Showing papers in "Chemistry of Heterocyclic Compounds in 2016"
TL;DR: This review article has focused on synthetic approaches for the creation of [1,2,4]triazolo[1,5-a]pyrimidine system.
Abstract: [1,2,4]Triazolo[1,5-a]pyrimidines are very interesting and trend class of fused heterocycles due to their valuable biological properties. Some [1,2,4]-triazolo[1,5-a]pyrimidines possess herbicidal activity,1 also they can act as antifungal,2 antitubercular,3 and antibacterial4 agents. Polycyclic systems containing [1,2,4]triazolo[1,5-a]-pyrimidine moiety are reported as antitumor,5 as corticotropin-releasing factor 1 receptor antagonists6 or calcium channel modulators;7 they can be used for treatment of Alzheimer's disease8 and insomnia.9 Complexes of triazolo-pyrimidines with Pt and Ru are highly active against parasites10 and can also be used in treating cancer.11
The synthetic ways for the preparation of [1,2,4]triazolo[1,5-a]-pyrimidines can be divided into two main groups: annulation of pyrimidine moiety to triazole ring and annulation of triazole fragment to pyrimidine ring. The Dimroth rearrangement of [1,2,4]triazolo[4,3-a]pyrimidines can also be used for the synthesis of [1,2,4]triazolo[1,5-a]pyrimidines. In this review article we have focused on synthetic approaches for the creation of [1,2,4]triazolo[1,5-a]pyrimidine system.
36 citations
TL;DR: A new series of 2-substituted quinazolin-4(3H)-one derivatives including coumarin nucleus has been synthesized and screened for their lipase and α-glucosidase inhibition properties.
Abstract: A new series of 2-substituted quinazolin-4(3H)-one derivatives including coumarin nucleus has been synthesized and screened for their lipase and α-glucosidase inhibition properties. Among the synthesized compounds, N'-{2-[2-(3,4-dichlorobenzyl)-4-oxoquinazolin-3(4H)-yl]acetyl}-2-oxo-2H-chromene-3-carbohydrazide and N'-{2-[2-(4-bromobenzyl)-4-oxoquinazolin-3(4H)-yl]acetyl}-2-oxo-2H-chromene-3-carbohydrazide showed the best inhibitory effect against α-glucosidase with IC50 values of 6.11 ± 0.40 and 7.34 ± 0.37 μM,respectively. These compounds also showed strong anti-lipase activity (IC50 3.52 ± 0.49 and 2.85 ± 0.27 μM, respectively).
34 citations
TL;DR: In this paper, a generalized and systematically arranged data about thermal, photochemical, and catalytic transformations of isoxazole-2-carbonyl-2H-azirine were published in the period from 1969 to 2015, and considered the possibilities for using these compounds in the synthesis of nitrogen heterocycles.
Abstract: This review contains a generalized and systematically arranged data about thermal, photochemical, and catalytic transformations of isoxazole–2-carbonyl-2H-azirine that were published in the period from 1969 to 2015, and considers the possibilities for using these compounds in the synthesis of nitrogen heterocycles. Radical and pericyclic steps of isomerization reactions have been discussed. Density functional theory calculations of the relative thermodynamic stability of isomeric isoxazoles and azirines have been performed. A total of 76 references are given.
33 citations
TL;DR: In this paper, the first analysis of scientific literature on diarylethene photoreactions is presented, which is based on a sigmropic hydrogen shift followed by the opening of one aromatic ring.
Abstract: The photocyclization of stilbenes and their heterocyclic analogs has gained major importance in the synthesis of poly(hetero)aromatic compounds. This reaction generally leads to the formation of phenanthrene derivatives or their isosteric heterocyclic analogs. Over the last 15 years, examples of a new type of diarylethene reactions have been published, leading to bicyclic, instead of tricyclic aromatic products. These reactions are based on a sigmatropic hydrogen shift followed by the opening of one aromatic ring, and these transformations are applicable to the preparation of various aromatic compounds. Similar reactions are also highly relevant to the photostability of photochromic diarylethenes and terarylenes, thus the study of these compounds is important for the development of photo-controlled advanced materials and devices. In this review we provide the first analysis of scientific literature on this new type of diarylethene photoreactions.
