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  • 1
    Electronic Resource
    Electronic Resource
    Ground state conformation of diphenylvinylphosphine sulfide and selenideDedicated to Professor Ernest L. Eliel on the occasion of his seventieth birthday. (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Heteroatom Chemistry 3 (1992), S. 37-40 
    Details
    ISSN: 1042-7163
    Keywords: Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Single-crystal X-ray diffraction experiments have been performed on diphenylvinylphosphine sulfide (1): C14H13PS, space group P21/c, a = 10.186(1) Ǎ, b = 11.918(1) Å, c = 11.426 Å, β = 112.22(2)°, V = 1284.1(2) Å3, Z = 4, and diphenylvinylphosphine selenide (2): C14H13PSe, space group Pbca, a = 9.141 (3) Å, b = 16.458 (1) Å, c = 17.451 (1) Å, V = 2625.4 (9) Å3, Z = 8. The structures were solved by direct methods and were refined by full matrix least-squares calculations to R = 0.046 and Rw = 0.058 using 2554 unique reflections with I 〉 3σ(I) in the case of 1, and to R = 0.052 and Rw = 0.065 using 1953 unique reflections with I 〉 3σ(I) in the case of 2. In close analogy to the previously studied vinyl phosphine oxides both 1 and 2 were found to exist in the s-cis conformation with the pertinent C=C—P=X dihedral angles equal to 12.5° and 2.9° for 1 and 2, respectively.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hc.520030108
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  • 2
    Electronic Resource
    Electronic Resource
    Crystal structure and stereochemistry of (PS*, 2S*, 3aS*)-hexahydro-2-(tert-butylvinylthiophosphinyl)-6,6- dimethylpyrrolo[1,2-b]isoxazole (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Heteroatom Chemistry 2 (1991), S. 661-664 
    Details
    ISSN: 1042-7163
    Keywords: Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The structure of the major product of the cycloaddition of 2,2-dimethyl-3,4-dihydro-2H-pyrrole N-oxide to tert-butyldivinylphosphine sulfide was analyzed by means of single-crystal X-ray diffraction technique. The analysis revealed two crystallographically independent molecules that differed in conformation of the fused five-membered heterocyclic rings. These rings were found to be two envelopes in one molecule and two half-chairs in the other. The studied compound was identified as an exo adduct of the expected erythro configuration and was found to favor a conformation in which the P=S and ring C-O bonds were anti and the C=C-P=S moiety was in the s-cis array. C14H26NOPS, space group P¯1, a = 10.6004(7) Å, b = 12.3225(6) Å, c = 13.4404(7) Å, α = 104.073(4)°, β = 92.758(4)°, γ = 95.968(5)°, V = 1688.802(4) Å3, Z = 4.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hc.520020609
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  • 3
    Electronic Resource
    Electronic Resource
    Enantiomerically Pure Dendrimers Based on atrans-3,4-Dihydroxypyrrolidine (1998)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1998 (1998), S. 2591-2597 
    Details
    ISSN: 1434-193X
    Keywords: Cascade molecules ; Dendrimers ; Chirality ; Amides ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of the first and second generation of enantiopure dendrimers based on a chiral trans-3,4-dihydroxypyrrolidine is reported. Benzenepolycarboxylic acids were used as central nucleus to afford linear and radial growth, and terephthalic acid was used as spacer between the pyrrolidine nuclei. The analysis of the chiroptical properties ([α]D, circular dichroism) of these new dendrimers suggests that those with radial growth present a self organisation of chiral units.
    Additional Material: 2 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    Complete Stereoselective Synthesis of Quasi-Enantiomeric Pseudo Imino-C-disaccharides: Parallel Kinetic Resolution of a Racemic cis-Dihydroxypyrroline N-Oxide by 1,2-Glycals (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 1319-1323 
    Details
    ISSN: 1434-193X
    Keywords: Parallel kinetic resolution ; Double asymmetric induction ; Chiral cyclic nitrones ; Cycloadditions ; Asymmetric synthesis ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: -Cycloadditions of hydroxylated enantiopure pyrroline N-oxides to 1,2-glycals display high double-asymmetric induction. The selectivity is controlled by the stereochemistry at C-3 of the glycal. A parallel kinetic resolution experiment with a racemic cis-dihydroxypyrroline N-oxide allowed the synthesis of two different pseudo imino-C-disaccharides precursors in a completely enantiopure form, totally avoiding the formation of minor cycloadducts.
