Showing papers in "ACS Combinatorial Science in 2013"
TL;DR: An efficient one-pot synthesis of functionalized 2-amino-4H-pyrans by a meglumine-catalyzed three-component reaction has been developed and provides an alternative approach for rapid access to construct a diversity-oriented library of 4H- pyrans.
Abstract: An efficient one-pot synthesis of functionalized 2-amino-4H-pyrans by a meglumine-catalyzed three-component reaction has been developed. A broad range of substrates including aromatic and heteroaromatic aldehydes, isatin derivatives, and acenaphthenequinone are condensed with enolizable C–H activated compounds and alkylmalonates to give the desired products in high to excellent yields. This methodology provides an alternative approach for rapid access to construct a diversity-oriented library of 4H-pyrans.
146 citations
TL;DR: A green reaction of isatins, active cyanomethanes, and cyclic 1,3-dicarbonyl derivatives for the efficient and simple one-pot three-component synthesis of spirooxindole fused heterocycles in refluxing water by use of magnetically recoverable and reusable catalyst is reported.
Abstract: A green reaction of isatins, active cyanomethanes, and cyclic 1,3-dicarbonyl derivatives for the efficient and simple one-pot three-component synthesis of spirooxindole fused heterocycles in refluxing water by use of magnetically recoverable and reusable catalyst is reported. The features of this procedure are, the use of magnetically recoverable and reusable catalyst, mild reaction conditions, high to excellent product yields, operational simplicity, and easy workup procedures. Most importantly of all, easy magnetic separation of the catalyst eliminates the requirement of catalyst filtration after completion of the reaction. Furthermore, the catalyst remained highly active even after 5 repeated uses.
94 citations
TL;DR: The results show that on-resin cyclization of medium- and large-sized rings (cyclohexapeptides and above) with PyBOP is essentially quantitative for ≥ 99.96% of the sequences, with small amounts of dimer formation observed for <4% of these sequences.
Abstract: Cyclic peptides are of considerable interest in drug discovery and nanotechnology. However, macrocyclization of peptides and other compounds has often been perceived as synthetically challenging and the cyclization yields are affected by several factors including the ring size, peptide sequence, and the reaction conditions. Through the screening of combinatorial peptide libraries, we analyzed the cyclization efficiency of >2 million peptide sequences to determine the effect of ring size, peptide sequence, and solvent on the backbone (N-to-C) cyclization of peptides. Our results show that on-resin cyclization of medium- and large-sized rings (cyclohexapeptides and above) with PyBOP is essentially quantitative for ≥ 99.96% of the sequences, with small amounts of dimer formation observed for <4% of these sequences. Cyclization of small rings (cyclotetrapeptides and cyclopentapeptides) is considerably more difficult and accompanied by significant cyclic dimer formation. Peptides that are difficult to cyclize are generally rich in Lys(Boc) and Arg(Pbf) residues as well as sterically hindered residues [e.g., Thr(tBu)] at the N-terminus. The majority of these difficult sequences can be cyclized to completion by the addition of aqueous additives to the cyclization reaction.
72 citations
TL;DR: A high-throughput approach to help define experimental formulations that enhance protein stability, which is based on differential scanning fluorimetry (DSF), which is simple to interpret and reliable enough that it has been implemented as a service through the Collaborative Crystallisation Centre.
Abstract: We present a high-throughput approach to help define experimental formulations that enhance protein stability, which is based on differential scanning fluorimetry (DSF). The method involves defining the thermal stability of a protein against a screen of 13 buffer systems, systematically sampling pH from 5.0 to 9.0 at high and low salt concentrations, using both redundancy and extensive controls to make the method robust. The screen allows rapid determination of a suitable base formulation for protein samples, and is particularly useful for difficult samples: those that are rapidly degraded or cannot be sufficiently concentrated for downstream analyses. Data obtained from three samples in this assay illustrate the vastly different values for thermal stability that can be obtained from different formulations. This approach is simple to interpret and reliable enough that it has been implemented as a service through the Collaborative Crystallisation Centre (C3).
72 citations
TL;DR: This synthesis was confirmed to follow the group-assisted-purification (GAP) chemistry process, which can avoid traditional purifications, chromatography, and recrystallization.
