Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 777
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Chem Pharm Bull (Tokyo) ; 67(8): 872-876, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31366835

RESUMO

A gold-catalyzed introduction of various terminal alkynes to acetals was investigated. Extensive optimization of the reaction conditions revealed that thermally stable cationic gold catalysts bearing bulky ligands such as 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene 3-1H-benzo[d][1,2,3]triazolyl gold trifluoromethanesulfonate (IPrAu(BTZ-H)OTf) were particularly suitable for the reaction. Additionally, significant solvent effects were observed. Ether solvents such as tetrahydrofuran (THF), cyclo pentyl methyl ether (CPME), and 1,4-dioxane were effective for the reaction. Studies on the scope of substrates and alkynes indicated that various alkynes and acetals were feasible to provide a wide range of propargylic ethers.


Assuntos
Acetais/química , Alquinos/química , Éteres/síntese química , Ouro/química , Alquinos/síntese química , Éteres/química , Estrutura Molecular
2.
Chem Pharm Bull (Tokyo) ; 67(1): 1-17, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30606946

RESUMO

This review reports on the development of new synthetic methods using oxiranyl anions and their application to the synthesis of polycyclic ether marine natural products. Novel iterative and convergent methods for large, complex polycyclic ether structures have been devised. In these, the reactions of sulfonyl-stabilized oxiranyl anions were employed to construct trans-fused polyether ring systems, along with 6-endo cyclization and ring expansion reactions. Total syntheses of polycyclic ether marine toxins, viz. hemibrevetoxin B, gambierol, and gymnocin-A, were achieved based on the oxiranyl anion strategy developed.


Assuntos
Álcoois/química , Produtos Biológicos/síntese química , Éteres/síntese química , Compostos Policíclicos/síntese química , Álcoois/síntese química , Ânions/síntese química , Ânions/química , Produtos Biológicos/química , Compostos de Epóxi/química , Éteres/química , Conformação Molecular , Compostos Policíclicos/química
3.
J Antibiot (Tokyo) ; 72(6): 364-374, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30607013

RESUMO

We describe a novel strategy for synthesizing the CD bicyclic ether substructure of the fused polycyclic ether natural product brevenal. This product arises from a three-step sequence beginning with (1) regio- and diastereoselective iodoetherification of an acyclic diene-diol, followed by (2) alkene metathesis with an epoxyalkene synthon, concluding with (3) palladium-catalyzed cycloisomerization. Despite the modest yield and long reaction period for the cycloisomerization step, these studies provide valuable insights into the nature of byproducts generated and the mechanisms by which they form. This work demonstrates a portion of a larger synthetic strategy for constructing the pentacyclic core of brevenal from an acyclic precursor.


Assuntos
Éteres/síntese química , Polímeros/síntese química , Catálise , Éteres/química , Estrutura Molecular , Paládio , Polímeros/química
4.
Eur J Med Chem ; 161: 543-558, 2019 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-30391816

RESUMO

A series of novel phenol ether derivatives were designed, synthesized, and evaluated as non-covalent proteasome inhibitors. Most compounds exhibited moderate to excellent proteasome inhibitory activity. In particular, compound 18x proved to be the most potent compound (chymotrypsin-like: IC50 = 49 nM), exhibiting a 2-fold higher potency compared to the reported PI-1840. Besides, compound 18x exhibited excellent metabolic stability and selective anti-proliferative activity against solid cancer cell lines including HepG2 and HGC27, providing incentive for the further development as a potential anticancer agent against solid cancers.


Assuntos
Antineoplásicos/farmacologia , Desenho de Fármacos , Éteres/farmacologia , Fenóis/farmacologia , Complexo de Endopeptidases do Proteassoma/metabolismo , Inibidores de Proteassoma/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Éteres/síntese química , Éteres/química , Humanos , Microssomos Hepáticos/química , Microssomos Hepáticos/metabolismo , Modelos Moleculares , Estrutura Molecular , Fenóis/síntese química , Fenóis/química , Inibidores de Proteassoma/síntese química , Inibidores de Proteassoma/química , Relação Estrutura-Atividade , Células Tumorais Cultivadas
5.
Org Biomol Chem ; 16(47): 9269-9273, 2018 12 05.
Artigo em Inglês | MEDLINE | ID: mdl-30465589

RESUMO

A simple and efficient protocol for the copper-catalyzed synthesis of aryl or alkyl 2,2,2-trifluoroethyl selenoethers has been developed. This reaction proceeded smoothly in the presence of CuI/phen as the catalyst, with elemental selenium, 1,1,1-trifluoro-2-iodoethane, and NaBH4 as reagents in DMF with a broad scope of functionalized (hetero)aryl or alkyl halides. Different functional groups were tolerated and moderate to excellent yields of 2,2,2-trifluoroethyl selenoethers were obtained. Some of the synthesized compounds exhibited promising insecticidal activities.


