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PubMed1979

[Chemical and pharmacological research on pyran derivatives. XII. Bis-(beta-chloroethyl)amino-substituted chromones and benzochromones].

By the reaction of phenols or naphthols with N,N-bis-(beta-methoxyethyl)ethoxycarbonylacetamide in the presence of phosphorus oxychloride the preparation of bis-(beta-methoxyethyl)amino substituted chromones or benzochromones was achieved. Treatment of these compounds with hydriodic acid at 95 degrees and then with thionyl chloride gave rise to the formation of the corresponding bis-(beta-chloroethyl)amino derivatives. When beta-naphthols reacted with N-ethoxycarbonylacetylmorpholine 1-oxo-3-morpholino-1H-naphtho[2,1-b]pyrans were obtained. These compounds as well as the corresponding 3-bis-(beta-methoxyethyl)amino derivatives afforded 1-oxo-3-bis-(beta-iodoethyl)amino-1H-naphtho[2,1-b]pyrans by treatment with hydriodic acid at reflux. The latter compounds were also easily transformed into 3-bis-(beta-chloroethyl)amino derivatives by reaction with phosphorus oxychloride in N,N-dimethylformamide. Pharmacological screening of some of the compounds described indicated no tumor-inhibiting activity.

Animals↗
PubMed1979

Clinical trial of a new chromone compound for systemic treatment of atopic dermatitis.

In a double-blind group comparative study, 14 adults with atopic dermatitis were treated systemically for 6 weeks with a new anti-allergic chromone compound (FPL 57787) 6 mg four times a day. A similar group of 13 adults was given placebo. Both groups improved during the trial in all the clinical assessments without significant differences, but there was a tendency to a decreased use of local treatment (hydrocortisone butyrate) in the active group during the trial. There were no drug-related complaints, but one patient in the active group had transiently elevated liver enzyme levels. Further investigations are warranted.

Administration, Topical↗
PubMed1997

Synthesis and antimycobacterial activity of some new 3-heterocyclic substituted chromones.

The aldol synthesis of benzimidazole, benzothiazole and benzothiazolium salt derivatives of chromones is described. The structures of the compounds have been proved by elemental analysis and 1H NMR spectra. The antimycobacterial activity of some of the prepared compounds have been tested in vitro against Mycobacterium tuberculosis (H37Rv) and Mycobacterium fortuitum (1021).

Antitubercular Agents↗
PubMed1985

The chromone inhibitor stigmatellin--binding to the ubiquinol oxidation center at the C-side of the mitochondrial membrane.

Stigmatellin, a chromone inhibitor acting at the Q0 center of the bc1 complex, binds to the heme b-566 domain of cytochrome b as well as to the Fe2S2 protein. Its binding induces a shift of the alpha-band of heme b-566 to 568 nm. It does not influence the ligand field of the heme b-562 center. Concomitant with the red shift, stigmatellin gives rise to an alteration of the EPR line shape of the Fe2S2 cluster, namely linewidth narrowing and g value shifts at all 3 principal values. The midpoint redox potential of the Fe2S2 protein is shifted from 290 to 540 mV.

Animals↗
PubMed2003

Two chromone-secoiridoid glycosides and three indole alkaloid glycosides from Neonauclea sessilifolia.

From the dried roots of Neonauclea sessilifolia, two new chromone-secoiridoid glycosides, sessilifoside and 7"-O-beta-D-glucopyranosylsessilifoside, and three novel indole alkaloid glycosides, neonaucleosides A, B, and C, were isolated along with the main known glycosides, 5-hydroxy-2-methylchromone-7-O-beta-D-apiofuranosyl-(1-->6)-beta-D-glucopyranoside, sweroside, loganin, grandifloroside, and quinovic acid 3 beta-O-beta-D-quinovopyranoside-28-O-beta-D-glucopyranoside. The structures of these new glycosides were determined by spectroscopic and chemical means. Neonaucleoside A and its C-3 epimer were prepared from secologanin and tryptamine.

Glycosides↗
PubMed2001

Electrolytic partial fluorination of organic compounds. 55. Highly regio- and stereoselective anodic monofluorination of 2,3-dihydrochroman-4-one and chromone derivatives.

Anodic monofluorination at the position alpha to the oxygen atom of the (E)-3-benzylidene-2,3-dihydrochroman-4-one derivatives was successfully carried out to provide the corresponding 2-fluorochromanones selectively. This is the first regioselective electrochemical fluorination of fused-type, oxygen-containing heterocyclic compounds. Anodic fluorination of a chromone derivative also gave a similar fluorinated chromanone stereoselectively.

Journal Article↗
PubMed2005

Salt effects on the phase behavior, structure, and rheology of chromonic liquid crystals.

