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At least 1,063 records · Page 59Linked to original sources
PubMed1989

[Synthesis of some halogenated indirubin derivatives].

Indirubin has been used clinically to treat chronic granulocytic leukemia, but poor solubility limited its absorption in the body. In order to reduce its side effect and raise its therapeutic effect on chronic granulocytic leukemia, six halogen-substituted derivatives were synthesized. Compounds I, II, III and V exhibited higher antitumor activity against L7212 bearing mice and W256 bearing rats than indirubin. In the parallel experiment, the most active compound III showed increase in life-span of mice bearing L7212 by 41-73%, and marked inhibitory action against W256 in rats with the inhibition rates of 48-83%, while indirubin showed 0 and 30% inhibition.

Animals↗
PubMed1978

[Correlations between chemical structure and cardiac effectivity of a group of beta-receptor blockaders].

13 compounds from the families of halogenated phenylethanolamines and phenoxypropanol-amines were tested for their antagonistic effect against an isoproterenol-induced increase in heart rate and lowering of blood pressure, and the AD50 values were determined. All the substances had beta-adrenolytical effects. 2.4-Difluoroisoproterenol and 1-(2.4-dichlorophenoxy)-3-t-butylaminopropanol-(2) showed a higher affinity to the beta1-receptors of the heart than to the beta2-receptors of the vessels. Correlations existing between chemical structure and action on the adrenergic beta-receptors are described.

Adrenergic beta-Antagonists↗
PubMed1977

[Photoallergy: results of photo patch testing in dermatological patients (author's transl)].

150 patients with light sensitivity of unknown aetiology were photo patch tested at the 2nd Department of Dermatology University of Vienna. 22 patients showed photoallergy. The identified photoallergens were mostly halogenated salicylanilides and other phenolic compounds. These substances are used as antimicrobials in soaps and cosmetics and as antimycotics in dermatological preparations. Four of the patients showed allergic contact photosensitivity to chlorpromazine. In two patients a new photoallergen has, perhaps, been discovered, namely a derivative of phthalic acid which is employed as fungicidal pesticide. The problems and consequences of photoallergy are discussed.

Adolescent↗
PubMed1979

Pyrazolidine derivatives: a comparative study of their effects on platelet aggregation.

Quantitative studies were carried out of the in vitro and ex vivo effects of phenylbutazone and 3-oxoalkyl substituted diphenyldioxopyrazolidines (kebuzone, tribuzone, benzopyrazone) on platelet aggregation. The specified pyrazolidine derivatives exhibited in vitro inhibitory effects on secondary platelet aggregation (induced by adrenaline and collagen), commensurable with the effects of sulfinpyrazone. The ex vivo efficacy was markedly influenced by the height of the drug level in blood and by differences in the elimination kinetics of the pyrazolidine derivatives in human organism. Inhibitory activities against primary aggregation (induced by ADP and thrombin) were found in vitro mainly in the phenyloxoalkyl derivative of diphenyldioxopyrazolidine (benzopyrazone) and its analogues. By substitution on the phenyl attached to its alkyl side chain (for example, by a halogen in the meta position), compounds were obtained which also possessed higher activities inhibiting secondary platelet aggregation.

Humans↗
PubMed2006

Oxyhalogen-sulfur chemistry: kinetics and mechanism of oxidation of N-acetylthiourea by chlorite and chlorine dioxide.

The oxidation reactions of N-acetylthiourea (ACTU) by chlorite and chlorine dioxide were studied in slightly acidic media. The ACTU-ClO(2)(-) reaction has a complex dependence on acid with acid catalysis in pH > 2 followed by acid retardation in higher acid conditions. In excess chlorite conditions the reaction is characterized by a very short induction period followed by a sudden and rapid formation of chlorine dioxide and sulfate. In some ratios of oxidant to reductant mixtures, oligo-oscillatory formation of chlorine dioxide is observed. The stoichiometry of the reaction is 2:1, with a complete desulfurization of the ACTU thiocarbamide to produce the corresponding urea product: 2ClO(2)(-) + CH(3)CONH(NH(2))C=S + H(2)O --> CH(3)CONH(NH(2))C=O + SO(4)(2-) + 2Cl(-) + 2H(+) (A). The reaction of chlorine dioxide and ACTU is extremely rapid and autocatalytic. The stoichiometry of this reaction is 8ClO(2)(aq) + 5CH(3)CONH(NH(2))C=S + 9H(2)O --> 5CH(3)CONH(NH(2))C=O + 5SO(4)(2-) + 8Cl(-) + 18H(+) (B). The ACTU-ClO(2)(-) reaction shows a much stronger HOCl autocatalysis than that which has been observed with other oxychlorine-thiocarbamide reactions. The reaction of chlorine dioxide with ACTU involves the initial formation of an adduct which hydrolyses to eliminate an unstable oxychlorine intermediate HClO(2)(-) which then combines with another ClO(2) molecule to produce and accumulate ClO(2)(-). The oxidation of ACTU involves the successive oxidation of the sulfur center through the sulfenic and sulfinic acids. Oxidation of the sulfinic acid by chlorine dioxide proceeds directly to sulfate bypassing the sulfonic acid. Sulfonic acids are inert to further oxidation and are only oxidized to sulfate via an initial hydrolysis reaction to yield bisulfite, which is then rapidly oxidized. Chlorine dioxide production after the induction period is due to the reaction of the intermediate HOCl species with ClO(2)(-). Oligo-oscillatory behavior arises from the fact that reactions that form ClO(2) are comparable in magnitude to those that consume ClO(2), and hence the assertion of each set of reactions is based on availability of reagents that fuel them. A computer simulation study involving 30 elementary and composite reactions gave a good fit to the induction period observed in the formation of chlorine dioxide and in the autocatalytic consumption of ACTU in its oxidation by ClO(2).

