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  • Inorganic Chemistry  (752)
  • Organic Chemistry  (646)
  • Analytical Chemistry and Spectroscopy  (332)
  • 1990-1994
  • 1970-1974  (1,730)
  • 1955-1959
  • 1972  (1,730)
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  • 1990-1994
  • 1970-1974  (1,730)
  • 1955-1959
Year
  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 754 (1972), S. 1-7 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Photochemical Cycloadditions, I. Addition of Dichlorovinylene Carbonate to BenzeneOn UV-irradiation of dichlorovinylene carbonate (DCVC) dissolved in benzene, cycloaddition to benzene in 1,2- and 1,4-position and substitution (6) is observed. The addition compounds are formed in a molar ratio DCVC/benzene of 1 : 1 (1 and 2), 2 : 1 (3) and 2 : 2 (4). The 1,2-addition compound 1 has an endo-structure. It is photochemically rearranged to the 1,4-isomer 2.
    Notes: Bestrahlt man Dichlorvinylencarbonat (DCVC) in Benzol mit UV-Licht, so werden 1.2- und 1.4-Cycloaddukte an Benzol sowie Substitutionsprodukte (z. B. 6) gebildet. Die Addukte treten im Molverhältnis DCVC/Benzol wie 1 : 1 (1 und 2), 2 : 1 (3) und 2 : 2 (4) auf. Für das 1.2-Addukt 1 wird eine endo-Struktur gefunden. Es lagert sich photochemisch in das 1.4-Addukt 2 um.
    Additional Material: 1 Ill.
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  • 2
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Rearrangements of Vinylogous Carboxylic Acid Chlorides, X1). 1.3-Shift in Polychlorinated Propenone SystemsTrichloroacrolein (1a) and β.β-dichloroacrolein (1b) rearrange in contact with V2A-steel at 100-135° into cis-α.β-dichloroacryloyl chloride (2a) and trans-β-chloroacryloyl chloride (2b) respectively. The trichlorovinyl ketones 1c-1k are stable under the same conditions. In presence of AlCl3 they are partly changed in another way. The isomerization of ketones is restricted to compounds with trichloromethyl substituents in the α-position of the vinyl group. The rearrangement of 11 is followed by spontaneous dehydrochlorination to 9. 1m yields a mixture of the allylisomeric acid chlorides trans-2m and 14a. A possible mechanism of the 1.3-propenone-shift is discussed.
    Notes: Trichloracrolein (1a) und β.β-Dichlor-acrolein (1b) lagern sich an V2A-Kontakten bei 100 bis 135° in cis-α.β-Dichlor-acrylsäurechlorid (2a) bzw. trans-β-Chlor-acrylsäurechlorid (2b) um. Die Trichlorvinylketone 1c-1k sind unter diesen Bedingungen stabil. In Gegenwart von AlCl3 werden sie zum Teil in anderer Weise verändert. Bei Ketonen tritt die Isomerisierung zum Carbonsäurechlorid nur ein, wenn sie in der α-Stellung der Vinylgruppe Trichlormethyl-substituiert sind. Beim Keton 11 ist die Umlagerung mit einer spontanen Dehydrochlorierung zu 9 verbunden. Das Keton 1m liefert ein Gemisch der allylisomeren Säurechloride trans-2m und 14a. Ein möglicher Mechanismus der 1.3-Propenon-Verschiebung wird diskutiert.
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 754 (1972), S. 107-112 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Antamanide, X. The Tyrosine6-Analogue of AntamanideAn analogue 1 of antamanide (2) with tyrosine instead of phenylalanine in position 6 has been synthesized by fragment condensation using O-benzyl tyrosine. 1 and its methyl ether 1b have the same protecting activity as 2 against phalloidine in the white mouse (0.5-1 mg/kg), whereas the O-benzyl derivative 1a is ineffective.
