Showing papers on "Pyran published in 2017"
TL;DR: The promising activities revealed by these pyran-based scaffolds undoubtedly place them at the forefront for the discovery of prospective drug candidates, and could therefore be of great interest to researchers working on the synthesis of antitumour drug candidates.
Abstract: Pyran is an oxygen-containing heterocyclic moiety, which exhibits an array of pharmacological properties. Pyran is also one of the important structural subunits found widely in natural products, e.g. coumarins, benzopyrans, sugars, flavonoids, xanthones, etc. The diverse anticancer capabilities of pyrans have been additionally evidenced by the fact that this heterocycle has recently been a focal point for researchers worldwide. This review provides a summary of pyran-based anticancer compounds, with emphasis on the past 10 years. It focuses on advancements in the field of naturally occurring pyrans as anticancer agents. The discussion also includes structure–activity relationships, along with the structures of the most promising molecules, their biological activities against several human cancer cell lines, as well as mechanistic insights discovered through the pharmacological evaluation and molecular modeling of pyran-based molecules. The promising activities revealed by these pyran-based scaffolds undoubtedly place them at the forefront for the discovery of prospective drug candidates. Thus, they could therefore be of great interest to researchers working on the synthesis of antitumour drug candidates.
143 citations
TL;DR: In this article, a highly efficient, eco-friendly protocol has been developed for synthesis of spirooxindole-pyran derivatives via one-pot, three-component reaction of isatins, malononitrile, and enolizable C-H activated compounds (2-hydroxynaphthalene-1,4-dione, 4-hydroxycoumarine and dimedone).
Abstract: A highly efficient, eco-friendly protocol has been developed for synthesis of spirooxindole-pyran derivatives via one-pot, three-component reaction of isatins, malononitrile, and enolizable C–H activated compounds (2-hydroxynaphthalene-1,4-dione, 4-hydroxycoumarine and dimedone) under visible-light irradiation in water-ethyl lactate at room temperature. The reported approach shows significant advantages such as a high yield, mild and clean reaction conditions, the application of clean visible light as a source of energy, the absence of catalyst, the use of ethyl lactate/water as an environmentally friendly solvent, a one-pot multicomponent reaction at room temperature, no chromatographic separation, and applicability for large-scale synthesis.
123 citations
TL;DR: A photocatalytic cascade cyclization of 1,7-enynes with acyl chlorides has been established and offers an operationally simple access to diverse fused pyran derivatives with a broad substrate scope in high yields from simple acylchlorides via an acyl radical intermediate.
82 citations
TL;DR: A new acidic ionic liquid, 1,4-diazabicyclo[2.2] octane-1, 4-diium dihydrogen phosphate {[H2-DABCO][H2PO4]2}, was prepared in a quick and straightforward process and characterized by using different methods such as FT-IR, NMR and Mass analysis as discussed by the authors.
62 citations
01 Jan 2017
TL;DR: In this paper, the influence of KCl and CaCl2 on the primary reactions of cellulose pyrolysis is studied using a wire-mesh reactor from 250°C to 600°C, focusing on the reaction intermediates.
Abstract: The influence of KCl and CaCl2 on the primary reactions of cellulose pyrolysis is studied using a wire-mesh reactor from 250 °C to 600 °C, focusing on the reaction intermediates. A pre- column derivatization with benzoyl chloride prior to HPLC analysis is applied for the quantification of anhydro-sugars (levoglucosan, cellobiosan, maltosan) from pyrolysis. At low temperatures, the additions of inorganics salts, especially CaCl2, weakens hydrogen bonds, resulting in high yields of levoglucosan and cellobiosan from the cleavage of glycosidic bonds rather than from dehydration reactions. At elevated temperatures, dehydration reactions in the sugar units are mainly responsible for the destruction of sugar rings followed by the scission of pyran rings, leading to the weight-loss of CaCl2-loaded cellulose in the form of low molecular weight organic species. Meanwhile, accumulated unsaturated structures suppress the cleavage of glycosidic bonds, leading to the formation of char. However, KCl appears to catalyze the cleavage of glycosidic bonds or the scission of pyran rings directly, which perhaps occurs through a homolytic mechanism, leading to low molecular weight species. Furthermore, maltosan is shown to be a secondary product and is catalyzed by KCl and CaCl2 indirectly through the repolymerization of levoglucosan in the solid phase. A modified mechanism is also proposed regarding cellulose pyrolysis and the primary catalysis of KCl and CaCl2.
