Showing papers on "Benzopyran published in 2011"
TL;DR: The Ph3PAuNTf2-catalyzed cyclization of aryl propargyl ethers was applied as a key step to the concise synthesis of the naturally occurring benzopyrans seselin, xanthyletin, precocenes I and II, 8-(3′,3′-dimethylallyl)wenteria chromene, and 2,2-dimmethyl-8-prenylchromene-6-propenoic acid as mentioned in this paper.
90 citations
TL;DR: A small library of glyco-fused benzopyran compounds has been synthesised and their interaction features with Aβ peptides have been characterised by using STD-NMR and trNOESY experiments.
39 citations
TL;DR: D Dependensin and its analogs were subjected to antimalarial growth inhibition assays against Plasmodium falciparum and found to have IC(50) values ranging between 1.9 and 3.9 μM.
35 citations
TL;DR: A new photochromic fused benzopyran presenting a bridge between the pyran double bond and the benzenic ring prevents the formation of the undesirable long-lived colored TT isomer and after laser irradiation the colored solution fades following a fast monoexponential decay.
35 citations
TL;DR: In this paper, an efficient two-step synthesis of indole-annulated dihydropyrano[3,4- c ]chromene derivatives was achieved via Knoevenagel condensation of O -propargylated salicylaldehyde derivatives with indolin-2-ones.
30 citations
TL;DR: A novel, rapid, and efficient synthesis of bicyclic pyrimidine nucleosides and benzopyran-4-ones through oxidation of homopropargyl alcohols and subsequent isomerization, intramolecular addition of enol to allenic ketone has been developed.
Abstract: A novel, rapid, and efficient synthesis of bicyclic pyrimidine nucleosides and benzopyran-4-ones through oxidation of homopropargyl alcohols and subsequent isomerization, intramolecular addition of enol to allenic ketone has been developed. This methodology provides an efficient and promising approach to the structurally and pharmaceutically interesting pyrano[2,3-d]pyrimidine-2,5-dione nucleoside and benzopyran-4-one derivatives.
30 citations
TL;DR: A tetrabutylammonium hydrogen sulfate (TBA-HS) mediated procedure for one pot synthesis of novel benzopyran-annulated pyrano[2,3-c]pyrazoles via domino/Knoevenagel-hetero-Diels-Alder reaction has been demonstrated.
27 citations
TL;DR: Vinylogous esters bearing para or meta methoxy benzyl groups undergo oxidative cyclisation with 5-20 mol% iodobenzene and m-CPBA to give spirofuran or benzopyran containing heterocycles, which allows rapid generation of skeletal complexity in good to excellent yields.
26 citations
TL;DR: In this paper, the synthesis of substituted salicylaldehydes with 4-chloro-3-oxobutanoate in the presence of piperidine in CH2Cl2 at room temperature, in good yields.
Abstract: Ethyl 2-(chloromethyl)-2-hydroxy-2H-chromene-3-carboxylates 2a–2j have been synthesized by reaction of substituted salicylaldehydes with ethyl 4-chloro-3-oxobutanoate, in the presence of piperidine in CH2Cl2 at room temperature, in good yields.
26 citations
TL;DR: In this paper, the first report of one-pot synthesis of 2-amino-4H-1-benzopyran-4-ylphosphonic acid dimethyl esters was given.
Abstract: Several (2-amino-4H-1-benzopyran-4-yl)phosphonates were efficiently synthesized by employing a multicomponent protocol involving a salicylaldehyde, malononitrile or ethyl cyanoacetate, and a trialkyl phosphite in polyethylene glycol The latter could be recovered and re-used No additional solvent or catalyst was required To the best of our knowledge, this is the first report of the one-pot preparation of (2-amino-4H-1-benzopyran-4-yl)phosphonic acid dimethyl esters
25 citations
TL;DR: The prepared compounds were tested for their interaction with DNA; bromovisnagin 2 showed the highest affinity and compounds 6, 15, 8a, > 14, > 16b, 17a, and 16a showed moderate activity in decreasing potency.