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  • 5
    Electronic Resource
    Electronic Resource
    Formal Desymmetrization by a “Mitsunobu Trick” - Enantiomerically Pure cis-3,4-Dihydroxypyrroline N-Oxides for the Enantiodivergent Synthesis of Trihydroxyindolizidines (1998)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1998 (1998), S. 419-421 
    Details
    ISSN: 1434-193X
    Keywords: Mitsunobu reaction ; Desymmetrization ; Cyclic nitrones ; Polyhydroxyindolizidines ; Glycosidase inhibitors ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A protocol is presented for a completely enantioselective formal desymmetrization of Cs-symmetric diols by monoprotection of the corresponding enantiopure C2 diols, followed by an inversion of configuration by a Mitsunobu reaction (“Mitsunobu trick”). Its application to the unprecedented synthesis of enantiopure cis-3,4-dihydroxypyrroline N-oxides, employed in the enantiodivergent synthesis of two selectively protected 1,2,7-trihydroxyindolizidines, is also reported.
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  • 6
    Electronic Resource
    Electronic Resource
    Intramolecular Cycloaddition/Rearrangement of Alkylidenecyclopropane Nitrones from Palladium(0)-Catalyzed Alkylation of Amino Acid Derivatives (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 2725-2739 
    Details
    ISSN: 1434-193X
    Keywords: Alkylidenecyclopropanes ; Palladium ; Intramolecular 1,3-dipolar cycloaddition ; Thermal rearrangement ; Pyrrolo[3,4-b]pyridine ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several alkylidenecyclopropanes have been synthesized in high yields and optical purity by palladium(0)-catalyzed substitution of 1-tosyloxy-1-vinyl cyclopropane using N-tosylamino esters or glycolic ester as nucleophiles. The new alkylidenecyclopropanes were transformed to the corresponding nitrones without loss of optical purity, except in the case of the phenylglycine derivative. The alkylidenecyclopropane nitrones underwent smooth in situ intramolecular cycloaddition with a stereoselectivity that was moderate with most substituted substrates, but complete with phenylglycine and proline derivatives. The spirocyclopropane isoxazolidines were transformed by selective thermal rearrangements in octahydro-2H-pyrrolo[3,4-b]pyridin-7-ones and octahydrofuro[3,4-b]pyridin-7-one, uncommon ring systems resembling biologically active natural and nonnatural products. An example of the extension of the process to an alkylidenecyclopropane nitrile oxide is also reported.
    Additional Material: 2 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    Insulin-like growth factor-I stimulates in vitro migration of preosteoclasts across bone endothelial cells (1997)
    Springer
    Cell & tissue research 288 (1997), S. 101-110 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Insulin-like growth factor-1 (IGF-I) ; Bone endothelial cells ; Preosteoclasts ; Co-culture ; Cell migration ; Electron microscopy (transmission and scanning) ; Bovine ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Little is known about the factors and the mechanisms involved in preosteoclast emigration from the vasculature. In this study, an in vitro model of bone endothelial lining was mimicked by culturing bone endothelial (BBE) cells at confluence on a 3-μm pore polycarbonate membranes. Preosteoclastic (FLG 29.1) cells were then added on top of the BBE cell monolayer and 10 nM insulin-like growth factor-1 (IGF-I) was added below the supporting membrane. Scanning and transmission electron microscopy were used to evaluate the chemotactic responses of preosteoclastic FLG 29.1 cells towards the IGF-I generated gradient. IGF-I potently stimulated chemotaxis in the FLG 29.1 cells, as shown by the migration of the preosteoclastic cells across the underlying BBE and through the intercellular junctions between adjacent endothelial cells. Subsequently, FLG 29.1 cells penetrated the pores of the supporting membrane and reached the lower face of the membrane. Thus, IGF-I, which is abundantly present in the bone tissue microenvironment, may play a paracrine role in the recruitment of the circulating preosteoclasts from the vascular compartment into the bone tissue. This in vitro model, which mimicks the in vivo phenomenon of preosteoclast extravasation, should prove useful in elucidating the molecular mechanisms that underlie this process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050797
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  • 8
    Electronic Resource
    Electronic Resource
