanos/síntese química , Alcanos/farmacologia , Sesquiterpenos/síntese química , Sesquiterpenos/farmacologia , Alcanos/química , Vias Biossintéticas , Modelos Moleculares , Sesquiterpenos/química
2.
J Am Chem Soc ; 140(50): 17433-17438, 2018 12 19.
Artigo em Inglês | MEDLINE | ID: mdl-30516995

RESUMO

A strategy for the installation of small alkyl fragments onto pharmaceutically relevant aliphatic structures has been established via metallaphotoredox catalysis. Herein, we report that tris(trimethylsilyl)silanol can be employed as an effective halogen abstraction reagent that, in combination with photoredox and nickel catalysis, allows a generic approach to Csp3-Csp3 cross-electrophile coupling. In this study, we demonstrate that a variety of aliphatic drug-like groups can be successfully coupled with a number of commercially available small alkyl electrophiles, including methyl tosylate and strained cyclic alkyl bromides. Moreover, the union of two secondary aliphatic carbon centers, a long-standing challenge for organic molecule construction, has been accomplished with a wide array of structural formats. Last, this technology can be selectively merged with Csp2-Csp3 aryl-alkyl couplings to build drug-like systems in a highly modular fashion.


Assuntos
Hidrocarbonetos Bromados/química , Compostos de Trimetilsilil/química , Alcanos/síntese química , Catálise/efeitos da radiação , Complexos de Coordenação/química , Complexos de Coordenação/efeitos da radiação , Irídio/química , Irídio/efeitos da radiação , Luz , Estrutura Molecular , Níquel/química
3.
J Am Chem Soc ; 140(44): 14836-14843, 2018 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-30303379

RESUMO

Alkyl chlorides are common functional groups in synthetic organic chemistry. However, the engagement of unactivated alkyl chlorides, especially tertiary alkyl chlorides, in transition-metal-catalyzed C-C bond formation remains challenging. Herein, we describe the development of a TiIII-catalyzed radical addition of 2° and 3° alkyl chlorides to electron-deficient alkenes. Mechanistic data are consistent with inner-sphere activation of the C-Cl bond featuring TiIII-mediated Cl atom abstraction. Evidence suggests that the active TiIII catalyst is generated from the TiIV precursor in a Lewis-acid-assisted electron transfer process.


Assuntos
Alcanos/síntese química , Hidrocarbonetos Clorados/química , Titânio/química , Alcanos/química , Alquilação , Catálise , Radicais Livres/química , Estrutura Molecular
4.
Molecules ; 23(10)2018 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-30322175

RESUMO

A custom-designed series of unsymmetrical spiroalkanedithiols having tailgroups comprised of a terminally fluorinated chain and a hydrocarbon chain of varying lengths were synthesized and used to prepare self-assembled monolayers (SAMs) on gold substrates. The specific structure of the adsorbates was of the form [CH3(CH2)n][CF3(CF2)7(CH2)8]C[CH2SH]2, where n = 7, 9, and 15 (designated as F8H10-C10, F8H10-C12, and F8H10-C18, respectively). The influence of the length of the hydrocarbon chain in the bidentate dithiol on the structure and interfacial properties of the monolayer was explored. A structurally analogous partially fluorinated monodentate alkanethiol and the corresponding normal alkanethiols were used to generate appropriate SAMs as reference systems. Measurements of ellipsometric thickness showed an unexpectedly low film thickness for the SAMs derived from the bidentate adsorbates, possibly due to disruptions in interchain packing caused by the fluorocarbon chains (i.e., phase-incompatible fluorocarbon-hydrocarbon interactions), ultimately giving rise to loosely packed and disordered films. Analysis by X-ray photoelectron spectroscopy (XPS) were also consistent with a model in which the films were loosely packed; additionally, the XPS spectra confirmed the attachment of the sulfur headgroups of the bidentate adsorbates onto the gold substrates. Studies of the SAMs by polarization modulation-infrared reflection-adsorption spectroscopy (PM-IRRAS) suggested that as the length of the hydrocarbon chain in the adsorbates was extended, a more ordered surface was achieved by reducing the tilt of the fluorocarbon segment. The wettability data indicated that the adsorbates with longer alkyl chains were less wettable than those with shorter alkyl chains, likely due to an increase in interchain van der Waals forces in the former.


