Showing papers on "Benzopyran published in 2005"

A new and efficient method for o-quinone methide intermediate generation: application to the biomimetic synthesis of the benzopyran derived natural products (±)-lucidene and (±)-alboatrin

Abstract: Lucidene and alboatrin are complex benzopyran derived natural products. A key step in their biogenesis may involve a hetero Diels–Alder cycloaddition between an o-quinone methide intermediate with a simple, or activated tri-substituted olefin. Experimental evidence is provided to support this hypothesis, with the biomimetic synthesis of both (±)-lucidene and (±)-alboatrin successfully achieved using a new and efficient method for o-quinone methide generation.

Benzopyran, biphenyl, and tetraoxygenated xanthone derivatives from the twigs of Garcinia nigrolineata.

Abstract: One new benzopyran, nigrolineabenzopyran A (1), two new biphenyls, nigrolineabiphenyls A and B (2, 3), and four new tetraoxygenated xanthones, nigrolineaxanthones T−W (4−7), were isolated from the ...

4-[(N-Imidazol-2-ylmethyl)anilino]pyranopyridine Analogs as Novel Anti-Angiogenic Agents

Abstract: We attempted to replace a benzopyran ring of 4-[(N-imidazol-2-ylmethyl)-4-chloroanilino]benzopyran, previously discovered as anti-angiogenic agent with antitumor activity, with pyranopyridines. The [3,2-c]-, [3,2-b]-, [2,3-c]-, and [2,3-b]-pyranopyridines with -(imidazol-2-ylmethyl)aniline moiety at the 4-position, were synthesized respectively, and evaluated for primary anti-angiogenic properties through primary cultured HUVEC tube formation assay. From this study, we found that the pyranopyridine ring, especially [3,2-b]- and [2,3-c]-isomer, can replace the benzopyran ring of the compound 1 and can be optimized through the introduction of substituents both on the pyranopyridine ring and the aniline moiety for the identification of a novel anti-angiogenic agent.

Concise synthesis of biologically interesting (′)-cannabichromene, (′)-cannabichromenic acid, and (′)-daurichromenic acid

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.

Supramolecular structure of S-(+)-marmesin—a linear dihydrofuranocoumarin

Abstract: The title compound, C14H14O4, a linear dihydrofuranocoumarin, was isolated from the bark ofAegle marmelos, a plant widely used in Ayurvedic system of medicine for the treatment of various ailments. The crystal structure was determined from X-ray diffraction data using direct methods. The compound crystallizes into monoclinic space group P21 with unit cell parameters:a] = 5.721(1) A, b= 13.810(1) A, c= 7.864(2) A, β = 100.39(1)°, Z = 2. The structure was refined by full-matrix least-squares to a finalR value of 0.0523 for 1184 observed reflections. The benzopyran moiety is perfectly planar. The dihedral angle between the pyrone and benzene rings is 0.3(1)°. The furan ring has a 2α-envelope conformation. The molecules are linked by O-H…O hydrogen bonds into chains and these chains are linked into sheets by C-H…O hydrogen bonds. Further, the π-π stacking and C-H…π (arene) interactions link all of the sheets into a supramolecular structure.

Antibacterial 4-amino-N-(5-methylisoxazol-3-yl)-N-[(4-oxo-2-phenyl-4H-1-benzopyran-6-yl)methyl]benzenesulfonamide.

Abstract: In the molecule of the title compound, C26H21N3O5S, a new type of sulfonamide derivative with potential antibacterial activity, the flavone moiety is almost planar. The isoxazole and aminophenyl rings are also planar and make dihedral angles of 77.0 (2) and 81.4 (1) degrees , respectively, with the best plane of the flavone ring system. The crystal structure is stabilized by intra- and intermolecular hydrogen bonds.

