Showing papers on "Benzopyrans published in 2005"
TL;DR: DBU-catalyzed reactions of salicylic aldehydes with 3-methylpenta-3,4-dien-2-one, 3-benzylpenta/3-4- dienoate gave the corresponding functionalized 2H-1-chromenes in good to excellent yields and good diastereoselectivities in some cases in DMSO, respectively.
113 citations
TL;DR: In this paper, an efficient and general synthesis of benzopyrans was achieved by ethylenediamine diacetate-catalyzed reactions of resorcinols with α,β-unsaturated aldehydes in moderated yields.
81 citations
TL;DR: The benzopyrans 1 and 2 showed weak in vitro antifungal activity against Cladosporium sphaerospermum and C. cladosporioides and were evaluated for their potential effects on mammalian cell line proliferation.
50 citations
TL;DR: In this paper, a new class of push-pull molecules bearing γ-methylene chalcogenapyran and benzopyran nucleus as proaromatic donors and methoxypentacarbonyltungstene carbene fragment as acceptors is described.
33 citations
TL;DR: Determination of cell cycle distribution demonstrated that the antiproliferative effect of the three benzopyrans could be associated to alterations in the cell cycle phase distribution, and it can be suggested that despite no differences among the cytotoxicity of theThree compounds, it was observed that the mechanism of their antiprology effects appears to be different.
33 citations
TL;DR: In this paper, 2-C -acetoxymethyl glycal derivatives react with aliphatic alcohols in the presence of InCl 3 to furnish the corresponding 2-c -methylene glycosides in excellent yields and with exclusive α-selectivity.
24 citations
TL;DR: The key step in the synthetic strategy involves the formation of benzopyrans by ethylenediamine diacetate-catalyzed reactions of resorcinols with α,β-unsaturated aldehydes.
Abstract: Total synthesis of biologically interesting (′)-cannabichromene, (′)-cannabichromenic acid, and (′)-daurichromenic acid is described. The key step in the synthetic strategy involves the formation of benzopyrans by ethylenediamine diacetate-catalyzed reactions of resorcinols with α,β-unsaturated aldehydes.
22 citations
TL;DR: Two new benzopyrans were isolated from the leaves of Mallotus apelta Muell.-Arg.
Abstract: Two new benzopyrans 6-[1′-oxo-3′(R)-hydroxy-butyl]-5, 7-dimethoxy-2,2-dimethyl-2H-1-benzopyran (1) and 6-[1′-oxo-3′(R)-methoxy-butyl]-5,7-dimethoxy-2,2-dimethyl-2H-1-benzopyran (2) were isolated from the leaves ofMallotus apelta Muell.-Arg., (Euphorbiaceae). Their chemical structures were elucidated by spectroscopic analyses, especially by 1D- 2D-NMR and MS spectra. Compound1 was found to have strong cytotoxic effect against two human cancer cell lines as human hepatocellular carcinoma (Hep-2, IC50: 0.49 μg/mL) and rhabdosarcoma (RD, IC50: 0.54 μg/mL), while compound2 showed moderate activity against Hep-2 cell line (IC50, 4.22μg/mL), byin vitro assay.
22 citations
TL;DR: In this paper, functionalized benzopyrans were regioselectively prepared by [3+3]-cyclization of 1,3-bis(trimethylsilyloxy)-7-chlorohepta-1,3dienes with 3-sily loxy-2-eno-1-ones and subsequent intramolecular Williamson reactions of the salicylates thus formed.
17 citations
TL;DR: Sulfamic acid catalyses the coupling of aldehydes, anilines and electron rich dienophiles such as dihydropyran, dihydrofuran and ethyl vinylether resulting in the formation of pyrano, furano and ethoxy benzopyrans as discussed by the authors.
Abstract: Sulfamic acid catalyses the one-pot three components coupling of aldehydes, anilines and electron rich dienophiles such as dihydropyran, dihydrofuran and ethyl vinylether resulting in the formation of pyrano, furano and ethoxy benzopyrans.
14 citations
TL;DR: An alkylation/cyclization sequence, with both steps mediated by the ortho-N-methylformamido-phenylsulfinyl function, provided two new C-C bonds and an efficient entry to 1-aryl-tetralins and 4-arylbenzopyrans as mentioned in this paper.
Journal Article•
TL;DR: In this paper, 3-Formyl-4- hydroxycoumarin is treated with malonic acid in the presence of zinc chloride catalyst to give 2H, 5H-2,5-dioxo-3-pyrano[3, 2-c]benzopyranoic acids la-d.
Abstract: 3-Formyl-4- hydroxycoumarin is treated with malonic acid in the presence of zinc chloride catalyst to give 2H, 5H-2,5-dioxo-3-pyrano[3, 2-c]benzopyranoic acids la-d which on treatment with methanol in the presence of thionyl chloride give methyl 2H, 5H-2,5-dioxopyrano[3, 2-c]benzopyran-3-oates 2a-d. Compounds 2a-d were converted into their acid hydrazides 3a-d. 3a-d on treatment with isatin yield IH, 2H-3-(2H, 5H-2,5-dioxopyrano[3, 2-c]benzopyran-3-carboxyhydrazono)-2-indolinones 4a-d which on cyclisation with conc. H 2 SO 4 afford 3-[1, 3, 4-oxadiazino[5, 6-b]indol-2-yl]-2,5-dioxopyrano[3,2-c]benzopyrans 5a-d. Acid hydrazides 3a-d on treatment with carbon disulfide in 10% KOH at room temperature followed by treatment with ortho-chlorobenzoic acid hydrazide furnish 3-(2H, 5H-2, 5-dioxopyrano[3, 2-c]benzopyran-3-yl)-4-{N-2'-chlorophenylcarboxamido]-5-mercapto-1,2,4-triazoles 6a-d.