Abstract: A facile and efficient one-pot procedure for the preparation of functionalized dihydro-1H-indol-4(5H)-ones by a catalyst-free, three-component reaction of 1,3-dicarbonyl compounds, arylglyoxal monohydrate and enaminones under mild conditions in excellent yield is reported. This synthesis was confirmed to follow the group-assisted-purification (GAP) chemistry process, which can avoid traditional purifications, chromatography, and recrystallization.
71 citations
TL;DR: Magnetic, supported, acidic ionic liquid was synthesized and identified as an efficient catalyst for the one-pot synthesis of novel spirooxindole derivatives at mild conditions and in good yields.
Abstract: Magnetic, supported, acidic ionic liquid was synthesized and identified as an efficient catalyst for the one-pot synthesis of novel spirooxindole derivatives at mild conditions and in good yields. Three component reaction of wide variety of substituted isatins, 1,3-dimethyl-2-amino uracil, and barbituric acid, thiobarbituric acid, and dimedon as 1,3-dicarbonyl compounds gives the target compounds. Operational simplicity, low cost, high yields, environmental friendliness, wide applicability and reusability and easy recovery of the catalyst using an external magnet are the key features of this methodology.
67 citations
TL;DR: A novel fluorescent dye with turn-on fluorescence emission and specific binding at HSA drug site 2 is identified and combined with dansylamide to develop a fluorescent dye cocktail for high-throughput mapping of the interaction between therapeutics at H SA drug-binding sites.
Abstract: Elucidating how molecules bind to HSA is fundamental for predicting drug incompatibilities. Through combinatorial screening, we identified a novel fluorescent dye (BD140) with turn-on fluorescence emission and specific binding at HSA drug site 2. We further combined it with dansylamide to develop a fluorescent dye cocktail for high-throughput mapping of the interaction between therapeutics at HSA drug-binding sites.
64 citations
TL;DR: An overview of attachment methods described in the literature for the preparation of protected peptides using Fmoc/tBu chemistry is provided, including the most commonly used acid-labile linkers along with the most recent and sophisticated.
Abstract: Protected peptide fragments are valuable building blocks for the assembly of large peptide sequences through fragment condensation approaches, whereas protected peptides are typically synthesized for the preparation of amide-bridge cyclic peptides in solution. Efficient synthesis of both protected peptides and protected peptide fragments by solid-phase peptide synthesis methodology requires handles that attach the growing peptides to the polymeric support and can be cleaved under appropriate conditions, while maintaining intact the side-chain protecting groups. Here, we provide an overview of attachment methods described in the literature for the preparation of protected peptides using Fmoc/tBu chemistry, including the most commonly used acid-labile linkers along with the most recent and sophisticated.
63 citations
TL;DR: A novel one-pot, three-component reaction employing variously substituted benzimidazole-linked amino pyridines, aldehydes, and isonitriles catalyzed by scandium(III) triflate under solvent-free conditions were accomplished.
Abstract: A novel one-pot, three-component reaction employing variously substituted benzimidazole-linked amino pyridines, aldehydes, and isonitriles catalyzed by scandium(III) triflate under solvent-free conditions were accomplished. This new synthetic methodology facilitates the rapid generation of intricate molecular frameworks in three-dimensional fashion leading to benzimidazole-imidazo[1,2-a] pyridines. This approach is envisioned as an environmentally benign process and a simple operation to the biological interesting compounds. The present synthetic sequence permits the introduction of three points of structural diversity to expand chemical space with high purity and excellent yields.
62 citations
TL;DR: A library of electrocatalysts for water electrolysis under acidic conditions was created by ink jet printing metal oxide precursors followed by pyrolysis in air to produce mixed metal oxides that perform better than the iridium oxide standard.
Abstract: A library of electrocatalysts for water electrolysis under acidic conditions was created by ink jet printing metal oxide precursors followed by pyrolysis in air to produce mixed metal oxides. The compositions were then screened in acidic electrolytes using a pH sensitive fluorescence indicator that became fluorescent due to the pH change at the electrode surface because of the release of protons from water oxidation. The most promising materials were further characterized by measuring polarization curves and Tafel slopes as anodes for water oxidation. Mixed metal oxides that perform better than the iridium oxide standard were identified.