26 citations
TL;DR: The reaction of aromatic aldehydes with Meldrum's acid and malononitrile dimer in the presence of triethylamine led to the formation of (4-aryl-3-cyano-6-oxopiperidin-2-ylidene)malononitriles.
Abstract: The reaction of aromatic aldehydes with Meldrum's acid and malononitrile dimer in the presence of triethylamine led to the formation of (4-aryl-3-cyano-6-oxo-1,4,5,6-tetrahydropyridin-2-yl)malononitrile triethylammonium salts, which were converted upon acidification to (4-aryl-3-cyano-6-oxopiperidin-2-ylidene)malononitriles. The reaction of these compounds with thioglycolic acid anilide was observed to produce derivatives of 1,6-naphthyridine or thieno[2,3-h][1,6]naphthyridine, depending on the conditions. Structures of (3-cyano-6-oxo-4-phenylpiperidin-2-ylidene)malononitrile and its triethylammonium salt were studied by X-ray structural analysis.
26 citations
TL;DR: Metal-catalyzed synthesis of isocoumarins has attracted considerable attention due to its economic advantages and good functional group tolerance, and recent reports on the Cu-, Pd, Ru, and Rh-catalystzed synthesis are reviewed here.
Abstract: Isocoumarins (1H-isochromen-1-ones), an important class of naturally occurring unsaturated lactones, exhibit a broad range of pharmacological activities including cytotoxicity toward HeLa cervical cancer cells,1 antioxidant activity in HepG2 cells exposed to oxidative stress conditions induced by H2O2,2 antiangiogenic,3 anticancer,4
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5 antifungal,6
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7 and antimicrobial activity.8 Isocoumarins are also important building blocks for the synthesis of a number of medicinally important heterocycles.9
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11 A number of conventional methods have been used for the synthesis of isocoumarins starting from homophthalic acids,12
,
13 but metal-catalyzed synthesis of isocoumarins has attracted considerable attention due to its economic advantages and good functional group tolerance.14
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15 Recent reports on the Cu-, Pd-, Ru-, and Rh-catalyzed synthesis of isocoumarins are reviewed here. Besides, an example of Re catalysis has appeared recently.16
26 citations
TL;DR: In this paper, the key methods of synthesis of 5-methylidene-3,5-dihydro-4H-imidazol-4-ones together with analysis of the relative efficiency for the substituent introduction at different positions of the ring are presented.
Abstract: This microreview presents the key methods of synthesis of 5-methylidene-3,5-dihydro-4H-imidazol-4-ones together with analysis of the relative efficiency for the substituent introduction at different positions of the ring. Also, examples of reactions typical for these compounds presented in the literature over the last seven years are given.
24 citations
TL;DR: In this article, the energy potential of solid composite rocket propellants on the basis of solid and liquid nitro derivatives of azo-and azoxyfurazans was studied by using thermochemical calculations.
Abstract: The energetic potential of solid composite rocket propellants on the basis of solid and liquid nitro derivatives of azo- and azoxyfurazans was studied by using thermochemical calculations. Quantitative relationships were established between the energetic parameters of propellants, the selected binder, and the properties of the studied component. It was shown that the studied solid nitrofurazans can serve as the foundation of metal-free compositions of solid composite rocket propellants, giving specific impulse over 263 s, while the use of liquid nitrofurazans as plasticizers of the binder can improve the ballistic effectiveness of rocket propellants containing aluminum hydride by 2–4 s.
22 citations
TL;DR: A systematic overview of synthetic approaches and reactivity data for chromone-3-carboxylic acid can be found in this article, where the authors present a review article.
Abstract: This review article presents a systematic overview of synthetic approaches and reactivity data for chromone-3-carboxylic acid, published from 1973 until 2015.
21 citations
TL;DR: In this article, a microreview summarizes the newly developed synthetic approaches to construct β-Caroline scaffolds, and summarizes the most commonly used synthetic approaches for β-caroline synthesis.