Assuntos
Alcanos/síntese química , Ouro/química , Compostos de Sulfidrila/síntese química , Alcanos/química , Halogenação , Estrutura Molecular , Espectroscopia Fotoeletrônica , Compostos de Sulfidrila/química , Propriedades de Superfície , Molhabilidade
5.
Org Lett ; 20(18): 5910-5913, 2018 09 21.
Artigo em Inglês | MEDLINE | ID: mdl-30188137

RESUMO

Asmic addresses the long-standing challenge of alkylating isocyanides, providing access to isocyanides with diverse substitution patterns. The o-anisylsulfanyl group serves a critical dual role by facilitating deprotonation-alkylation and providing a latent nucleophilic site through an unusual arylsulfanyl-lithium exchange.


Assuntos
Alcanos/síntese química , Cianetos/química , Alcanos/química , Alquilação , Lítio/química , Estrutura Molecular , Compostos Organometálicos/química , Compostos de Sulfidrila/química
6.
J Org Chem ; 83(11): 5954-5968, 2018 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-29717607

RESUMO

A general protocol is described for inducing enantioselective halolactonizations of unsaturated carboxylic acids using novel bifunctional organic catalysts derived from a chiral binaphthalene scaffold. Bromo- and iodolactonization reactions of diversely substituted, unsaturated carboxylic acids proceed with high degrees of enantioselectivity, regioselectivity, and diastereoselectivity. Notably, these BINOL-derived catalysts are the first to induce the bromo- and iodolactonizations of 5-alkyl-4( Z)-olefinic acids via 5- exo mode cyclizations to give lactones in which new carbon-halogen bonds are created at a stereogenic center with high diastereo- and enantioselectivities. Iodolactonizations of 6-substituted-5( Z)-olefinic acids also occur via 6- exo cyclizations to provide δ-lactones with excellent enantioselectivities. Several notable applications of this halolactonization methodology were developed for desymmetrization, kinetic resolution, and epoxidation of Z-alkenes. The utility of these reactions is demonstrated by their application to a synthesis of precursors of the F-ring subunit of kibdelone C and to the shortest catalytic, enantioselective synthesis of (+)-disparlure reported to date.


Assuntos
Lactonas/química , Naftóis/química , Alcanos/síntese química , Bromo/química , Catálise , Ciclização , Iodo/química , Estrutura Molecular , Estereoisomerismo , Xantonas/síntese química
7.
Org Biomol Chem ; 16(17): 3068-3086, 2018 05 02.
Artigo em Inglês | MEDLINE | ID: mdl-29630080

RESUMO

Nucleic acids, phospholipids and other organic phosphates play central roles in biological pathways. n-Alkyl phosphates and their derivatives have been recognized as amphiphilic molecules for nearly two centuries. In the last 50 years, n-alkyl phosphate derivatives such as di-alkyl phosphates, mono-alkyl phosphatidyl ethanol amines and mono-alkyl phosphocholines have become predominant compounds with applications in different areas, from food chemistry to life science. The aim of this review is to summarize the most relevant progress made in the field of the synthesis of these molecules and to provide a concise perspective on the use of these amphiphiles as possible prebiotic membrane constituents. The first part of the review is dedicated to the analysis of the most relevant syntheses carried out in recent years with respect to those reported from the second half of the nineteenth century. The second part is dedicated to a description of the latest reports on prebiotic synthesis of mono-alkyl phosphates. In this part, the authors did not report the phosphorylation of other relevant biomolecules, such as nucleosides, which have been excellently reviewed elsewere.


Assuntos
Técnicas de Química Sintética/métodos , Membranas Artificiais , Fosfatos/química , Fosfolipídeos/química , Alcanos/síntese química , Alcanos/química , Alquilação , Origem da Vida , Fosfatos/síntese química , Ácidos Fosfatídicos/síntese química , Ácidos Fosfatídicos/química , Fosfolipídeos/síntese química , Fosforilação
8.
Bioorg Med Chem ; 26(8): 1832-1847, 2018 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-29486951

RESUMO

The design and synthesis of a novel class of 7-azaspiro[3.5]nonane GPR119 agonists are described. In this series, optimization of the right piperidine N-capping group (R2) and the left aryl group (R3) led to the identification of compound 54g as a potent GPR119 agonist. Compound 54g showed a desirable PK profile in Sprague-Dawley (SD) rats and a favorable glucose lowering effect in diabetic rats.