    Notes: Ein Analoges 1 des Antamanids (2), welches in 6 Position Tyrosin anstelle von Phenylalanin enthält, wurde unter Verwendung von O-Benzyl-tyrosin durch Fragmentkondensation synthetisiert. 1 schützt die weiße Maus mit der gleichen Dosis (0.5-1 mg/kg) gegen Phalloidin wie 2; die O-Methyl-Verbindung 1b ist ebenso wirksam, während die O-Benzyl-Verbindung 1a keine antitoxische Wirkung besitzt.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 757 (1972), S. 187-192 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Phospholipase A (EC 3.1.1.4) from Bee Venom, II1a). - At Least Two Phospholipases A in Bee VenomPhospholipase A is separated from hyaluronidase and biologically active peptides by repeated chromatography on ion exchangers and Sephadex. Isoelectric focusing analysis gives a single protein peak with phospholipase activity. The enzyme is strongly basic, as indicated by its isoelectric point at pH 10.0. It is 30 times more active against egg lecithin than phospholipase A from Crotalus venom. N-Terminal is found isoleucine alone. Contrary to previous assumptions, the molecular weight is only 10900. Furthermore, 15-18 tryptic peptides are in close agrement with the data from amino acid analysis (table 1); there are 100-102 amino acids including 9 Lys and 4-5 Arg in the polypeptide chain. - Further separation of phospholipase A is achieved by disc electrophoresis (staining by amido black) revealing three bands in a ratio of 65 : 30 : 5. The main components phospholipase A 1 and A 2 show lecithinase activity. - Native phospholipase is readily hydrolysed by trypsin releasing two small fragments and residual phospholipase A. In contrast to the pancreas enzyme, bee venom phospholipase contains no enzymatically inactive precursor.
    Notes: Durch wiederholte Kationen-Austauschchromatographie von Bienengift mit anschließender Gelfiltration wird gereinigte Phospholipase A (EC 3.1.1.4) frei von Hyaluronidase und biologisch aktiven Peptiden erhalten. Sie erweist sich bei isoelektrischer Fokusierung als einheitlich und stark basisch (IP=10.0). Das Molekulargewicht beträgt nur 10900; die früher gefundenen höheren Werte lassen sich nicht bestätigen. N-Terminal liegt nur Isoleucin vor. Durch quantitative Aminosäureanalyse werden 100-102 Aminosäuren erhalten, davon 9 Lys und 4-5 Arg (Tab. 1). In guter Übereinstimmung damit stehen 15-18 Spaltstellen, wie durch tryptische Hydrolyse des mit Perameisensäure oxydierten Enzyms gezeigt wird. Im Lecithinase-Test ist die Phospholipase aus Bienengift 30mal aktiver als Phospholipase A aus Crotalus-Gift. - Auf Grund der Diskelektrophorese (Anfärbung mit Amidoschwarz) besteht die Phospholipase A aus drei Komponenten im Verhältnis 65 : 30 : 5. Die beiden Hauptkomponenten, Phospholipase A 1 und A 2, sind enzymatisch aktiv. - Native Phospholipase wird von Trypsin angegriffen, wobei zwei kleine basische Bruchstücke und Rest-Phospholipase A entstehen. Im Gegensatz zur Pankreas-Phospholipase A liegt das Bienengift-Enzym nicht als inaktives Zymogen vor.
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  • 5
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Bis-acetylenic Compounds, VIII. - Structure and Reactive Behaviour of Rhodium ComplexesThe bis-acetylenic compounds 1 - 3 form the very reactive complexes 5 - 8 with tris-[triphenyl-phosphine]-rhodium(I)-chloride (4). The formation and structure of these rhodium complexes as well as their reactive behaviour with acetylene derivatives, chalkogens and carbon monoxide are explained.
    Notes: Die Bis-acetylen-Verbindungen 1 - 3 geben mit Tris-[triphenylphosphin]-rhodium(I)-chlorid (4) die sehr reaktiven Komplexe 5 - 8. Bildung und Struktur dieser Rh-Komplexe sowie deren reaktives Verhalten mit Acetylenderivaten, Chalkogenen und Kohlenmonoxid werden erörtert.
