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PubMed2002

Benzo[1,2-c]1,2,5-oxadiazole N-oxide derivatives as potential antitrypanosomal drugs. Structure-activity relationships. Part II.

The preparation of new derivatives of benzo[1,2-c]1,2,5-oxadiazole N-oxide is described. These derivatives were chosen in order to investigate and confirm previous structural features found necessary to display an adequate antitrypanosomal activity. The compounds synthesized were tested in vitro against epimastigote forms of Trypanosoma cruzi. The presence of a bromine atom in the benzo system produced compounds less active than the corresponding de-halo analogues. However, 5-(bromomethyl)-7-bromobenzo[1,2-c]oxadiazole N-oxide (23) was the most cytotoxic compound against T. cruzi. For this, the 50% inhibitory dose (ID50) was determined, it was of the same order as that of Nifurtimox. From statistical analysis we could establish a relationship between lipophilic-hydrophilic balance of the derivatives with their effectiveness as antichagasic compounds.

Animals↗
PubMed2005

Iodo- and bromo-enolcyclization of 2-(2-propenyl)cyclohexanediones and 2-(2-propenyl)cyclohexenone derivatives using iodine in methanol and pyridinium hydrobromide perbromide in dichloromethane.

alpha-Allylcyclohexane-1,3-diones undergo one-pot iodine-methanol promoted iodocyclization and oxidative aromatization to afford variously substituted 2-iodomethyltetrahydrobenzofuran-4-ones (minor) and 2-iodomethyl-4-methoxydihydrobenzofuran derivatives (major). On the other hand, the alpha-allyl-1,3-cyclohexanediones react with pyridinium hydrobromide perbromide in dichloromethane to afford mixtures of 2-bromomethyltetrahydrobenzofuran-4-ones (major) and 3-bromomethyltetrahydrobenzopyran-5-ones (minor). The prepared products and their derivatives were characterized using a combination of NMR, FT-IR and mass spectroscopic techniques.

Allyl Compounds↗
PubMed2003

Brominated flame retardants and phenolic endocrine disrupters in Finnish human adipose tissue.

Brominated flame retardants and phenolic compounds, of which several have been shown to exhibit endocrine disrupting effects, were screened in extracts of Finnish human adipose tissue samples. The samples were collected during autopsy from 39 subjects, of which 23 were males and 16 females. The samples were homogenised and extracted, and then cleaned-up by preparative gel permeation chromatography. The phenolic compounds were determined in silylated extracts. A total of 21 individual compounds were analysed in the extracts by gas chromatography-mass spectrometry (HRGC-LRMS) in the selected ion monitoring mode. The most commonly occurring compounds were 4-octylphenol diethoxylate, 4,4'-dihydroxybiphenyl, and 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), but also some other alkylphenols, pentabromophenol, and 2,2',4,4',5-penta- and 2,2',4,4',5,5'-hexabromodiphenyl ether could be detected in 1-6 samples. The concentrations were ranging from trace amounts to 71 ng/g of lipid weight. The mean concentration of BDE-47 was 1.20 ng/g lipids, however, in 15 of the samples the concentration was below the detection limit. Compared to other European studies the average concentration of BDE-47 obtained in this study is at the lower end of the reported concentrations.

Adipose Tissue↗
PubMed2004

Regioselective Baeyer-Villiger oxidation in 4-carbonyl-2-azetidinone series: a revisited route toward carbapenem precursor.

A novel synthesis of acetoxyazetidinone 2 is presented. The azetidinone ring of compounds 7 is formed by C-3/C-4 cyclization of (2R,3R)-epoxybutyramide precursors 6, N-protected with a benzhydryl group. N-Deprotection by photoactivated bromination and acidic treatment leads to compounds 10 with various CO-R substituents at C-4. Transformation of these substituents by Baeyer-Villiger oxidation gives the desired regioisomer 11 with the cyclopropyl side-group which is the only group (among R = H, Ph, t-Bu, i-Pr, c-Pr) able to satisfy both the steric requirements of the cyclization step and the electronic requirements of the oxidative rearrangement step.

Journal Article↗
PubMed1982

Polybrominated biphenyls as aryl hydrocarbon hydroxylase inducers: structure-activity correlations.