TL;DR: In this paper, the synthesis of photochromic 2,2-di(4′-fluoro-phenyl)-2H-1-benzopyrans fused to an indole moiety is described.
Abstract: The synthesis of new photochromic 2,2-di(4′-fluoro-phenyl)-2H-1-benzopyrans fused to an indole moiety is described. Spectrokinetic data (λmax of colored form, colorability and rate constant of bleaching) obtained by UV-Visible spectroscopy and the structure of photomerocyanines elucidated by NMR spectroscopy, are reported.
TL;DR: In this article, the substitution of bromine in the title bromomethylpyranone 2 with phenylhydrazine as well as thiourea, like sodium acetate, brings about substitution of Bromine with bromide.
Abstract: Phenylhydrazine as well as thiourea, like sodium acetate, brings about substitution of bromine in the title bromomethylpyranone 2. The pyranone 2 gives the pyrano fused oxazine 9 with hydroxylamine, pyridiazines 10 and 11, respectively with hydrazine and phenylhydrazine, and thiophene 16 with thioacetamide.
Patent•
02 Mar 2005
01 Jan 2005
TL;DR: In this article, the DBU-catalyzed reactions of salicylic aldehydes with 3-methylpenta-3,4-dien-2-one, 3-benzyl penta-1,4,dienoate, or ethyl 2-methylbuta-2,3,3-diamoate gave the corresponding functionalized 2H-1-chromenes in good to excellent yields and good diastereoselectivities in some cases in DMSO, respectively.
Abstract: graph DBU-catalyzed reactions of salicylic aldehydes with 3-methylpenta-3,4-dien-2-one, 3-benzylpenta-3,4-dien-2-one, or ethyl 2-methylbuta-2,3-dienoate gave the corresponding functionalized 2H-1-chromenes in good to excellent yields and good diastereoselectivities in some cases in DMSO, respectively.
TL;DR: In this paper, the steric and electronic parameters of allenes that would allow for a regio- and diastereoselective synthesis of 2,3-disubstituted 3,4-dihydro-2H-1-benzopyrans, which could not be prepared via related catalytic protocols were defined.
Abstract: Insertion of monosubstituted allenes into stable oxapalladacycle I was studied. The aim of this work was to define steric and electronic parameters of allenes that would allow for a regio- and diastereoselective synthesis of 2,3-disubstituted 3,4-dihydro-2H-1-benzopyrans, which could not be prepared via related catalytic protocols. Allenes with electron-donating alkyl substituents R sterically unencumbered at the C-3 and C-4 carbons reacted with palladacycles I to afford benzopyrans IV in good yields (45-81%), exclusively as cis diastereomers. Less than 10% of the regioisomeric benzopyrans V was detected in the crude reaction mixtures. Methoxy 1,2-propadiene afforded benzopyran IV in 98% yield as the trans diastereomer in 92% de. In contrast, allenes with electron-withdrawing substituents yielded benzopyrans V with an E double bond exclusively. Nonracemic palladacycles featuring a palladium-bonded stereogenic carbon as the only element of asymmetry underwent the allene insertion with 63-93% retention of the stereochemical information, providing benzopyrans IV or V in 40-47% ee. These results demonstrated that O-bonded palladium enolates did not operate as predominant intermediates in the insertion process. The study highlights the configurational stability of carbon-bonded palladium ester enolates, especially notable in systems lacking chiral nonracemic auxiliary ligands.
TL;DR: In this article, functionalized benzopyrans were regioselectively prepared by [3+3]-cyclization of 1,3-bis(trimethylsilyloxy)-7-chlorohepta-1,3dienes with 3-sily loxy-2-eno-1-ones and subsequent intramolecular Williamson reactions of the salicylates thus formed.
Abstract: Functionalized benzopyrans were regioselectively prepared by [3+3]-cyclization of 1,3-bis(trimethylsilyloxy)-7-chlorohepta-1,3-dienes with 3-silyloxy-2-eno-1-ones and subsequent intramolecular Williamson reactions of the salicylates thus formed.
Patent•
30 Sep 2005
TL;DR: The subject of as mentioned in this paper concerns methods and compounds that have utility in the treatment of a condition associated with cyclooxygenase-2 mediated disorders and benzopyrans and their analogs defined by formula.
Abstract: The subject invention concerns methods and compounds that have utility in the treatment of a condition associated with cyclooxygenase-2 mediated disorders Compounds of particular interest are benzopyrans and their analogs defined by formula (1) Wherein Z, X, R1, R2, R3, and R4 are as described in the specification
TL;DR: In this article, a highly catalytic method for the synthesis of dihydrobenzopyrans from salicylaldehydes has been developed, and an extension of this method to pyrano[2,3, b ]benzopsopyran has also been achieved.
Abstract: A highly catalytic method for the synthesis of dihydrobenzopyrans from salicylaldehydes has been developed. An extension of this method to the synthesis of a pyrano[2,3, b ]benzopyran has also been achieved. Bi(OTf) 3 · x H 2 O (1 x H -1-benzopyrans as a mixture of diastereomers (9:1) in moderate yields. The relative configuration of the methoxy groups in the two diastereomers was established by NOE experiments. The advantages of this method include the use of an easy to handle, inexpensive and relatively non-toxic catalyst.
TL;DR: The title pyranone as discussed by the authors gives a mixture of pyridines 4 and 7 with ammonia, pyridine 5 and pyrazole 10 with phenylhydrazine, and Pyridine N-oxide 8 with hydroxylamine.
Abstract: The title pyranone 1 gives a mixture of pyridines 4 and 7 with ammonia, pyridine 5 and pyrazole 10 with phenylhydrazine, and pyridine N-oxide 8 with hydroxylamine.