Assuntos
Cobre/química , Inseticidas/síntese química , Compostos Organosselênicos/síntese química , Animais , Catálise , Éteres/síntese química , Éteres/química , Éteres/toxicidade , Halogenação , Insetos/efeitos dos fármacos , Inseticidas/química , Inseticidas/toxicidade , Compostos Organosselênicos/química , Compostos Organosselênicos/toxicidade
6.
Biomacromolecules ; 19(12): 4593-4606, 2018 12 10.
Artigo em Inglês | MEDLINE | ID: mdl-30376299

RESUMO

Amorphous solid dispersions are widely used to enhance the oral bioavailability of poorly water-soluble drugs. Polymeric additives are commonly used to delay crystallization of the drug from the supersaturated solutions formed upon ASD dissolution by influencing the nucleation and growth of crystals. However, there is limited evidence regarding the mechanisms by which polymers stabilize supersaturated drug solutions. The current study used experiments and computational modeling to explore polymer-drug interactions in aqueous solutions. Nucleation induction times for supersaturated solutions of nine drugs in the presence of five newly synthesized cellulose-based polymers were evaluated. The polymers had carboxylic acids substituents with additional variations in the side-chain structure: (1) one with a single side chain and a carboxylic acid termination, (2) three with a branched side chain terminated with a carboxylic and an alcohol group (varying the cellulose linkage and the length of the hydrocarbon side chain), and (3) one with a branched side chain with two carboxylic acid end groups. The polymers with a short side chain and one carboxylic acid were effective, whereas the polymers with the two carboxylic acids or a long hydrocarbon chain were less effective. Atomic force microscopy experiments, evaluating polymer adsorption onto amorphous drug films, indicated that the effective polymers were uniformly spread across the surface. These results were supported by molecular dynamics simulations of a polymer chain in the presence of a drug aggregate in an aqueous environment, whereby the effective materials had a higher probability of establishing close contacts and more negative estimated free energies of interaction. The insights provided by this study provide approaches to design highly effective polymers to improve oral drug delivery.


Assuntos
Celulose/química , Sistemas de Liberação de Medicamentos , Ésteres/química , Éteres/química , Disponibilidade Biológica , Ácidos Carboxílicos/química , Celulose/síntese química , Cristalização , Ésteres/síntese química , Éteres/síntese química , Humanos , Interações Hidrofóbicas e Hidrofílicas , Polímeros/química , Solubilidade , Água/química
7.
Org Lett ; 20(17): 5452-5456, 2018 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-30113173

RESUMO

A catalytic method for the synthesis of sterically hindered ethers and thioethers from α-bromo carbonyl compounds and the corresponding nucleophiles using an inexpensive Cu(I) catalytic system is reported. This facile transformation takes place at ambient temperature and does not require the exclusion of air or moisture; thus, it is well-suited for the functionalization and derivatization of complex organic molecules.


Assuntos
Bromo/química , Cobre/química , Éteres/química , Éteres/síntese química , Cetonas/química , Catálise , Técnicas de Química Sintética
8.
Angew Chem Int Ed Engl ; 57(39): 12921-12924, 2018 09 24.
Artigo em Inglês | MEDLINE | ID: mdl-30117646

RESUMO

Spirocyclic ethers can be found in bioactive compounds. This copper-catalyzed enantioselective alkene carboetherification provides 5,5-, 5,6- and 6,6-spirocyclic products containing fully substituted chiral carbon centers with up to 99 % enantiomeric excess. This reaction features the formation of two rings from acyclic substrates, 1,1-disubstituted alkenols functionalized with either arenes, alkenes, or alkynes, and clearly constitutes a powerful way to synthesize chiral spirocyclic ethers.


