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Proceedings, Volume 9, ECSOC-22

22nd International Electronic Conference on Synthetic Organic Chemistry

Online | 15 November–15 December 2018

Issue Editor: Julio A. Seijas Vázquez


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Cover Story (view full-size image) The Electronic Conferences on Synthetic Organic Chemistry (ECSOC) are a series of conferences that [...] Read more.
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Open AccessProceedings An Easy Approach to Obtain Alcohol-Amines by Reduction of Alcohol Functionalized Imines
Proceedings 2019, 9(1), 2; https://doi.org/10.3390/ecsoc-22-05697
Published: 14 March 2019
Viewed by 173 | PDF Full-text (475 KB)
Abstract
The reduction of functionalized imines to yield amines is often an intricate task, since most of the methods described in the literature to reduce imines to amines do not take into account that many reducing agents have also basic character. In this way, [...] Read more.
The reduction of functionalized imines to yield amines is often an intricate task, since most of the methods described in the literature to reduce imines to amines do not take into account that many reducing agents have also basic character. In this way, iminic compounds that have phenol functions usually produce the phenolic salt of the precursor when they are treated with a basic reducing agent, but not the desired amine. In this work, we describe an easy way of isolating very pure aminic compounds with alcoholic functions in its structure from the corresponding iminic compounds, by using NaBH4 as a reducing agent, and avoiding tedious chromatography or multiple solvent extraction steps. Full article
Open AccessProceedings Ultrasound Assisted Synthesis of Diethyl (2-(1-(morpholinomethyl)-2-Oxoindolin-3-ylidene)hydrazinyl) (Substituted Phenyl/heteryl) MethylphosphonateDerivatives
Proceedings 2019, 9(1), 3; https://doi.org/10.3390/ecsoc-22-05790
Published: 14 November 2018
Viewed by 34 | PDF Full-text (367 KB)
Abstract
This work reports ultrasound assisted synthesis diethyl (2-(1-(morpholinomethyl)-2-oxoindolin-3-ylidene)hydrazinyl) (substituted phenyl/heteryl) methylphosphonate 9(a–j) derivatives. The derivatives are synthesized using a green protocol. In the first step, 3-hydrazonoindolin-2-one is synthesized using ultrasound. In the second step, diethyl (substituted phenyl/heteryl)(2-(2-oxoindolin-3-ylidene)hydrazinyl) methylphosphonate 6(a–j) [...] Read more.
This work reports ultrasound assisted synthesis diethyl (2-(1-(morpholinomethyl)-2-oxoindolin-3-ylidene)hydrazinyl) (substituted phenyl/heteryl) methylphosphonate 9(a–j) derivatives. The derivatives are synthesized using a green protocol. In the first step, 3-hydrazonoindolin-2-one is synthesized using ultrasound. In the second step, diethyl (substituted phenyl/heteryl)(2-(2-oxoindolin-3-ylidene)hydrazinyl) methylphosphonate 6(a–j) derivatives are synthesized using cerric ammonium nitrate as catalyst. In the third step, diethyl (2-(1-(morpholinomethyl)-2-oxoindolin-3-ylidene)hydrazinyl) (substituted phenyl/heteryl) methylphosphonate 9(a–j) derivatives are synthesized using ultrasound. Isatin, chemically known as H-indole-2,3-dione, and its derivatives possess a broad range of biological and pharmacological properties. Isatin is widely used as a starting material for the synthesis of a broad range of heterocyclic compounds and as substrates for drug synthesis. The α-amino phosphonate derivatives constitute an important class of organophosphorus compounds on account of their versatile biological activity. Morpholine moiety has been found to be an eminent pharmacophore in medicinal chemistry. A number of molecules possessing morpholine moiety are clinically approved drugs. The importance of this ring is well understood by medicinal chemists, since they play a major role in molecular properties such as an electronic distribution, three dimensionality, scaffold flexibility/rigidity, lipophilicity or polarity and metabolic stability. Considering the importance of the three pharmacophores, this promoted us to club these pharmacophores together in a single molecule using a green synthetic protocol.The structures of the ultrasound synthesized compounds were confirmed by spectral analysis like IR, 1H NMR, 13C NMR, 31P NMR and MS. Full article
Open AccessProceedings Arylthienyl-vinyl-benzothiazoles as Efficient Second Harmonic Generators (SHG) for Nonlinear Optics
Proceedings 2019, 9(1), 4; https://doi.org/10.3390/ecsoc-22-05702
Published: 14 November 2018
Viewed by 42 | PDF Full-text (417 KB)
Abstract
New push-pull second harmonic generation (SHG) chromophores 2 were synthesized in order to study their linear and nonlinear optical properties. The donor-acceptor π-conjugated systems 2 were prepared in good to excellent yields by a simple aldol-type condensation of the precursor aldehydes 1 with [...] Read more.
New push-pull second harmonic generation (SHG) chromophores 2 were synthesized in order to study their linear and nonlinear optical properties. The donor-acceptor π-conjugated systems 2 were prepared in good to excellent yields by a simple aldol-type condensation of the precursor aldehydes 1 with 6-nitro-2-methyl-1,3-benzothiazole in the presence of NaOH. Hyper-Rayleigh scattering in dioxane solutions was used to evaluate their second-order nonlinear optical properties. The experimental results showed that the optical (linear and nonlinear) properties are influenced by the electron-donor strength of the groups of the π-conjugated bridge. The vinyl-benzothiazole derivative 2b, with methoxyl as the donor group, exhibited the largest first hyperpolarizability β (1660 × 10−30 esu, 40 times greater than the standard reference pNA molecule) and the highest decomposition temperature (Td = 360 °C). The good balance between nonlinearity and thermal stability makes this compound a promising candidate as second harmonic generator (SHG) for nonlinear optics. Full article
Open AccessProceedings MW-Assisted Synthesis of Eight New 6-Nitrilmethyl Pyrrolo[3,4-b]pyridin-5-Ones via a Domino Process: aza Diels–Alder/N-Acylation/Aromatization
Proceedings 2019, 9(1), 5; https://doi.org/10.3390/ecsoc-22-05779
Published: 14 November 2018
Viewed by 114 | PDF Full-text (382 KB)
Abstract
An efficient Microwave (MW)-assisted synthesis of eight new 6-nitrilmethyl-pyrrolo[3,4-b]pyridin-5-ones via a domino process: aza Diels–Alder/N-acylation/aromatization (dehydration–decarboxylation) from their corresponding 2-aminonitrile-oxazoles and maleic anhydride are described. The use of MW as a heat source and scandium (III) triflate as a [...] Read more.
An efficient Microwave (MW)-assisted synthesis of eight new 6-nitrilmethyl-pyrrolo[3,4-b]pyridin-5-ones via a domino process: aza Diels–Alder/N-acylation/aromatization (dehydration–decarboxylation) from their corresponding 2-aminonitrile-oxazoles and maleic anhydride are described. The use of MW as a heat source and scandium (III) triflate as a catalyst to promote the cycloaddition process was crucial to construct these polyfunctionalized products in very good yields (51–79%), considering both their molecular complexity and that only one domino-type experimental procedure was required for their synthesis. It is worth noting that all products reported herein have not been synthesized nor isolated anywhere. However, they can be of high interest for the synthetic and medicinal chemistry community because pyrrolo[3,4-b]pyridin-5-one is the structural core of various bioactive compounds. In the same context, it can be considered as a privileged aza analogue of the isoindolin-1-one, which in turn is the core of numerous anticancer agents. Full article
Open AccessProceedings Pyrrolidinodiones in Enol-Ugi, Enol-Passerini, and Anomalous Enol-Passerini Condensations
Proceedings 2019, 9(1), 6; https://doi.org/10.3390/ecsoc-22-05864
Published: 19 November 2018
Viewed by 115 | PDF Full-text (339 KB)
Abstract
In continuation of our recent research on the development of novel multicomponent reactions with isocyanides, we have used, for the first time, enols as the acid components in Ugi- and Passerini-type reactions. Thus, electron-poor pyrrolidinodiones react with aldehydes, amines, and isocyanides to give [...] Read more.