62 citations
TL;DR: Dz12-91 displays the highest known rate enhancement for the M(2+)-independent cleavage of all-RNA targets, which represents a step toward the generation of potentially therapeutically active DNAzymes and further underscores the usefulness of modified triphosphates in selection experiments.
Abstract: The convenient use of SELEX and related combinatorial methods of in vitro selection provides a formidable gateway for the generation of DNA enzymes, especially in the context of improving their potential as gene therapeutic agents. Here, we report on the selection of DNAzyme 12–91, a modified nucleic acid catalyst adorned with imidazole, ammonium, and guanidinium groups that provide for efficient M2+-independent cleavage of an all-RNA target sequence (kobs = 0.06 min–1). While Dz12–91 was selected for intramolecular cleavage of an all-RNA target, it surprisingly cleaves a target containing a lone ribocytosine unit with even greater efficiency (kobs = 0.27 min–1) than Dz9–86 (kobs = 0.13 min–1). The sequence composition of Dz12–91 bears a marked resemblance to that of Dz9–86 (kobs = 0.0014 min–1 with an all-RNA substrate) that was selected from the same library to cleave a target containing a single ribonucleotide. However, small alterations in the sequence composition have a profound impact on the substra...
TL;DR: A microwave-assisted regioselective reaction dealing with arylglyoxal monohydrate, diverse N-aryl enaminones, and indoles to achieve 3,2'- and 3,3'-bis-indoles by varying a substituted indole substrate is reported.
Abstract: A microwave-assisted regioselective reaction dealing with arylglyoxal monohydrate, diverse N-aryl enaminones, and indoles to achieve 3,2'- and 3,3'-bis-indoles by varying a substituted indole substrate is reported. The 2-unsubstituted indoles resulted in the 3,2'-bis-indole skeleton, whereas indoles bearing a methyl or phenyl group at C2 led to the 3,3'-bis-indoles with simultaneous formation of three sigma-bonds. The procedures feature excellent regioselectivity, short reaction times, convenient one-pot manner, and operational simplicity.
TL;DR: Cu(OAc)2·H2O, a Lewis acid being stable in air and water, was found to be an efficient catalyst for the 4CR synthesis of all the four different series of tetra-/pentasubstisuted dihydropyrroles.
Abstract: We previously reported the novel efficient proton/heat-promoted four-component reactions (4CRs) of but-2-ynedioates, two same/different primary amines, and aldehydes for the synthesis of tetra- and pentasubstituted polyfunctional dihydropyrroles. If aromatic and aliphatic amines were used as reagents, four different series of products should be obtained via the permutation and combination of aromatic and aliphatic primary amines. However, only three/two rather four different series of tetra-/pentasubstisuted dihydropyrroles could be prepared via the proton/heat-promoted 4CRs. Herein, Cu(OAc)2·H2O, a Lewis acid being stable in air and water, was found to be an efficient catalyst for the 4CR synthesis of all the four different series of tetra-/pentasubstisuted dihydropyrroles. The copper-catalyzed 4CR could produce target products at room temperature in good to excellent yields. Interestingly, benzaldehyde, in addition to being used as a useful reactant for the synthesis of pentasubstituted dihydropyrroles, was found to be an excellent additive for preventing the oxidation of aromatic amines with copper(II) and ensuring the sooth conduct of the 4CRs for the synthesis of tetrasubstituted dihydropyrroles with aryl R(3). In addition, salicylic acid was found to be needed to increase the activities and yields of the copper-catalyzed 4CRs for the synthesis of petasubstituted diyhydropyrroles. On the basis of experimental results, the enamination/amidation/intramolecular cyclization mechanism was proposed and amidation is expected to be the rate-limited step in the copper-catalyzed 4CRs.
TL;DR: The study illustrates an efficient, safe, and easily scalable preparation of sulfonamides by use of a meso-reactor apparatus, thus demonstrating the impact of flow technologies within drug discovery.
