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1.
Int J Mol Sci ; 22(19)2021 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-34638964

RESUMO

G-quadruplex existence was proved in cells by using both antibodies and small molecule fluorescent probes. However, the G-quadruplex probes designed thus far are structure- but not conformation-specific. Recently, a core-extended naphthalene diimide (cex-NDI) was designed and found to provide fluorescent signals of markedly different intensities when bound to G-quadruplexes of different conformations or duplexes. Aiming at evaluating how the fluorescence behaviour of this compound is associated with specific binding modes to the different DNA targets, cex-NDI was here studied in its interaction with hybrid G-quadruplex, parallel G-quadruplex, and B-DNA duplex models by biophysical techniques, molecular docking, and biological assays. cex-NDI showed different binding modes associated with different amounts of stacking interactions with the three DNA targets. The preferential binding sites were the groove, outer quartet, or intercalative site of the hybrid G-quadruplex, parallel G-quadruplex, and B-DNA duplex, respectively. Interestingly, our data show that the fluorescence intensity of DNA-bound cex-NDI correlates with the amount of stacking interactions formed by the ligand with each DNA target, thus providing the rationale behind the conformation-sensitive properties of cex-NDI and supporting its use as a fluorescent probe of G-quadruplex structures. Notably, biological assays proved that cex-NDI mainly localizes in the G-quadruplex-rich nuclei of cancer cells.


Assuntos
Adenocarcinoma/metabolismo , Neoplasias da Mama/metabolismo , DNA de Forma B/metabolismo , Corantes Fluorescentes/química , Corantes Fluorescentes/metabolismo , Quadruplex G , Imidas/química , Imidas/metabolismo , Substâncias Intercalantes/química , Substâncias Intercalantes/metabolismo , Conformação Molecular , Naftalenos/química , Naftalenos/metabolismo , Adenocarcinoma/patologia , Sítios de Ligação , Neoplasias da Mama/patologia , Sobrevivência Celular/efeitos dos fármacos , Feminino , Corantes Fluorescentes/farmacologia , Humanos , Imidas/farmacologia , Concentração Inibidora 50 , Substâncias Intercalantes/farmacologia , Ligantes , Células MCF-7 , Espectroscopia de Ressonância Magnética/métodos , Simulação de Acoplamento Molecular/métodos , Naftalenos/farmacologia
2.
Int J Mol Sci ; 22(17)2021 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-34502432

RESUMO

In the search for optimized thrombin binding aptamers (TBAs), we herein describe the synthesis of a library of TBA analogues obtained by end-functionalization with the electron-rich 1,5-dialkoxy naphthalene (DAN) and the electron-deficient 1,8,4,5-naphthalenetetra-carboxylic diimide (NDI) moieties. Indeed, when these G-rich oligonucleotides were folded into the peculiar TBA G-quadruplex (G4) structure, effective donor-acceptor charge transfer interactions between the DAN and NDI residues attached to the extremities of the sequence were induced, providing pseudo-cyclic structures. Alternatively, insertion of NDI groups at both extremities produced TBA analogues stabilized by π-π stacking interactions. All the doubly-modified TBAs were characterized by different biophysical techniques and compared with the analogues carrying only the DAN or NDI residue and unmodified TBA. These modified TBAs exhibited higher nuclease resistance, and their G4 structures were markedly stabilized, as evidenced by increased Tm values compared to TBA. These favorable properties were also associated with improved anticoagulant activity for one DAN/NDI-modified TBA, and for one NDI/NDI-modified TBA. Our results indicated that TBA pseudo-cyclic structuring by ad hoc designed end-functionalization represents an efficient approach to improve the aptamer features, while pre-organizing and stabilizing the G4 structure but allowing sufficient flexibility to the aptamer folding, which is necessary for optimal thrombin recognition.