Tricyclic benzopyran compound as anti-arrhythmic agents

Abstract: This invention relates to benzopyran derivatives of formula (I) or (II), or pharmaceutically acceptable salts thereof wherein R1 and R2 are independently of each other hydrogen atom, C1-6alkyl group or C6-14aryl group, R3 is hydrogen atom or C1-6alkylcarbonyloxy group, or together with R4 forms a bond, R4 is hydrogen atom, or together with R3 forms a bond, m is an integer of 0 to 4, n is an integer of 0 to 4, V is a single bond, CR7R8, NR9, O, S, SO or SO2, R5 is hydrogen atom or C1-6alkyl group, R6 is hydrogen atom, C1-6alkyl group, C3-8cycloalkyl group, C3-8cycloalkenyl group, amino group, C1-6alkylamino group, di-C1-6alkylamino group, C6-14arylamino group, C2-9heteroarylamino group, C6-14aryl group, C2-9heteroaryl group or C2-9heterocyclyl group, A is 5-, 6- or 7-member ring fused with benzene ring, as constituent atom of the ring, oxygen atom, nitrogen atom or sulfur atom may be contained in the number of 1 to 3 alone or in a combination thereof, the number of unsaturated bond in the ring is 1, 2 or 3 including an unsaturated bond of the benzene ring to be fused, carbon atoms constituting the ring may be carbonyl or thiocarbonyl. These compounds are useful as an anti-arrhythmic agent.

Negative photochromism of a spiropyran in a Langmuir-Blodgett film

Abstract: An indolinospiropyran possessing one long alkyl chain on the nitrogen atom of the indoline moiety and two nitro groups on the benzopyran ring, exhibiting negative photochromism in various organic s...

An efficient condensation of 4-oxo-4H-benzopyran-3-carbaldehydes with 3-methyl-1-phenyl-1H-pyrazol-5 (4H)-one

Abstract: An efficient synthesis of 3-methyl-4- ((4-oxo-4H-chromen-3-yl) methylene)-1-pheny-1H- pyrazol-5-(4H)-ones 3a-m in solid-state by grinding without solvent at room temperature. Keyword: Grinding, solid-state, 3-formyl chromone, pyrazolinone, Knoevenagel reaction

Reductive coupling of polyfunctionalized organobismuth and organolead arylating reagents in the synthesis of benzopyran derivatives

Abstract: Benzopyran derivatives were synthesized in good yields by the reactions of tris[2-(chloromethyl)phenyl]bismuth diacetate and 2-(halomethyl)aryllead triacetates with phenols and naturally occurring 4-hydroxycoumarins in the presence of bases according to a three-step one-pot procedure.

One-Pot Synthesis of 2-Amino-4-aryl-5-oxo-5,6,7,8-tetrahydro-4H-1-benzopyran-3-carbonitriles in Aqueous Media.

Abstract: The reaction of aromatic aldehyde, malononitrile and 1,3-cyclohexanediones in water in the presence of triethylbenzyl-ammonium chloride (TEBA) provides an efficient access to 3-cyano-substituted 2-...

8‐Bromo‐6‐chloro­‐1′,3′,3′,5′‐tetra­meth­ylspiro­[2H‐1‐benzopyran‐2,2′‐indoline]

Abstract: In the title compound, C20H19BrClNO, the pyrrolidine ring adopts an envelope conformation, while the pyran ring is in a twist-boat form.

Nitrile Oxide 1,3-Dipolar Cycloadditions in Water: Novel Isoxazoline and Cyclophane Synthesis

Abstract: Facile examples of one-pot 1,3-dipolar cycloadditions in water are described to generate novel benzopyran, quinoline and cyclophane isoxazolines.

Chemistry of 4-Oxo-4-H-1-benzopyran-3-carbonitrile

Abstract: The review article, primarily designed to complement an earlier one (J. Heterocycl. Chem. 2005, 42, 1035-1042), gives a comprehensive survey of the synthesis and chemistry of the title nitrile covering the literature published during 2005-2014.

Benzopyran compound useful for the treatment of arrhytmia

Abstract: This invention relates to benzopyran compounds of formula (I) wherein X is NR6, Y is a bond, SO or SO2, Z is C1-4alkyl group or phenyl group, W is hydrogen atom, hydroxy group, C1-6 alkoxy group, a halogen atom, C1-4alkyl group or C1-6alkylsulfonylamino group, R1 and R2 are independently of each other C1-3alkyl group, R3 is hydrogen atom, hydroxy group or methoxy group, m is an integer of 0 to 4, n is an integer of 0 to 4, V is a single bond, CR7R8, NR9, O, S, SO or SO2, R4 is hydrogen atom or C1-6alkyl group, R5 is hydrogen atom, C1-6alkyl group, C3-8cycloalkyl group, C3-8cycloalkenyl group, C6-14aryl group or C2-9heteroaryl group. These compounds are useful as an anti-arrhythmic agent.

