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  • 1
    Electronic Resource
    Electronic Resource
    Resolution and adrenergic activities of the optical isomers of 4-[1-(1-Naphthyl)ethyl]-1H-imidazole (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 432-438 
    Details
    ISSN: 0899-0042
    Keywords: α-adrenergic ; imidayole analogs ; metetomidine ; enantiomers ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Recently we synthesized a naphthalene analog of medetomidine, 4-[1-(1-naphthyl)ethyl]-1H-imidazole hydrochloride (1), and found it to be highly potent in adrenergic systems. The separation of optical isomers of this naphthalene analog was achieved by using the isomers of tartaric acid. The optical purities of the isomers were determined by HPLC using a chiral column. Using X-ray analysis the (+)-isomer was determined to have the S absolute configuration. It has been reported that the (+)-isomer of medetomidine (2) is the most potent enantiomer on α2-adrenergic receptors. There were both qualitative and quantitative differences in biological activities of the optical isomers of 1 in α1- and α2-adrenergic receptor systems of guinea pig ileum and human platelets. (+)-(S)-1, but not ( - )-(R)-1 was a selective agonist of α2-mediated responses in ileum whereas ( - )-(R)-1 was more potent than (+)-(S)-1 as an inhibitor of α2-mediated platelet aggregation. © 1992 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530040706
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  • 2
    Electronic Resource
    Electronic Resource
    Chiral assay methods for lifibrol and metabolites in plasma and the observation of unidirectional chiral inversion following administration of the enantiomers to dogs (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 6 (1994), S. 105-115 
    Details
    ISSN: 0899-0042
    Keywords: enantioselective ; chromatography ; validation ; column-switching ; robotic ; pharmacokinetic ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Lifibrol, a new drug for the treatment of hypercholesterolemia, contains a stereogenic center bearing a secondary alcohol group. A normal-phase achiral-chiral HPLC separation of the enantiomers of lifibrol and two of its metabolites was developed and validated for quantitation in dog plasma. A silica and a Chiralcel OD-H column were operated in series and all six enantiomeric components and internal standard were directly separated. An initial solid-phase extraction (phenyl) clean-up step and a column-switching step to eliminate late-eluting compounds were also utilized. The solid-phase extraction step was automated using a robotic system. Assay development, validation, and application of the method to a bioavailability study of the racemate and enantiomers of lifibrol in dogs are described. The lower limit of quantitation was 0.0125 μg/ml for each enantiomer of lifibrol using 200 μl of dog plasma with UV detection (255 nm). In dog plasma following oral or intravenous administration of the racemate, the (R)/(S) ratio of the enantiomers of lifibrol was greater than one and increased with time. Following administration of the individual enantiomers, chiral inversion of the (S)-enantiomer but not the (R)-enantiomer was observed. © 1994 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530060211
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  • 3
    Electronic Resource
    Electronic Resource
    Pharmacokinetics of ibutilide and its enantiomers in dogs (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 8 (1996), S. 18-23 
    Details
    ISSN: 0899-0042
    Keywords: racemate ; enantiomer ; bioavailability ; pharmacokinetic ; ibutilide ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ibutilide fumarate, a new drug for the treatment of cardiac arrhythmias, contains a stereogenic center bearing a secondary alcohol group. Several single dose and multiple dose studies of racemic ibutilide or its enantiomers were performed by the oral and intravenous routes in dogs. A chiral assay was used to examine racemization and the individual enantiomer pharmacokinetics. Following low oral or intravenous doses (approximately 0.3 mg/kg), the pharmacokinetics of the enantiomers were nearly identical, with no substantial chiral conversion. Both enantiomers exhibited high clearance rates, large volumes of distribution, and low oral bioavailability. As the dose increased, pharmacokinetic differences between the enantiomers were observed. The greatest differences (3-fold) were seen after oral administration at 4 mg/kg, indicating that first-pass metabolism of ibutilide was highly enantioselective at high doses. The clearances of the enantiomers differed by up to 34% at 5 mg/kg followed intravenous administration of the racemate. At high doses, other non-linear pharmacokinetic behavior was also apparent. The intravenous clearance of ibutilide declined from 5.3 L/h/kg at 0.3 mg/kg to 3.7 L/h/kg at a dose of 5 mg/kg. The absolute oral bioavailability of the racemate increased from 2% at 0.3 mg/kg to as much as 84% at 5 mg/kg. © 1996 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Structure-Activity Relationships of Oxygenated Morphinans. I. 4-Mono- and 3,4-dimethoxy-N-methylmorphinans and -N-methyl-morphinan-6-ones with unusually high antinociceptive potency. Preliminary communication (1981)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 64 (1981), S. 1298-1302 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The antinociceptive potency and receptor affinity of several optically active aromatic mono- and di-oxygenated N-methylmorphinans and N-methylmorphinan-6-ones, prepared from natural morphine, were determined. Thus, in order of antinociceptive potency, 4-methoxy-N-methylmorphinan-6-one ≈ 3,4-dimethoxy-N-methylmorphinan-6-one ≈ 3,4-dimethoxy-N-methylmorphinan 〉 4-methoxy-N-methylmorphinan ≈ 4-acetoxy-N-methylmorphinan-6-one 〉 4-acetoxy-N-methylmorphinan ≈ 4-hydroxy-N-methylmorphinan-6-one ≈ 4-hydroxy-N-methylmorphinan. The 4-hydroxy compounds were slightly less potent than morphine, and the 4-methoxy and 3,4-dimethoxy compounds were found to have three times the potency of morphine. 