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  • 6
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Photochemical Cycloadditions, II1). Relationship of Structure and Reactivity in Photochemical Cycloadditions. 1,4-Addition of Dichlorovinylene Carbonate to Aromatic CompoundsDichlorovinylene carbonate combines photochemically with a number of aromatic compounds in the 1,4 position to give the compounds 2 and 3. The reaction rates and the quantum yields are determined (table 2). An addition mechanism via a charge-transfer-complex is proposed. The NMR-, IR-, UV- and mass-spectra (tables 3-5) are discussed briefly.
    Notes: Dichlorvinylencarbonat addiert sich unter UV-Bestrahlung an eine Reihe von Aromaten in 1.4-Stellung zu 2 und 3. Die relativen Reaktionsgeschwindigkeiten sowie die Quantenausbeuten werden bestimmt (Tab. 2). Ein Additionsmechanismus über einen charge-transfer-Komplex wird vorgeschlagen. Die NMR-, IR-, UV- und MS-Spektren der Addukte (Tabb. 3-5) werden besprochen.
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  • 7
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Azo Dyes by Oxidative Coupling, XXIX. Derivatives of 3-Methyl-1,2-benzisothiazolone-2-, 1,3-Benzodithiolone-2- and 1,2-Benzodithiolone-3-hydrazonesThe hydrazones 5 and 6 are synthesized as well as some hydrazine derivatives of 1,2-benzisothiazol-2-one, the tautomerism of which is investigated. Oxidative coupling with 1-hydroxy-2-naphthoic acid anilide and dimethylaniline is successful in all cases. The properties of the dyes are discussed briefly. Oxidative coupling of 5 and 6 surpasses the previous limits of that very general reaction.
    Notes: Die Synthese der Hydrazone 5 und 6 wird beschrieben; ebenso die einiger Hydrazin-Derivate des 1.2-Benzisothiazolons-(2), deren Tautomerie untersucht wird. In allen Fällen gelingt die oxydative Kupplung mit 1-Hydroxy-naphthoesäureanilid-(2) sowie Dimethylanilin. Die Eigenschaften der Farbstoffe werden kurz diskutiert. Die oxydative Kupplung mit 5 und 6 überschreitet die bisherige Grenze dieser allgemeinen Reaktion.
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  • 8
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Studies on Seven-Membered Ring Systems, X. Conformational Aspects of the 2-Carboxy-tribenzotropylium lonThe reaction of (-)- and (+)-9e-hydroxy-9H-tribenzo[a.c.e]cycloheptene-2-carboxylic acid [(-)- and (+)-1b] with methanol/sulfuric acid giving (-)- and (+)-9e-methoxy-2-methoxycarbonyl-9H-tribenzo[a.c.e]cycloheptene [(-)- and (+)-4] proceeds under retention of conformation and partial retention of configuration. Similarly the (+)-acetate 5b is obtained by acetolysis of (+)-9e-[p-toluenesulfonyloxy]-9H-tribenzo[a.c.e]cycloheptene (+)-5a], where racemisation is the predominant process. These results are discussed by assuming a chiral, boat-shaped and rapidly inverting tribenzotropylium ion 2b.
    Notes: Die Umsetzung von (-)- und (+)-9e-Hydroxy-9H-tribenzo[a.c.e]cyclohepten-2-carbonsäure [(-)- und (+)-1b] mit Methanol/Schwefelsäure ergibt unter Konformations- und teilweiser Konfigurationserhaltung (-)- und (+)-9e-Methoxy-9H-tribenzo[a.c.e]cyclohepten-2-carbonsäuremethylester [(-)- und (+)-4]. Analog verläuft die Acetolyse des (+)-9e-[p-Toluolsulfonyloxy]-9H-tribenzo[a. c.e]cycloheptens [(+)-5a] zum Acetat (+)-5b, wobei jedoch weitgehend Racemisierung eintritt. Diese Ergebnisse werden mit der Annahme eines chiralen und schnell umklappenden Tribenzotropylium-Ions 2b diskutiert.
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  • 9
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Heterocyclic β-Enamino Esters, VIII. The Reaction of 2-Amino-3-ethoxycarbonyl-4,5-dihydrofuranes with Amidines and Hydrazines2-Amino-3-ethoxycarbonyl-4,5-dihydrofuranes 1 react with bifunctional N-bases (amidines, hydrazines) under ring cleavage to form substituted 6-pyrimidinones 2 and 5-pyrazolones 4. The 5-[2-hydroxyethyl]-6-pyrimidinones 2b, c are cyclized with conc. H2SO4 yielding furo-[2,3-d]pyrimidines 3.