Abstract: Bromination of visnagin (1) afforded 9-bromovisnagin (2) which on its alkaline hydrolysis afforded the 3-acetyl benzofuran derivative (3). The condensation of (3) with hydrazine hydrate, phenylhydrazine and/or hydroxylamine hydrochloride afforded the corresponding pyrazole derivatives (4a, b) and isoxazole derivative (4c). On the other hand, when compound 3 was condensed with some aromatic aldehydes, this yielded corresponding α, β-unsaturated keto derivatives (5a–e). Furthermore, when 1 was subjected to chlorosulfonation, the visnaginsulfonylchloride derivative 6 was afforded, which on amidation using morpholine, a sulonamido derivative (7) was obtained. Alkaline hydrolysis of the latter compound yielded 7-N-morpholinosulsamidobenzofuran (8) which was condensed with some aromatic aldehydes to yield the corresponding chalcone compounds (9a–e). Demethylation of visnagin afforded norvisnagin (10). The reaction of 10 with ethylbromoacetate in dry acetone yielded the ester benzopyran derivative (11) which reacted with hydrazine hydrate to afford the corresponding hydrazide derivative (12) and this was condensed with 3,4,5-trimethoxybenzaldehyde to give the corresponding hydrazone (13). A thaizolidinone derivative (14) was obtained by condensation of (13) with thioglycolic acid. Chloromethylation of norvisnagin afforded a 4-chloromethyl derivative (15) which reacted with different primary and secondary amines to yield the corresponding ethylamino derivative (16a, b). Moreover, mannich bases (16a, b) and (17a–c) were obtained by reacting norvisnagin with different primary and secondary amines in the presence of formalin but benzoylation of (16a, b) and (17a–c) afforded 4-oxybenzoyl derivative (18a–e). The prepared compounds were tested for their interaction with DNA; bromovisnagin 2 showed the highest affinity and compounds 6, 15, 8a, > 14, > 16b, 17a, and 16a showed moderate activity in decreasing potency. Moreover, compound 2 also was the most active as antiviral agent toward HS-I virus and compounds 6, 7, 15, 14, 16a, and 18a were found to be moderately active. CD50 of the active compounds were also measured.
TL;DR: In this paper, the Michael-type addition of a 4-hydroxycoumarin to a β-nitrostyrene (2-nitroethenyl)benzene in the presence of AcONH4 leads to substituted (3E)-3]-amino(aryl)methylidene]chroman-2,4-diones.
Abstract: The Michael-type addition of a 4-hydroxycoumarin (=4-hydroxy-2H-1-benzopyran-2-one) 1 to a β-nitrostyrene (=(2-nitroethenyl)benzene) 2 in the presence of AcONH4 leads to substituted (3E)-3-[amino(aryl)methylidene]chroman-2,4-diones (=(3E)-3-[amino(aryl)methylene]-2H-1-benzopyran-2,4(3H)-diones) 4 (Table 1). High yields, short reaction time, and easy workup are advantages of this novel one-pot three-component reaction.
TL;DR: Structural-activity relationships indicated that the inhibitory effect on the insulin secreting cells was related to the lipophilicity of the molecules and to the size of the substituent located at the 6-position.
TL;DR: In this paper, photochromic 5′-(1,3-benzothiazol-2-yl)-substituted spiro[indoline-2,3′-naphthopyrans] possessing luminescence properties in both the cyclic and merocyanine forms were synthesized.
Abstract: Novel photochromic 5′-(1,3-benzothiazol-2-yl)-substituted spiro[indoline-2,3′-naphthopyrans] possessing luminescence properties in both the cyclic and merocyanine forms were synthesized. Unlike the 8′-(1,3-benzothiazol-2-yl)-substituted benzopyran analogs, the synthesized compounds are characterized by the lower relative stability of the merocyanine isomers.