Assuntos
Anticoagulantes/química , Aptâmeros de Nucleotídeos/química , Quadruplex G , Álcoois/química , Anticoagulantes/farmacologia , Avaliação Pré-Clínica de Medicamentos , Imidas/química , Naftalenos/química
3.
Int J Cancer ; 149(11): 1961-1972, 2021 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-34469585

RESUMO

Adipocyte-rich omentum offers "good soil" for disseminating ovarian cancer (OvCa), contributing to therapeutic difficulty. However, little is understood about the association between adipocytes and tumor growth at peritoneal dissemination site. Herein, we report the induction of adipocyte dedifferentiation by OvCa cells and pro-tumorigenic effects of resulted adipocyte-derived fibroblasts. We confirmed that malignant ascites promoted the dedifferentiation of the primary human adipocytes obtained from surgical omental specimen into omental adipocyte-derived fibroblast (O-ADF) that possess both mesenchymal stem cell and myofibroblast-like features. This promotion of dedifferentiation by malignant ascites was blocked by addition of Wnt signaling inhibitor. The effects of dedifferentiated adipocytes in proliferation and migration of OvCa cells were analyzed with in vitro coculturing experimental models and in vivo mice model, and we demonstrated that OvCa cell lines showed enhanced proliferative characteristics, as well as increased migratory abilities upon coculturing with O-ADF. Additionally, exogenous transforming growth factor-ß1 augmented desmoplastic morphological change of O-ADF, leading to higher proliferative ability. Our results suggest that OvCa cells promote dedifferentiation of peritoneal adipocytes by activating Wnt/ß-catenin signaling, and generated O-ADFs exhibit pro-tumoral hallmarks.


Assuntos
Adipócitos/patologia , Fibroblastos Associados a Câncer/patologia , Omento/patologia , Neoplasias Ovarianas/patologia , Microambiente Tumoral , Células 3T3-L1 , Actinas/metabolismo , Adipócitos/efeitos dos fármacos , Adipócitos/metabolismo , Animais , Ascite/metabolismo , Fibroblastos Associados a Câncer/metabolismo , Desdiferenciação Celular/efeitos dos fármacos , Movimento Celular , Proliferação de Células , Feminino , Humanos , Imidas/farmacologia , Células-Tronco Mesenquimais/metabolismo , Células-Tronco Mesenquimais/patologia , Camundongos , Miofibroblastos/metabolismo , Miofibroblastos/patologia , Omento/metabolismo , Neoplasias Ovarianas/metabolismo , Neoplasias Peritoneais/metabolismo , Neoplasias Peritoneais/secundário , Quinolinas/farmacologia , Via de Sinalização Wnt/efeitos dos fármacos , Proteína Wnt3A/metabolismo
4.
Int J Mol Sci ; 22(17)2021 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-34502026

RESUMO

1H and 19F spin-lattice relaxation experiments have been performed for butyltriethylammonium bis(trifluoromethanesulfonyl)imide in the temperature range from 258 to 298 K and the frequency range from 10 kHz to 10 MHz. The results have thoroughly been analysed in terms of a relaxation model taking into account relaxation pathways associated with 1H-1H, 19F-19F and 1H-19F dipole-dipole interactions, rendering relative translational diffusion coefficients for the pairs of ions: cation-cation, anion-anion and cation-anion, as well as the rotational correlation time of the cation. The relevance of the 1H-19F relaxation contribution to the 1H and 19F relaxation has been demonstrated. A comparison of the diffusion coefficients has revealed correlation effects in the relative cation-anion translational movement. It has also turned out that the translational movement of the anions is faster than of cations, especially at high temperatures. Moreover, the relative cation-cation diffusion coefficients have been compared with self-diffusion coefficients obtained by means of NMR (Nuclear Magnetic Resonance) gradient diffusometry. The comparison indicates correlation effects in the relative cation-cation translational dynamics-the effects become more pronounced with decreasing temperature.


Assuntos
Hidrocarbonetos Fluorados/química , Imidas/química , Líquidos Iônicos/química , Espectroscopia de Ressonância Magnética/métodos
5.
J Phys Chem B ; 125(39): 11005-11016, 2021 10 07.
Artigo em Inglês | MEDLINE | ID: mdl-34570507

RESUMO

The study highlights the effect of acid- and base-rich conditions on the proton dynamics of diethylmethylammonium poly[4-styrenesulfonyl(trifluoromethylsulfonyl)imide, [DEMA][PSTFSI], a polymerized protic ionic liquid designed as a polymer electrolyte for nonhumidified polymer electrolyte membrane fuel cells. Different proportions of triflic acid (HTf) and diethylmethylamine (DEMA) were added to the pristine polymer. The thermal analysis of the mixtures revealed that the addition of the base increases the glassy/amorphous nature of the polymer; however, HTf plasticizes the polymer and lowers the Tg value, so that it falls outside of the differential scanning calorimetry-studied temperature range. 50 mol % doping of the HTf contents increases the conductivity upto 0.952 mS cm-1, and 50 mol % DEMA mixture has a conductivity of 0.169 mS cm-1 at 100 °C. Vogel-Tamman-Fulcher fitting of the ionic conductivities of the doped systems suggested that the ionic conductivities are completely decoupled from segmental motion of the polymer. A combination of Fourier transform infrared and static NMR studies demonstrated that HTf-added polymer composites show conduction via Grotthuss and vehicular mechanisms, while DEMA-added polymer composites show predominantly a Grotthuss mechanism by developing the aggregates of proton and added base.