60 citations
TL;DR: In this paper, a simple and efficient one-pot synthesis of tetrahydrobenzo[b]pyrans from the three-component reaction between dimedone, aldehydes, and active methylene compounds using NH 4 Al(SO 4 ) 2 ·12H 2 O (Alum) as a catalyst at 80°C is described.
47 citations
TL;DR: Solvent-controlled switchable domino reactions between 2-alkylidenebenzothiophene-3(2H)-ones and Morita-Baylis-Hillamn (MBH) carbonate exhibited excellent regioselectivity, producing a broad spectrum of benzothiopane-fused α-pyran, 2,3-dihydrooxepine, and oxatricyclodecene derivatives.
43 citations
TL;DR: The reported protocol has many benefits, such as ease of preparation, use of a green solvent, reduced reaction times, excellent product yields, and operational simplicity.
Abstract: A simple and versatile one-pot three-component synthetic protocol is devised for heterocycles, viz. 2,6-diamino-4-substituted-4H-pyran-3,5-dicarbonitrile derivatives, in short reaction times ([Formula: see text]30 min) at room temperature using ethanol as a solvent. This method involves the three-component reaction of malononitrile, substituted aldehydes, and cyanoacetamide catalyzed by chitosan-doped calcium hydroxyapatites (CS/CaHAps) giving good to excellent yields (86-96%). Twelve new pyran derivatives (4a-l) were synthesized and their structures were established and confirmed by different spectroscopic methods ([Formula: see text]H NMR, [Formula: see text]C NMR, [Formula: see text]N NMR, and HRMS). The heterogeneous catalyst, CS/CaHAp, was characterized by various instrumental techniques including XRD, TEM, SEM, and FT-IR and TGA spectroscopies. The catalyst was easily separable and reusable for up to six runs without any apparent loss of activity. The reported protocol has many benefits, such as ease of preparation, use of a green solvent, reduced reaction times, excellent product yields, and operational simplicity.
42 citations
TL;DR: KF/clinoptilolite nanoparticles were used as an effective heterogeneous catalyst for the synthesis of spiro[indole-3,2'-pyran] derivatives via three-component reactions of N -alkylisatins, 1,3-dicarbonyl compounds, and electron-deficient acetylenic compounds under solventfree conditions at 80°C.
Abstract: KF/clinoptilolite nanoparticles were used as an effective heterogeneous catalyst for the synthesis of spiro[indole-3,2'-pyran] derivatives via three-component reactions of N -alkylisatins, 1,3-dicarbonyl compounds, and electron-deficient acetylenic compounds under solventfree conditions at 80°C The present protocol has significant advantages, such as high yields, easy purification, and low environmental impact
36 citations
TL;DR: A simple and efficient method for the synthesis of 4H-chromenes and 1H-benzo[f]chromenes containing a trifluoroacetyl or aroyl group in the pyran ring from o-quinone methide precursors and push-pull enaminoketones has been developed.
Abstract: A simple and efficient method for the synthesis of 4H-chromenes and 1H-benzo[f]chromenes containing a trifluoroacetyl or aroyl group in the pyran ring from o-quinone methide precursors and push–pull enaminoketones has been developed. The chromenes are presumably formed through an initial oxa-Diels–Alder reaction, followed by an elimination of amine. The possibility of further transformations of given chromenes to o-hydroxybenzylated pyrazoles, isoxazoles, and pyridines has been demonstrated.
32 citations
TL;DR: The objectives of this study were analysis of the secondary metabolite products and evaluation antibacterial activity of Malva sylvestris and bioactive compounds identified in the methanolic extract.
Abstract: The objectives of this study were analysis of the secondary metabolite products and evaluation antibacterial activity.