Assuntos
Alcanos/química , Desenho de Fármacos , Receptores Acoplados a Proteínas-G/agonistas , Alcanos/síntese química , Alcanos/farmacocinética , Animais , Glicemia/análise , Linhagem Celular , Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Experimental/patologia , Teste de Tolerância a Glucose , Meia-Vida , Humanos , Hipoglicemiantes/síntese química , Hipoglicemiantes/química , Hipoglicemiantes/uso terapêutico , Microssomos Hepáticos/metabolismo , Piperidinas/química , Ratos , Ratos Sprague-Dawley , Receptores Acoplados a Proteínas-G/metabolismo , Relação Estrutura-Atividade
9.
Org Biomol Chem ; 16(9): 1557-1580, 2018 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-29437174

RESUMO

The present work deals with the synthesis of the 10-oxabicyclo[5.2.1]decane framework present in bioactive natural products like physalins, with potential as antitumor agents. This synthetic methodology involves several key reactions: (a) synthesis of polyfunctionalized cycloheptenones by [4 + 3] cycloaddition reactions of furan precursors with oxyallyl cations; (b) Nicholas reaction with propargyl cations stabilized as dicobalt hexacarbonyl complexes; (c) demetallation and hydration of the resulting acetylenes; (d) stereoconvergent aldol cyclization to generate a key oxatricyclic intermediate and (e) a ß-fragmentation process that affords, under hypoiodite photolysis, the desired product with moderate to good yield. The final compounds are the result of a radicalary ß-fragmentation at the level of C2-C6 with respect to the tertiary hydroxyl group on C6, with an unexpected contraction from a ten- to a nine-membered ring system, via a radical addition to the carbonyl group on C4. The synthetic methodology has been scaled up to multigram level with good overall yield. Further biological, biochemical and biophysical studies are being carried out in our laboratory on these 1,7-epoxycyclononane derivatives to determine the potential of this kind of oxabicyclic compound as future hits and/or leads for the development of new anticancer drugs. The preliminary evaluation of the anticancer activity of the representative synthesized compounds, against the leukaemia cancer cell lines K-562 and SR, shows a promising activity with a GI50 = 0.01 µM and a LC50 = 7.4 µM for a conveniently functionalized 10-oxabicyclo[5.2.1]decane.


Assuntos
Alcanos/química , Alcanos/síntese química , Antineoplásicos/química , Antineoplásicos/síntese química , Produtos Biológicos/química , Alcanos/farmacologia , Antineoplásicos/farmacologia , Ciclização , Reação de Cicloadição , Furanos/química , Humanos , Hidrogenação , Células K562 , Modelos Moleculares , Conformação Molecular , Pentanonas/química
10.
Org Lett ; 20(5): 1269-1271, 2018 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-29431447

RESUMO

The BINOL-amidine organic catalyst 1 was previously shown to promote highly efficient enantioselective halolactonization reactions of olefinic acids. As part of these studies, it was discovered that the enantioenriched iodolactones could be easily converted into enantioenriched cis-1,2-disubstituted epoxides. This halolactonization-epoxidation sequence was applied to the synthesis of (+)-disparlure, which resulted in the shortest catalytic enantioselective synthesis to date, requiring only five steps and proceeding in 33% yield.


Assuntos
Alcanos/síntese química , Lactonas/química , Naftóis/química , Catálise , Compostos de Epóxi/química , Estrutura Molecular , Oxirredução , Estereoisomerismo
11.
Bioorg Med Chem ; 25(20): 5586-5597, 2017 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-28870801

RESUMO

A novel series of twenty 1,3-diphenylbenzo[f][1,7]benzonaphthyrdine derivatives were designed and synthesized through intermolecular imino Diels-Alder reaction. Their in vitro cytotoxic activities were evaluated against six human cancer cell lines (NCIH23, HCT15, NUGC-3, ACHN, PC-3, and MDA-MB-231). Majority of synthesized compounds exhibited significant cytotoxic activities against all tested human cancer cell lines. Among them 4l, 4m, and 4o derivatives exhibited most promising cytotoxic activities. Furthermore these compounds were evaluated against human Topoisomerase IIα inhibition. Interestingly, the compound 4l exhibited 1.3 and 1.2 times more potent human Topoisomerase IIα inhibition than the reference drug etoposide in both 100µM and 20µM concentrations respectively. Molecular docking studies for the compound 4l have also been executed by Sybyl X-2.1 in which it reveals the binding site of the compound 4l with topo IIα DNA cleavage site where etoposide was situated. The benzo[f][1,7]naphthyridine ring was stacked between the DNA bases of the cleavage site.