Assuntos
Imidas , Líquidos Iônicos , Dietilaminas , Mesilatos , Prótons
6.
Chem Commun (Camb) ; 57(74): 9422-9425, 2021 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-34528967

RESUMO

The C-H/C-X cross-coupling of a benzimidazolium salt with 2Br-NDI afforded two unprecedented zwitterionic NDIs with di/mono-benzimidazolium and an extra negatively-charged oxygen substituent. They exhibited intensified red fluorescence in polar solvents and negative solvatochromism due to an intramolecular charge transfer process, and could specifically label lysosomes and the endoplasmic reticulum in living A549 cells, respectively. They represent a rare case of NDI-derived ionic fluorophores.


Assuntos
Benzimidazóis/química , Corantes Fluorescentes/química , Imidas/química , Naftalenos/química , Oxigênio/química , Células A549 , Humanos , Estrutura Molecular , Imagem Óptica
7.
Molecules ; 26(16)2021 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-34443620

RESUMO

G-quadruplexes (G4s) are higher-order supramolecular structures, biologically important in the regulation of many key processes. Among all, the recent discoveries relating to RNA-G4s, including their potential involvement as antiviral targets against COVID-19, have triggered the ever-increasing need to develop selective molecules able to interact with parallel G4s. Naphthalene diimides (NDIs) are widely exploited as G4 ligands, being able to induce and strongly stabilize these structures. Sometimes, a reversible NDI-G4 interaction is also associated with an irreversible one, due to the cleavage and/or modification of G4s by functional-NDIs. This is the case of NDI-Cu-DETA, a copper(II) complex able to cleave G4s in the closest proximity to the target binding site. Herein, we present two original Cu(II)-NDI complexes, inspired by NDI-Cu-DETA, differently functionalized with 2-(2-aminoethoxy)ethanol side-chains, to selectively drive redox-catalyzed activity towards parallel G4s. The selective interaction toward parallel G4 topology, controlled by the presence of 2-(2-aminoethoxy)ethanol side chains, was already firmly demonstrated by us using core-extended NDIs. In the present study, the presence of protonable moieties and the copper(II) cavity, increases the binding affinity and specificity of these two NDIs for a telomeric RNA-G4. Once defined the copper coordination relationship and binding constants by competition titrations, ability in G4 stabilization, and ROS-induced cleavage were analyzed. The propensity in the stabilization of parallel topology was highlighted for both of the new compounds HP2Cu and PE2Cu. The results obtained are particularly promising, paving the way for the development of new selective functional ligands for binding and destructuring parallel G4s.


Assuntos
Complexos de Coordenação/química , Cobre/química , Quadruplex G , Imidas/química , Naftalenos/química , Sítios de Ligação , DEET/química , Ligantes , Oxirredução , Polietilenoglicóis/química , Relação Estrutura-Atividade
8.
Comput Biol Chem ; 93: 107543, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34252797

RESUMO

Graphene quantum dot possesses advantageous characteristics like tunable fluorescence, nanometer size, low cytotoxicity, high biocompatibility enabling them as an ideal material for fluorescence bio-imaging. It exhibits a unique characteristic of DNA cleavage activity enhancer, gene/drug carrier, and anticancer targeting applications. In this article, we discussed the preparation of graphene quantum dot through the bottom-up method. Carbodiimide-activated amidation reactions were used for the functionalization of graphene quantum dot with Bovine Serum Albumin. Fluorescence spectroscopy data showed that the graphene quantum dot has size-dependent fluorescence emission. TEM and AFM studies showed that the size of graphene quantum dot was around 20 nm with narrow size distribution. Carbodiimide-activated amidation conjugation was successful in binding the protein onto graphene quantum dot and these conjugates were characterized by DLS, FTIR, fluorescence spectroscopy, and agarose gel electrophoresis. We also studied the structural-based in-silico molecular dynamic simulation by AutoDock, PyRx, and Discovery Studio Visualizer. Based on the virtual screening analysis and higher negative energy incorporation, it is observed that graphene quantum dot conjugated with bovine serum albumin quickly and formed is highly stable complex, which makes them a potential candidate for future applications in the field of bio-imaging, bio-sensing, gene/drug delivery, and tumor theragnostic.


