During a synthesis of coumarins to obtain new candidates for treating Alzheimer's Disease (AD), an unusual rearrangement of a benzopyran group to a benzofuran group occurred, offering a novel synthesis pathway of these benzofuran derivatives. The possible mechanism of the novel rearrangement was also discussed. All of the benzofuran derivatives have weak anti-AChE activities compared with the r...

1 The abbreviations used are: SNP, sodium nitroprusside; CR-6, 3,4-dihydro-6-hydroxy7-methoxy-2,2-dimethyl-1(2H)-benzopyran; ROS, reactive oxygen species; zVAD-fmk, (zVal-Ala-Asp-fluoro-methyl ketone); RP, retinitis pigmentosa; RNS, reactive nitrogen species; NOS, nitric oxide synthase; BHT, butylated hydroxytoluene; NAC, N-Acetyl-LJBC Papers in Press. Published on June 21, 2004 as Manuscript M...

A branching DOS strategy for an unbiased natural product-like library with embedded privileged benzopyran motif was established to provide complexity and diversity of resulting heterocycles with desired drug-likeness. The importance of skeletal diversity conducted on a privileged substructure was demonstrated through the biological evaluation of a small molecule library representing 22 unique c...

The mol-ecular conformation of the title compound, C(10)H(8)O(4), isolated from Laretia acualis, is stabilized by a strong intra-molecular hydrogen bond between the hydroxyl and carbonyl groups. The crystal packing shows π-π stacking inter-actions. The chromene (4H-1-benzopyran-4-one) unit is essentially planar.

The hydro-chloride salt of chiral l-nebivolol {systematic name: (+)-(R,S,S,S)-bis-[2-(6-fluoro-3,4-dihydro-2H-1-benzopyran-2-yl)-2-hydroxy-ethyl]ammonium chloride dihydrate}, C(22)H(26)F(2)NO(4) (+)·Cl(-)·2H(2)O, was obtained by chiral liquid chromatography as a dihydrate. The pyran rings adopt half-chair conformations. Hydrogen bonds between the cation, anions and water mol-ecules contribute t...

Density Functional Theory (DFT) calculations have been performed on the TTC-->TTT isomerization reaction of the open forms of the 1',3'-dihydro-8-bromo-6-nitro-1',3',3'-trimethylspiro[2H-1-benzopyran-2,2'-(2H)indole (8-Br-6-nitro-BIPS) system. The calculations were carried out in vacuo and in methylene chloride solution at different temperatures. Results are compared with the available experime...

A new C-8 prenylated 5,7-dimethoxycoumarin named omphamurrayin was isolated from the leaves of Murraya paniculata var. omphalocarpa, and its structure was established as 5,7-dimethoxy-8-(1-oxo-2-senecioyl-3-methyl-3-butenyl)-2H-1-benzopyran-2-one on the basis of the spectroscopic evidence. The taxonomic status of M. paniculata var. omphalocarpa is briefly discussed, along with its synonymity to...

The coumarin ring system in the title compound, C(15)H(18)O(5) [IUPAC name: 8-(2,3-dihydr-oxy-3-methyl-butyl)-7-meth-oxy-2H-1-benzopyran-2-one], isolated from Muraya paniculata, is planar (r.m.s. deviation 0.017 Å). In the crystal, the two hydr-oxy groups are involved in O-H⋯O hydrogen bonding with adjacent mol-ecules, forming a sheet structure.

2-Dimethyl-2H-Chromenes, Coumarin Derivatives, Phase-Transfer Catalysis 2,2-Dimethyl-5H-pyrano(3,2-c)-l-benzopyrano-5-one(2) and 4H-2,3-dihydro-3-methyl-2methylene-furan-l-benzopyran-4-one (3), two new coumarin derivatives were synthesised from 4-hydroxycoumarin by treating with 3-chloro-3-methylbut-l-yne and 3-chlorobut-l-yne respectively, both reactions progressing via the phase-transfer cata...