In continuation of our recent research on the development of novel multicomponent reactions with isocyanides, we have used, for the first time, enols as the acid components in Ugi- and Passerini-type reactions. Thus, electron-poor pyrrolidinodiones react with aldehydes, amines, and isocyanides to give the enaminic four-component adducts. Conversely, in the absence of the amine component, careful control of the reaction conditions allows the involvement of one or two molecules of isocyanide to afford, selectively, either Passerini-type or pseudo-enol-Ugi-type products. These unprecedented condensations of isocyanides, aldehydes, amines, and 4-substituted pyrrolidine-2,3-diones constitute an excellent strategy for the preparation of new biologically relevant pyrrolidinones having peptidic or pseudo-peptidic groups on carbon 3. Full article
Open AccessProceedings Synthesis of New Hyperbranched Phosphorus-Containing Polyesters Starting from Boltorn H20
Proceedings 2019, 9(1), 7; https://doi.org/10.3390/ecsoc-22-05862
Published: 16 November 2018
Viewed by 118 | PDF Full-text (255 KB)
Abstract
Upon gentle treatment with SOCl2, hyperbranched polyester Boltorn H20 afforded a mixture of terminal polychlorides. The latter react with an excess of triphenylphosphine in boiling toluene or with pyridine to give a mixture of polyesters with terminal triphenylphosphonium and pyridinium fragments, respectively. Full article
Open AccessProceedings Effects of Three Ionic Liquids on Microbial Activity of an Organic Soil. Microcalorimetric Study
Proceedings 2019, 9(1), 8; https://doi.org/10.3390/ecsoc-22-05861
Published: 16 November 2018
Viewed by 30 | PDF Full-text (745 KB)
Abstract
: Ionic liquids are considered as a potential green replacement for traditional volatile organic solvents, but their impact on the environment is not sufficiently studied. The effect of the addition of aqueous solutions of different amounts (from 0% to 75%) of three ionic [...] Read more.
: Ionic liquids are considered as a potential green replacement for traditional volatile organic solvents, but their impact on the environment is not sufficiently studied. The effect of the addition of aqueous solutions of different amounts (from 0% to 75%) of three ionic liquids, two based imidazolium, dimethylimidazolium dimethylphosphate ([MMIM][DMP] and 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) and choline dihydrogen phosphate ([Chol][DHP]) on the microbial activity of an acidic, organic soil, was determined in this work. For this propose, an isothermal microcalorimeter, TAM III of TA Instruments was used. This apparatus allows estimating the variation of the metabolic activity through the variation of the heat released after the addition of the ionic liquids (ILs) to the soil. The results showed that the most toxic IL is [BMIM][BF4] which presented a large stress effect and subsequent death on soil microorganisms for the highest concentration of the IL. On the contrary, [Chol][DHP] showed stimulation of the microbial activity for all the concentrations. Full article
Open AccessProceedings BODIPY Derivatives: Synthesis and Evaluation of Their Optical Properties
Proceedings 2019, 9(1), 10; https://doi.org/10.3390/ecsoc-22-05700
Published: 14 November 2018
Viewed by 36 | PDF Full-text (728 KB)
Abstract
Three 3-difluoroborodipyrromethene (BODIPY) derivatives functionalized at the meso and 2 positions were synthesized with 22–59% yield. The compounds were characterized by the usual spectroscopic techniques and a photophysical study was also undertaken. The BODIPY derivatives presented absorption bands in the 494–512 nm range [...] Read more.
Three 3-difluoroborodipyrromethene (BODIPY) derivatives functionalized at the meso and 2 positions were synthesized with 22–59% yield. The compounds were characterized by the usual spectroscopic techniques and a photophysical study was also undertaken. The BODIPY derivatives presented absorption bands in the 494–512 nm range and were also emissive with fluorescence bands in the 512–514 nm interval. A preliminary study on the sensing ability of a BODIPY derivative functionalized at position 2 with a benzimidazole was carried out in acetonitrile and acetonitrile/water (75:25) solutions in the presence of anions and cations, with environmental, biomedical, and analytical relevance. A highly selective response was obtained for Hg2+ and Fe3+ in acetonitrile/water solution. Full article
Open AccessProceedings Metallic Ion Sensing with a Benzothiazole-Based Fluorimetric Chemosensor
Proceedings 2019, 9(1), 11; https://doi.org/10.3390/ecsoc-22-05699
Published: 14 November 2018
Viewed by 38 | PDF Full-text (456 KB)
Abstract
An unnatural amino acid derivative, N-tert-butyloxycarbonyl asparagine benzyl ester bearing a benzothiazole unit at the side chain, was evaluated as a fluorimetric chemosensor for several transition metal cations with environmental, biological and analytic relevance. Spectrofluorimetric titrations of the heterocyclic asparagine derivative with [...] Read more.
An unnatural amino acid derivative, N-tert-butyloxycarbonyl asparagine benzyl ester bearing a benzothiazole unit at the side chain, was evaluated as a fluorimetric chemosensor for several transition metal cations with environmental, biological and analytic relevance. Spectrofluorimetric titrations of the heterocyclic asparagine derivative with the various ions were carried out in acetonitrile and acetonitrile/water (9:1). It was found that the unnatural amino acid had a remarkable fluorimetric response in the presence of Cu2+ in acetonitrile and in the presence of Fe3+ in acetonitrile/water (9:1). Full article
Open AccessProceedings Applications of Computational and NMR Methodologies to the Study of Homoallylic Alcohols Diastereomers
Proceedings 2019, 9(1), 12; https://doi.org/10.3390/ecsoc-22-05782
Published: 14 November 2018
Viewed by 23 | PDF Full-text (804 KB)
Abstract
Through reducing the system InCl3-Li-DTBB(cat.) in THF at room temperature and in the absence of any additives or anti-caking ligand, we have synthesized indium nanoparticles (InNPs) of about 4 nm. The catalyst was employed in the allylation of carbonyl compounds, giving [...] Read more.
Through reducing the system InCl3-Li-DTBB(cat.) in THF at room temperature and in the absence of any additives or anti-caking ligand, we have synthesized indium nanoparticles (InNPs) of about 4 nm. The catalyst was employed in the allylation of carbonyl compounds, giving excellent yields of the corresponding homoallylic alcohols. We have established that the reaction products come from a γ-coupling via a six members cyclic transition state, type Zimmerman–Traxler. Relative to the selectivity, the allylation with crotyl bromide of ortho substituted benzaldehydes (e.g., o-NO2, o-OMe, o-Cl, o-CF3) showed syn selectivity. With the aim to improve the mentioned selectivity, we synthetized o-iPrO-benzaldehyde, and evaluated the reaction with crotyl bromide and InNPs. The homoallylic alcohol 1-(2-isopropoxyphenyl)-2-methylbut-3-en-1-ol was obtained almost quantitatively after 1h as a mixture of the syn- and anti- isomers. The relationship observed by 1H-RMN was 75:25, but we did not know if the syn-isomer was the dominant because the product has not been reported in the scientific literature. Based on this, and in order to determinate which 1H-NMR signals correspond to each isomer, we started computational theoretical and NMR studies. The initial conformational analysis was performed using the semiempirical PM3 method, then we work with the B3LYP functional, applying the 6-31+G* basis set and the solvent effect (chloroform) was evaluated with the PCM model as implemented in Gaussian09. So, we found thirteen low-energy conformations for the syn-diastereomer and six low-energy conformations for the anti-diastereomer. On the other hand, we have carried out NMR experiments such as 1H, 13C, HSQC, to assign the signals of each diastereomer; and experiments such as NOESY, selective NOE, JRes, homo- and hetero-nuclear J-coupled and J-decoupling, to be able to measure coupling constants and establish the structure of each diastereomer. Full article
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Open AccessProceedings A General Stereoselective Approach to 1,2,4-Triazepane-3-thiones/ones via Reduction or Reductive Alkylation of 2,4,5,6-Tetrahydro-3H-1,2,4-triazepine-3-thiones/ones
Proceedings 2019, 9(1), 14; https://doi.org/10.3390/ecsoc-22-05683
Published: 14 November 2018
Viewed by 55 | PDF Full-text (357 KB)
Abstract
A general stereoselective approach to previously unknown 1,2,4-triazepane-3-thiones/ones based on reduction or reductive alkylation of readily available 2,4,5,6-tetrahydro-3H-1,2,4-triazepine- 3-thiones/ones has been developed. The approach involved treatment of tetrahydrotriazepines with sodium cyanoborohydride in MeOH at pH 3 or with sodium borohydride and excess of [...] Read more.