Bioactives are chemical compounds often referred to as secondary metabolites. Thirty six bioactive compounds were
identified in the methanolic extract of Malva sylvestris. The identification of bioactive chemical compounds is based on
the peak area, retention time molecular weight and molecular formula. GC-MS analysis of Malva sylvestris revealed the
existence of the1-Propanamine , 2-methyl-N-(2-methylpropyldene)- , Pyrrolidine,1-(1-oxo-2,5-octadecadienyl)- ,
Dimethyl sulfoxide , Cyclohexylamine ,N-ethyl- , N-(2-Methylbutylidene)isobutylamine , 1-Methyl-2-pyrrolideethanol ,
2-(2-Hydroxyethyl)piperidine , 1-Butanamine , 2-methyl-N-(2-methylbutylidene)- , 4-(Pyrrolidin-2-
ylcarbonyl)morpholine , Dithiocarbamate , S-methyl-,N-(2-methyl-3-oxobutyl)- , l-Gala-l-ido-octonic lactone , 1-(5'-
methylfurfuryl)pyrrolidine , 2-Methoxy-4-vinylphenol , Pyrrolizin-1,7-dione-6-carboxylic acid , methyl(ester) , 1-
Naphthaienol , 1,2,3,4-tetrahydro-2,5,8-trimethyl- , Pterin-6-carboxylic acid , N-(2-Acetamido)iminodiacetic acid , N-(1-
Hydroxy-4-oxo-1-phenylperhydroquinolizin-3-yl)carbamic , Cyclopropanedodecanoic acid , 2-octyl-,methyl ester ,
Cholestan-3-ol,2-methylene-,(3?,5?)- , 3-(N,N-Dimethyllaurylammonio)propanesulfonate , Pyrazole[4,5-b]imidazole ,
1-formyl-3-ethyl-6-?-d-ribofuranosyl- , Octahydrobenzo[b]pyran , 4a-acetoxy-5,5,8a-trimethyl- , Tetraacetyl-d-xylonic
nitrile , 4,6-Heptadien-3-one,1,7-diphenyl- , Pentanoic acid ,2,2,4-trimethyl-3-carboxyisopropyl , isobutyl ester , DFructose
, diethyl mercaptal, pentaacetate , Phytol , Hexadecanamide , Tributyl acetylcitrate , Cholestan-3-one,cyclic 1,2-
ethanediyl aetal , (5?)- , Dasycarpidan-1-methanol, acetate ( ester)- , 9-Desoxo-9-x-acetoxy-3,8,12-tri-O-acetylingol ,
(+)-y-Tocopherol, O-methyl- , Campesterol and Stigmasterol.
TL;DR: In this article, a review of 2H-pyran-2-ones is presented, where the properties, synthesis and their synthetic applications to generate various classes of heterocycles are discussed.
TL;DR: Pyridine-4-carboxylic acid (PYCA)-functionalized Fe3O4 nanoparticles were fabricated and characterized by Fourier transform infrared, X-ray powder diffraction, thermogravimetric analysis, transmission electron microscopy, scanning electron microscope, and VSM techniques.
Abstract: Pyridine-4-carboxylic acid (PYCA)-functionalized Fe3O4 nanoparticles as an organic–inorganic hybrid heterogeneous catalyst was fabricated and characterized by Fourier transform infrared, X-ray powder diffraction, thermogravimetric analysis, transmission electron microscopy, scanning electron microscope, and VSM techniques. The catalytic activity of the magnetic catalyst was probed through one-pot synthesis of tetrahydrobenzo[b]pyran derivatives from three-component reactions of aromatic aldehydes, malononitrile, and dimedone under solvent-free conditions. Simple procedure, high yields, short reaction time, and environmentally benign method are advantages of this protocol. The catalyst was readily separated using an external magnet and was reusable without significant loss of its catalytic efficiency.
TL;DR: A convenient, versatile, and easy to handle intramolecular hydrofunctionalization of alkenes (C-O and C-N bonds formation) is reported using a novel niobium-based catalytic system.
TL;DR: A series of pyran derivatives synthesized in good yields by utilizing Baylis–Hillman chemistry and further investigated for their in vitro anticancer, antibacterial, and antifungal activities exhibited promising antibacterial activity as compared to the standard towards Gram-positive bacterial strains.
Abstract: A series of pyran derivatives (5–27) were synthesized in good yields by utilizing Baylis–Hillman chemistry and were further investigated for their in vitro anticancer, antibacterial, and antifungal activities. Most of the tested compounds exhibited promising antibacterial activity as compared to the standard towards Gram-positive bacterial strains. The compounds 5–7, 11–13, and 17–19 displayed two-fold higher activity whereas compound 21 showed four-fold higher antibacterial activity against Staphylococcus aureus MTCC 96 as compared to the standard Neomycin. Some of these compounds exhibited moderate antifungal activity against all the tested fungal strains. Two compounds 16 and 23 showed promising anticancer activity against selected four human cancer cell lines such as A549, DU145, HeLa, and MCF7.