Assuntos
Cobre/química , Éteres/química , Propanóis/química , Compostos de Espiro/química , Alcenos/química , Alquinos/química , Catálise , Cristalografia por Raios X , Éteres/síntese química , Conformação Molecular , Propanóis/síntese química , Estereoisomerismo
9.
Chemistry ; 24(52): 13807-13814, 2018 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-29924885

RESUMO

Previous studies have indicated the presence of defined interactions between oligo or poly(ethylene glycol) (OEG or PEG) and lysine residues. In these interactions, the OEG or PEG residues "wrap around" the lysine amino group, thereby enabling complexation of the amino group by the ether oxygen residues. The resulting biochemical binding affinity and thus biological relevance of this supramolecular interaction however remains unclear so far. Here, we report that OEG-containing phosphophenol ether inhibitors of 14-3-3 proteins also display such a "lysine-wrapping" binding mode. For better investigating the biochemical relevance of this binding mode, we made use of the dimeric nature of 14-3-3 proteins and designed as well as synthesized a set of bivalent 14-3-3 inhibitors for biochemical and X-ray crystallography-based structural studies. We found that all synthesized derivatives adapted the "lysine-wrapping" binding mode in the crystal structures; in solution, a different binding mode is however observed, most probably as the "lysine-wrapping" binding mode turned out to be a rather weak interaction. Accordingly, our studies demonstrate that structural studies of OEG-lysine interactions are difficult to interpret and their presence in structural studies may not automatically be correlated with a relevant interaction also in solution but requires further biochemical studies.


Assuntos
Proteínas 14-3-3/antagonistas & inibidores , Éteres/síntese química , Lisina/química , Organofosfonatos/síntese química , Polietilenoglicóis/química , Proteínas/química , Proteínas 14-3-3/química , Cristalização , Éteres/química , Modelos Moleculares , Organofosfonatos/química , Ligação Proteica , Multimerização Proteica , Termodinâmica
10.
J Am Chem Soc ; 140(20): 6212-6216, 2018 05 23.
Artigo em Inglês | MEDLINE | ID: mdl-29714480

RESUMO

An enantioselective cross-dehydrogenative coupling (CDC) reaction to access tetrahydropyrans has been developed. This process combines in situ Lewis acid activation of a nucleophile in concert with the oxidative formation of a transient oxocarbenium electrophile, leading to a productive and highly enantioselective CDC. These advances represent one of the first successful applications of CDC for the enantioselective couplings of unfunctionalized ethers. This system provides efficient access to valuable tetrahydropyran motifs found in many natural products and bioactive small molecules.


Assuntos
Piranos/síntese química , Benzoquinonas/síntese química , Benzoquinonas/química , Catálise , Ésteres/síntese química , Ésteres/química , Éteres/síntese química , Éteres/química , Ácidos de Lewis/síntese química , Ácidos de Lewis/química , Modelos Moleculares , Oxirredução , Piranos/química , Estereoisomerismo
11.
Bioorg Med Chem Lett ; 28(11): 2050-2054, 2018 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-29748053

RESUMO

A series of diaryl ethers were designed and synthesized to discern the structure activity relationships against the two closely related mono-(ADP-ribosyl)transferases PARP10 and PARP14. Structure activity studies identified 8b as a sub-micromolar inhibitor of PARP10 with ∼15-fold selectivity over PARP14. In addition, 8k and 8m were discovered to have sub-micromolar potency against PARP14 and demonstrated moderate selectivity over PARP10. A crystal structure of the complex of PARP14 and 8b shows binding of the compound in a novel hydrophobic pocket and explains both potency and selectivity over other PARP family members. In addition, 8b, 8k and 8m also demonstrate selectivity over PARP1. Together, this study identified novel, potent and metabolically stable derivatives to use as chemical probes for these biologically interesting therapeutic targets.


