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  • 1
    ISSN: 0899-0042
    Keywords: chromatographic resolution of stereoisomers ; molecular modelling ; conformation ; κ-opiate receptor ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The four stereoisomers of the two peripherally selective κ-opioid agonists EMD 60 400 and EMD 61 753 were synthesized, tested for stereoisomeric purity, and examined for affinity to the κ opioid receptor. The relationships between the configuration of these molecules and their biological activity are discussed. © 1994 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 370-380 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Boron Complexes of Malonamides and MalonamidinesN,N,N′,N′-Tetramethylmalonamide (4) reacts with triethyloxonium tetrafluoroborate in boiling tetrachloroethane or with diethyl ether  -  boron trifluoride at room temperature to form the tetrafluoroborate 6a which was deprotonated with triethylamine to give 4,6-bis(dimethylamino)-2,2-difluoro-3-oxa-1-oxonia-2-borata-4,6-cyclohexadiene (7). With 4 and boron trichloride in CCl4 the neutral complex 9 is obtained, in CH2Cl2 the chelate complex 10. Similar to diethyl ether  -  boron trifluoride (2-aminoethoxy)diphenylborane (12) and triethylborane (15) condense with 4 to yield the salts 13 and 17, respectively, and the neutral complexes 14 and 16, respectively. N,N,N″,N″- Tetramethylmalonamidine (20) reacts with triethylborane (21a), ethoxydiphenylborane (21b) and trimethoxyborane (21c) to give the neutral complexes 22a-c which partly can be protonated with HBF4 to form the salts 23a, b.
    Notes: N,N,N′,N′-Tetramethylmalonsäurediamid (4) bildet mit Triethyloxonium-tetrafluoroborat in siedendem Tetrachlorethan oder mit Diethylether  -  Bortrifluorid bei Raumtemperatur das Tetrafluoroborat 6a, das sich mit Triethylamin zum 4,6-Bis(dimethylamino)-2,2-difluor-3-oxa-1-oxonia-2-borata-4,6-cyclohexadien (7) deprotonieren läßt. Bortrichlorid liefert mit 4 in CCl4 den Neutralkomplex 9, in CH2Cl2 den Chelatkomplex 10. Ähnlich wie Diethylether  -  Bortrifluorid kondensieren auch (2-Aminoethoxy)diphenylboran (12) und Triethylboran (15) mit 4 zu den Salzen 13 bzw. 17 und zu den Neutralkomplexen 14 bzw. 16. N,N,N″N″-Tetramethylmalonamidin (20) bildet mit Triethylboran (21a), Ethoxydiphenylboran (21b) und Trimethoxyboran (21c) die Neutralkomplexe 22a-c, die sich mit HBF4 teilweise zu den Salzen 23a,b protonieren lassen.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0268-2605
    Keywords: Organolead ; organomercury ; organotin ; toxicity ; lipid metabolism ; arachidonic acid ; Lands cycle ; cell culture ; HL-60 cells ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The concentration of free fatty acids within cells is mainly dependent upon the following enzyme activities: liberation by phospholipase A2 (PLA2), activation of free acids by acyl-CoA-synthetase and re-esterification by lysophospholipid acyltransferase (LAT). In many cell types, especially those of the haematopeotic system, this deacylation-reacylation cycle (‘Lands cycle’) plays an important role in the regulation of free fatty acid concentration, above all that of arachidonic acid.We have shown here that heavy-metal compounds affect this cycle mainly at two points and thereby lead to an increase of free fatty acids. On the one hand, organometals cause an inhibition of the reacylation of lysophospholipids; and on the other, the induction of PLA2 activity produces the same result. All compounds investigated such as methylmercury chloride (MeHgCl), diethyltriethyl-, and trimethyl-lead chloride (Et2PbCl2, Et3PbCl, Me3PbCl) as well as trimethyltin chloride (Et3SnCl) and di-t-butyltin dichloride (t-Bu2SnCl2) show at least one of these effects. In the case of Et3PbCl, the use of PLA2-inhibitors or pertussis toxin causes a drastic decrease in the amount of arachidonic acid liberated. These experiments demonstrate that the organometallic compounds inhibit the reacylation and/or stimulate the deacylation of fatty acids that are involved in many important biological or pathological mechanisms. The results suggest that in differentiated HL-60 cells the organometal compounds stimulate the Lands cycle by increasing the activity of the PLA2, possibly via a signal-transduction mechanism, and this effect is intensified via an inhibition of reesterification.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 331 (1989), S. 835-842 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Transformation of Uridine Derivatives into Cytidines via Selective AminationThe synthesis of some 5-fluorosubstituted cytidine 2 derivatives via amination of corresponding uridine derivatives 1 is described. 5-Substituted 4-tetrazolo pyrimidinone derivatives 5 are key intermediates in the procedure. The method used is extended to other fluorinated starting materials, e.g. fluorinated uridinedinueleotides 7 or 2′-deoxy-2′-fluorouridine 9. The fluoro containing products are easily available by fluorination with elemental fluorine or hydrogene fluoride.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0170-2041
    Keywords: Azapeptides ; Renin inhibitor ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A highly potent renin inhibitor of the azapeptide type (2) is synthesized by starting from the hydrazine derivative 3. This peptide analogue inhibits renin in the same range (nanomolar) as its purely peptidic original 2a, but reveals much higher specificity for renin than 2a does.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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