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  • Inorganic Chemistry  (5)
  • phenolic compounds  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Beaver (Castor canadensis) responses to major phenolic and neutral compounds in castoreum (1994)
    Springer
    Journal of chemical ecology 20 (1994), S. 3063-3081 
    Details
    ISSN: 1573-1561
    Keywords: Castor canadensis ; beaver ; castoreum ; communication ; social odors ; phenolic compounds ; neutral compounds ; territorial behavior ; response measures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract North American beaver (Castor canadensis) mark their territories with castoreum, a chemically complex secretion from their castor sacs. The phenolic and neutral fractions of castoreum have been shown to elicit specific behavioral responses from beavers in a field setting. Our objective was to identify compounds/mixtures that evoked responses similar to those stimulated by castoreum. We assayed recently identified phenolic compounds, some phenolics that had been determined to be biologically active in previous studies, the neutral compound borneol, and combinations of phenolic compounds, neutral compounds, and the two combined. Biological activity was measured by the elicitation and extent of specific responses and their strength (duration, frequency, and proportion of beavers responding). Generally, single compounds stimulated fewer responses than mixtures. A 26-compound mixture of phenolic and neutral compounds elicited responses in a similar proportion of trials as castoreum. However, responses to castoreum were stronger than to any synthetic sample. Further investigation of different measures of response, namely, elicitation, completeness, and strength, are deemed necessary to fully decipher the design of social odors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02033711
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  • 2
    Electronic Resource
    Electronic Resource
    Bioactivity of beaver castoreum constituents using principal components analysis (1995)
    Springer
    Journal of chemical ecology 21 (1995), S. 941-957 
    Details
    ISSN: 1573-1561
    Keywords: Beaver ; Castor canadensis ; castoreum ; communication ; neutral compounds ; phenolic compounds ; principal components ; social odors ; territory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract North American beaver (Castor canadensis) were observed to sniff from the water and make land visits to some synthetic chemical components of castoreum placed on experimental scent mounds (ESM). In previous analysis, the elicitation (presence/absence), completeness, and/or strength (number, duration) of these key responses served as separate measures of biological activity. In this paper, we used principal components analysis (PCA) to combine linearly six related measures of observed response and one index of overnight visitation calculated over all trials. The first principal component accounted for a majority of the variation and allowed ranking of the samples based on their composite bioactivity. A second PCA, based only on response trials (excluding trials with no responses), showed that responses to the synthetic samples, once elicited, did not vary greatly in completeness or strength. None of the samples evoked responses as complete or strong as the castoreum control. Castoreum also elicited more multiple land visits (repeated visits to the ESM by the same individual or by more than one family member) than the synthetic samples, indicating that an understanding of the castoreum chemosignal requires consideration of responses by the family unit, and not just the land visit by the initial responder.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02033800
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  • 3
    Electronic Resource
    Electronic Resource
    Phenolic compounds from male castoreum of the North American beaver,Castor canadensis (1993)
    Springer
    Journal of chemical ecology 19 (1993), S. 1491-1500 
    Details
    ISSN: 1573-1561
    Keywords: Castor canadensis ; beaver castor sac ; phenolic compounds ; coinjection ; fractionation ; synthesis ; identification ; territory marking