Assuntos
Amidas/síntese química , Imidas/química , Simulação de Dinâmica Molecular , Imagem Óptica , Soroalbumina Bovina/química , Amidas/química , Animais , Bovinos , Fluorescência , Grafite/química , Pontos Quânticos/química
9.
Bull Environ Contam Toxicol ; 107(2): 281-288, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34264365

RESUMO

The residues of bifenazate (sum of bifenazate and bifenazate-diazene) and etoxazole in whole citrus and pulp collected from twelve regions of China were monitored and their chronic dietary risk to consumer were also evaluated. The citrus samples were extracted by a QuEChERS (quick, easy, cheap, effective, rugged, and safe) method, and analyzed by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The average recoveries of target compounds were ranged from 83 to 100% with relative standard deviations (RSDs) of 0.59-11.8%. The limits of quantification (LOQs) for three analytes were 0.01 mg/kg. At the interval to harvest of 20 and 30 days, the residues of total bifenazate and etoxazole were from below 0.02 to 0.26 mg/kg and from below 0.01 to 0.30 mg/kg in citrus samples. The chronic risk quotients (RQs) were below 100%, indicating no unacceptable risk to consumers.


Assuntos
Citrus , Resíduos de Praguicidas , Carbamatos , Hidrazinas , Imidas , Oxazóis , Resíduos de Praguicidas/análise , Espectrometria de Massas em Tandem
10.
Soft Matter ; 17(30): 7168-7176, 2021 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-34263281

RESUMO

This study demonstrates how the self-assembly pattern of two different and isomeric peptide-appended core-substituted naphthalenediimides (NDIs) affects the modulation of their optoelectronic properties. Two isomeric peptide-attached NDIs were synthesized, purified and characterized. Interchanging the position of attachment of the peptide units and the alkyl chains in the NDI has altered the respective self-assembling patterns of these isomeric molecules in the aggregated states. The isomer having a peptide moiety in the core position and the alkyl chain in the imide position (compound N1) forms face to face stacking or 'H' aggregates in aliphatic solvents including n-hexane, and n-decane, whereas compound N2, in which the peptide moiety is at the imide position and the alkyl chain is attached at the core position of NDI exhibits edge to edge stacking or J aggregates under the same conditions as it is evident from their UV-vis studies. The H aggregated species (obtained from N1) show inter-connected nanofibers, whereas the J aggregated species (obtained from N2) exhibit the morphology of helical nanoribbons. FT-IR and X-ray diffraction studies are in favor of the same aggregation behavior. The individual packing patterns of these two peptide-based isomers have a direct impact on their respective electrical conductivity. Interestingly, the H aggregated species shows 100 times greater current conductivity than that of the J aggregate. Moreover, it is only the H aggregated species that exhibits a photocurrent, and no such photocurrent response is observed with the J aggregates. Computational studies also support that different types of aggregation patterns are formed by these two isomeric molecules in the same solvent system. This unique example of tuning of optoelectronic behavior holds future promise for the development of new peptide-conjugated π-functional materials.


Assuntos
Imidas , Naftalenos , Peptídeos , Espectroscopia de Infravermelho com Transformada de Fourier
11.
J Org Chem ; 86(15): 10455-10466, 2021 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-34275281

RESUMO

The development of efficient methods for facilitating N-C(O) bond activation in amides is an important objective in organic synthesis that permits the manipulation of the traditionally unreactive amide bonds. Herein, we report a comparative evaluation of a series of cyclic amides as activating groups in amide N-C(O) bond cross-coupling. Evaluation of N-acyl-imides, N-acyl-lactams, and N-acyl-oxazolidinones bearing five- and six-membered rings using Pd(II)-NHC and Pd-phosphine systems reveals the relative reactivity order of N-activating groups in Suzuki-Miyaura cross-coupling. The reactivity of activated phenolic esters and thioesters is evaluated for comparison in O-C(O) and S-C(O) cross-coupling under the same reaction conditions. Most notably, the study reveals N-acyl-δ-valerolactams as a highly effective class of mono-N-acyl-activated amide precursors in cross-coupling. The X-ray structure of the model N-acyl-δ-valerolactam is characterized by an additive Winkler-Dunitz distortion parameter Σ(τ+χN) of 54.0°, placing this amide in a medium distortion range of twisted amides. Computational studies provide insight into the structural and energetic parameters of the amide bond, including amidic resonance, N/O-protonation aptitude, and the rotational barrier around the N-C(O) axis. This class of N-acyl-lactams will be a valuable addition to the growing portfolio of amide electrophiles for cross-coupling reactions by acyl-metal intermediates.