A general stereoselective approach to previously unknown 1,2,4-triazepane-3-thiones/ones based on reduction or reductive alkylation of readily available 2,4,5,6-tetrahydro-3H-1,2,4-triazepine- 3-thiones/ones has been developed. The approach involved treatment of tetrahydrotriazepines with sodium cyanoborohydride in MeOH at pH 3 or with sodium borohydride and excess of carboxylic acid in tetrahydrofuran to give 1-unsubstituted or 1-alkyl-substituted 1,2,4-triazepane-3- thiones/ones, respectively. The latter were also prepared by reaction of 1-unsubstituted 1,2,4- triazepane-3-thiones/ones with sodium cyanoborohydride and aldehyde in MeOH in the presence of AcOH. Full article
Open AccessProceedings A New Approach to 5-Functionalized 1,2-Dihydropyrimidin-2-ones/imines via Base-Induced Chloroform Elimination from 4-Trichloromethyl-1,2,3,4-tetrahydropyrimidin-2-ones/imines
Proceedings 2019, 9(1), 15; https://doi.org/10.3390/ecsoc-22-05678
Published: 14 November 2018
Viewed by 24 | PDF Full-text (410 KB)
Abstract
A novel four-step methodology for the synthesis of 5-acyl- and 5-arylsulfonyl-1,2-dihydropyrimidin-2-ones has been developed. The reaction of readily available N-[(1-acetoxy-2,2,2-trichloro)ethyl]-ureas with Na-enolates of 1,3-diketones, β-oxoesters, or α-arylsulfonylketones followed by heterocyclization–dehydration of the oxoalkylureas formed gave 5-acyl- or 5-arylsulfonyl-4-trichloromethyl-1,2,3,4-tetrahydropyrimidin-2-ones. The latter, in the [...] Read more.
A novel four-step methodology for the synthesis of 5-acyl- and 5-arylsulfonyl-1,2-dihydropyrimidin-2-ones has been developed. The reaction of readily available N-[(1-acetoxy-2,2,2-trichloro)ethyl]-ureas with Na-enolates of 1,3-diketones, β-oxoesters, or α-arylsulfonylketones followed by heterocyclization–dehydration of the oxoalkylureas formed gave 5-acyl- or 5-arylsulfonyl-4-trichloromethyl-1,2,3,4-tetrahydropyrimidin-2-ones. The latter, in the presence of strong bases, eliminates CHCl3 to give the target compounds. The above methodology was also used in the synthesis of 5-acyl-1,2-dihydropyrimidin-2-imines starting from N-[(1-acetoxy-2,2,2-trichloro)ethyl]-N′-guanidine. Full article
Open AccessProceedings Synthesis of Small Organic Molecule Based on Malononitrile Group toward Green Energy Performance in Organic Photovoltaic Solar Cells
Proceedings 2019, 9(1), 16; https://doi.org/10.3390/ecsoc-22-05653
Published: 14 November 2018
Viewed by 45 | PDF Full-text (236 KB)
Abstract
In this study, a small organic compound containing cyano and N,N-dimethyl aniline as acceptor and donor groups, respectively linked through the conjugate system, were synthesized. Then, its structure was confirmed by FT-IR spectroscopy. Next, in order to investigate the photovoltaic properties [...] Read more.
In this study, a small organic compound containing cyano and N,N-dimethyl aniline as acceptor and donor groups, respectively linked through the conjugate system, were synthesized. Then, its structure was confirmed by FT-IR spectroscopy. Next, in order to investigate the photovoltaic properties of these organic molecules, it was tested in the fabrication of organic photovoltaic solar cells (OPVSCs). The organic solar cell with FTO/TiO2/dye molecules/electrolyte/Pt electrode configuration was constructed. Full article
Open AccessProceedings Acid Treatment Halloysite Nanoclay: Eco-Friendly Heterogeneous Catalyst for the Synthesis of Pyrrole Derivatives
Proceedings 2019, 9(1), 17; https://doi.org/10.3390/ecsoc-22-05654
Published: 14 November 2018
Viewed by 150 | PDF Full-text (275 KB)
Abstract
In this study, halloysite nanotubes (HNTs) as a green and available nano-mineral were used. The hydroxyl groups of HNTs were increased by acid treatment. So, the efficiency of HNTs was improved. The catalyst application of acid treatment HNTs was investigated in the synthesis [...] Read more.
In this study, halloysite nanotubes (HNTs) as a green and available nano-mineral were used. The hydroxyl groups of HNTs were increased by acid treatment. So, the efficiency of HNTs was improved. The catalyst application of acid treatment HNTs was investigated in the synthesis of pyrrole as an important heterocycle compound. The catalyst was characterized by Fourier transforms infrared spectroscopy (FT-IR). Easy and simple method, high efficiency and eco-friendly are the advantages of this report. Full article
Open AccessProceedings Insecticidal Activity Evaluation of Phenylazo and Dihydropyrrole-Fused Neonicotinoids Against Cowpea Aphids Using the MLR Approach
Proceedings 2019, 9(1), 18; https://doi.org/10.3390/ecsoc-22-05664
Published: 14 November 2018
Viewed by 145 | PDF Full-text (886 KB)
Abstract
This paper presents a Quantitative Structure-Activity Relationship (QSAR) study of a series of 24 dihydropyrrole-fused and phenylazo neonicotinoid derivatives, with insecticidal activity tested against Cowpea aphids (Aphis craccivora). In this regard, the conformational search ability of the OMEGA software was employed [...] Read more.
This paper presents a Quantitative Structure-Activity Relationship (QSAR) study of a series of 24 dihydropyrrole-fused and phenylazo neonicotinoid derivatives, with insecticidal activity tested against Cowpea aphids (Aphis craccivora). In this regard, the conformational search ability of the OMEGA software was employed to model neonicotinoid conformer ensembles, using molecular mechanics calculations based on the 94s variant of the Merck Molecular force field (MMFF94). The minimum energy conformers were used to calculate structural descriptors, which were further related to the insecticidal activity (pLC50 values), using the multiple linear regression (MLR) approach. The genetic algorithm was used for variable selection and several criteria for internal and external model validation. A robust model (r2 = 0.880, r2adj = 0.855, q2LOO = 0.827, s = 0.2098, F = 34.295) with predictive power (concordance correlation coefficient (CCC)ext = 0.945, r2m= 0.824) was obtained, using the QSARINS software. The developed model can be confidently used for the prediction of the insecticidal activity of new chemicals, saving a substantial amount of time and money. Full article
Open AccessProceedings In Silico Ligand-Based Methods Targeting Porcupine Receptor Inhibitors with Potential Anticancer Effect
Proceedings 2019, 9(1), 19; https://doi.org/10.3390/ecsoc-22-05674
Published: 14 November 2018
PDF Full-text (467 KB)
Abstract
Porcupine is a protein belonging to the O-acyltransferase family, involved in the catalyzing of palmitoylation of wingless-related integration (WNT) proteins. WNT signaling has significant roles in many physiological functions, e.g., hematopoiesis, homeostasis, neurogenesis, and apoptosis. Anomalous WNT signaling has been observed to be [...] Read more.