Abstract: A rapid and eco-friendly synthesis of a sulfonamide library under flow conditions is described. The study illustrates an efficient, safe, and easily scalable preparation of sulfonamides by use of a meso-reactor apparatus, thus demonstrating the impact of flow technologies within drug discovery. Waste minimization, employment of green media, and nontoxic reactants are achieved by the optimization of the flow setup and experimental protocol designed to sequentially synthesize primary, secondary, and tertiary sulfonamides. Isolation of the products involves only extraction and precipitation affording pure compounds in good to high yields without further purification for biological evaluation.
TL;DR: The functional properties examined included the degree of photoinduced hydrophilicity (PIH), UVC-photocatalysis, and thermochromism, and superhydrophilic contact angles could be achieved at all positions, even within a highly VO₂-rich composite.
Abstract: A combinatorial film with a phase gradient from V:TiO2 (V: Ti ≥ 0.08), through a range of TiO2–VO2 composites, to a vanadium-rich composite (V: Ti = 1.81) was grown by combinatorial atmospheric pressure chemical vapor deposition (cAPCVD). The film was grown from the reaction of TiCl4, VCl4, ethyl acetate (EtAc), and H2O at 550 °C on glass. The gradient in gas mixtures across the reactor induced compositional film growth, producing a single film with numerous phases and compositions at different positions. Seventeen unique positions distributed evenly along a central horizontal strip were investigated. The physical properties were characterized by wavelength dispersive X-ray (WDX) analysis, X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), and UV–visible spectroscopy. The functional properties examined included the degree of photoinduced hydrophilicity (PIH), UVC-photocatalysis, and thermochromism. Superhydrophilic contact angles could be achieved at all positions, even withi...
TL;DR: A high-throughput gas adsorption apparatus presented is a useful tool for the screening of novel adsorbents for different applications in gas separation, providing significant time savings in identifying potentially interesting materials.
Abstract: A high-throughput gas adsorption apparatus is presented for the evaluation of adsorbents of interest in gas storage and separation applications. This instrument is capable of measuring complete adsorption isotherms up to 40 bar on six samples in parallel using as little as 60 mg of material. Multiple adsorption cycles can be carried out and four gases can be used sequentially, giving as many as 24 adsorption isotherms in 24 h. The apparatus has been used to investigate the effect of metal center (MIL-100) and functional groups (CAU-10) on the adsorption of N2, CO2, and light hydrocarbons on MOFs. This demonstrates how it can serve to evaluate sample quality and adsorption reversibility, to determine optimum activation conditions and to estimate separation properties. As such it is a useful tool for the screening of novel adsorbents for different applications in gas separation, providing significant time savings in identifying potentially interesting materials.
TL;DR: It was found that the photoelectrolysis activity of the Bi-V oxides of various stoichiometries was best at a Bi/V ratio of 1 to 1 or the BiVO4 phase; the photocurrent generation of this phase was improved by the addition of various amounts of W, Cu, Fe, Mg, and Mn.
Abstract: The photoelectrochemical behavior of materials based on binary Bi–V oxides was investigated by preparing libraries of ternary metal oxides using high-throughput combinatorial inkjet printing of oxide precursors onto conductive glass substrates. Subsequent pyrolysis of the printed films, with addition of various levels of a third metal oxide precursor, produced libraries of metal oxides that were immersed under potential control into an electrolyte solution and evaluated for water photooxidation or photoreduction activity using a laser scanning technique to produce photocurrent images. It was found that the photoelectrolysis activity of the Bi–V oxides of various stoichiometries was best at a Bi/V ratio of 1 to 1 or the BiVO4 phase. The photocurrent generation of this phase was improved by the addition of various amounts of W, Cu, Fe, Mg, and Mn. Addition of W led to the largest increase in photocurrent of up to 18 times; however the electronic band gap was increased compared to that of unsubstituted BiVO4.
TL;DR: An efficient one-pot four-component domino protocol for the combinatorial synthesis of novel 1,4-dihydropyrano[2,3-c]pyrazol-6-amines has been achieved and the significant features include expedient one- Pot process, short reaction time, no column chromatographic purification, excellent yield, and readily available starting materials.