Chromonic liquid crystals are formed by the addition of aromatic molecules such as disodium chromoglycate (cromolyn) to water. In this study, we investigate the addition of salts to the lyotropic nematic phase of cromolyn aqueous solutions. The addition of sodium and potassium salts shifts the isotropic-nematic phase boundary upward by more than 10 degrees C, so that samples that were isotropic at room temperature are transformed into nematic phases. Salt effects are predominantly dictated by the cation, not the anion, and appear to differ based on cation size. In contrast to small, hydrated cations like sodium, large, weakly hydrated cations such as tetraethylammonium and tetrabutylammonium shift the phase boundary downward, thus stabilizing the isotropic phase at the expense of the nematic one. The phase behavior results are highly correlated with viscosity measurements, with an upward shift in the phase boundary correlating with an increase in solution viscosity and vice versa. We also probe the microstructure in cromolyn-salt solutions, both indirectly by small-angle neutron scattering (SANS) and directly by cryo-transmission electron microscopy (cryo-TEM). The cryo-TEM images show the presence of rodlike aggregates that possibly undergo a higher order aggregation into bundles in the presence of salt.

Cromolyn Sodium↗
PubMed2004

Study of the chromonic liquid-crystalline phases of bis-(N,N-diethylaminoethyl)perylene-3,4,9,10-tetracarboxylic diimide dihydrochloride by polarized optical microscopy and 2H NMR spectroscopy.

The chromonic liquid-crystalline properties of bis-(N,N-diethylaminoethyl)perylene-3,4,9,10-tetracarboxylic diimide dihydrochloride in an aqueous solution were investigated by polarized light microscopy and 2H NMR spectroscopy. Both techniques indicate a narrow I + N biphasic region and a broad N phase region at concentrations ranging from approximately 6.9 to approximately 30 wt % at room temperature. Optical microscopy indicates that a hexagonal M phase exists at higher concentrations. The variation of the I --> N + I and N + I --> N transition temperatures with concentration was studied by 2H NMR spectroscopy. Finally, the effects of temperature and concentration on the order parameter of the N phase were investigated by 2H NMR using a tetra-deuterated derivative. A value of 0.97 was obtained for the N phase at its upper concentration limit.

Journal Article↗
PubMed2005

Oriented monolayers prepared from lyotropic chromonic liquid crystal.

We use a layer-by layer electrostatic self-assembly technique to obtain in-plane oriented aggregates of mesogenic dye molecules cast from lyotropic chromonic liquid crystals (LCLCs) on mica substrates. The aqueous solutions of dye used for deposition are in the nematic phase. Atomic force microscopy and X-ray photoelectron spectroscopy of the dried film reveal that the LCLC molecules adsorb at the charged substrate preserving ordered aggregates of elongated shape characteristic of the nematic phase in the aqueous solution. These elongated aggregates of LCLC molecules form films with in-plane orientational order and are compositionally distinct from the substrate.

Journal Article↗
PubMed2005

Donor-substituted phenyl-pi-chromones: electrochemiluminescence and intriguing electronic properties.

Phenylethynylchromones bearing different donor groups at the phenyl moiety have been prepared and their photophysical and electrogenerated chemiluminescence (ECL) properties have been studied with respect to their structural features. Intriguingly, the presence and variation of donor groups do not much influence the absorption spectra, which can be compared with the spectrum of unsubstituted chromone, whereas the photoluminescence (PL) spectra show pronounced changes. Density functional theory (DFT) calculations indicate enhancement of HOMO energy levels upon increasing the donor strength. The photophysical properties have also been studied in various solvents, and the PL spectra in particular show the anticipated trend. The introduction of pi-extension imparts ECL to the new molecules and the electronic coupling between the donor and the acceptor moieties through C-C triple bond influences ECL emission maxima. Weaker donors impart excimer ECL while stronger donors impart monomeric intramolecular charge transfer (ICT) ECL.

Journal Article↗
PubMed2004

Diterpene derivative and chromone from Hypericum perforatum.

A novel diterpene derivative, 5-methyl-5-(4,8,12-trimethyl-tridecyl)-dihydro-furan-2-one (1) and a new chromone, 5-hydroxy-7-methoxy-3-methyl-chromen-4-one (2), along with a known compound, phytol (3) have been isolated from the aerial parts of Hypericum perforatum. Their structures were established on the basis of spectroscopic analysis and by comparison with published values.

Chromans↗
PubMed2004

Pretransitional fluctuations in the isotropic phase of a lyotropic chromonic liquid crystal.