Assuntos
Amidas/farmacologia , Desenho de Fármacos , Éteres/farmacologia , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Poli(ADP-Ribose) Polimerases/metabolismo , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Amidas/síntese química , Amidas/química , Relação Dose-Resposta a Droga , Éteres/síntese química , Éteres/química , Humanos , Estrutura Molecular , Inibidores de Poli(ADP-Ribose) Polimerases/síntese química , Inibidores de Poli(ADP-Ribose) Polimerases/química , Proteínas Proto-Oncogênicas/metabolismo , Relação Estrutura-Atividade
12.
ChemMedChem ; 13(13): 1353-1362, 2018 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-29756273

RESUMO

Despite major strides in reducing Plasmodium falciparum infections, this parasite still accounts for roughly half a million annual deaths. This problem is compounded by the decreased efficacy of artemisinin combination therapies. Therefore, the development and optimisation of novel antimalarial chemotypes is critical. In this study, we describe our strategic approach to optimise a class of previously reported antimalarials, resulting in the discovery of 1-(5-chloro-1H-indol-3-yl)-2-[(4-cyanophenyl)thio]ethanone (13) and 1-(5-chloro-1H-indol-3-yl)-2-[(4-nitrophenyl)thio]ethanone (14), whose activity was equipotent to that of chloroquine against the P. falciparum 3D7 strain. Furthermore, these compounds were found to be nontoxic to HeLa cells as well as being non-haemolytic to uninfected red blood cells. Intriguingly, several of our most promising compounds were found to be less active against the isogenic NF54 strain, highlighting possible issues with long-term dependability of malarial strains. Finally compound 14 displayed similar activity against both the NF54 and K1 strains, suggesting that it inhibits a pathway that is uncompromised by K1 resistance.


Assuntos
Antimaláricos/farmacologia , Éteres/farmacologia , Indóis/farmacologia , Sulfetos/farmacologia , Antimaláricos/síntese química , Antimaláricos/química , Antimaláricos/toxicidade , Eritrócitos/efeitos dos fármacos , Éteres/síntese química , Éteres/química , Éteres/toxicidade , Células HeLa , Hemólise/efeitos dos fármacos , Humanos , Indóis/síntese química , Indóis/química , Indóis/toxicidade , Estrutura Molecular , Testes de Sensibilidade Parasitária , Plasmodium falciparum/efeitos dos fármacos , Relação Estrutura-Atividade , Sulfetos/síntese química , Sulfetos/química , Sulfetos/toxicidade
13.
ChemMedChem ; 13(12): 1193-1209, 2018 06 20.
Artigo em Inglês | MEDLINE | ID: mdl-29771004

RESUMO

Cancer continues to be a worldwide health problem. Certain macrocyclic molecules have become attractive therapeutic alternatives for this disease because of their efficacy and, frequently, their novel mechanisms of action. Herein, we report the synthesis of a series of 20-, 21-, and 22-membered macrocycles containing triazole and bis(aryl ether) moieties. The compounds were prepared by a multicomponent approach from readily available commercial substrates. Notably, some of the compounds displayed interesting cytotoxicity against cancer (PC-3) and breast (MCF-7) cell lines, especially those bearing an aliphatic or a trifluoromethyl substituent on the N-phenyl moiety (IC50 <13 µm). Additionally, some of the compounds were able to induce apoptosis relative to the solvent control; in particular, (Z)-N-cyclohexyl-7-oxo-6-[4-(trifluoromethyl)phenyl]-11 H-3,10-dioxa-6-aza-1(4,1)-triazola-4(1,3),9(1,4)-dibenzenacyclotridecaphane-5-carboxamide (12 f) was the most potent in this regard (22.7 % of apoptosis).


Assuntos
Antineoplásicos/farmacologia , Éteres/farmacologia , Compostos Macrocíclicos/farmacologia , Triazóis/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Éteres/síntese química , Éteres/química , Humanos , Compostos Macrocíclicos/síntese química , Compostos Macrocíclicos/química , Estrutura Molecular , Relação Estrutura-Atividade , Triazóis/síntese química , Triazóis/química
14.
J Oleo Sci ; 67(6): 773-778, 2018 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-29760335

RESUMO

A facile method for synthesizing allyl propargyl ethers (APEs) was developed based on the dimerization of propargyl alcohols. The reaction proceeded via an oxaphosphetane intermediate, which was generated without the use of a strong base, thus making this process a pseudo-Wittig reaction under mild reaction conditions. A wide variety of functional groups, including formyl and pyridyl groups were tolerated, thus yielding the corresponding functionalized APEs, which are otherwise not readily prepared via conventional methods. Moreover, a cross-reaction was found to occur when the reaction was conducted in the presence of alcohols that were more acidic than propargyl alcohol, which suggests that the proton transfer from the intermediately formed betaine to the second alcohol is crucial for undergoing the dimerization.