Porcupine is a protein belonging to the O-acyltransferase family, involved in the catalyzing of palmitoylation of wingless-related integration (WNT) proteins. WNT signaling has significant roles in many physiological functions, e.g., hematopoiesis, homeostasis, neurogenesis, and apoptosis. Anomalous WNT signaling has been observed to be related to tumor generation, and metabolic and neurodegenerative disorders. Therefore, compounds that inhibit this pathway are of great interest for the development of therapeutic approaches. For a better understanding of the common traits of such compounds, we have undertaken an in silico study in order to develop a valid ligand-based pharmacophore model based on a series of porcupine inhibitors. The best pharmacophore hypothesis found after the 3D QSAR validation process is represented by the following features: one hydrogen bond donor (D), three rings (R) and one hydrophobic centroid (H). The 3D-QSAR model obtained using the DRRRH hypothesis shows statistically significant parameters: correlation coefficients for the training set: R2 of 0.90, and a predictive correlation coefficient for the test set, Q2 of 0.86. The assessment of the pharmacophore model was also done and provided very reliable metrics values (Receiver Operating Characteristic—ROC of 1; Robust Initial Enhancement—RIE of 17.97). Thereby, we obtained valuable results which can be further used in the virtual screening process for the discovery of new active compounds with potential anticancer activity. Full article
Open AccessProceedings Expeditious Multicomponent Synthesis of Xanthone Dimers
Proceedings 2019, 9(1), 19; https://doi.org/10.3390/ecsoc-22-05766
Published: 14 November 2018
Viewed by 63 | PDF Full-text (467 KB)
Abstract
Xanthones are a type of compound widely found in many natural products from plants, fungi, and lichens and are considered privileged structures. Frequently, xanthones occur in nature as dimers, which often exhibit singular and potent biological effects. Although diverse methods for the synthesis [...] Read more.
Xanthones are a type of compound widely found in many natural products from plants, fungi, and lichens and are considered privileged structures. Frequently, xanthones occur in nature as dimers, which often exhibit singular and potent biological effects. Although diverse methods for the synthesis of monomeric xanthones are known, dimeric xanthones remain synthetically challenging targets. Reported syntheses of dimeric xanthones are very scarce, and invariably involve a large number of synthetic steps. We have recently developed a multicomponent synthesis of xanthones starting from 3-carbonylchromones, isocyanides, and dienophiles. Here we report a similar one-pot tandem procedure, involving a [4+1]-[4+2] cycloaddition, that readily affords dimeric xanthones and dihydroxanthones, which are structurally similar to bioactive ergochromes. Full article
Open AccessProceedings Structural Study of Three 1,2,4-triazole Derivatives Prepared by Oxidative Cyclization of Thiosemicarbazides
Proceedings 2019, 9(1), 20; https://doi.org/10.3390/ecsoc-22-05852
Published: 14 November 2018
Viewed by 22 | PDF Full-text (553 KB)
Abstract
In the present research, 5,5-dimethyl-4-phenyl-4,5-dihydro-3H-1,2,4-triazole-3-thione (1) was prepared by condensation from N-phenylhydrazinecarbothioamide, while 4-phenyl-5-(pyrazin-2-yl)-2,4-dihydro-3H-1,2,4-triazole-3-thione (2) and 2-((5-(pyridin-2-yl) -4H-1,2,4-triazol-3-yl)thio)acetic acid (3) was prepared by oxidative cyclization from 2-(amino(pyrazin-2-yl)methylene)-N-phenylhydrazine-1-carbothioamide and 2-(amino(pyridine-2-yl)methylene)hydrazine-1-carbothioamide, respectively. The three compounds have been well characterized [...] Read more.
In the present research, 5,5-dimethyl-4-phenyl-4,5-dihydro-3H-1,2,4-triazole-3-thione (1) was prepared by condensation from N-phenylhydrazinecarbothioamide, while 4-phenyl-5-(pyrazin-2-yl)-2,4-dihydro-3H-1,2,4-triazole-3-thione (2) and 2-((5-(pyridin-2-yl) -4H-1,2,4-triazol-3-yl)thio)acetic acid (3) was prepared by oxidative cyclization from 2-(amino(pyrazin-2-yl)methylene)-N-phenylhydrazine-1-carbothioamide and 2-(amino(pyridine-2-yl)methylene)hydrazine-1-carbothioamide, respectively. The three compounds have been well characterized and their molecular structures studied by single-crystal X-ray diffraction. The supramolecular assembly of each crystal has also been analyzed and discussed. Full article
Open AccessProceedings Aluminum Triflate—Catalyzed Adamantylation of N-Nucleophiles
Proceedings 2019, 9(1), 21; https://doi.org/10.3390/ecsoc-22-05661
Published: 14 November 2018
Viewed by 79 | PDF Full-text (326 KB)
Abstract
An efficient method is proposed for N-adamantylation of primary carboxamides and sulfonamides, ethyl carbamate, and 4-nitroaniline using the stoichiometric amount of 1-adamantanol in the presence of 5 mol% aluminum triflate in nitromethane. Similarities and differences between adamantylation of some azoles catalyzed by aluminum [...] Read more.
An efficient method is proposed for N-adamantylation of primary carboxamides and sulfonamides, ethyl carbamate, and 4-nitroaniline using the stoichiometric amount of 1-adamantanol in the presence of 5 mol% aluminum triflate in nitromethane. Similarities and differences between adamantylation of some azoles catalyzed by aluminum triflate in nitromethane and the reaction catalyzed by Brønsted acids were revealed. Full article
Open AccessProceedings Validated HPTLC Method for the Determination of Nintedanib in Bulk Drug
Proceedings 2019, 9(1), 22; https://doi.org/10.3390/ecsoc-22-05675
Published: 14 November 2018
Viewed by 74 | PDF Full-text (268 KB)
Abstract
A simple, rapid, precise and accurate High-Performance Thin Layer Chromatography (HPTLC) method was developed and validated for the estimation of Nintedanib, a novel tyrosine kinase inhibitor used in idiopathic pulmonary fibrosis, in bulk drug. Chromatography was carried out using silica gel 60 F [...] Read more.
A simple, rapid, precise and accurate High-Performance Thin Layer Chromatography (HPTLC) method was developed and validated for the estimation of Nintedanib, a novel tyrosine kinase inhibitor used in idiopathic pulmonary fibrosis, in bulk drug. Chromatography was carried out using silica gel 60 F254 Thin Layer Chromatography (TLC) plate and mobile phase Chloroform: Methanol in the ratio 7:3 v/v. The densitometric determination was done at 386 nm. Regression analysis data for the calibration plot were indicative of a good linear relationship between response and concentration over the range of 800–3200 ng/band. The variance (r) was found to be 0.999. The Limit of Detection (LOD) and Limit of Quantitation (LOQ) were found to be 83.357 ng/band and 252.599 ng/band respectively. The method was validated according to the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use [ICH Q2(R1)] guideline. The method was precise and accurate with %RSD 0.5323 (intraday) and 0.6939 (interday) respectively and percentage recoveries in the range 99.65–101.43%. Full article
Open AccessProceedings Convenient Synthesis of 2-(1-Adamantyl)furans
Proceedings 2019, 9(1), 23; https://doi.org/10.3390/ecsoc-22-05667
Published: 14 November 2018
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Abstract
A simple method of obtaining 2-(1-adamantyl)furans using a smaller amount of catalyst, providing a higher yield of the target products, as well as the possibility of varying the substituents in the furan ring was developed. The result wasachieved by the adamantylation of furans [...] Read more.