We have studied isotropic-to-nematic pretransitional fluctuations in an aqueous solution of disodium cromoglycate (cromolyn) by static and dynamic light scattering. Cromolyn is a representative of lyotropic chromonic liquid crystals with building units being elongated rods formed by aggregates of disk-like molecules. By combining light-scattering and viscosity measurements we have determined the correlation length and relaxation time of the orientational order-parameter fluctuations and estimated the size of the cromolyn aggregates. The pretransitional behavior of light scattering does not completely follow the classic Landau-de Gennes model. This feature is most probably associated with the variable length of cromolyn aggregates. We have observed a dramatic increase of the shear viscosity near the transition to the nematic phase, the fact which correlates with the idea of growing supramolecular aggregates. The steep temperature dependence of the viscosity is accompanied by a practically temperature-independent translational diffusion coefficient.

Journal Article↗
PubMed2005

Real-time microbe detection based on director distortions around growing immune complexes in lyotropic chromonic liquid crystals.

We describe director distortions in the nematic liquid crystal (LC) caused by a spherical particle with tangential surface orientation of the director and show that light transmittance through the distorted region is a steep function of the particle's size. The effect allows us to propose a real-time microbial sensor based on a nontoxic lyotropic chromonic LC (LCLC) that detects and amplifies the presence of immune complexes. A cassette is filled with LCLC, antibody, and antigen-bearing particles. Small and isolated particles cause no macroscopic distortions of the LCLC. Upon antibody-antigen binding, the growing immune complexes distort the director and cause detectable optical transmittance between crossed polarizers.

Antigen-Antibody Complex↗
PubMed2005

Optical characterization of the nematic lyotropic chromonic liquid crystals: light absorption, birefringence, and scalar order parameter.

We report on the optical properties of the nematic (N) phase formed by lyotropic chromonic liquid crystals (LCLCs) in well aligned planar samples. LCLCs belong to a broad class of materials formed by one-dimensional molecular self-assembly and are similar to other systems such as "living polymers" and "wormlike micelles." We study three water soluble LCLC forming materials: disodium chromoglycate, a derivative of indanthrone called Blue 27, and a derivative of perylene called Violet 20. The individual molecules have a planklike shape and assemble into rodlike aggregates that form the phase once the concentration exceeds about 0.1 M. The uniform surface alignment of the N phase is achieved by buffed polyimide layers. According to the light absorption anisotropy data, the molecular planes are on average perpendicular to the aggregate axes and thus to the nematic director. We determined the birefringence of these materials in the N and biphasic N-isotropic (I) regions and found it to be negative and significantly lower in the absolute value as compared to the birefringence of typical thermotropic low-molecular-weight nematic materials. In the absorbing materials Blue 27 and Violet 20, the wavelength dependence of birefringence is nonmonotonic because of the effect of anomalous dispersion near the absorption bands. We describe positive and negative tactoids formed as the nuclei of the new phase in the biphasic N-I region (which is wide in all three materials studied). Finally, we determined the scalar order parameter of the phase of Blue 27 and found it to be relatively high, in the range 0.72-0.79, which puts the finding into the domain of general validity of the Onsager model. However, the observed temperature dependence of the scalar order parameter points to the importance of factors not accounted for in the athermal Onsager model, such as interaggregate interactions and the temperature dependence of the aggregate length.

Journal Article↗
PubMed1995

Inhibition of volume-activated chloride currents in endothelial cells by chromones.

1. We have studied the effects of the reported chloride channel blocker, sodium cromoglycate, on volume-activated Cl- currents in endothelial cells from bovine pulmonary artery by means of the whole-cell patch clamp technique. Cl- currents were activated by challenging the cells with a hypotonic extracellular solution of 60% of the normal osmolarity. 2. Half maximal activation of the current at +95 mV occurred after exposure of the cells for 148 +/- 10 s (n = 6) to hypotonic solution (HTS). At the same membrane potential but in the presence of 100 microM sodium cromoglycate (disodium-1,3-bis (2'-carboxylate-chromone-5'-yloxy)-2-hydroxy-propane) activation was delayed (253 +/- 25 s, n = 6) and the maximal current amplitude was reduced to 63 +/- 7% of the control (n = 13). 3. In comparison, an equimolar concentration of NPPB (5-nitro-2(3-phenyl) propylamino-benzoic acid), another Cl- channel blocker, completely blocked the volume-activated current in less than 20 s. 4. Sodium cromoglycate, applied at the time when the HTS-induced current was completely activated, dose-dependently inhibited this current with a concentration for half maximal inhibition of 310 +/- 70 microM. Data for nedocromil sodium were not significantly different from those for sodium cromoglycate. 5. Sodium cromoglycate, loaded into the endothelial cells via the patch pipette in ruptured patches, resulted in a decline of the HTS activated current with a time course that was compatible with diffusion of the compound from the pipette into the cell. Intracellulary applied sodium cromoglycate was also more effective and at 50 microM caused a decrease in the amplitude of the current to 25 +/- 6% (n = 10) of the control current.6 It is concluded that blockade of volume-activated Cl- currents by extracellular sodium cromoglycatemay be due to an intracellular action following its permeation across the cell membrane.

Animals↗