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  • Inorganic Chemistry  (7)
  • Life and Medical Sciences  (3)
  • 1995-1999  (10)
  • 1
    ISSN: 0009-2940
    Keywords: Reductive silylation ; Aminochlorophosphanes ; Silylphosphanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of alkyl(diorganylamino)chlorophosphanes R(R2′N)PCl 1 (1a: R = tBu, R′ = Et, 1b: R = iPr, R′ = iPr; 1c: R = iPr, R′ = Ph) with hexachlorodisilane, afforded alkyl(diorganylamino)trichlorosilylphosphanes R(R2′N)PSiCl3 2 (2a: R = tBu, R′ = Et; 2b: R = iPr, R′ = iPr; 2c: R = iPr, R′ = Ph) and silicon tetrachloride. An intermediate formed in the reaction of 1b with hexachlorodisilane, the adduct iPr(iPr2N)(Cl)P-Si(Cl)3-SiCl3 (3b = 1b · Si2Cl6), was detected by 31P- and 29Si-NMR spectra that indicate pentacoordinated silicon bound to tetracoordinated phosphorus and tetracoordinated silicon. Trichlorosilylphosphanes 2 are also available from 1 under very mild conditions by reductive trichlorosilylation with trichlorosilane in the presence of triethylamine. Compounds 2 were identified analytically, by mass spectroscopy, multinuclear NMR, and an X-ray structure determination of 2c.
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  • 2
    ISSN: 0009-2940
    Keywords: Trichlorosilylation ; Dichlorophosphanes ; Silylphosphanes ; Amino(silyl)phosphanes ; Silicon /Reductions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactions of hexachlorodisilane and of trichlorosilane/triethylamine with alkyl-and dialkylaminodichlorophosphanes RPCl2 1a-i [R = iPr: a; (Me3Si)2CH: b; R=1-adamantly: c: R=tBu: d; R=Et2N: e; R=iPr2M: f] furnish bis(trichlorosilyl)-phosphanes RP(SiCl3)2 3a-f. However, when less bulky substituents are attached to the phosphorus atom, so that there is little steric crowding, the double reductive silylations leading from 1 to 3 are accompanied by side reactions and decomposition of 3. Therefore, only 3b, 3c, 3d, and 3f wre isolated in a pure state. These compounds are more readily prepared by the; trichlorosilane/triethylamine method. 1H-, 31P- and 29Si-Nmr spectra confirm their constitution. The structure of solid 3f, the first aminobis(trichlorosilyl)phosphane, was determined by X-ray crystallography. 3f contains a phosphorus atom in a pyramidal environment surrounded by two silicon atoms and a planar nitrogen atom of the diisopropylamino group.
    Additional Material: 2 Ill.
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  • 3
    ISSN: 0009-2940
    Keywords: Dichlorogermylene ; Trichlorogermylphosphanes ; Insertion ; Silver bromide complex ; Carbene homologues ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chlorophosphanes RR'PCl (1a: R,R' = 1b: R = tBu, R' = iPr, 1c: R = iPr, R' = Et2N, 1d: R = Et2N react with the dichlorogermylene dioxane complex 2 furnishing trichlorogermylphosphanes RR'PGeCl3 4a-d. In the cases of 1c/4c and 1d/4d the insertion reaction remain incomplete; similarly, 4a always contains, shortly after isolation in pure state, small amounts of 1a that can be detected by NMR. A provided by the reaction of trichlorosilylphosphane tBu(Et2N)PSiCl3 (5d) with GeCl4. The alkyl(dialkylamino) trichlorogermylphosphane 4d exists only in an equilibrium with chlorophosphane 1d, which coordinates GeCl2 leading to the dichlorogermylene complex 3d. A 1:1 mixture of 4a with 1a is formed by the novel cleavage (“chlorogermylation”) of the P-P bond of tetraisopropyldiphosphane with germanium tetrachloride. Di-tert-butyl(trichlorogermyl)phosphane 4e (R, R' = tBu) reacts with silver bromide providing a crystalline silver complex 7. A structure determination by X-ray diffraction reveals that 7 is [Ag4Br4(tBu2PCl)2(tBu2PGeCl3)2]. 2C7H8. Two of the Ag atoms of the cubane-like (AgBr)4 core of 7 are coordinated by chlorophosphane 1e, the other two by trichlorogermylphosphane 4e.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1765-1770 
    ISSN: 0009-2940
    Keywords: Phosphinic acid ; Phosphaindole bromination and chlorination ; Layer structure ; Hydrogen bonds ; Bromine-bromine interaction ; Phosphorus heterocycles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The bromination of 1-ethoxy-1-oxophosphindolin-3-one (1) with two equivalents oi bromine occurs with elimination of hydrogen bromide and ethyl bromide, providing 2,2-di- bromo-1-hydroxy-1-oxophosphindolin-3-one (4) in high yield. In the presence of triethylamine this process leads to 2,2-dibromo-1-ethoxy-1-Oxophosphindolin-3-one (3) instead. Triethylamine deprotonates 4, providing the solid triethylammonium salt 5. Silylation of 4 with chlorotrimethylsilane leads to the trimethylsilyl ester 6. Monobromination in a two-phase reaction allows the isolation of a mixture of isomers of 2-bromo-1-ethoxy-1-oxophosphindolin-3-one (2a, b). Chlorination with chlorine furnishes 2,2-dichloro-1-ethoxy-1-oxo-phosphindolin-3-one (7). The new compounds 2-7 were characterized analytically and spectroscopically (EI-MS, 1H, 13C and 31P NMR). The crystal structure of acid 4 was determined by X-ray diffraction. Solid 4 consists of aryl stacks connected by chains of P—OH…O==P hydrogen bonds and secondary Br…Br contacts.