A simple method of obtaining 2-(1-adamantyl)furans using a smaller amount of catalyst, providing a higher yield of the target products, as well as the possibility of varying the substituents in the furan ring was developed. The result wasachieved by the adamantylation of furans with 1-adamantanol in a nitromethane medium in the presence of a Lewis acid, for which aluminum or bismuth triflate was used in an amount of 10 mol%. Full article
Open AccessProceedings Synthesis of 4-(1,3,5-Thiadiazinan-2-ylidene)-2-(3,4- dihydro-2H-1,3,5-thiadiazin-6-yl)pent-2-enedinitriles
Proceedings 2019, 9(1), 24; https://doi.org/10.3390/ecsoc-22-05681
Published: 14 November 2018
Viewed by 20 | PDF Full-text (350 KB)
Abstract
The reaction of cyanothioacetamide with diethyl ethoxymethylenemalonate in the presence of triethylamine in hot EtOH proceeds non-selectively and leads to the formation of a mixture of triethylammonium 1,5-diamino-2,4-dicyano-5-thioxopenta-1,3-diene-1-thiolate (minor) and triethylammonium 3-cyano-5-ethoxycarbonyl-6-oxo-1Н-pyridine-2-thiolate (major). Upon treatment with primary amines and 37% aqueous HCHO in [...] Read more.
The reaction of cyanothioacetamide with diethyl ethoxymethylenemalonate in the presence of triethylamine in hot EtOH proceeds non-selectively and leads to the formation of a mixture of triethylammonium 1,5-diamino-2,4-dicyano-5-thioxopenta-1,3-diene-1-thiolate (minor) and triethylammonium 3-cyano-5-ethoxycarbonyl-6-oxo-1Н-pyridine-2-thiolate (major). Upon treatment with primary amines and 37% aqueous HCHO in boiling aqueous ethanol, the reaction product affords only 4-(1,3,5-thiadiazinan-2-ylidene)-2-(3,4-dihydro-2H-1,3,5-thiadiazin- 6-yl)pent-2-enedinitrile derivatives, instead of the expected pyrido[2,1-b][1,3,5]thiadiazines. Triethylammonium 3-cyano-5-ethoxycarbonyl-6-oxo-1Н-pyridine-2-thiolate does not react under these conditions. The structure of the resulted products was confirmed by means of NMR, IR spectroscopy, and LCMS. The mechanism of the formation of the products is discussed. Full article
Open AccessProceedings The Reaction of 5-Amino-3-(cyanomethyl)-1H-pyrazol-4-carbonitrile with beta-Cycloketols
Proceedings 2019, 9(1), 25; https://doi.org/10.3390/ecsoc-22-05679
Published: 14 November 2018
Viewed by 63 | PDF Full-text (361 KB)
Abstract
The reaction of 5-amino-3-(cyanomethyl)-1H-pyrazole-4-carbonitrile with 3-aryl-2,4-di (ethoxycarbonyl)-5-hydroxy-5-methylcyclohexanones in boiling acetic acid leads to the formation of new 4,5,6,7,8,9-hexahydropyrazolo[1,5-a]quinazolines. The mechanism is discussed. The structure of the products was confirmed by means of 1Н и 13С (DEPTQ) NMR, as well as 2D NMR (NOESY, [...] Read more.
The reaction of 5-amino-3-(cyanomethyl)-1H-pyrazole-4-carbonitrile with 3-aryl-2,4-di (ethoxycarbonyl)-5-hydroxy-5-methylcyclohexanones in boiling acetic acid leads to the formation of new 4,5,6,7,8,9-hexahydropyrazolo[1,5-a]quinazolines. The mechanism is discussed. The structure of the products was confirmed by means of 1Н и 13С (DEPTQ) NMR, as well as 2D NMR (NOESY, 1Н–13С HSQC, HMBC). Full article
Open AccessProceedings The First Synthesis of [1,2]oxaphosphinino[6,5-c]pyrazoles by Thiophosphorylation of 6-Aminopyrano[2,3-c]pyrazole-5-Carbonitriles
Proceedings 2019, 9(1), 26; https://doi.org/10.3390/ecsoc-22-05680
Published: 14 November 2018
Viewed by 19 | PDF Full-text (553 KB)
Abstract
The reaction of 6-amino-3-methyl-2,4-dihydropyrano[2,3-c]pyrazole-5-carbonitriles with phosphorus sulfide in boiling pyridine leads to the formation of the unexpected [1,2]oxaphosphinino[6,5-c]pyrazoles. The structure of the products was confirmed with 2D Nuclear Magnetic Resonance (NMR) spectroscopy and X-ray analysis. Full article
Open AccessProceedings Comparison of Complex Formation Mechanisms in Hydrogen Abstraction Reaction between the Nitro Compound and Ammonia
Proceedings 2019, 9(1), 27; https://doi.org/10.3390/ecsoc-22-05771
Published: 14 November 2018
Viewed by 43 | PDF Full-text (343 KB)
Abstract
The present work aims to compare two possible pathways of a pre-reaction complex in the reaction of transfer of a hydrogen atom from ammonia to a nitro compound forming. Nitrobenzene, nitromethane, and HNO2 were used as nitro compounds. The proposed paths are: [...] Read more.
The present work aims to compare two possible pathways of a pre-reaction complex in the reaction of transfer of a hydrogen atom from ammonia to a nitro compound forming. Nitrobenzene, nitromethane, and HNO2 were used as nitro compounds. The proposed paths are: nitro compound intersystem crossing with a subsequent search for a substrate, or the formation of a complex with its subsequent excitation. The calculations were performed using TDPBE0/TDA/aug-cc-pVDZ method in NWChem-6.8 program. For verification purposes, some additional calculations were performed using RASCI/aug-cc-pVDZ method in PSI4 program. The location of the levels and the geometry of the complexes shows that the triplet complex (exciplex) is more stable than the singlet complex. The weak coupling between molecules in the singlet complex indicates that the probability of its excitation is very small. Moreover, there are experimental data, where the quantum yields of such reactions reach 0.3. The presented calculations confirm the mechanism of the nitro compound intersystem crossing with a subsequent search for a substrate. Full article
Open AccessProceedings Our Experience of Using Thermally Recycled Silica Gel in a Teaching and Small Research Laboratory Setting
Proceedings 2019, 9(1), 28; https://doi.org/10.3390/ecsoc-22-05696
Published: 14 November 2018
Viewed by 135 | PDF Full-text (570 KB)
Abstract
Organic synthetic research laboratories generate a large amount of waste. Some of the waste is the silica gel used as the stationary phase in column chromatographic separations. Here, the authors discuss the possibility of recycling silica gel wastes thermally at 600 °C, at [...] Read more.
Organic synthetic research laboratories generate a large amount of waste. Some of the waste is the silica gel used as the stationary phase in column chromatographic separations. Here, the authors discuss the possibility of recycling silica gel wastes thermally at 600 °C, at which temperature the remnant adsorbed organic material combusts. It could be shown that the recycled silica gel maintains its adsorption characteristics. The process could be repeated 10 times with any discernable deterioration of the separation properties of the silica gel for the product mixture of the reactions used in this research. In those cases where triphenyl oxide remained on the silica gel after the separation of the reaction mixture, such as after Wittig olefination and Appel-type reactions, an increase of phosphorus content was noted in the silica gel after thermal treatment. The original and recycled silica gel was partly analyzed by Brunauer-Emmett-Teller (BET) surface measurements, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and in inductively coupled plasma optical emission spectroscopy (ICP-OES). The process significantly reduced waste production in our laboratory and also led to a reduction in costs associated with acquiring new silica gel and with the management and the disposal of spent silica gel. A simple environmental impact assessment has been carried out. Full article
Open AccessProceedings Thermophysical Characterization of Two DyethylMethylAmmonium Ionic Liquids
Proceedings 2019, 9(1), 29; https://doi.org/10.3390/ecsoc-22-05792
Published: 14 November 2018
Viewed by 67 | PDF Full-text (541 KB)
Abstract
Density (ρ), speed of sound (U), and the derived magnitudes of two diethylmethylammoniumionic liquids (ILs) against temperature have been studied in this work. The chosen ILs were diethylmethylammonium trifluoromethanesulfonate [C2C2C1N][OTf] and diethylmethylammonium methanesulfonate [C2C2 [...] Read more.