Assuntos
Amidas , Lactamas , Reações Cruzadas , Imidas , Piperidonas
12.
Chemistry ; 27(37): 9465, 2021 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-34128275

RESUMO

Invited for the cover of this issue is Toshikazu Ono, Yoshio Hisaeda and co-workers at Kyushu University and their collaborators at Ochanomizu University, Chuo University, and Institute for Molecular Science. The image depicts a molecular assembly structure shining like a jewel, glowing in the red-to-near infrared region. Read the full text of the article at 10.1002/chem.202100906.


Assuntos
Imidas , Naftalenos , Humanos , Estrutura Molecular , Temperatura
13.
Int J Mol Sci ; 22(11)2021 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-34073046

RESUMO

The application of ionic liquids (ILs) has grown enormously, from their use as simple solvents, catalysts, media in separation science, or electrolytes to that as task-specific, tunable molecular machines with appropriate properties. A thorough understanding of these properties and structure-property relationships is needed to fully exploit their potential, open new directions in IL-based research and, finally, properly implement the appropriate applications. In this work, we investigated the structure-properties relationships of a series of alkyltriethylammonium bis(trifluoromethanesulfonyl)imide [TEA-R][TFSI] ionic liquids in relation to their thermal behavior, structure organization, and self-diffusion coefficients in the bulk state using DSC, FT-IR, SAXS, and NMR diffusometry techniques. The phase transition temperatures were determined, indicating alkyl chain dependency. Fourier-transformed infrared spectroscopy studies revealed the structuration of the ionic liquids along with alkyl chain elongation. SAXS experiments clearly demonstrated the existence of polar/non-polar domains. The alkyl chain length influenced the expansion of the non-polar domains, leading to the expansion between cation heads in polar regions of the structured IL. 1H NMR self-diffusion coefficients indicated that alkyl chain elongation generally caused the lowering of the self-diffusion coefficients. Moreover, we show that the diffusion of anions and cations of ILs is similar, even though they vary in their size.


Assuntos
Imidas/química , Líquidos Iônicos/química , Compostos de Amônio Quaternário/química , Difusão , Modelos Químicos , Estrutura Molecular , Transição de Fase , Temperatura de Transição
14.
J Phys Chem B ; 125(23): 6264-6271, 2021 06 17.
Artigo em Inglês | MEDLINE | ID: mdl-34097825

RESUMO

In a set of recent articles, we have highlighted that friction is highly inhomogeneous in a typical ionic liquid (IL) with charge networks that are stiff and charge-depleted regions that are soft. This has consequences not only for the dynamics of ILs but also for the transport properties of solutes dissolved in them. In this article, we explore whether the family of alkylimidazolium ILs coupled with bis(trifluoromethylsulfonyl)imide (with similar Coulombic interactions but different alkyl tails), when dynamically "equalized" by having a similar shear viscosity, display q-dependent structural relaxation time scales that are the same across the family. Our results show that this is not the case, and in fact, the relaxation of in-network charge alternation appears to be significantly affected by the presence of separate polar and apolar domains. However, we also find that if one was to assign weight factors to the relaxation of the structural motifs, charge alternation always contributes about the same amount (between 62.1 and 66.3%) across systems to the running integral of the stress tensor correlation function from which the shear viscosity is derived. Adjacency correlations between positive and negative moieties also contribute an identical amount if a prepeak is not present (about 38%) and a slightly smaller amount (about 28%) when intermediate range order exists. The prepeak only contributes about 6% to viscoelastic relaxation, highlighting that the dynamics of the smaller scale motifs is the most important.