01 Dec 2017
TL;DR: In this paper, a ladder-type heteroarene benzodi(thienopyran) (BDTP) was designed and synthesized by embedding pyran rings in [2,2-(2,5-dialkyloxy-1,4-phenylene)dithiophene] (PDT) for organic photovoltaic (OPV) applications.
Abstract: To meet the imminent requirement of fullerene-free electron acceptors, a new ladder-type heteroarene benzodi(thienopyran) (BDTP) is designed and synthesized by embedding pyran rings in [2,2-(2,5-dialkyloxy-1,4-phenylene)dithiophene] (PDT) for organic photovoltaic (OPV) applications. Originating from the strong p–π conjugation of the oxygen atom in the pyran rings, electron-rich BDTP results in the BDTP-cored molecular acceptor, NBDTP, with strong intramolecular charge transfer effect. With sp3 carbons in pyran rings, NBDTP have the flexibility of targeted modification to resolve the solubility as well as the morphological tuning by handy alkyl chain attachment. As a result, the fusion of pyran rings in BDTP means that the acceptor exhibits a narrow optical band gap of 1.58 eV and a high LUMO energy level of −3.79 eV. Meanwhile, blend morphology of NBDTP-based OPVs shows fine tunability via thermal annealing. Owing to the beneficial optical absorption, suitable energy-level alignment, favorable molecule packing, and proper morphology, the optimized NBDTP-based OPVs achieve a power conversion efficiency of up to 10.1%, which exemplifies the potential of utilizing molecular acceptors featuring ladder-type heteroarenes for high-performance OPVs.
TL;DR: In this article, a simple, versatile, and efficient synthesis of 4H-pyran derivative compounds is achieved via a three-component cyclocon-densation of aldehydes, malononitrile, and ethyl acetoacetate, using ammonium hydroxide as the catalyst, promoted by infrared irradiation.
Abstract: A simple, versatile, and efficient synthesis of 4H-pyran derivative compounds is achieved via a three-component cyclocon- densation of aldehydes, malononitrile, and ethyl acetoacetate, using ammonium hydroxide as the catalyst, promoted by infrared irradiation. The present method offers several advantages, such as high yields, non hazardous reaction conditions as well as short reaction times.
TL;DR: In this article, a nanomagnetic catalyst was used in the one-pot synthesis of pyrano[3,2-b]pyran derivatives by the three-component reaction of various aldehydes, malononitrile and kojic acid or chlorokjic acid at room temperature under ultrasonic irradiation.
Abstract: Abstract Ferrocene-containing ionic liquid supported on silica-coated Fe3O4 magnetic nanoparticles (nano Fe3O4@SiO2-IL-Fc), a novel heterogeneous nanocatalyst, was synthesized. The structure of the catalyst was characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction patterns (XRD), energy-dispersive X-ray spectroscopy (EDX) and field emission scanning electron microscopy (FE-SEM). The novel nanomagnetic catalyst was used in the one-pot synthesis of pyrano[3,2-b]pyran derivatives by the three-component reaction of various aldehydes, malononitrile and kojic acid or chlorokojic acid at room temperature under ultrasonic irradiation. This new method has many advantages such as simplicity, short reaction times, high yields, easy workup and easy purification. Also, the nanocatalyst can be separated on an external magnet and reused for at least six consecutive runs without any significant loss of its catalytic activity.
29 Sep 2017
TL;DR: The hyper-crosslinked microporous polyphenanthrene spheres were fabricated simply by the polymerization of phenanthrene using bromomethyl methyl ether as a bridging agent in the absence of any templates.
Abstract: The hyper-crosslinked microporous polyphenanthrene spheres were fabricated simply by the polymerization of phenanthrene using bromomethyl methyl ether as a bridging agent in the absence of any templates. The organic spheres were subjected to amine-functionalizing on the periphery of them using unreacted bromomethyl groups. The amine-functionalized microporous polyphenthrene could be employed as a highly effective and stable solid basic catalyst for the syntheses of functionalized 2-amino-tetrahydro-4 H -chromene and pyran derivatives. The significant features of these reactions are high product yields, environmental benignity, short reaction time, broad substrate scope, and non-requirement of toxic solvents. Furthermore, the catalyst can be reused up to four times without significant loss of activity.