TL;DR: Out of all the compounds screened, compounds 16, 17, and 18 were found to be active against the virulent strain M. tubercolosis H37Rv displaying MIC in the range of 6.25–1.56 μg/ml against.
Abstract: A series of hybrid molecules (7–9, 12, 13, and 14–18) consisting of chromans and pyrolidines or cyclic amines were prepared either by (3 + 2) cycloaddition of nitrostyrenes and azomethine ylide or by three component reactions of chromanyl aldehydes, acetylenes, and cyclic amines. All the synthesized compounds were evaluated against both avirulent (H37Ra) and virulent (H37Rv) strains of Mycobacterium tuberculosis. Out of all the compounds screened, compounds 16, 17, and 18 were found to be active against the virulent strain M. tubercolosis H37Rv displaying MIC in the range of 6.25–1.56 μg/ml against.
TL;DR: New potent and selective lead compounds with improved metabolic properties were identified and binding free energies predicted by free energy perturbation theory yielded good agreement with experimental results.
TL;DR: Different benzopyran derivatives were synthesized by a green and practical procedure in the presence of catalytic amount of Bronsted acid ionic liquid (BAIL) [(CH 2 ) 4 SO 3 HMIM][HSO 4 ] in water as discussed by the authors.
Abstract: Different benzopyran and 3-substituted coumarin derivatives were synthesized by a green and practical procedure in the presence of catalytic amount of Bronsted acid ionic liquid (BAIL) [(CH 2 ) 4 SO 3 HMIM][HSO 4 ] in water. KEY WORDS : Benzopyran derivatives, 3-Substituted coumarin derivatives, Bronsted acid ionic liquid, 1-(4-Sulfonic acid)butyl-3-methylimidazolium hydrogen sulfate Bull. Chem. Soc. Ethiop. 2011 , 25(2), 315-320.
TL;DR: Synthesis and physico-chemical properties of two 3-substituted phenacyl-thiazolidine-2,4-diones (2c-d) and four 3- substituting phenacy l-5-[2-phenyl-4H-4-oxo-1-benzopyran-6-yl)methyl-enyl]- thiazolidin e- 2, 4- diones are described.
Abstract: Synthesis and physico-chemical properties of two 3-substituted phenacyl-thiazolidine-2,4-di-ones (2c-d) and four 3-substituted phenacyl-5-[2-phenyl-4H-4-oxo-1-benzopyran-6-yl)methyl-enyl]-thiazolidine-2.4-diones (4a-d) are described. These products were synthesized by Knoevenagel reaction from flavone-6-carboxaldehydc (3) and 3-(substituted phenacyl)-thiazolidine-2,4-diones (2a-d). Antibacterial and antifungal activities were investigated for these compounds.
TL;DR: In this article, a concise synthesis of (±)-rhinacanthin A is achieved in two steps by epoxidation of dehydro-α-lapachone, followed by chemo and regioselective reduction.
Abstract: A concise synthesis of (±)-rhinacanthin A is achieved in two steps by epoxidation of dehydro-α-lapachone, followed by chemoand regioselective reduction. Dehydro-α-lapachone was also synthesized in two steps starting from 4-methoxy-1-naphthol by ethylenediamine diaetate (EDDA)-catalyzed benzopyran formation and a CAN-mediated oxidation reaction. β-Lapachone was synthesized in three steps from 4-methoxy-1-naphthol by benzopyran formation, catalytic hydrogenation, and Jones oxidation. As additional reactions, synthesis of pyranonaphthoquinone derivatives with the pyranokunthone B skeleton has been achieved in a single step from readily available 2-hydroxy-6-methoxy1,4-naphthoquinone and 2-hydroxy-7-methoxy-1,4-naphthoquinone.
TL;DR: In this article, the functionalized chromenes were synthesized on the basis of reaction of 1-bromo-1-nitro-3, 3,3,3-trichloropropene I with salicylic aldehyde and its derivatives.