Abstract: β-Carbolines are an important class of heterocyclic compounds because of their broad spectrum of biological profiles. Consequently, many methodologies have been described to construct the β-carboline scaffold. This microreview summarizes these newly developed synthetic approaches.
19 citations
TL;DR: In this article, a series of 1H-benzo[f]chromene-2-carbaldehydes was obtained from naphthol Mannich bases and 3-(N,N-diethylamino)acrolein via a cascade reaction comprising [4+2] cycloaddition of generated in situ 1,2-naphthoquinone-2methides and a push-pull β-enaminoaldehyde with consecutive elimination of diethylamine.
Abstract: A series of 1H-benzo[f]chromene-2-carbaldehydes was obtained from naphthol Mannich bases and 3-(N,N-diethylamino)acrolein via a cascade reaction comprising [4+2] cycloaddition of generated in situ 1,2-naphthoquinone-2-methides and a push-pull β-enaminoaldehyde with consecutive elimination of diethylamine.
TL;DR: In this article, a review of cyclic azomethine imines is presented, focusing on the issues of regio-and stereoselectivity, the effects of the structure of starting materials, solvents, and catalysts on the reaction direction and yields of cycloadducts.
Abstract: This review considers new methods for the synthesis of N,N
ʹ- and C,N-cyclic azomethine imines, as well as the most characteristic of their transformations – (3+2)-dipolar cycloaddition reactions. Particular attention was focused on the issues of regio- and stereoselectivity, the effects of the structure of starting materials, solvents, and catalysts on the reaction direction and yields of cycloadducts. The review covers literature data about the chemistry of cyclic azomethine imines published over the previous 10 years. There are 71 references given.
TL;DR: The structure of reaction products obtained from 3,5-dicyano-4,4-dimethyl-6-oxo-1,4,5,6-tetrahydropyridine-2-thiolates, primary amines, and formaldehyde substantially depends on the nature of counter-ion (morpholinium or N-methylmorpholine), as well as on the primary amine structure and the ratio of reactants.
Abstract: The structure of reaction products obtained from 3,5-dicyano-4,4-dimethyl-6-oxo-1,4,5,6-tetrahydropyridine-2-thiolates, primary amines, and formaldehyde substantially depends on the nature of counter-ion (morpholinium or N-methylmorpholinium), as well as on the primary amine structure and the ratio of reactants. Aminomethylation of these thiolates with highly nucleophilic amines RCH2NH2 and excess formalin (2 equiv and more) produced 7-RCH2-9,9-dimethyl-2-oxo-4-thioxo-3,7-diazabicyclo[3.3.1]nonane-1,5-dicarbonitrile salts, which gave the respective bispidines upon acidification. Performing this reaction with aromatic amines in the case of N-methylmorpholinium 3,5-dicyano-4,4-dimethyl-6-oxo-1,4,5,6-tetrahydropyridine-2-thiolate led to analogous bispidines, while the morpholinium salt gave 3-aryl-8,8-dimethyl-7-[(morpholin-4-yl)methyl]-6-oxo-3,4,7,8-tetrahydro-2H,6H-pyrido[2,1-b][1,3,5]thiadiazine-7,9-dicarbonitriles. The treatment of thiolates with 1 equiv of НСНО and 1 equiv of RCH2NH2 led to 7-RCH2-4-amino-9,9-dimethyl-2-oxo-6-thioxo-3,7-diazabicyclo[3.3.1]non-3-ene-1-carbonitriles. The molecular and crystal structures of key compounds were studied in detail by X-ray structural analysis.
TL;DR: In this paper, the introduction of nitro groups was studied in the case of pyrazoles containing a 1- or 5-tetrazole substituent at position 3(5), and all possible isomeric C-mononitropyrazoles were synthesized.
Abstract: Regioselective introduction of nitro groups was studied in the case of pyrazoles containing a 1- or 5-tetrazole substituent at position 3(5). All the possible isomeric C-mononitropyrazoles were synthesized. The reduction of these compounds gave the respective 3(5)-amino-5(3)-tetrazolylpyrazoles, which were nitrated to 3(5)-nitramino-4-nitro-5(3)-tetrazolylpyrazoles. The reaction of 1-(nitropyrazol-3(5)-yl)tetrazoles with hydroxylamine-O-sulfonic acid produced the respective N-amino derivatives.