Assuntos
Alcanos/química , Desenho de Fármacos , Piridinas/síntese química , Piridinas/farmacologia , Alcanos/síntese química , Alcanos/farmacologia , Sítios de Ligação , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , DNA Topoisomerases Tipo II/metabolismo , Ensaios de Seleção de Medicamentos Antitumorais , Ativação Enzimática/efeitos dos fármacos , Humanos , Simulação de Acoplamento Molecular , Piridinas/química , Inibidores da Topoisomerase II/síntese química , Inibidores da Topoisomerase II/química , Inibidores da Topoisomerase II/farmacologia
12.
ChemSusChem ; 10(20): 4102-4108, 2017 10 23.
Artigo em Inglês | MEDLINE | ID: mdl-28834404

RESUMO

The catalytic synthesis of liquid alkanes from renewable biomass has received tremendous attention in recent years. However, bio-based platform chemicals have not to date been exploited for the synthesis of highly branched lubricant alkanes, which are currently produced by hydrocracking and hydroisomerization of long-chain n-paraffins. A selective catalytic synthetic route has been developed for the production of highly branched C23 alkanes as lubricant base oil components from biomass-derived furfural and acetone through a sequential four-step process, including aldol condensation of furfural with acetone to produce a C13 double adduct, selective hydrogenation of the adduct to a C13 ketone, followed by a second condensation of the C13 ketone with furfural to generate a C23 aldol adduct, and finally hydrodeoxygenation to give highly branched C23 alkanes in 50.6 % overall yield from furfural. This work opens a general strategy for the synthesis of high-quality lubricant alkanes from renewable biomass.


Assuntos
Alcanos/química , Alcanos/síntese química , Biomassa , Lubrificantes/química , Lubrificantes/síntese química , Acetona/química , Técnicas de Química Sintética , Furaldeído/química , Hidrogenação , Oxigênio/química
13.
Int Immunopharmacol ; 50: 6-13, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28618389

RESUMO

Activated macrophages produce various pro-inflammatory mediators such as inducible nitric oxide synthase (iNOS)-derived nitric oxide (NO) and cyclooxygenase (COX)-2-derived prostaglandin E2 (PGE2) during inflammatory response. However, overproduction of NO and PGE2 appears to be involved in pathogenesis of various inflammatory diseases. Therefore, inhibition of NO and PGE2 production might be useful for the treatment of inflammatory-related diseases. In this study, the bis[(5-methyl)2-furyl](4-nitrophenyl)methane or BFNM was evaluated for the anti-inflammatory activity and mechanism of action in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage. BFNM inhibited NO and PGE2 production in a concentration-dependent manner and down-regulated the expression of iNOS and COX-2 at mRNA and protein levels. BFNM suppressed nuclear translocation of NF-κB p65 subunit only very slightly, and failed to decrease NF-κB DNA binding activity. In contrast, the compound significantly reduced phosphorylation of p38 MAPK and ATF-2, a component of AP-1 known to be involved in the transcriptional regulation of iNOS and COX-2, in a dose-dependent manner in LPS-induced cells. Collectively, these results suggest that BFNM has an anti-inflammatory effect in RAW 264.7 macrophages, at least in part, by suppression of NO and PGE2 production. The inhibitory effect of BFNM is mediated mainly via the p38 MAPK/ATF-2 signaling pathway. Thus, BFNM would be a lead compound for the development of novel anti-inflammatory agents.