Abstract: Chromene (benzopyran) ring is a key fragment of some drugs. In particular, it is a part of the molecules of known blood anticoagulants warfarin [1, 2] and neodicoumarinum [3], antitumor drug 8-methoxypsoralen, or furocoumarin [1], and it forms also the structure of tocopherols (vitamin E), the natural antioxidants [1]. Synthetic representative of the benzopyran series, cromakalim, shows antihypertensive properties [1]; some benzopyrans containing electronacceptor substituents at the third position of the ring show radioprotective effect [4]. We synthesized the functionalized chromenes on the basis of reaction of 1-bromo-1-nitro-3,3,3-trichloropropene I with salicylic aldehyde and its derivatives. The reaction proceeds at 18–20°С in chloroform or dichloromethane solution in the presence of equimolar amount of triethylamine (method a) to give a readily separated mixtures of the respective chromanols II–V and chromenes VI–IX in 33 and 40% yields, respectively, and at using a two-fold excess of this base (method b) only the corresponding chromenes VI–IX were obtained. DOI: 10.1134/S1070363211010294
01 Dec 2011
TL;DR: In this article, multicomponent reactions (MCR) continue to attract significant interest due to their important role in the preparation of structurally diverse chemical structures, such as benzopyran and naphthopyrans.
Abstract: Multicomponent reactions (MCR) continue to attract significant interest due to an important role in the preparation of structurally diverse chemical structures 1 . Benzopyran and benzopyran derived molecules display potent biological and pharmacological activities 2 . Similarly, naphthopyrans, the polyfunctionalized benzopyrans have attracted considerable attention due to their interesting photochromic properties 3 and also their presence in
Journal Article•
TL;DR: All compounds have been screened for their antimicrobial activity and have been found to exhibit significant antibacterial and antifungal activities.
Abstract: Aminocoumarins on refluxing with ethyl acetoacetate in 1,2-dichloroethane gave two products: 3i- (2-oxo-2H-benzopyran-6-yl-amino)-but-2i-enoic acid ethyl ester 2a-c and N-(-2-oxo-2H-benzopyran-6-yl)-3i- oxo-butyramide 3a-c. Compounds 2a-c on treatment with 1,4-benzoquinone in N2-atmosphere yielded 1i-( 2- oxo-2H-benzopyran-6-yl)-5i-hydroxy-2i-methyl-3i-carbethoxyindoles 4a-c, which on further treatment with hydrazine hydrate gave 1i-(2-oxo-2H-benzopyran-6-yl)-5i-hydroxy-2i-methylindole-3i-acid hydrazides 5a-c. These acid hydrazides were treated with benzaldehyde to give 1i-(2-oxo-2H-benzopyran-6-yl)-5i-hydroxy-2i- methylindole-3i-benzylidene hydrazides 6a-c, which on further treatment with mercaptoacetic acid in 1,4-diox- ane yielded 1i-(2-oxo-2H-benzopyran-6-yl)-5i-hydroxy-2i-methylindole-3i-amido-2ii-phenylthiazolidene-4ii- ones 7a-c. The structures of the compounds have been established on the basis of spectral and analytical data. All compounds have been screened for their antimicrobial activity and have been found to exhibit significant antibacterial and antifungal activities.
TL;DR: In this article, a simple and inexpensive procedure for the synthesis of 8-methoxy-3,4-dihydro-2H-1-benzopyran-3-ol was described.
TL;DR: The central, partially saturated pyrimidine rings of both independent molecules were found to assume unsymmetrical half-chair conformations.