TL;DR: In this article, isoxazoline and pyrazoline derivatives of N-substituted saccharin were synthesized in good yields by 1,3-dipolar cycloaddition of n-crotonoyl- or N-cinnamoylsaccharin as dipolarophile to arylnitrile oxides or nitrile imines using p-HAP300 as catalyst under solvent free microwave conditions.
Abstract: Novel isoxazoline and pyrazoline derivatives of N-substituted saccharin were synthesized in good yields by 1,3-dipolar cycloaddition of N-crotonoyl- or N-cinnamoylsaccharin as dipolarophile to arylnitrile oxides or nitrile imines using p-HAP300 as catalyst under solventfree microwave conditions. In this process, the yields were significantly improved compared to classical conditions without alteration of the selectivity. The regioselectivity as well as the nonthermal specific microwave effect are discussed.
TL;DR: In this article, the detailed mechanism of thermal ring opening reactions of 2H-pyran and 2H 1,4-oxazine systems in a broad range of spiropyran derivatives was studied by density functional methods.
Abstract: The detailed mechanism of thermal ring opening reactions of 2H-pyran and 2H-1,4-oxazine systems in a broad range of spiropyran and spiro-1,4-oxazine derivatives was studied by density functional methods (PBE0/6-311+G(d,p)). The study revealed mechanistic features and the dependence of activation parameters of this electrocyclic reaction on the steric and electronic properties of spiroconjugated fragments of the studied compounds.
TL;DR: A Mannich reaction of isatin with monosubstituted piperazines in the presence of aqueous formaldehyde was used to synthesize new, as well as two previously described derivatives of 1-piperazinomethylisatins, which were further converted to isoindigo derivatives as discussed by the authors.
Abstract: A Mannich reaction of isatin with monosubstituted piperazines in the presence of aqueous formaldehyde was used to synthesize new, as well as two previously described derivatives of 1-piperazinomethylisatins, which were further converted to isoindigo derivatives. The antimicrobial activity of the obtained heterocycles was evaluated.
TL;DR: In this article, the tandem process involving the formation of NH-1,2,3-triazoles and their reactions with electrophilic reactants in the synthesis of 1,4,5-substituted 1, 2, 3, 3 triazoles was used.
Abstract: A renewal of interest in the chemistry of 1,2,3-triazoles has occurred since the beginning of the 21 century. The application of metal catalysis and organocatalysis to the classical Huisgen and Dimroth reactions has provided access to a wide range of 1,2,3-triazole derivatives for a variety of chemical and biological studies. This, in turn, has resulted in the use of these compounds in biological and medicinal chemistry, technology, and medicine. In this report we focus on using the tandem process involving the formation of NH-1,2,3-triazoles and their reactions with electrophilic reactants in the synthesis of 1,4,5-substituted 1,2,3-triazoles.
TL;DR: Magnetic Fe3O4 nanoparticles as a heterogeneous catalyst were found to be efficient for the synthesis of a series of pyrrole and indole derivatives using three-component reactions of primary amines, 1,3-dicarbonyl compounds, and activated acetylenic compounds under solvent-free conditions at room temperature as mentioned in this paper.
Abstract: Magnetic Fe3O4 nanoparticles as a heterogeneous catalyst were found to be efficient for the synthesis of a series of pyrrole and indole derivatives using three-component reactions of primary amines, 1,3-dicarbonyl compounds, and activated acetylenic compounds under solvent-free conditions at room temperature. The present protocol offers the advantages of clean reaction, short reaction time, high yield, easy purification, and affordability of the catalyst.
TL;DR: In this article, a series of 2,3 disubstituted naphtho[2,3-f]quinoxaline-7,12-dione derivatives by condensing 1,2-diaminoanthraquinone and various benzil compounds in glacial acetic acid with excellent yield and fully characterized.