Abstract: An efficient one-pot four-component domino protocol for the combinatorial synthesis of novel 1,4-dihydropyrano[2,3-c]pyrazol-6-amines has been achieved. This transformation presumably occurs via cyclization–Knoevenagel condensation–Michael addition–tautomerism–intramolecular O-cyclization–elimination sequence of reactions. The significant features of this reaction include expedient one-pot process, short reaction time, no column chromatographic purification, excellent yield, and readily available starting materials.
TL;DR: A divergent cascade organocatalysis strategy for the facile construction of new "privileged" substructure-based DOS (pDOS) library is presented, which significantly minimizes time- and cost-consuming synthetic works.
Abstract: In this article, we present a new approach by merging two powerful synthetic tactics, divergent synthesis and cascade organocatalysis, to create a divergent cascade organocatalysis strategy for the facile construction of new “privileged” substructure-based DOS (pDOS) library. As demonstrated, notably 5 distinct molecular architectures are produced facilely from readily available simple synthons thiazolidinedione and its analogues and α,β-unsaturated aldehydes in 1–3 steps with the powerful strategy. The beauty of the chemistry is highlighted by the efficient formation of structurally new and diverse products from structurally close reactants under the similar reaction conditions. Notably, structurally diverse spiro-thiazolidinediones and -rhodanines are produced from organocatalytic enantioselective 3-component Michael–Michael–aldol cascade reactions of respective thiazolidinediones and rhodanines with enals. Nevertheless, under the similar reaction conditions, reactions of isorhodanine via a Michael–cycl...
TL;DR: Dispiro-pyrrolidino/ pyrrolizidino fused oxindoles/acenaphthoquinones have been derived from andrographolide via azomethine ylide cycloaddition to the conjugated double-bond under microwave (MW) irradiation.
Abstract: Dispiro-pyrrolidino/pyrrolizidino fused oxindoles/acenaphthoquinones have been derived from andrographolide via azomethine ylide cycloaddition to the conjugated double-bond under microwave (MW) irradiation. The reactions are chemo-, stereo-, and regioselective in nature. Change in amino acid from sarcosine/N-benzyl glycine to l-proline changes the regiochemistry. A representative library of 40 compounds along with in vitro anticancer evaluation is reported.
TL;DR: This study identified several peptides that can be used as tools to precisely unravel the origin of hemolysis and thus help to design even further optimized nontoxic very active short antibacterial peptides.
Abstract: High systemic toxicity of antimicrobial peptides (AMPs) limits their clinical application to the treatment of topical infections; in parenteral systemic application of AMPs the problem of hemolysis is one of the first to be tackled. We now show that the selectivity of lipidated short synthetic AMPs can be optimized substantially by reducing their hemolytic activity without affecting their activity against methicillin resistant Staphylococcus aureus (MRSA). In order to identify the optimized peptides, two sets of 32 diastereomeric H-(D)Arg-WRWRW-(L)Lys(C(O)CnH2n+1)-NH2 (n = 7 or 9) peptides were prepared using a split-split procedure to perform a systematic L-to-D exchange scan on the central WRWRW-fragment. Compared to the all-L C8-lipidated lead sequence, diastereomeric peptides had very similar antibacterial properties, but were over 30 times less hemolytic. We show that the observed hemolysis and antibacterial activity is affected by both differences in lipophilicity of the different peptides and specific combinations of L- and D-amino acid residues. This study identified several peptides that can be used as tools to precisely unravel the origin of hemolysis and thus help to design even further optimized nontoxic very active short antibacterial peptides.
TL;DR: From the results, it is suggested that the electro-modification of Pd through strong metal-metal oxide interaction with IrO2-CeO2 was a reason for the enhanced ORR activity.
Abstract: A combinatorial library having 66 different ternary compositions of Pd–Ir–Ce was prepared via the impregnation method to find the optimum ternary composition with the highest performance toward oxygen reduction reaction (ORR) in acid media. Its performance in ORR activity of the combinatorial array was evaluated through two different combinatorial high-throughput screening methods to gain validity: (1) multielectrode half-cell method and (2) optical screening method. From the combinatorial results, the spot at 79:12:9 for Pd–Ir–Ce (at. %) in the array showed the highest ORR activity. The electrochemical characterizations of the single catalyst demonstrates that the optimized Pd79Ir12Ce9/C catalyst shows 1.5 times the ORR activity compared to that of Pd/C catalyst at 0.85 V (vs. RHE). In the Pd–Ir–Ce based catalysts, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) results reveal that Ir and Ce are present in the form of IrO2 and CeO2, respectively, and the electron configuration of Pd is...