Assuntos
Líquidos Iônicos , Imidas , Simulação de Dinâmica Molecular , Viscosidade
15.
J Colloid Interface Sci ; 601: 746-757, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34098449

RESUMO

HYPOTHESIS: Taking advantage of photoinduced electron transfer, one dimensional organic nanomaterials with tunable donor-acceptor (D-A) interface provide a promising avenue to get high optoelectric properties. However, strong charge transfer interaction between D and A segments impedes the formation of long-range ordered structure, which limits the charge transport through efficient π electronic delocalization. Incorporation of chiral peptide offering various hydrogen bonding (H-bonding) along with asymmetric molecular structure enables substantially controllable D-A interface and tunable organization of the π-conjugates. EXPERIMENTS: A new amphiphilic perylene diimide (CUPDI) with PDI as an acceptor is designed and synthesized. A polar chiral dipeptide composed of ß-alanine and l-histidine with the imidazole ring as the donor i.e., l-carnosine, is incorporated at one of imides. Transition of various supramolecular assemblies of CUPDI is realized by changing CUPDI concentration and solvents. The photoelectronic properties of the assemblies are investigated as well as their association with the microstructure of the nanomaterials. FINDINGS: Delicately tuned hydrogen bonds between the peptides and π-π interaction between PDI cores in different solvents enable the formation of assemblies with multifarious microstructures such as small spherical aggregates, nanowires with uniform diameter, nanobelts, and irregular aggregates. The maximum amount of photocurrent enhancement is up to 1.08 µA observed for the nanobelt, four times higher than that of irregular aggregates. However, the nanowires show the best performance of 7.1-fold in response to ammonia. Thus, the photoelectric performances are strongly dependent on the the molecular arrangement within the nanomaterials.


Assuntos
Carnosina , Perileno , Imidas , Conformação Molecular , Estrutura Molecular
16.
J Phys Chem B ; 125(29): 7967-7974, 2021 07 29.
Artigo em Inglês | MEDLINE | ID: mdl-34128379

RESUMO

Singlet fission (SF) is an intriguing process in which a singlet exciton produces two triplet excitons in molecular aggregates. Perylenediimide (PDI) derivatives are promising materials for SF-based photovoltaics, and the SF process in PDI aggregates is important to investigate for their applications. In this work, we studied the entire SF process occurring in the colloidal nanoparticles of a PDI derivative in solutions by using time-resolved fluorescence and transient absorption (TA) experiments. PE-PDI was found to form the colloidal nanoparticles of H- and J-aggregates in polar solvents. The TA signals of PE-PDI aggregates in solutions were selectively measured by wavelength-dependent excitation. The TA signals were analyzed by using a global fitting analysis, and all kinetic parameters involved in the entire SF process were determined. Our current investigation has confirmed that fast SF occurs on the surface of the colloidal nanoparticles of PDI aggregates via the charge transfer mediated mechanism, giving a high quantum yield of triplet excitons.


Assuntos
Nanopartículas , Perileno , Imidas , Cinética , Perileno/análogos & derivados
17.
ACS Appl Mater Interfaces ; 13(21): 24431-24441, 2021 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-34008949

RESUMO

pH-responsive smart gating membranes were developed using a two-step fabricating process. In the first step, a porous polyimide (PI) support membrane with ordered, regular, and well-defined pores was obtained with a 248 nm KrF excimer laser using a lithography technique. The porous membranes were then grafted with poly(acrylic acid) (PAAc) hydrogel by free radical polymerization using the same excimer laser. The number of pulses and frequency could be varied to obtain a range of water permeabilities. Permeability of membrane changed significantly due to swelling and deswelling of PAAc inside the pores at pH 7 and pH 3, respectively. These hydrogel networks were firmly grafted inside pores and remained mechanically intact even after using high pressure during permeability studies. PAAc grafting was confirmed using ATR-FTIR. PAAc hydrogel distribution inside membrane pores was analyzed using SEM and fluorescence microscopy. To quantify the amount of polymer grafted, TGA studies were carried out. Diffusion studies were also carried out using caffeine as a drug molecule to evaluate the application of membrane in drug delivery devices. The linear drug release profile obtained from the study confirmed the potential application of membrane for drug delivery purposes. Results obtained also suggest that the fabrication method developed is fast, efficient, solvent-free, and economical.