Density (ρ), speed of sound (U), and the derived magnitudes of two diethylmethylammoniumionic liquids (ILs) against temperature have been studied in this work. The chosen ILs were diethylmethylammonium trifluoromethanesulfonate [C2C2C1N][OTf] and diethylmethylammonium methanesulfonate [C2C2C1N][MeSO3]. In order to analyze the influence of water content, saturated and dried samples of these ILs were studied. The ILs were dried using a vacuum pump, and the saturation level (28% and 6% in weight for [C2C2C1N][MeSO3] and [C2C2C1N][OTf], respectively) was achieved by keeping the ILs in an open bottle at ambient temperature. Direct measurements of density and speed of sound were taken with an Anton Paar DSA 5000. Linear equations were used to express the correlation of both properties with temperature, and the thermal expansion coefficient, αp, and the adiabatic bulk modulus constant, KS, have been also obtained. Additionally, results were compared with previous literature data in order to have a deeper understanding of the liquid properties and detect possible anomalous behaviors. The effect of water content is different on both properties. Thus, the density of the samples slightly increases when water is removed, whereas the opposite behavior was found with regard to the speed of sound, which decreased when the water content was completely removed. Full article
Open AccessProceedings Design and Synthesis of Novel Chalcone-Phenylpyranone Derivatives as Estrogen Receptor Modulators
Proceedings 2019, 9(1), 30; https://doi.org/10.3390/ecsoc-22-05874
Published: 23 November 2018
Viewed by 32 | PDF Full-text (546 KB)
Abstract
Selective estrogen receptor modulators (SERMs) are a class of drugs that act on the estrogen receptor (ER). SERMs are used for treatment and reduction of risk of breast cancer. Herewith we had designed, synthesized, and evaluated chalcone-phenylpyran-2-one derivatives bearing a N,N [...] Read more.
Selective estrogen receptor modulators (SERMs) are a class of drugs that act on the estrogen receptor (ER). SERMs are used for treatment and reduction of risk of breast cancer. Herewith we had designed, synthesized, and evaluated chalcone-phenylpyran-2-one derivatives bearing a N,N-dimethyl ethylamine side chain for their anti-breast cancer activity on MCF-7 and Zr-75-1 cell lines in-vitro. The pharmacological data indicated that most of tested compounds showed moderate to significant cytotoxicity and high selectivity toward the estrogen receptor. The Structure activity relationaship analyses indicated that compounds 5f with 2,6-dichloro substitution was more effective. Docking study was performed to predict binding orientation towards the estrogen receptor-α. Full article
Open AccessProceedings Synthesis of 7-thia-1,4,6,8-tetraazabenzo[de]anthracenes
Proceedings 2019, 9(1), 31; https://doi.org/10.3390/ecsoc-22-05682
Published: 14 November 2018
Viewed by 24 | PDF Full-text (278 KB)
Abstract
New polyheterocyclic ensembles of 8,9,10,11-tetrahydro-7-thia-1,4,6,8-tetraazabenzo[de]anthracenes were prepared by reaction of easily available 5Н-pyrido[2’,3’:2,3]thiopyrano[4,5-b]pyridines with Ас2О or acyl chlorides. The starting 5Н-pyrido[2’,3’:2,3]thiopyrano[4,5-b]pyridines were prepared by reaction of N-methylmorpholinium 4-aryl-3-cyano-6-oxo-1,4,5,6-tetrahydropyridine-2-thiolates with malononitrile dimer. Full article
Open AccessProceedings Synthesis of New bis 1- and 5-Substituted 1H-Tetrazoles via Huisgen-Type 1,3-Dipolar Cycloadditions
Proceedings 2019, 9(1), 32; https://doi.org/10.3390/ecsoc-22-05780
Published: 1 April 2019
Viewed by 150 | PDF Full-text (393 KB)
Abstract
The synthesis and characterization of one symmetrical bis-1-substituted-1H-tetrazole (69%) via a Huisgen-type 1,3-dipolar cycloaddition, as well as, one symmetrical aza-linked bis-5-substituted-1H-tetrazole (57%) via a classic Huisgen 1,3-dipolar cycloaddition followed by a reductive aza-coupling under greener [...] Read more.
The synthesis and characterization of one symmetrical bis-1-substituted-1H-tetrazole (69%) via a Huisgen-type 1,3-dipolar cycloaddition, as well as, one symmetrical aza-linked bis-5-substituted-1H-tetrazole (57%) via a classic Huisgen 1,3-dipolar cycloaddition followed by a reductive aza-coupling under greener reaction conditions are described. The main reason behind these tetrazole-based ligands is to construct novel Metal-Organic Framework (MOF) architectures to evaluate their CO2 capture properties under relative humidity conditions. It is worthy to note that both herein reported products have not been synthesized nor isolated, anywhere. Besides, the synthesis of new ligands to fabricate novel MOFs with potential application in environmental remediation has become a highly valued field of opportunity for synthetic chemists and materials engineers. Full article
Open AccessProceedings Electrochemical Reduction of Oxygen Using a Metal–Organic Complex of Cu2+
Proceedings 2019, 9(1), 33; https://doi.org/10.3390/ecsoc-22-05785
Published: 1 April 2019
Viewed by 157 | PDF Full-text (414 KB)
Abstract
A biphenyl-based copper complex was evaluated as electrocatalyst for the oxygen reduction reaction (orr), for a possible application as cathode material in fuel cells. To carry out this evaluation, the complex was supported on Vulcan carbon and deposited as a film [...] Read more.
A biphenyl-based copper complex was evaluated as electrocatalyst for the oxygen reduction reaction (orr), for a possible application as cathode material in fuel cells. To carry out this evaluation, the complex was supported on Vulcan carbon and deposited as a film on a glassy carbon rotating disk electrode by drop-casting a 1-μL drop of a suspension of carbon in a solution of the complex in dimethyl sulfoxide containing Nafion as ionic conductive binder, and drying under vacuum. The cyclic voltammogram in 0.1 M NaOH solution showed voltammetric peaks between 0.8 and 1.0 V vs. reference hydrogen electrode, which suggest the existence of electron transfer processes from/toward the ligand. The orr was tested in oxygen-saturated (1 atm) solution by linear sweep voltammetry, which showed significant orr current at relatively low overpotential (around −0.4 V), demonstrating the ability of the complex to electrocatalyze the orrefficiently. Full article
Open AccessProceedings Efficient Synthesis of New α-β-Unsaturated Alkyl-Ester Peptide-Linked Chiral Amines
Proceedings 2019, 9(1), 34; https://doi.org/10.3390/ecsoc-22-05769
Published: 14 November 2018
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Abstract
Four new α-β-unsaturated alkyl-ester chiral amines were synthesized in excellent yields (77–95%) via peptide couplings from their corresponding α-β-unsaturated alkyl-ester anilines and N-Boc protected chiral aminoacids. To our delight, these polyfunctionalized compounds are being used as starting reagents in Ugi-type three-component reactions [...] Read more.
Four new α-β-unsaturated alkyl-ester chiral amines were synthesized in excellent yields (77–95%) via peptide couplings from their corresponding α-β-unsaturated alkyl-ester anilines and N-Boc protected chiral aminoacids. To our delight, these polyfunctionalized compounds are being used as starting reagents in Ugi-type three-component reactions (Ugi-3CR) together with alkyl- and aryl-aldehydes and a chain-ring tautomerizable amino acid-containing isocyanide to synthesize novel oxazole-based macrocycle precursors. Thus, the aim of this communication is to show our most recent results of the synthesis and use of new and complex chiral amines to assemble macrocyclic polypeptides with potential application in medicinal chemistry, such as the post-surgical antibiotic Vancomycin. Full article
Open AccessProceedings Synthesis of a Novel Series of Phosphonate-Functionalized 1,2,3-Triazoles as potential candidates for Allosteric Modulation of α7 Nicotinic Acetylcholine Receptors
Proceedings 2019, 9(1), 35; https://doi.org/10.3390/ecsoc-22-05689
Published: 14 November 2018
Viewed by 14 | PDF Full-text (346 KB)
Abstract
Nicotinic acetylcholine receptors (nAChR) are ligand-gated ion channels formed by the assembly of five subunits. Receptor activity could be subjected to both positive and negative modulation at allosteric sites by endogenous neurotransmitters as well as synthetic ligands such as steroids, bivalent cations, alcohols, [...] Read more.