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  • 5
    ISSN: 0009-2940
    Keywords: Alkyldichlorophosphanes ; Insertions ; Carbene homologues ; Germanium ; Phosphonium germanate(II) ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reactions of alkyldichlorophosphanes 1 (RPCl2; R = tert-butyl: 1a, R = isopropyl; 1b, R = 1-adamantyl: 1c) with the germanium dichloride dioxane complex were followed by 31P NMR. Depending on the organic substituents and the reaction conditions, mixtures of trichlorogermylphosphanes RP(GeCl3)2 4a-c, RPHGeCl3 5a-c, diphosphanes R(H)PP(H)GeCl3 6a-c, R(Cl)PP(H)GeCl3 7a, b cyclophosphanes, and Ge-P heterocycles such as triphosphadigermolanes (RP)3(GeCl2)2 8a, b and tetraphosphagermolane (RP)4)GeCl2 10b are formed. As a further unexpected byproduct of the reaction of 1a with GeCl2-dioxane, a small amount of tri-tert-butyl(trichlorogermyl)cyclotetraphosphane 9a was isolated. From the reaction of 1c with two equivalents of GeCl2-dioxane, separation from byproducts 5c and 6c by crystallisation furnished colourless crystals of 4c (R = 1-adamantyl) as the first pure organylbis(trichlorogermyl)phosphane. Surprisingly, the reaction of isoprophylphosphane with germanium tetrachloride, intended to prepare 5a, led to crystalline isopropylphosphonium trichlorogermanate(II) 11. The structures of molecular 4c and 9a and ionic 11 were determined by X-ray crystallography.
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 275-277 
    ISSN: 0009-2940
    Keywords: Titanium complexes ; Amido-cyclopentadienyl ligand ; Tridentate ligand ; Lewis acidity ; Chelate effect ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two new titanium complexes of the general type Ti(η5:η1-C5H4SiMe2NCH2CH2X)Cl2 (X = NMe2 OMe), containing a tridentate ligand, were prepared by reaction of Ti(η5-C5H4Si—Me2Cl)Cl3 with the lithium amide Li(NHCH2CH2X) (X = NMe2, OMe). The 1H—NMR chemical shifts for the protons of the ethylene link were found to vary considerably as a function of the temperature, indicating the presence of an equilibrium between the tri- and bidentate bonding mode of the ligand. A single-crystal X-ray structural analysis of Ti(η5:η1—C5H4SiMe2NCH2CH2OMe)Cl2 revealed that the methoxy function is not intramolecularly coordinated in the solid state.
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  • 7
    ISSN: 0009-2940
    Keywords: Hexafluoroacetone ; Phosphorus, pentacoordinated ; Diphosphane diselenide ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reduction of the isoprene - PCl3 adduct 1 with magnesium powder, or with Si2Cl6, furnished P-chloro-3-methyl-phosphol-2-ene, 2, in satisfactory yield. Further reduction of 2 with Si2Cl6 gave the new trichlorosilyl-3-methylphosphol-2-ene, 3. The reaction of 2 with magnesium powder, with 3, or with 1/2 equivalent of Si2Cl6 provided the new γ3P-γP-diphosphane 1,1′-bi(3-methylphosphol-2-ene) 4. Reduction of 4 with Si2Cl6 led to 3. Oxidation of 4 with selenium gave the 1,2-diphosphane diselenide, 5. The oxidation of 4 with hexafluoroacetone led to a mixture of products, from which a novel tricyclic phosphorane 6 was separated. the structure of 196 was determined by X-ray diffraction; the coordination geometry at phosphorus in distorted trigonal bipyramidal, with a very long equatorial P - C(CF3)2 bond of 193.2(2) pm.