Catalysis↗
PubMed2000

EOX and organochlorine compounds in fish and ringed seal samples from Lake Ladoga, Russia.

Information about the pollution of Lake Ladoga, the largest lake in Europe, has been controversial. Various effluents and drainage waters affect the quality of the lake water. Wastewaters have caused eutrophication of parts of Lake Ladoga, but concentrations of persistent organic pollutants in the lake's food webs are poorly understood. In this study, concentrations of some organochlorine compounds, chlorophenols (CPs), and extractable organic halogen (EOX) were determined in smelt (Osmerus eperlanus), vendace (Coregonus albula), pikeperch (Lucioperca lucioperca), whitefish (Coregonus lavaretus), and the Ladoga seal (Phoca hispida ladogensis) from the northern part of the lake. The concentrations of organochlorine compounds in fish were low. Concentrations were between 0.07 and 0.15, 0.65 and 1.0, and 0.29 and 0.48 mg/kg lipids for hexachlorobenzene, total polychlorinated biphenyl (PCB) and p,p'-DDE, respectively. The results indicated biomagnification from smelt and vendace to pikeperch and ringed seal. In ringed seals, concentrations of PCB and DDT were 12 and 29 times higher than in fish used by ringed seals as major food sources.

Adipose Tissue↗
PubMed2003

Halogenation of a capsaicin analogue leads to novel vanilloid TRPV1 receptor antagonists.

1. The C-5 halogenation of the vanillyl moiety of resiniferatoxin, an ultrapotent agonist of vanilloid TRPV1 receptors, results in a potent antagonist for these receptors. Here, we have synthesized a series of halogenated derivatives of 'synthetic capsaicin' (nonanoyl vanillamide=nordihydrocapsaicin) differing for the nature (iodine, bromine-chlorine) and the regiochemistry (C-5, C-6) of the halogenation. 2. The activity of these compounds was investigated on recombinant human TRPV1 receptors overexpressed in HEK-293 cells. None of the six compounds exerted any significant agonist activity, as assessed by measuring their effect on TRPV1-mediated calcium mobilization. Instead, all compounds antagonized, to various extents, the effect of capsaicin in this assay. 3. All 6-halo-nordihydrocapsaicins behaved as competitive antagonists against human TRPV1 according to the corresponding Schild's plots, and were more potent than the corresponding 5-halogenated analogues. The iodo-derivatives were more potent than the bromo- and chloro-derivatives. 4. Using human recombinant TRPV1, 6-iodo-nordihydrocapsaicin (IC(50)=10 nM against 100 nM capsaicin) was about four times more potent than the prototypical TRPV1 antagonist, capsazepine, and was tested against capsaicin also on native TRPV1 in: (i) rat dorsal root ganglion neurons in culture; (ii) guinea-pig urinary bladder; and (iii) guinea-pig bronchi. In all cases, except for the guinea-pig bronchi, the compound was significantly more potent than capsazepine as a TRPV1 antagonist. 5. In conclusion, 6-iodo-nordihydrocapsaicin, a stable and easily prepared compound, is a potent TRPV1 antagonist and a convenient replacement for capsazepine in most of the in vitro preparations currently used to assess the activity of putative vanilloid receptor agonists.

Animals↗
PubMed2005

Indazole estrogens: highly selective ligands for the estrogen receptor beta.