    Notes: 2-Amino-3-äthoxycarbonyl-4.5-dihydro-furane 1 reagieren mit bifunktionellen Stickstoffbasen (Amidinen, Hydrazinen) unter Ringöffnung zu substituierten Pyrimidonen-(6) 2 und zu Pyrazolonen-(5) 4. Die 5-[2-Hydroxy-äthyl]-pyrimidone-(6) 2b, c werden mit konz. Schwefelsäure zu Furo[2.3-d]pyrimidinen 3 cyclisiert.
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  • 10
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses of Heterocyclic Compounds, CLXX1). - Reactions of Cyclic Oxalyl Compounds, X2). - Reaction of 2-Quinoxalinones with Polyphosphoric AcidWith polyphosphoric acid as cyclization reagent the 2-quinoxalinones 1a, b yield the imidazo-[1.5-α]quinoxalines 3a, b. The quinoxalinone 1c is hydrolyzed under these conditions to the ketone 6. Its isomer 2 gives by a Fischer synthesis the indole derivative 7. The formation of the compounds 3a, b is effected by a Beckmann rearrangement.
    Notes: Die 2-Chinoxalinone 1a, b lagern sich bei Einwirkung von Polyphosphorsäure in die Imidazo-[1.5-α]chinoxaline 3a, b um. Das Chinoxalinon 1c wird unter diesen Bedingungen zum Keton 6 hydrolysiert. Sein Isomeres 2 ergibt in einer Fischer-Synthese das Indol-Derivat 7. Die Bildung der Verbindungen 3a, b wird über eine Beckmann-Umlagerung bewirkt.
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  • 11
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Investigations about the Antibacterial Activity of Quinolonecarboxylic Acids, II1). - Synthesis of 1-Ethyl-4-quinolone-3-carboxylic Acids with Fused Five-membered Heterocyclic RingsThe present contribution describes the synthesis of 1-ethyl-4-quinolone-3-carboxylic acids having a furan, thiophene, pyrrole or dihydrofuran ring fused to positions 5 and 6 or a dihydrofuran ring fused to positions 6 and 7.
    Notes: Es wird die Synthese von 1-Äthyl-4-chinolon-3-carbonsäuren beschrieben, in denen an der 5.6-Stellung ein Furan-, Thiophen-, Pyrrol- oder Dihydrofuran-Ring oder an der 6.7-Stellung ein Dihydrofuran-Ring kondensiert ist.
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  • 12
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 762 (1972), S. 73-82 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Benzodiazepines with Psychotropic Activity, V1). - 1,5-Benzodiazepinetriones and Their PrecursorsThe oxidation of the 3-aminomethylene-1,5-benzodiazepine-1,4-diones 1 to the 1,5-benzodiazepine-2,3,4-triones 5 proceeds via the corresponding 3-formyl-3-hydroxy- and 3-hydroxy-1,5-benzodiazepine-2,4-diones of type 2 and 3. Compounds of type 3 are not present in the enediol form as is the case with dialuric acid. The benzodiazepinetriones may be converted into 6-membered ring systems. A possible reaction mechanism is discussed and a comparison is made with the stability of analogous mono- and dioxo-1,5-benzodiazepines.
    Notes: Die Oxidation der 3-Aminomethylen-1.5-benzodiazepin-2.4-dione 1 zu den 1.5-Benzodiazepin-2.3.4-trionen 5 führt über die entsprechenden 3-Formyl-3-hydroxy- und 3-Hydroxy-1.5-benzodiazepin-2.4-dione vom Typ 2 bzw. 3. Verbindungen des Typs 3 liegen nicht wie Dialursäure in der Endiol-Form vor. Die Benzodiazepin-trionen 5 lassen sich in 6-Ring-Systeme umwandeln. Dazu wird ein möglicher Mechanismus diskutiert. Ihre Stabilität wird mit der analoger Mono- und Dioxo-1.5-benzodiazepine verglichen.