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract North American beaver (Castor canadensis) mark their territories with castoreum, the contents of their castor sacs. In their territories, beaver respond with scent marking to experimental scent marks consisting of castoreum, or selected single components. In part, the unique odor of castoreum is due to large amounts of phenolic compounds. Purified phenolic components were analyzed by GC, GC-MS, and NMR; identifications were confirmed by comparing the spectra of synthetic phenols with those of the isolated phenols. Of the 15 phenols reported elsewhere, only five were confirmed in our analysis; the other 10 phenolic compounds are either absent or are not volatile enough to be detected by our methods. In addition, 10 phenolic compounds have been identified in this study that were not reported in the previous papers concerning the constitution of castoreum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00984892
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  • 4
    Electronic Resource
    Electronic Resource
    Übergangsmetallaktivierte organische Verbindungen, XXXVIII. Chemoselektive nucleophile Methylierungen durch In-Situ-Blockierung von Aldehydgruppen unter α1-Phosphonioalkoxid-BildungHerrn Professor Ulrich Schöllkopf zum 65. Geburtstag gewidmet. (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 459-464 
    Details
    ISSN: 0009-2940
    Keywords: Chemoselectivity ; Titanium complexes ; Niobium complexes ; Tantalum complexes ; Methylation of aldehydes and ketones ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Transition Metal-Activated Organic Compounds, XXXVIII[1].  -  Chemoselective Nucleophilic Methylation Reactions by In-Situ-Blocking of Aldehyde Groups by α1-Phosphonioalkoxide FormationHerrn Professor Ulrich Schöllkopf zum 65. Geburtstag gewidmet.For the selective methylation of a keto group in the presence of an aldehyde group the complex MeTiCl3·PPh3 and especially the reagent system [TiC]4·PPh3 + 0.5 Me2Zn] proved to be favourable. For instance, 6-oxoheptanal (8) was methylated by [TiCl4·PPh3 + 0.5 Me2Zn] at the keto group with 89% yield and 99:1 selectivity, whereas it was methylated by [TiCl4 + 0.5 Me2Zn] at the aldehyde group with 81% yield and 96:4 selectivity. A selective methylation of benzaldehyde in the presence of heptanal was achieved with MeNbCl4·PPh3 or [NbCl5·PPh3 + 0.75 Me2Zn] to give (1-chloroethyl)benzene (14; yield 92 or 53%; selectivity in each case 93:7) or with [TaCl5·PPh3 + 1.5 Me2Zn] to give mainly 1-phenylethanol (15) besides 16. A 96:4-selective benzylation (yield 74%) of a ketone in the presence of an aliphatic aldehyde was possible with [TiCl4·PPh3 + 1 PhCH2MgBr].  -  The high chemoselectivity is caused by irreversible blocking of aliphatic aldehyde groups by α1-phosphonioalkoxide formation[1], whilst the corresponding reaction of keto groups[1] and of benzaldehyde is reversible.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19931260225
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  • 5
    Electronic Resource
    Electronic Resource
    Übergangsmetallaktivierte organische Verbindungen, XXXVII. über eine neue Aldehyd-und Ketonreaktion: Synthese und spektroskopische Untersuchung von α1-Phosphonioalkoxy-übergangsmetallkomplexenHerrn Professor Ulrich Schöllkopf zum 65. Geburtstag gewidmet. (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 453-457 
    Details
    ISSN: 0009-2940
    Keywords: Aldehydes ; Ketones ; Titanium complexes ; Niobium complexes ; Tantalum complexes ; Phosphonium chlorides ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Transition Metal-Activated Organic Compounds, XXXVII[1].  -  A Novel Reaction of Aldehydes and Ketones: Synthesis and Spectroscopic Investigation of α1-Phosphonioalkoxy Transition Metal ComplexesHerrn Professor Ulrich Schöllkopf zum 65. Geburtstag gewidmet.By treatment of aldehydes and ketones with one mole equivalent of a Lewis acid (TiCl4, NbCl5, TaCl5) and one mole equivalent of PPh3, or in one case of Ph2PCH2CH2PPh2, the aldehyde derivates [R1CH(P+Ph2R2)-OMCln]Cl- (4-8; M=Ti, Nb, Ta; R2=Ph or CH2CH2PPh2) and the ketone derivatives [R1R2C(P+Ph3)-ONbCl4]Cl- (9-10) were prepared. Complexes 4-10 were isolated as air-and water-sensitive solids. According to the NMR spectra some of the obtained aldehyde derivatives 4-8 exist in solution as a mixture of isomers or oligomers, whereas the ketone derivatives 9 and 10 form in solution an equilibrium with the free ketone and the complex NbCl5 · PPh3. The chloride ion of 4-10 is perhaps coordinated to the metal.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19931260224