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  • 8
    ISSN: 0730-2312
    Keywords: mechanical strain ; interleukin (IL)-α and β gene expression ; proliferation ; protein synthesis ; morphology ; keratinocyte biology ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Recent studies in our laboratory have demonstrated that mechanical strain alters many facets of keratinocyte biology including proliferation, protein synthesis, and morphology. IL-1 is known to play an important role in the autocrine regulation of these basic cellular properties under basal and stimulated conditions. However, it is not known whether IL-1 plays a role in strain-induced alteration of keratinocyte biology. Thus, the objective of this study was to test the hypothesis that cyclic strain stimulates IL-1 expression and that strain-induced changes in keratinocyte function is regulated by IL-1. To test this hypothesis, we examined the effect of cyclic strain (10% average deformation) on keratinocyte IL-1 gene expression and the effect of neutralizing antibodies of IL-1α and IL-1β on strain-induced changes in keratinocyte proliferation, morphology, and orientation. Northern blot analyses demonstrated that steady state levels of IL-1α and β mRNA were elevated by 4 h, peaked at 12 h of cyclic strain (IL-1α, 304 ± 14.2%; IL-1β, 212 ± 5.6% increase vs. static controls) and decreased gradually by 24 h. IL-1 antibodies (IL-1α, 0.01 μg/ml; IL-1β, 0.01 μg/ml) significantly blocked strain-induced keratinocyte proliferation as well as the basal rate of proliferation. In contrast, IL-1 antibodies (IL-1α, 0.01 μg/ml; IL-1β, 0.1 μg/ml) had no effect on strain-induced morphological changes such as elongation and alignment. We conclude that mechanical strain induces IL-1 mRNA expression in keratinocytes. The role of IL-1 in mediating strain-induced changes in keratinocyte biology remains to be determined but appears to be independent of morphological changes. J. Cell. Biochem. 69:95-103, 1998. © 1998 Wiley-Liss, Inc.
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  • 9
    Electronic Resource
    Electronic Resource
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 71 (1998), S. 491-501 
    ISSN: 0730-2312
    Keywords: diabetic microangiopathy ; endothelium ; HMEC-1 ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Diabetic microangiopathy has been implicated as a fundamental feature of the pathological complications of diabetes including retinopathy, neuropathy, and diabetic foot ulceration. However, previous studies devoted to examining the deleterious effects of elevated glucose on the endothelium have been performed largely in primary cultured cells of macrovessel origin. Difficulty in the harvesting and maintenance of microvascular endothelial cells in culture have hindered the study of this relevant population. Therefore, the objective of this study was to characterize the effect of elevated glucose on the proliferation and involved signaling pathways of an immortalized human dermal microvascular endothelial cell line (HMEC-1) that possess similar characteristics to their in vivo counterparts. Human dermal microvascular endothelial cells (HMEC-1) were grown in the presence of normal (5 mM) or high D-glucose (20 mM) for 14 days. The proliferative response of HMEC-1 was compared under these conditions as well as the cAMP and PKC pathways by in vitro assays. Elevated glucose significantly inhibited (P 〈 0.05) HMEC-1 proliferation after 7, 10, and 14 days. This effect was not mimicked by 20 mM mannitol. The antiproliferative effect was more pronounced with longer exposure (1-14 days) to elevated glucose and was irreversible 4 days after a 10-day exposure. The antiproliferative effect was partially reversed in the presence of a PKA inhibitor, Rp-cAMP (10-50 μM), and/or a PKC inhibitor, Calphostin C (10 nM). HMEC-1 exposed to elevated glucose (20 mM) for 14 days caused an increase in cyclic AMP accumulation, PKA, and PKC activity but was not associated with the activation of downstream events such as CRE and AP-1 binding activity. These data support the hypothesis that HMEC-1 is a suitable model to study the deleterious effects of elevated glucose on microvascular endothelial cells. Continued studies with HMEC-1 may prove advantageous in delineation of the molecular pathophysiology associated with diabetic microangiopathy. J. Cell. Biochem. 71:491-501, 1998. © 1998 Wiley-Liss, Inc.
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Biologie in unserer Zeit 27 (1997), S. X 
    ISSN: 0045-205X
    Keywords: Life and Medical Sciences
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
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