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  • 13
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Alkynones with Nucleophilic Reagents such as 1,2-Diaminobenzene, 2-Aminomercaptobenzene and N1-Disubstituted HydrazinesThe aromatic 1,2-diamines 1 and 4 or the 2-aminomercaptobenzene react with alkynones 2, depending on their substituents, by addition to the triple bond, giving 6 and 7, or by cyclization leading to 1,5-benzodiazepines 3 and 5, or 1,5-benzothiazepines 8.
    Notes: 1.2-Diamine vom Typ des o-Phenylendiamins (1, 4) oder o-Amino-thiophenol reagieren mit den Acetylenketonen 2 je nach deren Substitution unter Addition an die Dreifachbindung zu 6 bzw. 7 oder Ringschluß zu 1.5-Benzodiazepinen (3, 5) bzw. 1.5-Benzothiazepinen (8).
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  • 14
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaction of Aminoaroxyls with Triarylphosphines, I.  -  A Simple Method for the Preparation of o-Hydroxyphosphine Imines2-Amino-4,6-dialkylphenols (e. g. 1) in ethanolic solution are oxidized by air to the corresponding phenoxyls 2. These radicals react smoothly with triarylphosphines to give the o-hydroxyphosphine imines 3. The properties of the new compounds and the course of reaction are described.
    Notes: 2-Amino-4.6-dialkyl-phenole (z. B. 1) werden in äthanolischer Lösung durch Luftsauerstoff in die entsprechenden Phenoxyle 2 übergeführt. Diese Radikale reagieren mit tertiären aromatischen Phosphinen in guten Ausbeuten zu den o-Hydroxy-phosphiniminen 3. Die Eigenschaften der neuen Verbindungen und der Reaktionsweg werden beschrieben.
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  • 15
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 755 (1972), S. 51-57 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Thalidomide Analogues, IVThe synthesis and identification by thin-layer chromatography of the potential metabolities of a non-teratogenic congener of thalidomide (test compound „K-2004“, 1) are described. The increased resistance against hydrolysis of 1 compared with thalidomide (2) is demonstrated and a possible connection with the altered biological activity is discussed.
    Notes: Die Synthese und dünnschichtchromatographische Identifizierung der potentiellen Metaboliten eines nicht teratogenen Thalidomid-Abkömmlings (Testsubstanz „K-2004“, 1) werden beschrieben. Die erhöhte Hydrolysebeständigkeit von 1 im Vergleich zu Thalidomid (2) wird demonstriert und ein möglicher Zusammenhang mit der veränderten biologischen Aktivität diskutiert.
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  • 16
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 762 (1972), S. 160-166 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Nucleoside Analogues of 5-HydroxymethyluracilThe hydroxymethyl group of 5-hydroxymethyluracil (1a) reacts with 2,3-dihydrofuran and -pyran in the presence of acid catalysts to form 2a and 2b, respectively. N1,N3-Dimethyl-5-hydroxymethyluracil (1b) reacts analogously. By condensation of persilylated 1a (3) with 2-chlorotetrahydrofuran or 2-chlorotetrahydropyran the corresponding N3-substituted derivatives 5 and 4 are obtained. The nucleoside analogues are converted into the compounds 2e-2h by reaction of the hydroxymethyl group with 2,3-dihydrofuran and -pyran, respectively. In these substances two oxygen-containing rings are connected with uracil. These biologically interesting compounds can be regarded as models of the naturally occuring 5-O-glycoside derivatives of 5-hydroxymethylcytosine.
    Notes: Die Hydroxymethylgruppe des 5-Hydroxymethyl-uracils (1a) liefert bei der säurekatalysierten Reaktion mit 2.3-Dihydro-furan bzw. -pyran die Verbindungen 2a bzw. 2b. Analog reagiert N1.N3-Dimethyl-5-hydroxymethyl-uracil (1b) zu 2c bzw. 2d. Kondensation von persilyliertem 1a (3) mit 2-Chlor-tetrahydrofuran bzw. -tetrahydropyran führt zu den entsprechenden N3-substituierten Verbindungen 5 bzw. 4. Diese Nucleosid-Analoga setzen sich mit 2.3-Dihydro-furan bzw. -pyran an der 5-ständigen Hydroxymethylgruppe zu den Verbindungen 2e-2h um, in denen zwei sauerstoffhaltige Ringe mit Uracil verknüpft sind. Diese biologisch interessanten Verbindungen sind Modelle für das natürlich vorkommende 5-O-glykosidierte 5-Hydroxymethyl-cytosin.
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  • 17
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 763 (1972) 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 18
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 763 (1972), S. 17-38 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Silylation of Amino Acids and Synthesis of Peptides with Amino Acid TrimethylsilylestersThe silylation of amino acids or oligopeptides by various methods is investigated and compared. Under suitable conditions amino acids are converted quantitatively by trimethylchlorosilane into either amino acid trimethylsilylesters 2 or N-trimethylsilyl amino acid trimethylsilylesters 1. These compounds can be used for peptide syntheses without isolation. The reactivity of the trimethylsilylesters 2 toward different activated amino acid derivatives is investigated and compared with that of the corresponding N-trimethylsilyl amino acid trimethylsilylesters 1.
    Notes: Verschiedene Methoden der Silylierung von Aminosäuren und Oligopeptiden werden untersucht und verglichen. Unter geeigneten Reaktionsbedingungen lassen sich Aminosäuren mit Trimethylchlorsilan quantitativ in Aminosäuretrimethylsilylester 2 oder in N-Trimethylsilyl-aminosäuretrimethylsilylester 1 überführen. Diese werden im Eintopfverfahren direkt zur Peptidsynthese weiterverwendet. Die Reaktivität der Aminosäuretrimethylsilylester 2 gegenüber verschiedenartig aktivierten Aminosäurederivaten wird untersucht und mit der von N-Trimethylsilyl-aminosäuresilylestern 1 verglichen.
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  • 19
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Ring Cleavage of Cyclic Azo Compounds, V1). - 2-Mesityl-2H-benzo[c]-1.2-thiazet-1,1-dioxide, a Stable Benzo-β-sultamPhotolysis of 2-mesityl-2H-benzo[e]-1,2,3,4-thiatriazine-1,1-dioxide (3a) yields the stable 2-mesityl-2H-benzo[c]-1,2-thiazet-1,1-dioxide (4a), whilst irradiation of 2-phenyl-2H-benzo[e]-1,2,3,4-thiatriazine-1, 1-dioxide (3b) gives under similar reaction conditions carbazole (7) and the known dibenzo[c.e]-1,2-thiazine-1,1-dioxide (6).
    Notes: Die Photolyse des 2-Mesityl-2H-benzo[e]-1.2.3.4-thiatriazin-1.1-dioxids (3a) führt zu dem stabilen 2-Mesityl-2H-benzo[c]-1.2-thiazet-1.1-dioxid (4a). Dagegen ergibt das 2-Phenyl-2H-benzo[e]-1.2.3.4-thiatriazin-1.1-dioxid (3b) unter denselben Reaktionsbedingungen Carbazol (7) und Dibenzo[c.e]-1.2-thiazin-1.1-dioxid (6).
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  • 20
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Long-chain Organometallic Alkali Compounds of the Type RCH2CH(CN)M: Synthesis, Spectroscopic and Conductometric CharacteristicsSoluble compounds of the type RCH2CH(CN)M (2) were synthesized by reacting acrylonitrile (1) with polybutadienylalkali compounds. Ultraviolet and conductometric measurements with the Li, Na, and K derivatives 10-12 between -70 to +25° were carried out, and dissociation constants, enthalpies of dissociation, and C-M distances were calculated. As follows from these data, compounds 10-12 exist in tetrahydrofuran as stable contact ion pairs.
    Notes: Durch Reaktion zwischen Acrylnitril (1) und Alkalimetallpolybutadienylen wurden lösliche Agenzien vom Typ RCH2CH(CN)M (2) hergestellt. An derartigen Li-, Na- und K-Verbindungen 10-12 wurden UV-spektrometrische und konduktometrische Bestimmungen im Temperaturbereich von -70 bis +25° ausgeführt sowie Dissoziationskonstanten, Dissoziationsenthalpien und C-M-Distanzen berechnet. Entsprechend diesen Ergebnissen treten die Verbindungen 10-12 in Tetrahydrofuran als beständige Kontakt-Ionenpaare auf.
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  • 21
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Aluminium Alkyls with Carbonyl Compounds, III. - Hydroalumination of Ketoenol Acetates, A New Synthesis of 2,4-DiolsThe Enolacetates 2a-g of aliphatic and aromatic ketones are treated with HAl(i-C4H9)2 at room temperature to afford, after subsequent acetolysis, the 2,4-diacetates 3a-g. The diacetates are isolated in 65-80% yields and analyzed by gaschromatography. In hydroalumination of a mixture of 2-acetoxy-1-butene and 2-acetoxy-2-butene there is no selection between the two isomers.
    Notes: Die Enolacetate 2a-g aliphatischer und aromatischer Ketone werden durch Umsetzung mit HAl(iso-C4H9)2 bei Raumtemperatur und anschließender Acetolyse in die 2.4-Diacetate 3a-g übergeführt. Die Diacetate werden destillativ in Ausbeuten von 65-80% isoliert und gaschromatographisch analysiert. Bei der Hydroaluminierung einer Mischung von 2-Acetoxy-1-buten und 2-Acetoxy-2-buten wird keine Selektion zwischen den beiden Isomeren festgestellt.
    Additional Material: 3 Tab.
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  • 22
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Ubiquinones and Related Compounds, XXIII1). - Synthesis of Quinones with Novel Condensing AgentsHydroquinones can be condensed with isoprenoid alcohols with the help of N-sulfinylamines (table 1). By this method, 6-phytyl- (trans-5a), 6-farnesyl- (trans-5b), 6-geranyl- (trans-5c), 6-neryl-2,3-dimethoxy-5-methyl-1,4-benzoquinone (cis-5c), 2,3,5-trimethyl-6-phytyl-1,4-benzoquinone (trans-6), and 2-methyl-3-phytyl-1,4-naphthoquinone (trans-7) are synthesized. The reaction mechanism is studied in detail, and the stereospecifity is discussed.
    Notes: Hydrochinone können mit isoprenoiden Alkoholen mit Hilfe von N-Sulfinylaminen kondensiert werden (Tab. 1). Nach dieser Methode lassen sich 6-Phytyl- (trans-5a), 6-Farnesyl-(trans-5b), 6-Geranyl- (trans-5c), 6-Neryl-2.3-dimethoxy-5-methyl-1.4-benzochinon (cis-5c) und 2.3.5-Trimethyl-6-phytyl-1.4-benzochinon (trans-6) sowie 2-Methyl-3-phytyl-1.4-naphthochinon (trans-7) synthetisieren. Der Reaktionsmechanismus wird näher untersucht und die Stereospezifität diskutiert.
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  • 23
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Ubiquinones and Related Compounds, XXII1). - Synthesis of 2,3-Dimethoxy-5-methyl-1,4-benzoquinone and its Ethylhomologues2,3-Dimethoxy- (1a), 2,3-diethoxy-5-methyl- (1b), and 2,3-dimethoxy-5-ethyl-1,4-benzoquinone (12) are synthesized by oxidation of phenolic compounds or appropriate alkyl ethers with peracids. 3,4,5-Trimethoxy- (5a) and 3,4,5-triethoxytoluene (5b), which are obtained from gallic acid in relatively good yields, give 1a and 1b, respectively. 2,3-Dimethoxy-6-ethyl-phenol (11) and 2,3,4-trimethoxytoluene (13), which are synthesized from pyrogallol, give 12, 1a, and 2,6-dimethoxy-3-methyl-1,4-benzoquinone (14) in the same way. Intermediates and by-products of some reactions are isolated, and the reaction mechanisms are discussed.