Nicotinic acetylcholine receptors (nAChR) are ligand-gated ion channels formed by the assembly of five subunits. Receptor activity could be subjected to both positive and negative modulation at allosteric sites by endogenous neurotransmitters as well as synthetic ligands such as steroids, bivalent cations, alcohols, and a range of drugs. The subtype of α7 nAChR has been considered a potential therapeutic target for Alzheimer’s disease, schizophrenia and other neurological and psychiatric disorders. In this work we present the synthesis of a novel series of phosphonate-functionalized 1,4-disubstituted 1,2,3-triazoles with potential activity over α7 AChR. These compounds were synthetized through the copper-catalyzed Huisgen 1,3-dipolar cycloaddition of organic azides and alkynes. Copper nanoparticles (CuNPs) immobilized on different supports were prepared using the CuCl2-Li-DTBB reducing system previously reported by our group. Full article
Open AccessProceedings Functionalized BODIPY Derivatives as Potential Fluorescent Labels
Proceedings 2019, 9(1), 36; https://doi.org/10.3390/ecsoc-22-05701
Published: 14 November 2018
Viewed by 22 | PDF Full-text (365 KB)
Abstract
4,4-Difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) derivatives 1 and 2 were obtained with 16% and 33% yield by a two-step reaction: condensation of a pyrrole with the corresponding aldehyde followed by oxidation with 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) in the presence of boron trifluoride diethyl etherate (BF3 [...] Read more.
4,4-Difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) derivatives 1 and 2 were obtained with 16% and 33% yield by a two-step reaction: condensation of a pyrrole with the corresponding aldehyde followed by oxidation with 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) in the presence of boron trifluoride diethyl etherate (BF3OEt2). The two compounds were characterized by the usual spectroscopic techniques and a detailed photophysical study was undertaken. The compounds exhibited intense absorption bands at 502 nm and 497 nm, respectively. Emission studies of the compounds 1 and 2 showed emission bands with maximum wavelength at 518 nm and 519 nm, respectively. Full article
Open AccessProceedings Synthesis and Characterization of Various Amino Acid Derived Thiohydantoins
Proceedings 2019, 9(1), 37; https://doi.org/10.3390/ecsoc-22-05690
Published: 14 November 2018
Viewed by 27 | PDF Full-text (426 KB)
Abstract
Hydantoins and their sulfur containing analogues, thiohydantoins, are cyclic ureides that have attracted huge attention ever since their discovery. Most of them are biologically active compounds and several points of structural diversity have made them very synthetically attractive. Although substituents can be introduced [...] Read more.
Hydantoins and their sulfur containing analogues, thiohydantoins, are cyclic ureides that have attracted huge attention ever since their discovery. Most of them are biologically active compounds and several points of structural diversity have made them very synthetically attractive. Although substituents can be introduced to the hydantoin nucleus, most substituted hydantoins are synthesized from substrates already containing these groups, while forming the hydantoin nucleus. This is a common route to the synthesis of hydantoins and one of them is employed in this study. A series of 3-allyl-2-thiohydantoins is synthesized from various α-amino acids in a reaction with allyl isothiocyanate. The substitution of the acquired thiohydantoin depends on the structure of the starting α-amino acid. The residual group of the α-amino acid becomes the substituent at the C5-position, while N-monosubstituted amino acids give rise to a substituent in the N1-position. The reaction is carried out in a two-step process and the reaction conditions generally depend on the nature of the amino acid itself. All thiohydantoins are obtained in a good yield and fully characterized by NMR and IR spectroscopy, as well as X-ray crystallography. Full article
Open AccessProceedings Unexpected Migration of Benzoyl Group in the Synthesis of 3-Benzoyl-2-Phenylbenzofurans under Wittig Conditions
Proceedings 2019, 9(1), 38; https://doi.org/10.3390/ecsoc-22-05656
Published: 14 November 2018
Viewed by 32 | PDF Full-text (237 KB)
Abstract
In the present work, we report the unexpected formation of isomeric 3-benzoyl-2-phenylbenzo[b]furans using triphenylphosphonium salt and benzoyl chlorides under Wittig conditions. In particular, we found that the o-[(benzoyloxy)benzyl]-triphenyl-phosphoranes constitute the key intermediate that reasonably undergoes benzoyl group migration. Full article
Open AccessProceedings Byphenyl [email protected]2 Composite: Synthesis and Evaluation of a New Chemosensor System for the Detection of Cu2+
Proceedings 2019, 9(1), 39; https://doi.org/10.3390/ecsoc-22-05672
Published: 14 November 2018
Viewed by 17 | PDF Full-text (335 KB)
Abstract
In the present work a byphenyl hydrazone/SiO2 composite was synthetized by a simple procedure. First, the mesoporous SiO2 and the byphenyl hydrazone ligand were prepared. To prepare the composite, the mesoporous silica and the ligand were dispersed in ethanol/water by a [...] Read more.
In the present work a byphenyl hydrazone/SiO2 composite was synthetized by a simple procedure. First, the mesoporous SiO2 and the byphenyl hydrazone ligand were prepared. To prepare the composite, the mesoporous silica and the ligand were dispersed in ethanol/water by a microwave assisted process. Then, the composite was characterized by different techniques to evaluate its chemosensor properties. The physicochemical characterization of the composite confirmed the selectivity and sensitive capacity to detect Cu+2 ions. Full article
Open AccessProceedings Sustainable Carbon-Based Materials as Heterogeneous Catalysts in Solvent-Free Acetylation Reactions
Proceedings 2019, 9(1), 40; https://doi.org/10.3390/ecsoc-22-05685
Published: 18 November 2018
Viewed by 21 | PDF Full-text (516 KB)
Abstract
The catalytic activity of six different carbons was tested in the solvent-free acetylation reaction of alcohols, phenols, and monosaccharides with acetic anhydride. Three commercial carbons—a basic activated carbon M (Merck KGaA), a moderately basic carbon gel X (Xerolutions S.L.), and an activated carbon [...] Read more.
The catalytic activity of six different carbons was tested in the solvent-free acetylation reaction of alcohols, phenols, and monosaccharides with acetic anhydride. Three commercial carbons—a basic activated carbon M (Merck KGaA), a moderately basic carbon gel X (Xerolutions S.L.), and an activated carbon N (Norit Netherland B.V.)—were studied. From these commercial carbons, three acidic activated carbons—M-S, X-S, and N-S—were obtained by treatment with sulfuric acid. All six carbons were characterized by means of nitrogen adsorption capacity, porosimetry, elemental organic analysis, X-ray photoelectron spectroscopy (XPS), and point of zero charge (PZC) determination. The experiments carried out showed good catalytic activity, the magnitude of which depended on the type of carbon used. The best catalyst was X-S, which combined high acidity with the largest mesoporous volume. Second in line was the commercial carbon M, which was the most basic. The protocol reported herein encompasses several of the characteristics related to the sustainability of chemical processes, such as the innocuous nature and the affordable cost of the catalytic material, the absence of reaction solvent, and the ease of reaction work-up. Full article
Open AccessProceedings Solvent-Free Synthesis of Imidazo [1,2-a] pyridin-tetrazolo [1,5-a] Quinolines via an IMCR One-Pot Process
Proceedings 2019, 9(1), 41; https://doi.org/10.3390/ecsoc-22-05796
Published: 14 November 2018
Viewed by 82 | PDF Full-text (676 KB)
Abstract
A solvent-free and catalyst-free synthesis of fused bis-heterocycles containing imidazo[1,2-a]pyridine and tetrazolo[1,5-a]quinoline frameworks is reported via a one-pot process. This Groebke–Blackburn–Bienaymé reaction (GBBR)/SNAr/ring-chain azido tautomerization cascade proceeds under eco-friendly conditions. The tetrazolo[1,5-a]quinoline and imidazo[1,2-a]pyridine scaffolds [...] Read more.