Assuntos
Alcanos/farmacologia , Anti-Inflamatórios/farmacologia , Ativação de Macrófagos/efeitos dos fármacos , Macrófagos/fisiologia , Fator 2 Ativador da Transcrição/metabolismo , Alcanos/síntese química , Animais , Ciclo-Oxigenase 2/metabolismo , Dinoprostona/metabolismo , Ligases/metabolismo , Lipopolissacarídeos/imunologia , Camundongos , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase Tipo II/metabolismo , Células RAW 264.7 , Transdução de Sinais/efeitos dos fármacos , Fator de Transcrição AP-1/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
14.
Molecules ; 22(6)2017 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-28594367

RESUMO

Differences on herringbone molecular arrangement in two forms of long-chain 1,ω-alkanediols (CnH2n+2O2 with n = 10, 11, 12, 13) are explained from the analysis of O-H···O hydrogen-bond sequences in infinite chains and the role of a C-H···O intramolecular hydrogen-bond in stabilization of a gauche defect, as well as the inter-grooving effectiveness on molecular packing. GIXD (Glancing Incidence X-ray Diffraction) experiments were conducted on polycrystalline monophasic samples. Diffracted intensities were treated with the multi-axial March-Dollase method to correlate energetic and geometrical features of molecular interactions with the crystalline morphology and textural pattern of samples. The monoclinic (P21/c, Z = 2) crystals of the even-numbered members (n = 10, 12; DEDOL and DODOL, respectively) are diametrical prisms with combined form {104}/{-104}/{001} and present a two-fold platelet-like preferred orientation, whereas orthorhombic (P212121, Z = 4) odd-numbered members (n = 11, 13; UNDOL and TRDOL, respectively) present a dominant needle-like orientation on direction [101] (fiber texture). We show that crystalline structures of medium complexity and their microstructures can be determined from rapid GIXD experiments from standard radiation, combined with molecular replacement procedure using crystal structures of compounds with higher chain lengths as reference data.


Assuntos
Alcanos/química , Ligação de Hidrogênio , Modelos Moleculares , Álcoois/química , Alcanos/síntese química , Cristalografia por Raios X , Ácidos Graxos/química , Conformação Molecular , Estrutura Molecular , Novobiocina/síntese química , Novobiocina/química , Propriedades de Superfície , Difração de Raios X
15.
J Am Chem Soc ; 139(16): 5684-5687, 2017 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-28406620

RESUMO

An asymmetric Ni-catalyzed reductive cross-coupling of (hetero)aryl iodides and benzylic chlorides has been developed to prepare enantioenriched 1,1-diarylalkanes. As part of these studies, a new chiral bioxazoline ligand, 4-heptyl-BiOX (L1), was developed in order to obtain products in synthetically useful yield and enantioselectivity. The reaction tolerates a variety of heterocyclic coupling partners, including pyridines, pyrimidines, indoles, and piperidines.


Assuntos
Alcanos/síntese química , Níquel/química , Alcanos/química , Catálise , Hidrocarbonetos Clorados/química , Hidrocarbonetos Iodados/química , Estrutura Molecular , Oxirredução , Estereoisomerismo
16.
Molecules ; 22(3)2017 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-28287474

RESUMO

The solventless synthesis of tris(pyrazolyl)phenylmethane ligands of formula C6H5C(PzR2)3 (R = H, Me), starting from PhCCl3 and 3,5-dimethylpyrazole (PzMe2) or pyrazole (Pz) was performed. The sterically crowded C6H5C(PzMe2)3 is thermally transformed into the bis(pyrazolyl)(p-pyrazolyl)phenylmethane ligand PzMe2-C6H4CH(PzMe2)2. In this compound both PzMe2 rings are linked through the N-atom to the methine C-atom. At higher temperatures, the binding mode of PzMe2 changes from N1 to C4. All transformations occurred via quinonoid carbocation intermediates that undergo an aromatic electrophilic substitution on the 4-position of PzMe2. Reaction conditions were established to obtain five tris(pyrazolyl)phenylmethane ligands in moderate to good yields. ¹H- and 13C-NMR spectroscopy and X-ray diffraction of single crystals support the proposed structures.