TL;DR: Evidence in vitro indicated that compound 36 might induce the apoptosis of A549 cancer cells via a mitochondria-dependent pathway.
TL;DR: In order to prepare Dπ-A-π-D analogs have the ability to use in optical applications, 4 H -pyran fragment conjugated with two styryl groups and their combination play π-spacer role between donor and acceptor groups as discussed by the authors.
TL;DR: In this article, the synthesis of pyran annulated heterocyclic scaffolds has been achieved from the multicomponent reaction of aldehyde, malonitrile and a third participant such as dimedone, barbituric acid and 3-methyl-1H-pyrazol-5(4H)-one.
Abstract: Molecular diversity for the synthesis of pyran annulated heterocyclic scaffolds has been achieved from the multicomponent reaction of aldehyde, malonitrile and a third participant such as dimedone, barbituric acid and 3-methyl-1H-pyrazol-5(4H)-one. The reactions completed successfully using in situ-developed benzylidenemalononitriles via Knoevenagel reaction catalyzed by aspartic acid as a new efficient organo-catalyst in aqueous ethanol as a green medium at ambient conditions.
TL;DR: In this paper, a one-pot three-component condensation reaction of arylaldehyde and malononitrile with methyl acetoacetate and 8-hydroxyquinoline was used to synthesize 2-amino-4 H -pyran-3-carbonitriles.
11 Aug 2017
TL;DR: In this article, an operationally simple and high yielding procedure for the synthesis of spirooxindole and spiroacenaphthylene derivatives is described by the condensation reaction between isatin/acenAPHthenequinone derivatives, malono derivatives, and C−H activated carbonyl compounds in the presence of a catalytic amount of 1,4-Diazabicyclo[2.2]octane (DABCO) in ethanol or H2O/EtOH mixture under reflux conditions.
Abstract: An operationally simple and high yielding procedure for the synthesis of spirooxindole and spiroacenaphthylene derivatives is described by the condensation reaction between isatin/acenaphthenequinone derivatives, malono derivatives, and C−H activated carbonyl compounds in the presence of a catalytic amount of 1,4-Diazabicyclo[2.2.2]octane (DABCO) in ethanol or H2O/EtOH mixture under reflux conditions. This procedure has also been applied successfully for the synthesis of novel bis-benzo[b]pyran derivatives.The ability of synthesized compounds in inhibition of Sirtuin 2 were investigated both in-vitro and in-silico. Some of these compounds showed moderate level activity against Sirtuin 2.
TL;DR: Succinimide-N-sulfonic acid as an efficient Bronsted acid catalyzed the synthesis of pyrano[4,3-b]pyrans by using solar energy as a green source of energy under solvent-free conditions as discussed by the authors.
TL;DR: An asymmetric aldol-desymmetrization sequence was developed which provided highly efficient access to important bicyclic oxygen-containing scaffolds with multiple chiral centers and one is a quaternary stereogenic center containing a free hydroxy group.
Abstract: An asymmetric aldol-desymmetrization sequence was developed which provided highly efficient access to important bicyclic oxygen-containing scaffolds with multiple chiral centers and one is a quaternary stereogenic center containing a free hydroxy group. Moreover, starting from racemic precursors, the final products were obtained as two separable diastereomers by flash chromatography. Several other heterocycles could also be easily generated with this strategy.
TL;DR: In this article, an efficient and rapid synthesis of coumarin derivatives was accomplished via reactions of 3-(3-(4-methoxyphenyl)acryloyl)-2H-chromen-2-one (3) with different carbon nucleophiles such as ethyl acetoacetate, ethyl cyanoacetate and malononitrile, and ethyl benzoylacetate via conventional heating and microwave irradiation conditions.
TL;DR: In this article, an acid-treated montmorillonite coating with K2CO3 was used as a catalyst for an efficient, rapid, one-pot synthesis of 4H-pyran derivatives in good yield under ultrasonic irradiation.
29 Sep 2017