Preparation and crystal structure of spiro(5,7-dimethoxy- 1(1H)oxo-2-benzopyran-3(4H),1 -cyclohexane)

Abstract: Spiro(5,7-dimethoxy-1(1H)oxo-2-benzopyran-3(4H),1′-cyclohexane) (C16H20O4) was prepared by alkylation of o-lithio 3,5-dimethoxy-N-methyl benzamide with methylene cyclohexane oxide followed by alkaline hydrolysis and its crystal structure was determined by X-ray crystallographic techniques. The compound crystallizes into monoclinic space group P21/c with unit cell parameters: a = 11.914(3) A, b = 9.861(3) A, c = 12.508(7) A, β = 91.34(3)∘, Z = 4. The structure has been solved by direct methods and refined to R = 0.039 for 1870 observed reflections. The heterocyclic ring adopts distorted sofa conformation while cyclohexane ring assumes a highly symmetric chair conformation. The dihedral angle between the mean planes of isocoumarin nucleus and cyclohexane ring is 105.51(5)∘. Molecules are held together in the crystal by C=H ... O hydrogen bonds.

Candida rugosa Lipase‐Mediated Enantioselective Acetylation Studies on (.+‐.)‐3‐Arylmethyl‐3‐hydroxymethyl‐2,3‐dihydro‐1‐benzopyran‐4(H)‐ones.

Abstract: Candida rugosa lipase, catalyzed enantioselective acetylation reactions have been performed on novel (′)-3-arylmethyl-3-hydroxymethyl-2,3-dihydrobenzopyran-4-ones in diisopropyl ether. The Candida rugosa lipase-catalyzed acetylations exhibit the enantiomeric separation of the racemic compounds 5a-g, the enantioselectivity of the reaction has been found to be highly dependent on the structure of the substrate. The enantiomeric excess (ee) values are determined by 1 H NMR spectral analysis of their O-acetylmandelic acid esters and highest enantiomeric excess obtained is 79% in case of 5c.

Process for preparing substituted benzopyran compounds

Abstract: The present invention relates to a novel method of synthesizing substituted benzopyran compounds, their novel intermediates and a method of their preparation thereof.

5,7‐Dihydr­oxy‐6,2′‐dimethoxy­isoflavone

Abstract: The title compound, C17H14O6, has been isolated for the first time from Rhazya stricta. The dihedral angle between the mean planes through the benzopyran ring system and o-anisole group is 59.78 (5)°. The mol­ecular packing is stabilized by O—H⋯O and C—H⋯O hydrogen bonds.

A Three-Component Reaction of Phenol, Aldehyde, and Active Methylene Substrate under Lewis Acid Catalysis: Successful Trapping of o-Quinone Methide to Afford Benzopyran Systems.

Abstract: A three-component condensation involving reactive phenols, aldehydes, and active methylene substrates is described under BF3.Et2O catalysis to afford benzopyranyl products in satisfactory yields.

5‐Hydr­oxy‐7,8,2′‐trimethoxy­flavone

Abstract: Mol­ecules of the title compound, C18H16O6, are almost planar. The dihedral angle between the benzopyran system and the benzene ring is 3.36 (5)°. In addition to an intra­molecular O—H⋯O hydrogen bond, mol­ecules are connected by weak inter­molecular C—H⋯O hydrogen bonds to form a two-dimensional framework.

Ceric ammonium nitrate catalyzed efficient and chemoselective method for protection and deprotection of 4-oxo-4 H -1-benzopyran-3-carbaldehydes

Abstract: A chemoselective, solvent-free, mild and efficient method for the synthesis of acylals and their deprotection to 4-oxo-4H-1-benzopyran-3-carbaldchydes catalyzed by cerie ammonium nitrate (CAN) are carried out in good yields and all compounds 2a-h are characterized by IR, 1 H NMR and 1 3 C NMR spectral data.

6‐Bromo‐1′‐ethyl‐4‐(1‐ethyl‐3,3‐dimethyl‐1H‐indolin‐2‐ylidenemeth­yl)‐3′,3′‐dimethyl­spiro­[3,4‐dihydro‐2H‐1‐benzopyran‐2,2′(3′H)‐1′H‐indoline], a dicondensed spiro­pyran

Abstract: The title mol­ecule, C33H37N2O, as a dicondensed spiro­pyran (DC), contains a benzopyran and two indoline ring systems. Each of the three systems is nearly planar. While both indolines are almost perpendicular to the benzopyran, they make a dihedral angle of 33.6 (4)° with each other. The two chiral C atoms have the same chirality (RR or SS).