The estrogen receptors, ERalpha and ERbeta, are important pharmaceutical targets. To develop ERbeta-selective ligands, we synthesized a series of nonsteroidal compounds having a phenyl-2H-indazole core with different groups at C-3. Several of these show high affinity and good ERbetaselectivity, especially those with polar and/or polarizable substituents at this site (halogen, CF(3), nitrile); the best compounds have affinities for ERbeta comparable to estradiol, with ERbetaaffinity selectivity >100. This potency and ERbeta selectivity is also seen in cell-based transcriptional assays, where several compounds showed ERbeta efficacies equivalent to that of estradiol with ERbeta potency selectivities of 100. These compounds might prove useful as selective pharmacological probes to study the biological actions of estrogens mediated through ERbeta, and they might lead to the development of useful pharmaceuticals. These findings also contribute to an evolving pharmacophore that characterizes certain nonsteroidal ligands having high ERbeta subtype affinity and potency selectivity.

Binding, Competitive↗
PubMed1999

Androgenic and anti-androgenic effects of progesterone derivatives with different halogens as substituents at the C-6 position.

The pharmacological activities of four pregnane derivatives: 17alpha-hydroxy-16beta-methylpregna-4,6-diene-3,20-dio ne (7), 17alpha-acetoxy-16beta-methylpregna-4,6-diene-3,20-dio ne (8), 17alpha-acetoxy-6-bromo-16beta-methylpregna-4,6-diene- 3,20-dione (10), and 17alpha-acetoxy-6-chloro-16beta-methylpregna-4,6-diene -3,20-dione (11), were determined. The derivatives were evaluated on gonadectomized male hamster flank organs and seminal vesicles. The results indicate that topical applications of testosterone (T) on the flank organs increased the diameter of the pigmented spot. Similarly, the same phenomenon occurred on the glands treated with compound 11, whereas compound 10 decreased the size of the spot significantly. In this study, we determined the effects of several new steroids on the conversion of T to DHT in flank organs and seminal vesicles. The results show that compound 10 inhibited T conversion to DHT, but compound 11, at a dose of 200 microg, stimulated T conversion in both flank organs and seminal vesicles. However, when 2 mg of compound 11 was applied, it inhibited the conversion of T to DHT, suggesting that this compound also represses gonadotropin release. The difference between compounds 10 and 11 involves the electronegativity of the halogen at the C-6 position of the progesterone skeleton. These data clearly indicate that by decreasing the electronegativity of the halogen at C-6 (compound 10), 5alpha-reductase is inhibited in both tissues and at different pHs. On the other hand, when the electronegativity of the halogen atom was increased (11), there was a much lower inhibitory effect on the conversion of T to DHT.

Androgen Antagonists↗
PubMed1971

Antifungal activity of substituted nitrobenzenes and anilines.

Series of 1,3-dihalogeno-5-nitrobenzenes, 3- and 3,5-halogenoanilines, and 2,6-dihalogeno-4-nitroanilines were tested for fungitoxicity against Aspergillus niger, A. oryzae, Trichoderma viride, Myrothecium verrucaria, and Trichophyton mentagrophytes in shaken culture by using Sabouraud dextrose broth enriched with yeast extract as the test medium. 1,3-Dichloro-5-nitrobenzene, 1,3-dibromo-5-nitrobenzene, 3-iodoaniline, 3,5-dichloroaniline, and 3,5-dibromoaniline were found to possess sufficient activity, compared with 8-quinolinol, to warrant further study.

Aniline Compounds↗
PubMed1975

Fluorocarbons: properties and syntheses.

The paper discusses custom syntheses of fluorocarbons for potential use as artificial blood substitutes. The term "fluorocarbon" designates a perfluorinated carbon compound which does not contain another halogen or hydrogen. Prominent requirements of an artificial blood substitute are: 1) efficient oxygen/carbon dioxide transport, 2) biological inertness, 3) low vapor pressure, 4) dispersibility to form emulsion. Fluorocarbons are superior to other liquids in dissolving oxygen and carbon dioxide. The most biologically inert halogenated alkanes are fully fluorinated. Introduction of another halogen or unsaturation decreases biological inertness. Boiling points of fluoroalkanes can be estimated from the Kinney equation. The most common method of fluorination, namely electrofluorination, is briefly described and applied to several types of organic compounds. Hydrocarbons give low yields of perfluoroalkanes. Alternatively, perfluoroalkanes may be prepared through reaction of functionalized substrates. Innert perfluorocyclic ethers are obtained from substrate ethers or acid fluorides. All types of amines perfluorinate but only perfluorotertiary amines are inert. Divalent organo-sulfur compounds afford inert perfluorinated products with sulfur in the hexavalent state. Sulfonyl fluorides give perfluorosulfonyl fluorides which can be pyrolytically coupled producing perfluoroalkanes. The Schoniger combustion method and neutron activation are described as analytical means for determining fluorine content.