The synthesis of all possible laterally-substituted polybrominated biphenyl (PBB) congeners containing two para bromines is described. Using enzymic, electrophoretic and ligand-binding assays that distinguish between phenobarbitone(PB)- and 3-methylcholanthrene(MC)-type inducers, the synthetic PBBs were evaluated as inducers of liver microsomal drug-metabolizing enzymes in the immature male Wistar rat. 4,4'-Dibromobiphenyl resembled PB in its mode of induction whereas all the meta-brominated derivatives of 4,4'-dibromobiphenyl, namely 3,4,4'-tri, 3,4,4',5-tetra-, 3,3', 4,4'-tetra-, 3,3',4,4',5-penta- and 3,3',4,4',5,5'-hexabromobiphenyl, resembled MC in their mode of induction. The results obtained with 3,4,4'-tribromobiphenyl demonstrate that, in contrast to the polychlorinated biphenyls (PCBs), a single meta halogen substituent is sufficient to abolish the PB-type characteristics of 4,4'-dibromobiphenyl and convert it to a strictly MC-type inducer. PBBs which induce AHH activity must be substituted at both para positions and at one, two, three or four meta positions. Ortho-substitution of PBBs which contain only lateral bromine groups may also give compounds which are aryl hydrocarbon hydroxylase (AHH) inducers. One of the MC-type PBBs, namely 3,3',4,4'-tetrabromobiphenyl, which has been tentatively identified in the commercial PBB mixture, fireMaster BP-6, was at least 50 times more potent as an inducer of AHH activity than the commercial PBB mixture. The induction of AHH by 3,3',4,4'-tetrabromobiphenyl was accompanied by a dose-dependent decrease in both thymus and spleen weights. The thymus and/or spleen weights were decreased in rats treated with the other MC-type PBBs which further supports the correlation between the toxicity of the PBBs and their ability to induce AHH.

Animals↗
PubMed2005

Hazardous substances in separately collected grey- and blackwater from ordinary Swedish households.

The objective of this paper is to present the mass flows of a number of selected hazardous substances in raw, separate grey- and blackwater from ordinary Swedish households. The Vibyasen housing area was selected for the investigation since its wastewater system has separate flows for grey- and blackwater. Due to the high analytical costs, a limited number of hazardous substances had to be selected and the number of samples restricted. The greywater flow was manually measured and the samples were collected at set time intervals. The blackwater samples were randomly collected from a blackwater tank. A total of 105 selected hazardous substances were measured in both fractions. Of the 24 elements (Ca, Fe, K, Mg, Na, S, Al, Ag, As, Ba, Bi, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Pt, Sb, Sn, Te, Zn) measured in both fractions, 22 were detected in the greywater and 23 in the blackwater. 81 organic substances were selected and measured in both fractions (nonylphenol- and octylphenol ethoxylates, brominated flame-retardants, organotin compounds, PAH, PCB, phthalates, monocyclic aromatics, and triclosan). 46 organic substances were found in greywater and 26 in blackwater. PCB was the only group found in neither grey- nor blackwater. The greywater flow fluctuated, with a specific average flow of 66 L per person and day. The composition of blackwater also fluctuated, with shifting proportions of urine, faeces, and flush water. The specific average blackwater flow was 28.5 L per person and day. The mixture of substances in separate wastewater fractions from Swedish households was too complex to exactly distinguish their specific sources.

Hazardous Substances↗
PubMed1998

Iodinated and fluorinated steroid 2'-aryl-[3,2-c] pyrazoles as potential glucocorticoid receptor imaging agents.

We have synthesized several halogenated steroids as potential glucocorticoid receptor mediated imaging agents. These compounds are analogs of aryl-pyrazolo steroids, similar to the potent glucocorticoid, cortivazol. Compounds containing the halogens, iodine, bromine, and fluorine, as well as the E- and Z-iodovinyl side chain at the para position of 2'-phenyl-11 beta,17,21-trihydroxy-16 alpha-methyl-20-oxo-pregn-4-eno[3,2-c] pyrazole were prepared. They were tested as ligands for the glucocorticoid receptor by competition for the binding of [3H]dexamethasone and for glucocorticoid potency by the induction of alkaline phosphatase in HeLa cells. None of the iodinated steroids were good ligands for the glucocorticoid receptor or potent glucocorticoids. The bromo analog was only slightly better than the iodinated steroids as a ligand, and it had a potency in the HeLa cell assay about half that of dexamethasone. The fluoro analog good binding to the glucocorticoid receptor and was a very potent glucocorticoid, approximately seven times that of dexamethasone. Consequently, it appears that the fluoro steroid, 2'-(4-fluorophenyl)-11 beta,17,21-trihydroxy-16 alpha-methyl-20-oxo-pregn-4-eno[3,2-c] pyrazole, when labeled with 18F, would make an excellent glucocorticoid receptor-mediated imaging agent for positron emission tomography.

Animals↗
PubMed2003

The diversity of naturally produced organohalogens.

