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  • 1
    Electronic Resource
    Electronic Resource
    Kombination von Dünnschicht-Chromatographie und infrarotspektrographischer Bestimmung von Mikrogramm-Mengen, gezeigt am Beispiel der Analyse von oralen Antikonzipientien (1967)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 230 (1967), S. 347-355 
    Details
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Am Beispiel der Analyse der oralen Antikonzipientien wird gezeigt, daß infrarotspektrographische Bestimmungen mit Mikrogramm-Mengen mit Hilfe einer Spiegeltechnik möglich sind. Die auf einen Reflektor von 2 mm Durchmesser aufgebrachte, in Nujol gelöste Substanz läßt sich mit einer Standardabweichung von 10–15% im Bereich von 5–50 μg messen. Die Dünnschicht-Chromatographie (Kieselgel; Äthylacetat/Cyclohexan) eignet sich zur Trennung von Oestrogen-Gestagen-Verhältnissen bis 1∶100. Die getrennten Substanzen werden mit Chloroform vom Kieselgel eluiert und auf die Spiegel übergeführt.
    Notes: Summary The combination of thin-layer chromatography and a micro method for infrared analysis is described. By means of an infrared reflection-technique microgram amounts can be determined quantitatively. A small mirror with a diameter of 2 mm is used as a sample carrier. The sample is dissolved in nujol. The standard deviation of the method is 10–15% in the range from 5–50 μg. The determination of the content of oral anticoncipients in pharmaceutical preparations is taken as an example for the application. Oestrogens and gestagens (in ratios up to 1∶100) are separated by thin-layer chromatography (silicagel; ethylacetate/cyclohexane). The separated substances are eluted from the silicagel layer by chloroform. The chloroform solution is transferred to the mirror and evaporated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00511097
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  • 2
    Electronic Resource
    Electronic Resource
    Verdampfung von Uranspaltprodukten in Wasserstoff, Stickstoff und Sauerstoff (1966)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 219 (1966), S. 93-102 
    Details
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die Verdampfung der Spaltprodukte Germanium, Arsen, Molybdän, Ruthenium, Cadmium, Zinn, Antimon und Tellur aus bestrahltem U3O8 im Wasserstoff-, Stickstoff- und Sauerstoffstrom wurde zwischen 900 und 1500° C untersucht. Bei 1500° C verdampfen die meisten dieser Elemente innerhalb 1 Std mit hoher Ausbeute.
    Notes: Summary The volatization of the fission products germanium, arsenic, molybdenum, ruthenium, cadmium, tin, antimony and tellurium from neutron-irradiated uranium oxide in flowing hydrogen, nitrogen or oxygen of atmospheric pressure was investigated between 900 and 1500° C. At 1500° C, most of these elements are volatized with high yield within one hour.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00534727
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  • 3
    Electronic Resource
    Electronic Resource
    Camptothecin and 10-hydroxycamptothecin in callus and plantlets of t Camptotheca acuminata (1997)
    Springer
    Plant cell, tissue and organ culture 49 (1997), S. 213-218 
    Details
    ISSN: 1573-5044
    Keywords: in vitro culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The process of callus induction, organogenesis and plantlets regeneration of Camptotheca acuminata Decne is reported. The highest growth rate of callus was observed on MS medium with 1 mg l−1 NAA, 1 mg l−1 kinetin and 60 g l−1 sucrose. All tissues and organs developed in vitro contain camptothecin and 10-hydroxycamptothecin. The presence of 10-hydroxycamptothecin in shoots and callus of Camptotheca acuminata Decne is reported for the first time. The alkaloids were detected and identified using HPLC methods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005704429339
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  • 4
    Electronic Resource
    Electronic Resource
    Quantitative photometrische Bestimmung der Pyrrolizidinalkaloide in Symphity Radix (1992)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 343 (1992), S. 621-624 
    Details
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Eine bereits in der Literatur beschriebene Farbreaktion für 1,2-ungesättigte Pyrrolizidinalkaloide (PAs) wird zur Gehaltsbestimmung der toxischen PAs in Symphyti Radix herangezogen. Durch Veränderung einiger Versuchsparameter konnte die Erfassungsgrenze auf 1 Mikrogramm herabgesetzt und die Reproduzierbarkeit der Messung erheblich verbessert werden. Für die alkaloidreichen Beinwellwurzeln wurde eine einfache Extraktionsmethode validiert, die einen Nachweis von 10 ppm in einem Gramm getrockneter Droge gestattet (0,001%).