Animals↗
PubMed2005

Supramolecular chemistry of halogens: complementary features of inorganic (M-X) and organic (C-X') halogens applied to M-X...X'-C halogen bond formation.

Electronic differences between inorganic (M-X) and organic (C-X) halogens in conjunction with the anisotropic charge distribution associated with terminal halogens have been exploited in supramolecular synthesis based upon intermolecular M-X...X'-C halogen bonds. The synthesis and crystal structures of a family of compounds trans-[MCl(2)(NC(5)H(4)X-3)(2)] (M = Pd(II), Pt(II); X = F, Cl, Br, I; NC(5)H(4)X-3 = 3-halopyridine) are reported. With the exception of the fluoropyridine compounds, network structures propagated by M-Cl...X-C halogen bonds are adopted and involve all M-Cl and all C-X groups. M-Cl...X-C interactions show Cl...X separations shorter than van der Waals values, shorter distances being observed for heavier halogens (X). Geometries with near linear Cl...X-C angles (155-172 degrees ) and markedly bent M-Cl...X angles (92-137 degrees ) are consistently observed. DFT calculations on the model dimers {trans-[MCl(2)(NH(3))(NC(5)H(4)X-3)]}(2) show association through M-Cl...X-C (X not equal F) interactions with geometries similar to experimental values. DFT calculations of the electrostatic potential distributions for the compounds trans-[PdCl(2)(NC(5)H(4)X-3)(2)] (X = F, Cl, Br, I) demonstrate the effectiveness of the strategy to activate C-X groups toward halogen bond formation by enhancing their electrophilicity, and explain the absence of M-Cl...F-C interactions. The M-Cl...X-C halogen bonds described here can be viewed unambiguously as nucleophile-electrophile interactions that involve an attractive electrostatic contribution. This contrasts with some types of halogen-halogen interactions previously described and suggests that M-Cl...X-C halogen bonds could provide a valuable new synthon for supramolecular chemists.

Journal Article↗
PubMed1988

Novel halogenated dihydropyridine derivatives with high vascular selectivity.

Calcium channel antagonists of the dihydropyridine type exhibit preferential vasodilator properties. To study whether this vascular selectivity is due to distinct steric modifications or may be influenced by the physicochemical nature of these drugs, contractility in guinea pig heart isolated papillary muscles, vasodilator properties in isolated rabbit femoral arteries and the lipophilicity of some novel halogenated dihydropyridines have been examined. All newly synthesized derivatives exhibited dose-dependent negative inotropic and vasodilator effects. The negative inotropic potency of all the halogenated derivatives was weaker than that of the parent compound nitrendipine. In contrast, compared to nitrendipine the vasodilator potency of the ester substituted derivatives was slightly increased, while halogen substitution in position 2 and 6 of the dihydropyridine nucleus decreased the vasodilator potency. As a result of the different influence on cardiac and vascular smooth muscle an improved vascular selectivity of the drugs was attained. The ester-substituted dihydropyridine derivatives showed a 9 times (3-bromoethyl-nitrendipine) or 11 times (3-chloroethyl-nitrendipine) higher vascular selectivity with respect to nitrendipine. Correlation of the lipophilicity with the physiological properties showed an increase in biological activity with decreasing lipophilicity. Within the ester-halogenated dihydropyridine derivatives an inverse trend was observed (increasing vasodilation with increasing lipophilicity), indicating a different influence of lipophilicity with the ester-substituted compounds on the different tissues examined. The improved vascular selectivity of the novel halogenated dihydropyridines may be at least in part a consequence of the different lipophilicity of the drugs. In addition, differences in the binding affinities of the dihydropyridines subordinate to distinct voltage dependent conformation states of the calcium channel may contribute.

Animals↗
PubMed1990

Characterization of the requirements and substrates for reductive dehalogenation by strain DCB-1.

An obligately anaerobic bacterium known as strain DCB-1 was grown under a variety of conditions to determine the requirements for dehalogenation as well as factors which stimulated or inhibited the process. Dechlorination was obligately anaerobic since introduction of O2 immediately inhibited the reaction. Sulfuroxy anions, which also serve as electron acceptors for DCB-1, inhibited dechlorination but NO3- and fumarate did not. The optimum growth medium for dechlorination was 0.2% Na pyruvate and 20% rumen fluid in basal salts. Media with either pyruvate or rumen fluid alone did not support dechlorination. DCB-1 also consumed H2 but typical substrate concentrations of H2 (80 kPa) delayed dechlorination. Once the H2 concentration was reduced to less than 20 microM (2.67 kPa), dechlorination resumed. Dehalogenation by DCB-1 was restricted to the meta substituted benzoates as halogens in other positions and chloroaromatic compounds with other functional groups were not dechlorinated.

Animals↗