Assuntos
Alquinos/química , Alquinos/síntese química , Éteres/síntese química , Fosfinas/química , Propanóis/química , Betaína , Dimerização , Fenômenos de Química Orgânica , Prótons
15.
J Am Chem Soc ; 140(18): 5895-5898, 2018 05 09.
Artigo em Inglês | MEDLINE | ID: mdl-29665329

RESUMO

This report details a palladium-catalyzed process to access highly functionalized, optically active allylic aryl ethers. A number of electron-deficient alkenyl triflates underwent enantioselective and site-selective coupling with acyclic aryl enol ethers in the presence of a chiral palladium catalyst. This transform provides chiral allylic ether products in high yields and excellent enantiomeric ratios, furnishing a unique disconnection to incorporate heteroatoms at a stereocenter. Finally, the applicability of the products to target synthesis was demonstrated through the formation of a chiral allylic alcohol and the generation of a flavone-inspired product.


Assuntos
Álcoois/química , Compostos Alílicos/síntese química , Éteres/síntese química , Paládio/química , Compostos Alílicos/química , Catálise , Éteres/química , Estrutura Molecular , Estereoisomerismo
16.
ChemMedChem ; 13(7): 748-753, 2018 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-29409113

RESUMO

The Hedgehog (Hh) signaling pathway is critical for embryonic patterning and postembryonic tissue regeneration. Constitutive pathway activation has also been linked to human malignancies such as basal cell carcinoma (BCC) and medulloblastoma; therefore, multiple small-molecule scaffolds that inhibit Hh signaling are in development. Previously, Grundmann's alcohol, also known as the "northern region" of vitamin D3 (VD3), has been identified as a moderate Hh pathway inhibitor. In this study, isomers of Grundmann's alcohol with different orientations of the C4 hydroxy group and C3α proton were investigated to determine the optimal configuration for this hexahydroindane scaffold with respect to Hh inhibition. A series of analogues containing Grundmann's alcohol linked to a substituted phenyl or benzyl ring through an ether or thioether linker were synthesized and evaluated for their anti-Hh activity. Of these, analogue 17 ((1R,3aR,4R,7aR)-1-[(R)-1,5-dimethylhexyl]-4-(4-aminophenoxy)-7a-methyloctahydro-1H-indene) demonstrated potent anti-Hh activity in Hh-dependent BCC cells and did not activate canonical vitamin D receptor signaling, demonstrating its selective nature for the Hh signaling pathway.


Assuntos
Colecalciferol/análogos & derivados , Colecalciferol/farmacologia , Éteres/farmacologia , Proteínas Hedgehog/antagonistas & inibidores , Transdução de Sinais/efeitos dos fármacos , Sulfetos/farmacologia , Animais , Linhagem Celular Tumoral , Colecalciferol/síntese química , Éteres/síntese química , Éteres/química , Camundongos , Estrutura Molecular , Estereoisomerismo , Relação Estrutura-Atividade , Sulfetos/síntese química , Sulfetos/química
17.
Eur J Med Chem ; 144: 730-739, 2018 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-29291440

RESUMO

Multidrug resistance is a widespread problem among various diseases and cancer is no exception. We had previously described the chemo-sensitizing activity of ecdysteroid derivatives with low polarity on drug susceptible and multi-drug resistant (MDR) cancer cells. We have also shown that these molecules have a marked selectivity towards the MDR cells. Recent studies on the oximation of various steroid derivatives indicated remarkable increase in their antitumor activity, but there is no related bioactivity data on ecdysteroid oximes. In our present study, 13 novel ecdysteroid derivatives (oximes, oxime ethers and a lactam) and one known compound were synthesized from 20-hydroxyecdysone 2,3;20,22-diacetonide and fully characterized by comprehensive NMR techniques revealing their complete 1H and 13C signal assignments. The compounds exerted moderate to strong in vitro antiproliferative activity on HeLa, SiHa, MCF-7 and MDA-MB-231 cell lines. Oxime and particularly oxime ether formation strongly increased their inhibitory activity on the efflux of rhodamine 123 by P-glycoprotein (P-gp), while the new ecdysteroid lactam did not interfere with the efflux function. All compounds exerted potent chemo-sensitizing activity towards doxorubicin on a mouse lymphoma cell line and on its MDR counterpart, and, on the latter, the lactam was found the most active. Because of its MDR-selective chemo-sensitizing activity with no functional effect on P-gp, this lactam is of high potential interest as a new lead for further antitumor studies.