    Notes: Summary A colour reaction for unsaturated pyrrolizidine alkaloids (PAs), which has already been published, is used for spectrophotometric determination of the toxic PAs in Symphyti Radix (Symphytum officinale L., Boraginaceae). By changing several parameters it was possible to reduce the detection limit to 1 microgram and to improve significantly the reproducibility of the quantitative determination. For Symphyti Radix a simple extraction method allowing the detection of 10 ppm PAs in 1 gram dried drug (0.001%) was validaded.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00324124
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  • 5
    Electronic Resource
    Electronic Resource
    Synthese von 2,3-Dihydro-7-methyl-1H-pyrrolizin-1-on, dem Sexualpheromon Danaidon (1985)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1985 (1985), S. 1708-1710 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of 2,3-Dihydro-7-methyl-1H-pyrrolizin-1-one, the Sex Pheromone DanaidoneDanaidone (4) can easily be obtained in high yields from ethyl 3-methyl-1H-pyrrole-2-carboxylate (1) via Dieckmann reaction of the N-propanoate derivative 2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198519850817
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  • 6
    Electronic Resource
    Electronic Resource
    Synthese von 2,3-Dihydro-1H-pyrrolizin-7-carbaldehyd, dem Sexualpheromon Danaidal (1986)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1986 (1986), S. 1645-1647 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of 2,3-Dihydro-1H-pyrrolizine-7-carbaldehyde, the Sex Pheromone DanaidalDanaidal (4) can easily be obtained in high yields from ethyl 2,3,5,6-tetrahydro-1H-pyrrolizine-7-carboxylate (1) via sulphur dehydrogenation or MnO2 oxidation, subsequent reduction to dehydrosupinidine (3), and further oxidation to the desired title compound 4.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198619860915
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  • 7
    Electronic Resource
    Electronic Resource
    Synthese von (1α,7α,8β)-(±)-7-Hydroxy-1-(hydroxymethyl)pyrrolizidin, der Necin-Base rac-Platynecin (1990)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1990 (1990), S. 607-609 
    Details
    ISSN: 0170-2041
    Keywords: Necine ; rac-Platynecine ; Pyrrolizidine ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of (1α,7α,8β)-(±)-7-Hydroxy-1-(hydroxymethyl)pyrrolizidin, the Necine rac-Platynecinerac-Platynecine (rac-7) can easily be obtained in high yields from diethyl (±)-cis-2,3-pyrrolidinedicarboxylate (rac-1) by N-alkylation to ethyl (±)-cis-2,3-bis(ethoxycarbonyl)-1-pyrrolidinepropionate (rac-2), Dieckmann reaction to ethyl (1α,8β)-(±)-6-ethoxycarbonyl-7-oxo-1-pyrrolizidinecarboxylate (rac-3), subsequent saponification, decarboxylation, reduction to (1α,7α,8β)-(±)-pyrrolizidine-1,7-carbolactone (rac-6), and further reduction to the desired title compound rac-7.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.1990199001113
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  • 8
    Electronic Resource
    Electronic Resource
    Synthese von 2,3-Bis(ethoxycarbonyl)-1H-pyrrol-1-propionsäure-ethylester (1987)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1987 (1987), S. 1117-1119 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of Ethyl 2,3-Bis(ethoxycarbonyl)-1H-pyrrole-1-propionateEthyl 2,3-bis(ethoxycarbonyl)-1H-pyrrole-1-propionate (7) can easily be obtained in high yields from ethyl 4-iodobutyrate (1) via reaction with dibenzylamine and diethyl oxalate, catalytic debenzylation to diethyl cis-2,3-pyrrolidinedicarboxylate (5), subsequent dehydrogenation to diethyl 1H-pyrrole-2,3-dicarboxylate (6), and further N-alkylation to the desired title compound 7.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198719870883
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  • 9
    Electronic Resource
    Electronic Resource
    Zur Synthese von β-Alkyl-α-methylen-γ-butyrolactonen (1992)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1992 (1992), S. 177-181 
    Details
    ISSN: 0170-2041
    Keywords: Succinic acid, 3-alkylidene-, monoethyl esters ; γ-Butyrolactones ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of β-Alkyl-α-methylene-γ-butyrolactonesThe ylene 1 reacts with aldehydes to give 3-alkylidenesuccinic acid monoethyl esters 2, which form β-alkylidene-γ-butyrolactones 3 when treated with sodium diethyldihydroaluminate. Hydrogenation of the double bond leads to the β-alkyl-γ-butyrolactones 4. The β-alkyl-α-methylene-γ-butyrolactones 5 are obtained by Mannich reaction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199219920133
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  • 10
    Electronic Resource
    Electronic Resource
    Azepinoindole, III. Synthese von Azepino[3,4-b]indoldionen durch Cyclisierung von N-(2-Indolylcarbonyl)-β-aminosäuren (1978)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1978 (1978), S. 1390-1398 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Azepinoindoles, III.  -  Cyclization of N-(2-Indolylcarbonyl)-β-amino Acids to Azepino[3,4-b]indoledionesN-(2-Indolylcarbonyl)-β-amino acids 2 cyclize with polyphosphoric acid, forming azepino[3,4-b]indolediones 3. N-(2-Indolylcarbonyl)-α-amino acids 4 are cyclized to the corresponding pyrido[3,4-b]indolediones 5.
    Notes: Die Behandlung den N-(2-Indolylcarbonyl)-β-aminosäuren 2 mit Polyphosphorsäure führt in guten Ausbeuten zu den Azepino[3,4-b]indoldionen 3. Die N-(2-Indolylcarbonyl)-α-aminosäuren 4 cyclisieren zu den entsprechenden Pyrido[3,4-b]indoldionen 5.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197819780905
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