A solvent-free and catalyst-free synthesis of fused bis-heterocycles containing imidazo[1,2-a]pyridine and tetrazolo[1,5-a]quinoline frameworks is reported via a one-pot process. This Groebke–Blackburn–Bienaymé reaction (GBBR)/SNAr/ring-chain azido tautomerization cascade proceeds under eco-friendly conditions. The tetrazolo[1,5-a]quinoline and imidazo[1,2-a]pyridine scaffolds are present in various compounds with interesting pharmacological properties and could lead to the discovery of novel bioactive molecules. Full article
Open AccessProceedings A One-Pot Process for the Synthesis of Alkyne-3-tretrazolyl-tetrazolo [1,5-a] Quinolines
Proceedings 2019, 9(1), 42; https://doi.org/10.3390/ecsoc-22-05798
Published: 14 November 2018
Viewed by 18 | PDF Full-text (854 KB)
Abstract
An efficient synthesis of alkyne-3-tetrazolyl-tetrazolo[1,5-a] quinolones via a one-pot isocyanide-based multicomponent reaction (IMCR) process: I-MCR Ugi-azide/SNAr/ring-chain azido tautomerization was performed under eco-friendly conditions. We report the one-pot synthesis of tris-heterocycles containing a tetrazolo[1,5-a] quinoline connected to a [...] Read more.
An efficient synthesis of alkyne-3-tetrazolyl-tetrazolo[1,5-a] quinolones via a one-pot isocyanide-based multicomponent reaction (IMCR) process: I-MCR Ugi-azide/SNAr/ring-chain azido tautomerization was performed under eco-friendly conditions. We report the one-pot synthesis of tris-heterocycles containing a tetrazolo[1,5-a] quinoline connected to a 1,5-disubstituted-tetrazole (1,5-DS-T). The synthesis of these compounds is of great interest in synthetic and medicinal chemistry because these heterocycles are considered privileged scaffolds and their preparation and evaluation may lead to the discovery of novel bioactive molecules. Full article
Open AccessProceedings Preparation and Hydro-Lipophilic Properties of Methoxylated and Methylated 1-Hydroxynaphthalene-2-Carboxanilides
Proceedings 2019, 9(1), 43; https://doi.org/10.3390/ecsoc-22-05660
Published: 14 November 2018
Viewed by 20 | PDF Full-text (411 KB)
Abstract
A series of variously methoxylated and methylated N-aryl-1-hydroxynaphthalene-2-carboxanilides was prepared and characterized as potential anti-invasive agents. As it is known that lipophilicity significantly influences the biological activity of compounds, the hydro-lipophilic properties of these mono-, di- and tri-substituted 1-hydroxynaphthalene-2-carboxanilides are investigated in the [...] Read more.
A series of variously methoxylated and methylated N-aryl-1-hydroxynaphthalene-2-carboxanilides was prepared and characterized as potential anti-invasive agents. As it is known that lipophilicity significantly influences the biological activity of compounds, the hydro-lipophilic properties of these mono-, di- and tri-substituted 1-hydroxynaphthalene-2-carboxanilides are investigated in the study. All the discussed hydroxynaphthalene derivatives were analyzed using the reversed-phase, high-performance liquid chromatography method, to measure lipophilicity. The procedure was performed under isocratic conditions with methanol as an organic modifier in the mobile phase, using an end-capped, non-polar C18 stationary reversed-phase column. The present study discusses the correlations between the logarithm of the capacity factor k and log P/Clog P values, calculated in various ways, as well as the relationships between the lipophilicity and the chemical structure of the studied compounds. Full article
Open AccessProceedings Tetraalkynylstannanes in Synthesis of α,β-Acetylenic Ketones
Proceedings 2019, 9(1), 44; https://doi.org/10.3390/ecsoc-22-05691
Published: 14 November 2018
Viewed by 11 | PDF Full-text (245 KB)
Abstract
Akynyl ketones were synthesized from tetraalkinylstannanes and both aliphatic and aromatic acyl chlorides under Lewis acid catalysis. The structure of products was confirmed by means of NMR, IR, GC-MS. The method is suitable for the synthesis of long-chain acetylenic ketones. Full article
Open AccessProceedings Theoretical Study of a New Diarylic Ligand for M2+ Cations Detection
Proceedings 2019, 9(1), 45; https://doi.org/10.3390/ecsoc-22-05671
Published: 14 November 2018
Viewed by 5 | PDF Full-text (645 KB)
Abstract
A novel byphenyl hydrazone ligand developed as a chemosensor for the detection of Cu2+ was studied using a theoretical analysis based on the density functional theory (DFT) and time-dependent DFT (TD-DFT). The geometries of the ligand (L) and the Cu2+-ligand [...] Read more.
A novel byphenyl hydrazone ligand developed as a chemosensor for the detection of Cu2+ was studied using a theoretical analysis based on the density functional theory (DFT) and time-dependent DFT (TD-DFT). The geometries of the ligand (L) and the Cu2+-ligand complex were optimized at the CAM-B3LYP/631+G(d,p) level of theory in dimethyl sulfoxide, using the conductor-like polarizable continuum model. The adsorption spectra of these molecular systems were analyzed and compared with the experimental data. Theoretical study of the structural, electronics and optical properties allowed us to understand the chemical changes that the ligand undergoes in the complexation process with the Cu+2 ion. Full article
Open AccessProceedings Ultrasound Assisted Green One Pot Synthesis of Bound Type bis-Heterocyclic furan-2-yl imidazo [1,2-a] Pyridines via GBBR
Proceedings 2019, 9(1), 46; https://doi.org/10.3390/ecsoc-22-05799
Published: 14 November 2018
Viewed by 14 | PDF Full-text (266 KB)
Abstract
A series of six new 3-imidazo[1,2-a] pyridine furan bound type tris-heterocycles were synthesized by Ultrasound Irradiation (USI) assisted Groebke-Blackburn-Bienaymé reaction (GBBR), by employing ammonium chloride (10 mol%) as a catalyst in excellent yields (80–93%) under green conditions. This efficient and [...] Read more.
A series of six new 3-imidazo[1,2-a] pyridine furan bound type tris-heterocycles were synthesized by Ultrasound Irradiation (USI) assisted Groebke-Blackburn-Bienaymé reaction (GBBR), by employing ammonium chloride (10 mol%) as a catalyst in excellent yields (80–93%) under green conditions. This efficient and mild protocol has silent features such as green inexpensive and easily available catalyst and solvent at room temperature. Full article

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Open AccessExtended Abstract A New Approach to the Synthesis of Functionalized Bicyclo[3.2.1]octanes
Proceedings 2019, 9(1), 1; https://doi.org/10.3390/ecsoc-22-05794
Published: 14 March 2019
Viewed by 167 | PDF Full-text (618 KB)
Abstract
oxobicyclo[3.2.1]octane-2,4-dicarboxylates. The structures of the products were confirmed by NMR and X-ray analysis. Full article
Open AccessExtended Abstract Rearrangement of 3-(4,5-dimethoxy -2-vinylphenyl)-2-methyl -5-nitroisoquinolin-1(2H)-one to 2-(6,7-dimethoxy-1-oxoisoquinolin -2(1H)-yl)-N-methylbenzamide: A Mechanistic Proposal
Proceedings 2019, 9(1), 9; https://doi.org/10.3390/ecsoc-22-05767
Published: 14 November 2018
Viewed by 21 | PDF Full-text (328 KB)
Abstract
1-Benzylisoquinolines are biogenetic precursors of a wide range of natural products of
pharmacological interest [...] Full article
Proceedings EISSN 2504-3900 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
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