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  • 6
    Electronic Resource
    Electronic Resource
    Fully Chlorinated N-Silyl Amides of Titanium and Tungsten  -  Crystal Structure of Cl3SiNW(Cl3)N(SiCl3)2 (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 701-704 
    Details
    ISSN: 0009-2940
    Keywords: N-Silyl amides ; Precursor ; 14N-NMR ; Titanium ; Tungsten ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of hexachlorodisilazanyllithium (Cl3Si)2NLi (1), with TiCl4 leads selectively to the novel fully chlorinated amides (Cl3Si)2NTiCl3 (2) or [(Cl3Si)2N]2 TiCl2 (3), respectively, depending on the molar ratio of the starting materials. The analogous reaction of 1 with WCl6 yielded the amide imide Cl3SiN=W(Cl3)N(SiCl3)2 (5) by elimination of SiCl4. The relative amounts of the starting materials had no effect on the formation of 5. 14/15N- and 29Si-NMR data on the starting materials and products show significantly different effects, when compared with those of analogous N-trimethylsilyl derivatives, due to the lower energy of the electrons in the N—Si and N—M ß bonds. The crystal structure of 5 (triclinic, space group P1) was determined by X-ray structure analysis.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300605
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  • 7
    Electronic Resource
    Electronic Resource
    Reaction of Hexamethyldisilazane with Borane in Tetrahydrofuran (1996)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 622 (1996), S. 2048-2052 
    Details
    ISSN: 0044-2313
    Keywords: Borane ; diborane ; borazine ; NMR spectroscopy ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaktion von Hexamethyldisilazan mit Boran in TetrahydrofuranHexamethyldisilazan 1 reagiert mit Boran in Tetrahydrofuran (THF—BH3, 2) zunächst unter Bildung des Addukts (Me3Si)2NH—BH3 (3), das dann entweder in N,N-Bis(trimethylsilyl)-μ-aminodiboran(6) 5 oder in eine Mischung aus 5 und N-Trimethylsilyl-μ-aminodiboran(6) 6 übergeht, abhängig von den Reaktionsbedingungen. Die Verbindungen 5 und 6 lassen sich quantitativ in das N,N′,N″-Tris(trimethylsilyl)borazin 4 überführen. Dabei werden drei Zwischenstufen identifiziert, nämlich N,N-Bis(trimethylsilyl)aminoboran 7, N,N-Bis(trimethylsilyl)amino(N′-trimethylsilylamino)boran 8 und N-Trimethylsilylaminoboran-Trimer 9. Alle Produkte und Zwischenstufen wurden mittels Multikern-NMR-Spektroskopie charakterisiert, und Kopplungskonstanten 1J(29Si, 15N) in 5 und 6 wurden mit der Hahn-echo extended (HEED) INEPT Pulssequenz in den 29Si NMR Spektren bestimmt.
    Notes: Hexamethyldisilazane 1 reacts with borane in tetrahydrofuran (THF—BH3, 2) first by formation of an adduct (Me3Si)2NH—BH3 (3), and then either to the N,N-bis-(trimethylsilyl)-μ-aminodiborane 5 or to the mixture of 5 and N-trimethylsilyl-μ-aminodiborane(6) 6, depending on the reaction conditions. The compounds 5 and 6 can be quantitatively converted to the N,N′,N″-tris(trimethylsilyl)borazine 4. Three intermediates can be identified, namely N,N-bis(trimethylsilyl)borane 7, N,N-bis(trimethylsilyl)amino(N′-trimethylsilylamino)borane 8 and N-trimethylsilylaminoborane-trimer. All products and intermediates were characterized by multinuclear NMR spectroscopy, and coupling constant 1J(29Si, 15N) were measured from 29Si NMR spectra by using the Hahn-echo-extended (HEED) INEPT pulse sequence.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19966221208
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  • 8
    Electronic Resource
    Electronic Resource
    Über die Racemisierungs-Geschwindigkeit des d-Benzoins in alkalischen Lösungen (4. Mitteil. über Oxydations-Vorgänge) (1931)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 64 (1931), S. 1200-1204 
    Details
    ISSN: 0365-9631
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19310640542
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