Assuntos
Antineoplásicos/farmacologia , Ecdisteroides/farmacologia , Éteres/farmacologia , Lactamas/farmacologia , Neoplasias/tratamento farmacológico , Nitrogênio/farmacologia , Oximas/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Resistência a Múltiplos Medicamentos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Ecdisteroides/síntese química , Ecdisteroides/química , Éteres/síntese química , Éteres/química , Humanos , Lactamas/síntese química , Lactamas/química , Estrutura Molecular , Neoplasias/patologia , Nitrogênio/química , Oximas/síntese química , Oximas/química , Relação Estrutura-Atividade , Células Tumorais Cultivadas
18.
Carbohydr Polym ; 180: 192-199, 2018 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-29103495

RESUMO

Antimicrobial cotton fabrics received much attention for the demand of health and hygiene fields. In this work, an antimicrobial copolymer was prepared via a reaction between polyhexamethylene guanidine hydrochloride and polypropylene glycol diglycidyl ether. The copolymer has amphiphilic characteristic and excellent antimicrobial properties. When the copolymer was adhered onto cotton fabrics through physical adsorption and chemical bonding using dipping-drying method, the resultant cotton fabrics had excellent and durable antimicrobial properties. The antimicrobial rates against Escherichia coli and Staphylococcus aureus were higher than 99.99% when the adsorption amount of the copolymer was above 35.5mg/g. The antimicrobial cotton fabrics remained the excellent antimicrobial properties even after laundered with detergent solution.


Assuntos
Anti-Infecciosos/química , Fibra de Algodão , Éteres/química , Guanidina/análogos & derivados , Polietilenoglicóis/química , Éteres/síntese química , Polietilenoglicóis/síntese química , Tensoativos/química
19.
Bioorg Med Chem ; 26(4): 938-944, 2018 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-28751197

RESUMO

The evolution of a scalable process for the preparation of methylcyclobutanol-pyridyl ether 1 is described. Key aspects of this development including careful control of the stereochemistry, elimination of chromatography, and application to kilogram-scale synthesis are addressed.


Assuntos
Ciclobutanos/química , Éteres/química , Cromatografia Gasosa , Desenho de Fármacos , Éteres/síntese química , Estereoisomerismo , Relação Estrutura-Atividade
20.
Molecules ; 22(12)2017 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-29231861

RESUMO

The etherification of glycerol with tert-butyl alcohol in the liquid phase, over different sulfonic acid functionalized zeolites, has been studied. The reaction was carried out using microwaves as a way of heating, measured at autogenous pressure and without any solvent. Dealuminated HY and HZSM-5 zeolites by acid treatment were functionalized with two different organosilica precursors: 3-mercaptopropyltrimethoxysilane (M), which incorporates thiol groups, and 2-(4-chlorosulfonylphenyl)ethyltrimethoxysilane (C), which incorporates the sulfonic acid groups directly. The thiol groups were oxidized into sulfonic groups employing hydrogen peroxide. The textural and structural properties of the solids were studied by XRD and N2 adsorption-desorption isotherms, whereas the incorporation of the organosilica in the zeolites was studied by TGA and XPS. The novelty functionalization of M gave rise to solids with the highest acidity, and exhibited the highest yields with more substituted ethers (Yh-GTBE = 13%), at 75 °C and 15 min of reaction time. In addition to the acidity, the textural properties of the zeolites played an important role in their activity; HY, with the largest size of the channels, were more active than the HZSM-5.


Assuntos
Éteres/síntese química , Glicerol/química , Ácidos Sulfônicos/química , Zeolitas/química , terc-Butil Álcool/química , Catálise , Cromatografia Gasosa-Espectrometria de Massas/métodos , Peróxido de Hidrogênio/química , Micro-Ondas , Nitrogênio/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA