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  • 1985-1989  (2)
  • 1960-1964  (2)
  • 1830-1839
  • 1820-1829
  • 1988  (2)
  • 1964  (2)
  • Hydrolysis
  • 1
    Electronic Resource
    Electronic Resource
    Evaluation of mono- and dibenzoyl esters of dopamine as potential pro-drugs for dopamine in the central nervous system (1988)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 338 (1988), S. 497-503 
    Details
    ISSN: 1432-1912
    Keywords: Pro-drug ; Monobenzoyldopamine ; Dibenzoyldopamine ; Lipophilicity ; Hydrolysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In this study, two ester pro-drugs of dopamine (DA) were synthesized and evaluated. These derivatives were the monobenzoyl (MBDA) and dibenzoyl (DBDA) esters of DA. MBDA was 300-fold and DBDA was 20,000-fold more lipophilic than DA itself. The half-lives of hydrolysis for MBDA and DBDA at physiologic pH and temperature were 15 and 420 min respectively. These compounds were radiolabelled and their uptake into brain measured. 14C-DBDA penetrated the brain rapidly; 0.28% of the dose injected was taken up per gram of brain tissue at 5 min. However DBDA did not produce measurable increases in DA levels in the brain. 14C-MBDA was found not to penetrate the brain. However, when MBDA was administered intracerebroventricularly (i.c.v.) to rats, it caused DOPAC levels to increase significantly both in the striatum and in the rest of the brain. The increase in the amount of DOPAC measured in the striatum was 3 to 10-fold greater than that seen in the rest of the brain. In rats that were pretreated with the MAO inhibitor, pargyline, MBDA given i.c.v. caused increases in DA levels in both the striatum and in the rest of the brain. The increased DA levels in striatum were considerably greater than those seen in the rest of the brain. From these results, it is inferred that MBDA is being hydrolyzed in vivo in the brain to form DA which is then taken up into dopaminergic neurons. Given this, it seems likely that an ester pro-drug of DA can be obtained that will have sufficient lipophilicity to penetrate the brain as well as a rate of hydrolysis that will produce increases in DA in the brain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00179320
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Synthese von 1,1′-Biphenyl-3-carbonsäure-und 3,5-dicarbonsäurederivaten unter Verwendung von Ethoxymethylenmalononitril (1988)
    Springer
    Monatshefte für Chemie 119 (1988), S. 91-96 
    Details
    ISSN: 1434-4475
    Keywords: 1,1′-Biphenyl-3-carboxylate ; Hydrolysis ; Sandmeyer-reaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Reaction of ethoxymethylenemalononitrile with ethyl 4-phenylacetoacetate leads to ethyl 1,1′-biphenyl-6-amino-5-cyano-2-hydroxy-3-carboxylate (3). Acid or basic hydrolysis of the ester and cyano group of3 affords the new derivatives4,5 and6.7 a, b are obtained bySandmeyer-reaction of3. Basic hydrolysis of7 a gives the 3,5-dicarboxylic acid derivative8.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00810090
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    The Reaction of Oxides with Water at High Pressures and TemperaturesDedicated to Prof. Dr. H. Brockmann on the occasion of his 60th birthday (1964)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 3 (1964), S. 47-54 
    Details
    ISSN: 0570-0833
    Keywords: Oxides ; Water ; High-pressure chemistry ; Hydrolysis ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reactions of the oxides SiO2, MoO3, and WO3 with steam at temperatures between 400 and 700 °C and pressures of 5 to 500 atm were studied by means of the transfer method. The results were evaluated by a new method. In the system Sio2/H2O the formation of gaseous Si(OH)4, Si2O(OH)6, and [SiO2(OH)2]x was found to occur in three different water-density ranges. In the systems MoO3/H2O and WO3/H2O the gaseous compounds MoO2(OH)2 and WO2(OH)2, which were already known, exist up to densities of approximately 0.05g/cm3. At higher densities, at which the supercritical phase begins to show the properties of a liquid to an ever increasing extent, isopolymolybdic or isopolytungstic acids appear.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.196400471
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Proton Transfer, Acid-Base Catalysis, and Enzymatic Hydrolysis. Part I: ELEMENTARY PROCESSESPart II (Catalytic Mechanisms) will appear shortly in this journal.Dedicated to Dr. W. Foerst on the occasion of his 65th birthday (1964)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 3 (1964), S. 1-19 
    Details
    ISSN: 0570-0833
    Keywords: Proton transfer ; Catalysis ; Enzyme catalysis ; Hydrolysis ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The proton occupies a special position as a promoter and mediator in chemical reactions occurring in solution. Many reactions in organic chemistry are catalysed by acids or bases; likewise, most enzymes contain active groups which promote acid-base catalysis. To understand the reaction mechanisms involved, it is necessary to identify the elementary steps as well as their course in time. Systematic investigation of these elementary steps as well as their course in time. Systematic investigation of these elementary steps has become possible only with the development of new methods for studying very fast reactions. The present paper reviews the information obtained in this type of investigation. The result is a relatively complete picture of the elementary proton transfer mechanisms and a comprehensive description of the modes and laws of acid-base and enzymatic catalysis.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.196400011
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    Paper (German National Licenses)
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