4-Methoxy-N-methylmorphinan-6-one showed an opiate receptor affinity one-third that of morphine; this is a remarkably high affinity for a non-phenolic compound.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19810640506
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  • 5
    Electronic Resource
    Electronic Resource
    Structure Determination of Brominated Morphinan-6-ones by 13C-NMR. Spectroscopy: A novel closure of the oxygen bridge using 4-acetoxymorphinan-6-onesDedicated to Professor George H. Büchi on the occasion of his 60th birthday (1981)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 64 (1981), S. 1672-1681 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bromination of (-)-4-hydroxy-N-methylmorphinan-6-one (3), prepared from natural morphine, with 1 mol of bromine in acetic acid, afforded the 1-bromo ketone 5. The structure of 5 was assigned by 13C-NMR.spectroscopy, and confirmed by X-ray diffraction analysis of its hydrobromide salt. It is suggested that monobromination of synthetic (±)-2,4-dihydroxy-N-formylmorphinan-6-one (7) takes in principle a similar course, although the 13C-NMR.spectrum of the primary reaction product 9 could not be measured because of insolubility in commonly used solvents. Monobromination of (-)-4-acetoxy-N-formylmorphinan-6-one (12) of the natural series, and of (±)-2,4-diacetoxy-N-formylmorphinan-6-one (8) of the synthetic series, followed by treatment of the monobrominated ketones with potassium carbonate in methanol resulted in closure of the O-bridge, and afforded after acid hydrolysis, the corresponding 4,5-epoxy-morphinan-6-ones (-)-16 and (±)-17 respectively. This variation of the ring closure reaction represents a novel and convenient method to convert 4-hydroxymorphinan-6-ones into their corresponding 4,5-epoxymorphinan-6-ones, without involving aromatic bromination and with only 1 mol of bromine.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19810640545
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  • 6
    Electronic Resource
    Electronic Resource
    Total Synthesis of (±)-3-Deoxy-7,8-dihydromorphine, (±)-4-Methoxy-N-methylmorphinan-6-one and 2,4-Dioxygenated (±)-CongenersThe morphinanones reported in this paper are racemic entities. Only (±)-2 and (±)-3 obtained by total synthesis shall be recorded with prifix, in order to differentiate them from their (±)-enantiomers 2 and 3 prepared from natural morphine(1) (1982)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 65 (1982), S. 1576-1589 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A total synthesis of racemic 3-deoxy-7,8-dihydromorphine ((±)-2) and 4-me-thoxy-ALmethylmorphinan-6-one ((±)-3) is described. The key intermediate was 2,4-dihydroxy-N-formylmorphinan-6-one (11), obtained from 3,5-dibenzyloxy-phenylacetic acid (4) in 41.8% overall yield. Bromination of 11, and treatment with aqueous NaOH-solution afforded, after N-deblocking and reductive N-methylation with concomitant removal of the aromatic bounded Br-atom, the morphinanone 14. Elimination of the HO-C(2) group in 14 was accomplished by hydrogenolysis of its N-phenyltetrazolyl ether 15, to give 3-deoxy-6,0-didehydro-7,8-dihydromorphine (16). Reduction of 16 with L-Selectride at low temperature provided (±)-2 in high yield. The ether 15 directly afforded, under more vigorous reduction conditions, 4-hydroxy-N-methylmorphinan-6-one (17). and after O-methylation of 17, the methyl ether (±)-3 was obtained. A (1:l)-mixture of 4-hydroxy-2-methoxy-N-methylmor-phinan-6-one (28) and its 2-hydroxy-4-methoxy isomer 30 svere obtained by Grewe-cyclization of a mono-methoxylated aromatic precursor similar to that which afforded 11. The 2,4-dioxygenated N-methylmorphinan-6-ones 29, 31 and 38 were also prepared and characterized.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19820650531
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  • 7
    Electronic Resource
    Electronic Resource
    Total Synthesis of (±)-3-Deoxy-7,8-dihydromorphine. Preliminary Communication (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2042-2045 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: (±)-3-Desoxy-7, 8-dihydromorphin ((±)-1) wurde aus 3,5-Dihydroxyphenylessigsäure und 3-Methoxyphenäthylamin über elf isolierte Zwischenstufen totalsynthetisiert. Als Schlüsselverbindung diente dabei (±)-N-Formyl-2, 4-dihydroxymorphinan-6-on (3). Das daraus über mehrere Zwischenstufen erhaltene (±)-3-Desoxy-6, O-didehydro-7, 8-dihydromorphin ( = N-Methyl-4, 5a-epoxymorphinan-6-on, 12), ergab bei der Reduktion mit Lithiumselectrid stereospezifisch das gewünschte (±)-1, während bei der katalytischen Reduktion und unter energischeren Bedingungen (±)-4-Hydroxy-N-methylmorphinan-6-on ((±)-2) anfiel. Damit ist die Totalsynthese von 2 realisiert worden.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19800630731
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