    Functional and structural interactions between osteoblastic and preosteoclastic cells in vitro (1995)
    Springer
    Cell & tissue research 281 (1995), S. 33-42 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Osteoblasts ; Preosteoclasts ; Cell differentiation ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Osteoblasts are involved in the bone resorption process by regulating osteoclast maturation and activity. In order to elucidate the mechanisms underlying osteoblast/preosteoclast cell interactions, we developed an in vitro model of co-cultured human clonal cell lines of osteoclast precursors (FLG 29.1) and osteoblastic cells (Saos-2), and evaluated the migratory, adhesive, cytochemical, morphological, and biochemical properties of the co-cultured cells. In Boyden chemotactic chambers, FLG 29.1 cells exhibited a marked migratory response toward the Saos-2 cells. Moreover, they preferentially adhered to the osteoblastic monolayer. Direct co-culture of the two cell types induced: (1) positive staining for tartrate-resistant acid phosphatase in FLG 29.1 cells; (2) a decrease of the alkaline phosphatase activity expressed by Saos-2 cells; (3) the appearance of typical ultrastructural features of mature osteoclasts in FLG 29.1 cells; (4) the release into the culture medium of granulocyte-macrophage colony stimulating factor. The addition of parathyroid hormone to the co-culture further potentiated the differentiation of the preosteoclasts, the cells tending to fuse into large multinucleated elements. These in vitro interactions between osteoblasts and osteoclast precursors offer a new model for studying the mechanisms that control osteoclastogenesis in bone tissue.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307956
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  • 9
    Electronic Resource
    Electronic Resource
    Multinuclear magnetic resonance study of organomercury fulminates. The structure of mercury fulminate in solution (1984)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 22 (1984), S. 372-375 
    Details
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1H, 13C, 14N and 199Hg NMR data were obtained for organomercury fulminates, RHgCNO (R — Me, Ph, CNO). The relatively slow relaxation processes effective for the quadrupolar nitrogen muclei of these compounds allow the detection of 199Hg—14N scalar coupling constants. This feature is ascribed to the presence of low electric field gradients around the 14N nucleus, owing to the presence of the mercury atom. In mercury fulminate, the 199Hg nucleus appears to be coupled with two equivalent 14N nuclei, thus indicating the existence of a covalent structure Hg(CNO)2 in solution.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1270220605
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  • 10
    Electronic Resource
    Electronic Resource
    Functional and structural interactions between osteoblastic and preosteoclastic cells in vitro (1995)
    Springer
    Cell & tissue research 281 (1995), S. 33-42 
    Details
    ISSN: 1432-0878
    Keywords: Osteoblasts ; Preosteoclasts ; Cell differentiation ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Osteoblasts are involved in the bone resorption process by regulating osteoclast maturation and activity. In order to elucidate the mechanisms underlying osteoblast/preosteoclast cell interactions, we developed an in vitro model of co-cultured human clonal cell lines of osteoclast precursors (FLG 29.1) and osteoblastic cells (Saos-2), and evaluated the migratory, adhesive, cytochemical, morphological, and biochemical properties of the co-cultured cells. In Boyden chemotactic chambers, FLG 29.1 cells exhibited a marked migratory response toward the Saos-2 cells. Moreover, they preferentially adhered to the osteoblastic monolayer. Direct co-culture of the two cell types induced: (1) positive staining for tartrate-resistant acid phosphatase in FLG 29.1 cells; (2) a decrease of the alkaline phosphatase activity expressed by Saos-2 cells; (3) the appearance of typical ultrastructural features of mature osteoclasts in FLG 29.1 cells; (4) the release into the culture medium of granulocyte-macrophage colony stimulating factor. The addition of parathyroid hormone to the co-culture further potentiated the differentiation of the preosteoclasts, the cells tending to fuse into large multinucleated elements. These in vitro interactions between osteoblasts and osteoclast precursors offer a new model for studying the mechanisms that control osteoclastogenesis in bone tissue.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307956
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