Assuntos
Resinas Acrílicas/química , Concentração de Íons de Hidrogênio , Imidas/química , Criptônio/química , Lasers
18.
J Chromatogr A ; 1647: 462144, 2021 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-33957352

RESUMO

This work highlights the effect of the stationary phase coating process on the separation efficiency of gas chromatography microcolumns. The stationary phase coating quality was characterized by three different bis(trifluoromethylsulfonyl)imide (NTf2) anion based ionic liquids. The ionic liquids containing NTf2 anion are used for gas chromatography due to their high temperature stability. In this work, the chemical and physical approaches of column deactivation as well as the temperature treatment were evaluated by separating a mixture of 20 organic components and saturated alkanes. The results show that higher oven temperature treatment provides higher efficiency while losing a bit of peak symmetry. The thermal treated 1-butylpyridinum bis(trifluoromethylsulfonyl) imide [BPY][NTf2] stationary phase at 240°C demonstrated as high as 8300 plates per meter for naphthalene. This was a 5-fold increase in separation efficiency in comparison to those of the columns treated at 200°C. Albeit being within acceptable ranges, the peak tailing degraded from 1.17 to 1.46 for naphthalene when the processing temperature for coating increased. Both chemical and physical deactivation process increased separation efficiencies and peak resolution.


Assuntos
Cromatografia Gasosa/instrumentação , Cromatografia Gasosa/métodos , Líquidos Iônicos/química , Alcanos/análise , Alcanos/isolamento & purificação , Ânions/química , Hidrocarbonetos Fluorados/química , Imidas/química , Temperatura
19.
J Med Chem ; 64(9): 5863-5873, 2021 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-33886333

RESUMO

Although multivalent glycosidase inhibitors have shown enhanced glycosidase inhibition activities, further applications and research directions need to be developed in the future. In this paper, two positional isomeric perylene bisimide derivatives (PBI-4DNJ-1 and PBI-4DNJ-2) with 1-deoxynojirimycin conjugated were synthesized. Furthermore, PBI-4DNJ-1 and PBI-4DNJ-2 showed positional isomeric effects on the optical properties, self-assembly behaviors, glycosidase inhibition activities, and hypoglycemic effects. Importantly, PBI-4DNJ-1 exhibited potent hypoglycemic effects in mice with 41.33 ± 2.84 and 37.45 ± 3.94% decreases in blood glucose at 15 and 30 min, respectively. The molecular docking results showed that the active fragment of PBI-4DNJ-1 has the highest binding energy (9.649 kcal/mol) and the highest total hydrogen bond energy (62.83 kJ/mol), which were related to the positional isomeric effect on the hypoglycemic effect in mice. This work introduced a new means to develop antihyperglycemic agents in the field of multivalent glycomimetics.


Assuntos
Glucosamina/análogos & derivados , Glicosídeo Hidrolases/metabolismo , Hipoglicemiantes/química , Imidas/química , Perileno/análogos & derivados , Administração Oral , Animais , Sítios de Ligação , Glicemia/análise , Glucosamina/química , Glicosídeo Hidrolases/antagonistas & inibidores , Ligação de Hidrogênio , Hipoglicemiantes/administração & dosagem , Hipoglicemiantes/metabolismo , Isomerismo , Cinética , Camundongos , Conformação Molecular , Simulação de Acoplamento Molecular , Perileno/química , Ligação Proteica , Termodinâmica
20.
J Org Chem ; 86(8): 5852-5862, 2021 04 16.
Artigo em Inglês | MEDLINE | ID: mdl-33829782

RESUMO

This report describes the development and optimization of the one-pot method for the synthesis of N-protected 1-aminoalkylphosphonium salts based on the three-component coupling of aldehydes and either amides, carbamates, lactams, imides, or urea in the presence of triarylphosphonium salts. The proposed strategy is very efficient and easy to carry out even on a larger scale (20 g) in any typical laboratory. Most reactions occur at temperatures between 50 and 100 °C in a short time (1-2 h) without requiring any catalyst, and simple workup procedures afford good to excellent yields. The exceptions are condensations with imides, which require much higher temperatures (150-170 °C) and longer reaction times (even 30 h). The possibility of carrying out the synthesis under solvent-free conditions (neat reactions) is also demonstrated. It is especially important for less reactive substrates (imides), and reactions required high temperature (or generally harsher conditions). Finally, we prove the developed one-pot methodology can be successfully applied for the synthesis of structurally diverse N-protected 1-aminoalkylphosphonium salts. Mechanistic studies showed the intermediate products of described couplings are 1-hydroxyalkylphosphonium salts, not N-hydroxyalkylamides, -imides, etc., as initially expected.


Assuntos
Amidas , Imidas , Carbamatos , Lactamas , Estrutura Molecular , Sais
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