More than 3800 organohalogen compounds, mainly containing chlorine or bromine but a few with iodine and fluorine, are produced by living organisms or are formed during natural abiogenic processes, such as volcanoes, forest fires, and other geothermal processes. The oceans are the single largest source of biogenic organohalogens, which are biosynthesized by myriad seaweeds, sponges, corals, tunicates, bacteria, and other marine life. Terrestrial plants, fungi, lichen, bacteria, insects, some higher animals, and even humans also account for a diverse collection of organohalogens.

Animals↗
PubMed1997

Extractable organohalogens in tissues of beluga whales from the Canadian Arctic and the St. Lawrence estuary.

Samples of blubber, brain, kidney, liver, and muscle of individual beluga whales were extracted and analyzed for extractable organic Cl (EOCl), Br (EOBr), and I (EOI) by neutron activation analysis. The highest levels of EOCl (554 microg g(-1) lipid) were found in the kidney of Arctic beluga and the lowest (24 microg g(-1) lipid) in the blubber. Levels in brain and liver lipids were on average of equal magnitude. The unequal distribution of EOCl in tissue lipids is in marked contrast to the equal distribution, in lipid, demonstrated for organochlorines such as DDTs and PCBs by a number of investigations. The distribution of brominated (EOBr) and iodinated (EOI) compounds was similar and markedly different from that of EOCl. The tissue distribution of EOCl seems to be related to the proportion to polar lipids in the tissues. Beluga from St. Lawrence had significantly higher brain EOCl levels than the Arctic samples whereas the levels of EOCl in liver and kidney were higher in the Arctic whales.

Journal Article↗
PubMed2006

Total syntheses of the telomerase inhibitors dictyodendrin B, C, and E.

Concise and flexible total syntheses of the pyrrolo[2,3-c]carbazole alkaloids dictyodendrin B (2), C (3), and E (5) are described. These polycyclic telomerase inhibitors of marine origin derive from the common intermediate 18 which was prepared on a multigram scale by a sequence comprising a TosMIC cycloaddition with formation of the pyrrole A-ring, a titanium-induced reductive oxoamide coupling reaction to generate an adjacent indole nucleus, and a photochemical 6pi-electrocyclization/aromatization tandem to forge the pyrrolocarbazole core. Conversion of 18 into dictyodendrin C required selective manipulations of the lateral protecting groups and oxidation with peroxoimidic acid to form the vinylogous benzoquinone core of the target. Zinc-induced reductive cleavage of the trichloroethyl sulfate ester then completed the first total synthesis of 3. Its relatives 2 and 5 also originate from compound 18 by a selective bromination of the pyrrole entity followed by elaboration of the resulting bromide 27 via metal-halogen exchange or cross-coupling chemistry, respectively. Particularly noteworthy in this context is the generation of the very labile p-quinomethide motif of dictyodendrin E by a palladium-catalyzed benzyl cross-coupling reaction followed by vinylogous oxidation of the resulting product 41 with DDQ. The Suzuki step could only be achieved with the aid of the borate complex 40 formed in situ from p-methoxybenzylmagnesium chloride and 9-MeO-9-BBN, whereas alternative methods employing benzylic boronates, -trifluoroborates, or -stannanes met with failure.

Amides↗
PubMed1976

Synthesis, antimalarial activity, and phototoxicity of some benzo(h)quinoline-4-methanols.

Nine alpha-dibutylaminomethylbenzo[h]quinoline-4-methanols were synthesized from the corresponding 1-amino-naphthalenes by the following sequence: 1-aminonaphthalene leads to 1H-benz[g]indole-2,3-dione leads to benzo[h]quinoline-4-carboxylic acid leads to acid chloride leads to bromomethyl ketone leads to epoxide leads to benzo[h]quinoline-4-methanol. Several acid chlorides substituted in the 3 position reacted incompletely with ethereal diazomethane but were efficiently converted, without isolation of the intermediates, to the bromomethyl ketones by reaction with ethoxymagnesium diethylmalonate, bromination, hydrolysis, and decarboxylation. Several compounds prepared, especially alpha-dibutylaminomethyl-2-(2',4'-dimethylphenyl)-3-methyl-6-chlorobenzo[h]quinoline-4-methanol, showed significant antimalarial activity against Plasmodium berghei in infected mice but were moderately phototoxic.

Animals↗
PubMed1975

Synthesis and central nervous system effects of 8.9-dihydro(1)benzazepino(3,2.1-ak)(1,4)benzodiazepin-1(2H)-ones and (1) binzazepino(3,2,1-jk)(1,4)benzodiazepin-1(2H)-ones.

A series of 4-alkyl-8,9-dihydro[1]benzazepino[3,2,1-jk][1,4]benzodiazepin-1(2H)-ones and brominated derivatives was synthesized. Two approaches for the synthesis of 4-alkyl[1]benzazepino[3,2,1-jk][1,4]benzodiazepin-1(2H)-ones and brominated derivatives are described. All compounds were evaluated for CNS activity. None showed significant activity. The results obtained indicate that in the case of the 1,3-dihydro-5-phenyl-2H-1,4-benzodiazepin-2-one a phenyl group at the 1 position causes a fall in CNS activity not only when it is free but also when fused to the benzodiazepine system.

Animals↗
PubMed2004

Sulfur extrusion with tin radical: synthesis of 4',5'-didehydro-5'-deoxy-5'-(tributylstannyl)adenosine, an intermediate for potential inhibitors against S-adenosyl homocysteine hydrolase.

A new approach has been developed for the synthesis of potential inhibitors of S-adenosyl-l-homocysteine (AdoHcy) hydrolase. The key intermediate 9-[2,3-bis-O-(tert-butyldimethylsilyl)-5-(Z)-(tributylstannyl)-5-deoxy-beta-d-erythro-pent-4-enofuranosyl]adenine (12) was prepared by sulfur extrusion reaction of 4',5'-didehydro-5'-deoxy-5'-(phenylthio)adenosine (11) with tributyltin radical. It was found that this reaction proceeds stereoselectively, forming 12 irrespective of the geometry of 11. Compound 12 readily underwent iodination, bromination, and chlorination with retention of configuration, whereas fluorination gave both (Z)- and (E)-isomers of vinyl fluoride. Because of the susceptibility of 12 to protodestannylation, the (Z)-vinyl iodide (13), prepared in quantitative yield from 12, was used as a substrate for C-C bond formation. Various types of carbon substituents (phenyl, vinyl, trifluorovinyl, ethynyl, and cyano) were introduced to the 5'-position of the 5-deoxy-beta-d-erythro-pent-4-enofuranosyl structure to open up a new route to potential inhibitors of AdoHcy hydrolase.

Adenosine↗
PubMed2003

Differential substituent effects of beta-halogens in water-soluble porphyrins.

The first water-soluble beta-octafluorinated porphyrins, 5,10,15,20-tetrakis(4-sulfonatophenyl)-2,3,7,8,12,13,17,18- octafluoroporphyrin, 1, and 5,10,15,20-tetrakis(2,6-difluoro-3-sulfonatophenyl)-2,3,7,8,12,13,17,18- octafluoroporphyrin, 2, have been prepared and their aqueous aggregation, acid-base, and optical properties have been characterized. The porphyrins are tetraanionic at neutral pH (at pH = 3-11 for 1 and pH = 0-9 for 2). Semiempirical (AM1) calculations provide evidence that somewhat unusual acidity characteristics of the fluorinated compounds (with respect to similar brominated porphyrins) can be rationalized solely on the basis of chemical hardness and electronegativity arguments. These results indicate that the large conformational differences seen in the structures of brominated and fluorinated water-soluble porphyrins have little impact upon N-H acidity. Metalation of 1 and 2 with ZnCl2 yielded the zinc complexes, which were characterized by optical spectroscopy and electrochemistry.

Journal Article↗
PubMed2000

Antimicrobial activities of some amino derivatives of 5,7-dibromo-2-methyl-8-hydroxyquinoline.

The bromine atoms of the title compound, 5,7-dibromo-2-methyl-8-hydroxyquinoline were replaced by the requisite amino compound to afford 6 amino derivatives viz: bis(diethylamino)-, bis(dibutylamino)-, bis(dicyclohexylamino)-, dipyrolidino-, dipiperidino- and dipiperazino derivatives. The antimicrobial activity of these compounds were investigated against selected gram positive (Staphylococcus aureus and Bacillus subtilis), gram negative bacteria (Escherichia coli and Pseudomonas aeruginosa) and yeast (Candida albicans). All the compounds showed significant activity against the test microorganisms, from 5-30 times compared to the title compound. It was observed that all derivatives were more effective against gram positive bacteria. No correlation has been established between the minimum inhibitory (MIC) concentrations of the derivatives and the structural modifications.

Anti-Bacterial Agents↗
PubMed2000

[Studies on response characteristics of Cl, Br, I of microwave plasma torch atomic emission detector for gas chromatography].

The present paper deals with a microwave plasma torch atomic emission detector for gas chromatography. Argon is used as support gas, carrier gas and make-up gas. The effect of oxygen scavenger gas on the detection performance for chlorine, bromine and iodine is discussed. Detection limits, dynamic ranges, relative standard deviations and response characteristics of GC-MPT-AED for chlorine, bromine and iodine in organic compounds were studied. The results are favorable in comparing with GC-ICP-AED.

Bromides↗