Abstract: In this work, we have prepared a series of 2,3-disubstituted naphtho[2,3-f]quinoxaline-7,12-dione derivatives by condensing 1,2-diaminoanthraquinone and various benzil compounds in glacial acetic acid with excellent yield and fully characterized. Optical properties of the synthesized compounds were studied in solvents of varying polarity and thin solid film. Electrochemical properties of the compounds were studied by the cyclic voltammetry. The ionization potentials (HOMO) and electron affinity (LUMO) were found to be in the range of −6.364 to −6.644 eV and −3.247 to −3.511 eV, respectively. Thermal investigations were carried out by thermogravimetric analysis and differential scanning calorimetry.
TL;DR: In this paper, a microreview of ring opening reactions of non-activated aziridines and their applications in heterocycle synthesis is presented, where only recent methods published in the last five years are discussed.
Abstract: This microreview deals with ring opening reactions of non-activated aziridines and their applications in heterocycle synthesis. Only recent methods published in the last five years are discussed.
TL;DR: In this article, CoFe2O4@SiO2-PrNH2 nanoparticles have been used as an efficient and magnetically recoverable catalyst for the preparation of trans-3-aryl-2-(4-bromobenzoyl)-2,3-dihydro-4H-furo[3,2-c]chromen-4-ones by multicomponent reaction of 2,4'-dibromoacetophenone, aromatic aldehydes, and 4-hydroxycoumarin in the presence
Abstract: CoFe2O4@SiO2–PrNH2 nanoparticles have been used as an efficient and magnetically recoverable catalyst for the preparation of trans-3-aryl-2-(4-bromobenzoyl)-2,3-dihydro-4H-furo[3,2-c]chromen-4-ones by multicomponent reaction of 2,4'-dibromoacetophenone, aromatic aldehydes, and 4-hydroxycoumarin in the presence of pyridine in ethanol under microwave irradiation. It was demonstrated by 1H NMR spectroscopy and single crystal analysis that the obtained furo[3,2-c]coumarins were the trans-isomers.
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TL;DR: In this paper, a review summarizes the reported data on the Butin reaction, i.e., acid-catalyzed transformations of furans to a range of other heterocycles via intramolecular attack of nucleophile, connected to the α-carbon atom of furan ring by three- to six-membered linker.
Abstract: This review summarizes the reported data on the Butin reaction, i.e., acid-catalyzed transformations of furans to a range of other heterocycles via intramolecular attack of nucleophile, connected to the α-carbon atom of furan ring by three- to six-membered linker, on the same α-carbon atom.
TL;DR: In this paper, a method for the synthesis of 3-nitro-2-phenyl-2-(trifluoromethyl)-2H-chromenes by tandem condensation of salicylic aldehydes with triethylamine was proposed.
Abstract: A method is proposed for the synthesis of 3-nitro-2-phenyl-2-(trifluoromethyl)-2H-chromenes by tandem condensation of salicylic aldehydes with (E)-3,3,3-trifluoro-1-nitro-2-phenylprop-1-ene in the presence of triethylamine. The example of 3-nitro-2-phenyl-2-(trifluoromethyl)-2H-chromene was used to demonstrate conjugated addition reactions with enamines, nitromethane, and aniline, which are characteristic for this class of compounds. The structure of the obtained products was confirmed by X-ray structural analysis.
TL;DR: In this article, a method for the preparation of 5-nitro[1,2,5]selenadiazolo[3,4-e]benzofuroxan has been developed.
Abstract: A method for the preparation of 5-nitro[1,2,5]selenadiazolo[3,4-e]benzofuroxan has been developed. Employing the reactivity of this compound in pericyclic (4+2) and (3+2) cycloaddition reactions as a dienophile or dipolarophile (at the C=C–NO2 bond) with a heterodiene (fragment C=C–N(O)=O) representatives of novel types of fused polycyclic heterosystems were synthesized.
TL;DR: A summary of the most recent approaches toward indolizine derivatives can be found in this paper, where a microreview covers the latest selected examples on the synthesis of indoline derivatives that might be gathered in four distinct categories: cyclocondensations, cycloadditions, cyclization/eliminations, and cycloisomerizations.
Abstract: A summary of the most recent approaches toward indolizine derivatives is discussed. The microreview covers the latest selected examples on the synthesis of indolizines that might be gathered in four distinct categories: cyclocondensations, cycloadditions, cyclization/eliminations, and cycloisomerizations.