Abstract: There are two crystallographically independent mol-ecules in the asymmetric unit of the title compound, C(21)H(18)N(4)O(4). The substituted benzopyran portion of one of the independent mol-ecules exhibits disorder [occupancy 0.5248 (18):0.4752 (18)], which was modelled by using two sets of atomic positions and restraints on the chemically equivalent bond lengths and angles. The central, partially saturated pyrimidine rings of both independent mol-ecules were found to assume unsymmetrical half-chair conformations. The hy-droxy-phenyl substituent occupies an equatorial position in both mol-ecules, and is rotated by 55.6 (1)° from the mean plane of the pyrimidine ring in one independent mol-ecule, and by 53.4 (1)° in the other. In the crystal, there are two types of inter-molecular hydrogen bond present: reciprocal N-H⋯N inter-actions join the two crystallographically independent mol-ecules into a dimer and O-H⋯N inter-actions link the dimers into sheets in the ab plane.
TL;DR: The title compound, C16H12N2O4S, was obtained by the condensation of 3-acetyl-4-hydroxycoumarin with thien-2-ylcarbonyl hydrazide and adopts a 2,4-dione tautomeric form.
Abstract: The title compound, C16H12N2O4S, was obtained by the condensation of 3-acetyl-4-hydroxycoumarin with thien-2-ylcarbonyl hydrazide. The pyran ring adopts a 2,4-dione tautomeric form. The benzopyran ring system is almost coplanar with the thiophene ring [dihedral angle 0.9 (2)°]. The exocyclic C=C double bond has an E geometry. The molecular conformation is stabilized by an intramolecular N—H⋯O hydrogen bond. In the crystal, intermolecular N—H⋯O hydrogen bonds link the molecules into chains along the a axis.
TL;DR: In this paper, an expeditious one-pot synthesis of a novel heterocyclic system, 3′-(2-aminobenzimidazolyl)-2-phenyl spiro[4H-benzopyran-4,2′-thiazolidin]-4-ones has been accomplished by condensing substituted hydrazinobenzymidine, flavanone, and mercaptoacetic acid by conventional heating in ethanol or toluene, and in an ionic liquid, viz., 1-butyl-3-
Abstract: An expeditious one-pot synthesis of a novel heterocyclic system, 3′-(2-aminobenzimidazolyl)-2-phenyl spiro[4H-benzopyran-4,2′-thiazolidin]-4-ones, has been accomplished by condensing substituted hydrazinobenzimidazole, flavanone, and mercaptoacetic acid by conventional heating in ethanol or toluene, and in an ionic liquid, viz., 1-butyl-3-methyl-imidazolium hexafluorophosphate. Excellent yields (85%–90%) and higher purity are obtained in the ionic-liquid-mediated synthesis as compared with the conventional procedure (55%–60%). Further, these compounds were acylated with trifluoroacetic anhydride. The structures of the compounds were confirmed by IR, 1H NMR, 13C NMR, mass spectral data, and elemental analysis. The compounds, upon evaluation for their antibacterial, antifungal, and insecticidal activities, exhibited excellent results. [Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the follo...
TL;DR: In the presence of formalin, 2-(Arylamino)-4-oxo-4H-1-benzopyran-3-carbanilide and 3-alkylaminomethylenechroman-2,4-dione rearranges to 3.
TL;DR: A new gold(I) complex is used as an efficient catalyst for intramolecular cycloisomerizations to afford benzopyran and oxazoline in high yields.
Abstract: A new gold(I) complex is used as an efficient catalyst for intramolecular cycloisomerizations to afford benzopyran (II) and oxazoline (VI) in high yields.
TL;DR: In this paper, a new homologous series of isoflavone-based ethers, 7-(4-bromoalkyloxy)-3-(4′-decyloxyphenyl)-4H-1-benzopyran-4-ones were synthesized and characterized.
TL;DR: A tetrabutylammonium hydrogen sulfate (TBA-HS) mediated procedure for one pot synthesis of novel benzopyran-annulated pyrano[2,3-c]pyrazoles via domino/Knoevenagel-hetero-Diels-Alder reaction has been demonstrated.
Abstract: A tetrabutylammonium hydrogen sulfate (TBA-HS) mediated procedure for one pot synthesis of novel benzopyran-annulated pyrano[2,3-c]pyrazoles via domino/Knoevenagel-hetero-Diels–Alder reaction has been demonstrated