Assuntos
Alcanos/síntese química , Metano/química , Pirazóis/síntese química , Técnicas de Química Sintética , Temperatura Alta , Ligantes , Modelos Moleculares , Estrutura Molecular , Compostos Organometálicos/química , Pirazóis/química
17.
ChemSusChem ; 10(5): 825-829, 2017 03 09.
Artigo em Inglês | MEDLINE | ID: mdl-28032695

RESUMO

For the first time, we demonstrated two integrated processes for the direct synthesis of dodecanol or 2,4,8-trimethylnonane (a jet fuel range C12 -branched alkane) using methyl isobutyl ketone (MIBK) that can be derived from lignocellulose. The reactions were carried out in dual-bed continuous flow reactors. In the first bed, MIBK was selectively converted to a mixture of C12 alcohol and ketone. Over the Pd-modified magnesium- aluminium hydrotalcite (Pd-MgAl-HT) catalyst, a high total carbon yield (73.0 %) of C12 oxygenates can be achieved under mild conditions. In the second bed, the C12 oxygenates generated in the first bed were hydrogenated to dodecanol over a Ru/C catalyst or hydrodeoxygenated to 2,4,8-trimethylnonane over a Cu/SiO2 catalyst. The as-obtained dodecanol can be used as feedstock in the production of sodium dodecylsulfate (SDS) and sodium dodecyl benzene sulfonate (SDBS), which are widely used as surfactants or detergents. The asobtained 2,4,8-trimethylnonane can be blended into conventional jet fuel without hydroisomerization.


Assuntos
Alcanos/síntese química , Dodecanol/síntese química , Metil n-Butil Cetona/química , Alcanos/química , Catálise , Técnicas de Química Sintética , Dimerização , Dodecanol/química
18.
ChemSusChem ; 10(4): 747-753, 2017 02 22.
Artigo em Inglês | MEDLINE | ID: mdl-27863146

RESUMO

A one-pot method for the selective production of high-grade diesel-range alkanes from biomass-derived furfural and 2-methylfuran (2-MF) was developed by combining the hydroxyalkylation/alkylation (HAA) condensation of furfural with 2-MF and the subsequent hydrodeoxygenation (HDO) over a multifunctional Pd/NbOPO4 catalyst. The effects of various reaction conditions as well as a variety of solid-acid catalysts and metal-loaded NbOPO4 catalysts were systematically investigated to optimize the reaction conditions for both reactions. Under the optimal reaction conditions up to 89.1 % total yield of diesel-range alkanes was obtained from furfural and 2-MF by this one-pot method.


Assuntos
Alcanos/síntese química , Furaldeído/química , Furanos/química , Alquilação , Biomassa , Catálise , Gasolina , Hidrogenação , Nióbio/química , Paládio/química
19.
Arch Pharm Res ; 39(10): 1391-1403, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27585596

RESUMO

3-Azabicyclo[3.2.2]nonanes are already reported as antiprotozoal agents. Structural variations were performed by attachment of several basic side chains, being part of drugs in use, to the ring nitrogen. The structures of the new compounds were established using one and two dimensional NMR measurements. All compounds were investigated for their antiplasmodial and antitrypanosomal activities against Plasmodium falciparum K 1 (multiresistant) and Trypanosoma brucei rhodesiense. Their cytotoxicity was assessed against L6 cells. The results are compared to the activities of formerly synthesized compounds. Structure-activity relationships are discussed.


Assuntos
Alcanos/síntese química , Alcanos/farmacologia , Antiprotozoários/síntese química , Antiprotozoários/farmacologia , Compostos Azabicíclicos/síntese química , Compostos Azabicíclicos/farmacologia , Animais , Humanos , Camundongos , Testes de Sensibilidade Parasitária/métodos , Plasmodium falciparum/efeitos dos fármacos , Plasmodium falciparum/fisiologia , Relação Estrutura-Atividade , Trypanosoma brucei rhodesiense/efeitos dos fármacos , Trypanosoma brucei rhodesiense/fisiologia
20.
Chem Pharm Bull (Tokyo) ; 64(10): 1474-1483, 2016 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-27452927

RESUMO

We have developed a new method for synthesizing chiral isotwistane and homoisotwistane skeletons as well as aminocyclitols in a highly stereoselective manner. These results were achieved through the use of a common intermediate, which was derived from the ytterbium-catalyzed asymmetric Diels-Alder reaction of Danishefsky diene.


Assuntos
Alcanos/síntese química , Hidrocarbonetos Aromáticos com Pontes/síntese química , Ciclitóis/síntese química , Cicloexenos/química , Alcanos/química , Hidrocarbonetos Aromáticos com Pontes/química , Catálise , Ciclitóis/química , Reação de Cicloadição , Estrutura Molecular , Estereoisomerismo , Itérbio/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA