Biphenyl sulfonic acid ligands for catalytic C-N cross coupling of aryl halides with anilines and secondary amines

The use of two biphenyl sulfonic acid ligands for the catalytic C-N cross coupling of aryl halides with anilines, 3-aminopyridine, and secondary amines is reported. Our results represent a significant improvement compared to state of the art methods especially with regards to the removal of palladium.     

Synthesis of one dimensional tin selenides in supercritical amines

Three new crystalline tin selenide salts have been prepared from the reactions of [PPh₄]₂[Sn(Se₄₃] in supercritical solvents. The starting material pyrolyzes in supercritical acetonitrile to form [PPh₄]₄[Sn₆Se₂₁] (I), and it also reacts with SnSe in supercritical ammonia leading to a mixture of [PPh₄]₄[Sn₃Se₁₁]₂ (II). and [PPh₄]₂[Sn(Se₄)(Se₆)₂] (III). All three compounds have been characterized by single crystal X-ray diffraction. Crystallographic data: for I, C₉₆H₉₀P₄Se₂₁Sn₆, space group triclinic, P-1, A = 18.763(3), B = 24.600(4), C = 13.137(1) Å, = 102.63(1), β = 93.66(1), γ = 108.72(1)°, V = 5544(1) ų, Z = 2, R = 0.0350, R_W = 0.0317: for II, C₉₆H₈₀P₄Se₂₂Sn₆, space group monoclinic P2₁/c, A = 31.500(4), B = 16.572(3), C = 22.352(3) Å, β = 103.53(1)°, V = 11344(3) ų, Z = 4, R = 0.0771, R_W = 0.0664: for III, C₄₈H₄₀P₂Se₁₆Sn, space group monoclinic, C2/c, A = 25.381(2), B = 13.934(4), C = 19.465(3) Å, β = 121.587(8)°, V = 5867(2) ų, Z = 4, R = 0.0807, R_W = 0.0650. One of the compounds, [PPh₄]₂[Sn(Se₄(Se₆₂], is a molecular cluster while the other two complexes [PPh₄]₄[Sn₃Se₁₁]₂ and [PPh₄]₄[Sn₆Se₂₁], are one dimensional tin selenide chains. The structures of the two chains are related and consits of tetrahedral and distorted trigonal bipyramidal tin(IV) centers bridged by Se²⁻, Se₂²⁻ and Se₃²⁻ chains.     

In vivo genotoxicity of heterocyclic amines detected by a modified alkaline single cell gel electrophoresis assay in a multiple organ study in the mouse

We used a modification of the alkaline single cell gel electrophoresis (SCG) (Comet) assay to test the in vivo genotoxicity of 6 heterocyclic amines, Trp-P-1 (25 mg/kg), Trp-P-2 (13 mg/kg), IQ (13 mg/kg), MeIQ (13 mg/kg), MeIQx (13 mg/kg) and PhIP (40 mg/kg), in mouse liver, lung, kidney, brain, spleen, bone marrow and stomach mucosa. Mice were sacrificed 1, 3, and 24 h after intraperitoneal injection. Trp-P-2, IQ, MeIQ, and MeIQx yielded statistically significant DNA damage in the stomach, liver, kidney, lung and brain; Trp-P-1 in the stomach, liver and lung; and PhIP in the liver, kidney and brain. None of the heterocyclic amines induced DNA damage in the spleen and bone marrow. Our results suggest that the alkaline SCG assay applied to multiple organs is a good way to detect organ-specific genotoxicity of heterocyclic amines in mammals.     

Determination of serotonin, catecholamines and their metabolites by direct injection of supernatants from chicken brain tissue homogenate using liquid chromatography with electrochemical detection

An isocratic liquid chromatographic method with electrochemical detection for the determination of

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-3,4-dihydroxyphenylalanine, dopamine, norepinephrine, epinephrine, serotonin, and their major metabolites, 3,4-dihydroxyphenylacetic acid, 4-hydroxy-3-methoxyphenylacetic acid and 5-hydroxyindole-3-acetic acid in chicken brain tissue is described. Chickens were killed at different ages, the brains were quickly frozen and 300-μm cryostat sections were made. From these sections, two to six tissue micropunches (1 mm in diameter) were punched out from 20 different areas of the hypothalamus and homogenated in 100 μl 0.1 M perchloric acid which included 0.01% cysteine as antioxidant. Fifty-μl supernatants were injected directly onto the LC system, separated on a 3-μm Phase II ODS column (100×3.2 mm I.D.) and detected by an electrochemical detector at a potential of +0.75 V. Standard curves, recoveries, analytical precision and detection limits were investigated for each monoamine neurotransmitter and its metabolites. The method was applied to study the influence of food restriction on the concentration of monoamine neurotransmitters in different brain areas, known to be involved in feeding and reproductive behaviour of female broiler chickens. Over 1000 micropunched tissue samples from ad libitum fed and food-restricted female broiler chickens were analyzed. Our results provide a possible role for catecholamines and indolamines in the altered feeding and reproductive behaviour of the broiler chicken.     

Synthesis and biological activities of peptidomimetic analogues of compound A71623, a potent and selective CCK-A receptor agonist

Summary The involvement of cholecystokinin receptors in the phenomenon of satiety has been the impetus for significant research efforts, leading to the design and synthesis of CCK-A selective agonists for the possible treatment of obesity. The Abbott laboratories have described a novel series of pseudotetrapeptides represented by compound A71623, a highly potent and selective peripheral receptor agonist, but possessing very poor bioavailability. Starting from the structural requirements of this series of compounds, a peptidomimetic study was investigated, especially focusing on the N-terminal part of A71623. Using standard coupling methods, introduction of unnatural aromatic amino acids bearing a 2-carboxyethyl side chain on their α-amino group, along with backbone length modulation, afforded selective analogues, presenting a highly modified peptidic backbone. From our two lead compounds, further optimization is under development, tending towards nonpeptidic structures.     

Biogene Amine im Gehirn vom Frosch (Rana esculenta)

Zusammenfassung Mit Hilfe der Methode zur fluoreszenzmikroskopischen Lokalisation von Catechol- und Tryptaminen wurde die Verteilung dieser Stoffe im ZNS von Rana esculenta untersucht. Catecholamin- und serotoninhaltige Neurone liegen im Nucleus reticularis mesencephali. Außerdem finden sich catecholaminhaltige Nervenzellen im Organon vasculosum hypothalami und in der Area praeoptica. Diese aminproduzierenden Zellen entsenden Zellfortsätze durch die Ependymschicht in den Ventrikel. Über diese Ausläufer erfolgt möglicherweise eine Sekretion biogener Amine in den Liquor cerebrospinalis. Catecholamin- und serotoninhaltige Axone erreichen voneinander verschiedene Kerngebiete und Areale. Neben dem periventrikulären Zellager im Tuber cinereum und in der Area praeoptica werden vor allem der ventrolaterale Teil des lateralen Septumkerns, Striatum ventrale und Epistriatum von Endstrecken catecholaminhaltiger Axone durchdrungen. Serotoninhaltige Varicositäten finden sich dagegen vor allem in Kerngebieten, die in sensorische Bahnen eingeschaltet sind (Nucleus isthmi, corpus geniculatum laterale, Area praetectalis, Tectum opticum, Thalamus dorsalis, Neostriatum). Weitere Ausbreitungsgebiete 5-Hydroxytryptamin-haltiger Fasern sind die Habenula und der Nucleus interpeduncularis, Kerngebiete, über die Erregungen aus dem limbischen System auf vegetative Zentren der Medulla oblongata geleitet werden.

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Biogenic amines in the brain of the frog (Rana esculenta)

Summary The distribution of biogenic amines in the central nervous system of Rana esculenta was investigated by means of the fluorescence-microscopical detection of catecholand tryptamines. The nucleus reticularis mesencephali was found to contain numerous neurones rich in catechol- and tryptamines. Apart from this nucleus nerve cells in the organon vasculosum hypothalami and in the area praeoptica were found to contain catecholamines. The clublike processes of these neurones penetrate the ependymal layer and extend into the ventricle. These structures are presumably responsible for a secretion of biogenic amines into the cerebrospinal fluid. Catecholamine- and serotonin-containing axons terminate on different nuclei and areas. Besides the periventricular cellular layer of the tuber cinereum and the area praeoptica, the pars ventrolateralis of the nucleus septalis lateralis, striatum ventrale and epistriatum are pervaded by terminals of catecholamine-containing neurons. Serotonincontaining varicosities are mainly to be found in nuclei, which are intercalated in sensory pathways (nucleus isthmi, corpus geniculatum laterale, area praetectalis, tectum opticum, thalamus dorsalis, neostriatum). Further areas of distribution of 5-hydroxytryptamine-fibers are the habenula and the nucleus interpeduncularis, nuclei which coordinate impulses from the limbic system projecting them on visceral centers of the medulla oblongata.

Mit dankenswerter Unterstützung durch die Deutsche Forschungsgemeinschaft.     

Analysis of Biogenic Amines in Bovine Retina by Gas Chromatography-Negative Ion Chemical Ionisation Mass Spectrometry

Biogenic amines in bovine retina have been identified and quantified by an extraction-derivatisation procedure involving their reaction with 3,5-di(trifluoromethyl)benzoyl chloride (DTFMBCl) in the aqueous phase followed by extraction into an organic solvent, hydrolysis of phenolic esters, and conversion of free hydroxyl groups to trimethylsilyl ethers. Subsequent analysis of these DTFMB-trimethylsilyl derivatives by gas chromatography-negative ion chemical ionisation mass spectrometry revealed that the molecular ion carried most (greater than 60%) of the ion current, which made the method highly specific and gave a potential limit of detection below the picogram level. This method establishes unequivocally that the principal amines in bovine retina are p-tyramine, dopamine, and 5-hydroxytryptamine.     

Methanogenesis in the hypersaline Solar Lake (Sinai)

Abstract Enrichment studies on microbial mat sediments (potential stromatolites) from the hypersaline Solar Lake (Sinai) indicated high numbers of methanogenic bacteria (up to 10⁵ ml⁻¹ sediment) in spite of the high sulfate reduction rate, sulfate concentration and salinity. Among H₂/CO₂, acetate and monomethylamine, the methylated amine was the preferred substrate. The predominant species enriched was a Methanosarcina sp. The findings indicate that methanogenic bacteria play an important role in hypersaline sulfate-enriched anoxic sediments and stromatolithic microbial mats.     

Effects of biogenic amines on fat cells of Glossina morsitans in vitro

Lipid synthesis from leucine by fat cells of Glossina morsitans in vitro was inhibited by dopamine, adrenaline, noradrenaline and octopamine. Noradrenaline and octopamine were most active with maximal response occurring at 10^?4 and 10^?5 M respectively. The release of free fatty acids and the synthesis of proline from alanine by fat cells were stimulated by octopamine but not by the other amines. Maximal release of material from fat cells occurred at an octopamine concentration of 10^?2 M but at higher concentrations the response was diminished.The inhibition of lipid synthesis by octopamine was blocked by the α-adrenergic antagonist phentolamine but not by the β-adrenergic antagonist propranolol. Neither receptor-blocking-agent affected the action of corpora cardiaca extracts upon fat cells indicating that separate receptors are present for amines and the peptide hormones.     

Exposure to static electric fields leads to changes in biogenic amine levels in the brains of Drosophila

Natural and anthropogenic static electric fields are commonly found in the environment and can have both beneficial and harmful effects on many animals. Here, we asked how the fruitfly responds to these fields and what the consequences of exposure are on the levels of biogenic amines in the brain. When given a choice in a Y-tube bioassay Drosophila avoided electric fields, and the greater the field strength the more likely Drosophila were to avoid it. By comparing wild-type flies, flies with wings surgically removed and vestigial winged flies we found that the presence of intact wings was necessary to produce avoidance behaviour. We also show that Coulomb forces produced by electric fields physically lift excised wings, with the smaller wings of males being raised by lower field strengths than larger female wings. An analysis of neurochemical changes in the brains showed that a suite of changes in biogenic amine levels occurs following chronic exposure. Taken together we conclude that physical movements of the wings are used by Drosophila in generating avoidance behaviour and are accompanied by changes in the levels of amines in the brain, which in turn impact on behaviour.