TL;DR: An efficient and direct synthesis of 2-arylideneamino-3-aryl-4H-furo[3,2-c]chromen-4-ones has been developed via four-component reaction from substituted nitrostyrenes, aromatic aldehydes, coumarins, and ammonium acetate under very mild conditions.
Abstract: An efficient and direct synthesis of 2-arylideneamino-3-aryl-4H-furo[3,2-c]chromen-4-ones has been developed via four-component reaction from substituted nitrostyrenes, aromatic aldehydes, coumarins, and ammonium acetate under very mild conditions, which involves sequentially a Michael addition, an aza-nucleophilic addition, of the imine to the double bond, an intermolecular nucleophilic addition and a dehydration reaction. The resulting biologically intriguing structures could have broad applications in related biomedical-program structures.
TL;DR: This approach should allow one to rapidly screen an OBOC library and identify novel peptide ligands against cell surface targets in their native conformation and is compatible with matrix-assisted laser desorption ionization time-of-flight mass spectrometry-based peptide sequence deconvolution.
Abstract: Screening approaches based on one-bead–one-compound (OBOC) combinatorial libraries have facilitated the discovery of novel peptide ligands for cellular targeting in cancer and other diseases. Recognition of cell surface proteins is optimally achieved using live cells, yet screening intact cell populations is time-consuming and inefficient. Here, we evaluate the Complex Object Parametric Analyzer and Sorter (COPAS) large particle biosorter for high-throughput sorting of bead-bound human cell populations. When a library of RGD-containing peptides was screened against human cancer cells that express αvβ3 integrin, it was found that bead-associated cells are rapidly dissociated when sorted through the COPAS instrument. When the bound cells were reversibly cross-linked onto the beads, however, we demonstrated that cell/bead mixtures can be sorted quickly and accurately. This reversible cross-linking approach is compatible with matrix-assisted laser desorption ionization time-of-flight mass spectrometry-based p...
TL;DR: An efficient one-pot synthesis of novel pyrano[3,2-b]pyrazolo[4,3-e]pyridin-8(1H)-ones via three-component condensation of kojic acid, 1-H-pyrazol-5-amines and aldehydes in the presence of a catalytic amount of Zn(OTf)(2) followed by H(2)O(2)-mediated oxidation is reported.
Abstract: An efficient one-pot synthesis of novel pyrano[3,2-b]pyrazolo[4,3-e]pyridin-8(1H)-ones via three-component condensation of kojic acid, 1-H-pyrazol-5-amines and aldehydes in the presence of a catalytic amount of Zn(OTf)2 followed by H2O2-mediated oxidation is reported. Furthermore, the synthesis of 1′H-spiro[indoline-3,4′-pyrano[2,3-b]pyrazolo[3,4-e]pyridine]-2,8′(9′H)-diones were chosen for the library validation.
TL;DR: The method developed is suitable for the synthesis of diverse libraries including the mentioned types of heterocycles, which have significant importance in current drug discovery.
Abstract: 4-Chloro-2-fluoro-5-nitrobenzoic acid is a commercially available multireactive building block that can serve as a starting material in heterocyclic oriented synthesis (HOS) leading to various condensed nitrogenous cycles. This work describes its ability for the preparation of substituted nitrogenous heterocycles having 5–7-membered cycles via polymer-supported o-phenylendiamines. Immobilization of this compound on Rink resin followed by further chlorine substitution, reduction of a nitro group and appropriate cyclization afforded benzimidazoles, benzotriazoles, quinoxalinones, benzodiazepinediones and succinimides. The method developed is suitable for the synthesis of diverse libraries including the mentioned types of heterocycles, which have significant importance in current drug discovery. In this paper, we also report limitation of these method and unsuccessful attempt to prepare an 8-membered benzodiazocine cycle.