TL;DR: Condensation of 1,2-diaminobenzimidazole with N-arylitaconimides was studied in this article, where it was found that 2-(10-amino-N-aryl-2-oxo-2,3,4,10-tetrahydropyrimido[1,2a]benzimidrazol-3-yl)acetamides were formed in the course of this reaction upon brief heating to reflux of the reagent mixture in 2-propanol in the presence of catalytic
Abstract: Condensation of 1,2-diaminobenzimidazole with N-arylitaconimides was studied. It was found that 2-(10-amino-N-aryl-2-oxo-2,3,4,10-tetrahydropyrimido[1,2-a]benzimidazol-3-yl)acetamides were formed in the course of this reaction upon brief heating to reflux of the reagent mixture in 2-propanol in the presence of catalytic amounts of acetic acid.
TL;DR: In this paper, a short summary is provided of several selected recently published applications of the method in the field of naturally occuring and chiral compounds, which is applicable to almost every type of furan ring-containing organic substances (steroids, carbohydrates, amino acids and peptides, aromatic and heteroaromatic compounds).
Abstract: is particularly attractive because of the mild conditions and cheap reagents it needs (cat. RuCl3/NaIO4 or O3) and also because it tolerates many functional groups. Another advantage is the availability of starting furan derivatives which can be prepared via the Michael addition, alkylation, Mannich reaction, cycloaddition, cross coupling, and many other methods. Here, a short summary is provided of several selected recently published applications of the method in the field of naturally occuring and chiral compounds. Oxidative degradation of furans to corresponding carboxylic acids is a valuable tool in organic synthesis, which provides additional synthetic opportunities in comparison to established methods like nitrile chemistry, organometallic carboxylation, transition metalcatalyzed carbonylation. The proposed approach is applicable to almost every type of furan ring-containing organic substances (steroids, carbohydrates, amino acids and peptides, aromatic and heteroaromatic compounds). It Chemistry of Heterocyclic Compounds 2016, 52(2), 87–89
TL;DR: In this article, a microreview of data from the last 10 years regarding the synthesis of 1H-benzo[d]oxazine-2,4-dione derivatives without considering the preparation of its heteroaromatic analogs is presented.
Abstract: [1,3]oxazine-2,4-dione ring: cyclization of anthranilic acids, catalytic carbonylation of substituted anilines, transformation of phthalic anhydride derivatives, oxidation of isatin derivatives, and oxidation of indoles with Oxone. This microreview covers data from the last 10 years regarding the synthesis of 1H-benzo[d][1,3]oxazine-2,4-dione derivatives without considering the preparation of its heteroaromatic analogs. Isatoic anhydride (1H-benzo[d][1,3]oxazine-2,4-dione) and its derivatives are convenient building blocks for the synthesis of various nitrogen-containing heterocyclic structures, such as quinazolines, quinazolones, quinazolinediones, benzodiazepines, quinolinones, and tryptanthrin derivatives. The following methods have been applied to the construction of benzo[d]Chemistry of Heterocyclic Compounds 2016, 52(2), 90–92
TL;DR: A series of novel coumarin derivatives were synthesized from commercially available chemical agents and 2-bromoethoxy)-2H-chromen-2-one exhibited the highest growth inhibition against MGC-803 cell line and the latter compound was also the most active against E. coli and M. albicans.
Abstract: A series of novel coumarin derivatives were synthesized from commercially available chemical agents. All prepared compounds were evaluated for their in vitro antiproliferative activity against five selected human cancer cell lines (EC109, MGC-803, PC-3, MCF-7, and EC9706) and their in vitro antimicrobial activity against E. coli and M. albicans. 4-(3-Bromopropoxy)-2H-chromen-2-one exhibited the highest growth inhibition against MGC-803 cell line (IC50 47.7 μM) and 7-(2-bromoethoxy)-2H-chromen-2-one exhibited the highest growth inhibition against MCF-7 cell line (IC50 48.3 μM). The latter compound was also the most active against E. coli (MIC50 0.27 μg/ml).