TL;DR: This study presents a novel HT workflow for the investigation of cationic polymers for gene delivery applications, which allows many different polymers and parameters to be tested for transfection properties and cytotoxicity, giving faster insights into structure-activity relationships for biological activity.
Abstract: In recent years, “high-throughput” (HT) has turned into a keyword in polymer research. In this study, we present a novel HT workflow for the investigation of cationic polymers for gene delivery applications. For this purpose, various poly(ethylene imine)s (PEI) were used as representative vectors and investigated via HT-assays in a 96-well plate format, starting from polyplex preparation up to the examination of the transfection process. In detail, automated polyplex preparation, complex size determination, DNA binding affinity, polyplex stability, cytotoxicity, and transfection efficiency were performed in the well plate format. With standard techniques, investigation of the biological properties of polymers is quite time-consuming, so only a limited number of materials and conditions (such as pH, buffer composition, and concentration) can be examined. The approach described here allows many different polymers and parameters to be tested for transfection properties and cytotoxicity, giving faster insight...
TL;DR: It is interesting that the designed reactions gave aromatized or unaromatized products, which depend on the reaction temperature and reactants of 1,3-dicarbonyl compounds.
Abstract: A combinatorial synthesis of pyrrolo[3,2-f]quinoline and pyrrolo[3,2-a]acridine derivatives is described as a three-component reaction of aromatic aldehyde, 1H-indol-5-amine, and 1,3-dicarbonyl compounds under catalyst-free conditions. The 1,3-dicarbonyl compounds include 5,5-dimethylcyclohexane-1,3-dione, cyclopentane-1,3-dione, and 2H-indene-1,3-dione. It is interesting that the designed reactions gave aromatized or unaromatized products, which depend on the reaction temperature and reactants of 1,3-dicarbonyl compounds.
TL;DR: A library of some new fluorescent chromenopyrimidine derivatives has been synthesized by new approaches and the details of an interesting exchangeable intramolecular H- bonding of two of the new compounds are reported by X-ray analysis data.
Abstract: A library of some new fluorescent chromenopyrimidine derivatives has been synthesized by new approaches. Water-promoted and one-pot reaction can produce new dialkylylamino)-5H-chromeno[2,3-d]pyrimidin-2-yl) phenols. These compounds can also be produced using domino reaction. Two parallel methods are compared. Novel N-alkyl-N-phenyl-5H-chromeno[2,3-d]-pyrimidin-4-amines and 4-alkoxy-5H-chromeno[2, 3-d]pyrimidines are synthesized by Lewis-acid catalyzed reactions. The fluorescence emission intensity of the four compounds from each of libraries after excitation in 290 nm is measured. Compound 2-(4,5-bis(N-methyl-N-phenylamino)-5H-chromeno[2,3-d]pyrimidin-2-yl)phenol was isolated as a byproduct. The details of an interesting exchangeable intramolecular H- bonding of two of the new compounds are reported by X-ray analysis data.
TL;DR: In this paper, an artificial neural network (ANN) is first applied to perovskite catalyst design and revealed the relative importance and criticality of preparation parameters of optimum catalysts.
Abstract: In this paper, an artificial neural network (ANN) is first applied to perovskite catalyst design. A series of perovskite-type oxides with the LaxSr1–xFeyCo1–yO3 general formula were prepared with a sol–gel autocombustion method under different preparation conditions. A three-layer perceptron neural network was used for modeling and optimization of the catalytic combustion of toluene. A high R2 value was obtained for training and test sets of data: 0.99 and 0.976, respectively. Due to the presence of full active catalysts, there was no necessity to use an optimizer algorithm. The optimum catalysts were La0.9Sr0.1Fe0.5Co0.5O3 (Tc = 700 and 800 °C and [citric acid/nitrate] = 0.750), La0.9Sr0.1Fe0.82Co0.18O3 (Tc = 700 °C, [citric acid/nitrate] = 0.750), and La0.8Sr0.2Fe0.66Co0.34O3 (Tc = 650 °C, [citric acid/nitrate] = 0.525) exhibiting 100% conversion for toluene. More evaluation of the obtained model revealed the relative importance and criticality of preparation parameters of optimum catalysts. The structu...