    Notes: Durch Persäure-Oxydation geeigneter Phenole oder Alkyläther lassen sich 2.3-dimethoxy-(1a) und 2.3-Diäthoxy-5-methyl-1.4-benzochinon (1b) sowie 2.3-Dimethoxy-5-äthyl-1.4-benzochinon (12) darstellen. 3.4.5-Trimethoxy- (5a) und 3.4.5-Triäthoxy-toluol (5b), die aus Gallussäure mit relativ guten Ausbeuten dargestellt werden, ergeben dabei 1a bzw. 1b. 2.3-Dimethoxy-6-äthyl-phenol (11) und 2.3.4-Trimethoxy-toluol (13), welche, ausgehend von Pyrogallol, synthetisiert werden, ergeben ebenfalls 12 bzw. 1a und 2.6-Dimethoxy-3-methyl-1.4-benzochinon (14). Zwischenstufen und Nebenprodukte einiger Reaktionen werden isoliert und die Reaktionsmechanismen diskutiert.
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  • 24
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Ubiquinones and Related Compounds, XXIV1). - Syntheses of Quinones in the Presence of Metals1,4-Benzoquinones (1, 2, 5) and their hydroquinones (3, 4, 6) can be condensed with isoprenyl bromides 7 and 8 in petroleum ether in the presence of amalgamated zinc or palladium to give isoprenoid quinones 9-14. The condensation mechanism is discussed.
    Notes: 1.4-Benzochinone (1, 2, 5) oder deren Hydrochinone (3, 4, 6) lassen sich mit den Bromiden der isoprenoiden Alkohole 7 und 8 in Petroläther unter der Einwirkung von Zinkamalgam oder Palladium zu den isoprenoiden Chinonen 9-14 kondensieren. Der Kondensationsmechanismus wird diskutiert.
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  • 25
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 763 (1972), S. 135-147 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Alkylation of Quinones with Radicals: Generation of Radicals in Redox ReactionsCarbon radicals are generated from organic solvents by H-abstraction with OH• (Fenton's reagent). They are scavenged by quinones whereby alkylated quinones are formed. They alkylation proceeds with good yields when the radicals are produced by oxidative decarboxylation of carboxylic acids (with silver ions and persulfate).
    Notes: C-Radikale werden durch H-Abstraktion aus dem organischen Lösungsmittel mit OH-Radikalen (Fentons Reagenz) erzeugt. In Anwesenheit von Chinonen werden die Radikale abgefangen, wobei alkylierte Chinone gebildet werden. Die Alkylierung verläuft in guten Ausbeuten, wenn die Radikale durch oxydative Decarboxylierung von Carbonsäuren (mit Silberionen und Persulfat) erzeugt werden.
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  • 26
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The α,α-Dimethyl-3,5-dimethoxybenzyloxycarbonyl (Ddz) Residue, an N-Protecting Group Labile toward Weak Acids and IrradiationThe synthesis of α,α-dimethyl-3,5-dimethoxybenzyloxycarbonyl azide (7) and its reactions with several amino acids are described. It is shown that the N-acyl residue can easily be cleaved from the Ddz-amino acids under weakly acidic conditions. Moreover it is possible to eliminate the protecting group by UV-irradiation in a continuous procedure without side reactions. Fission products of the acyl residue are isolated and identified.
    Notes: Die Synthese des α.α-Dimethyl-3.5-dimethoxybenzyloxycarbonylazids (7) und seine Umsetzung mit einer Reihe von Aminosäuren zu den Ddz-aminosäuren wird beschrieben. Es wird gezeigt, daß der neue N-Acyl-Rest leicht unter schwach sauren Bedingungen abgespalten werden kann. Außerdem ist es möglich, die Schutzgruppe in einem kontinuierlichen Verfahren durch Bestrahlung mit UV-Licht ohne Nebenreaktionen zu entfernen; dabei entstehende Spaltstücke der Schutzgruppe werden isoliert und identifiziert.
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  • 27
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 763 (1972), S. 198-207 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of 5-Oxo-pyrrolines via Acyl-enehydrazines5-Oxo-pyrrolines 3 are obtained in good yields by heating acyl-enehydrazines 2 with sodium methylate. This synthesis constitutes a convenient new general method of preparation of pyrrolinones. - Acyl-hydrazones 18 lead to 5-oxo-pyrrolines only in special cases. The mechanism of the pyrrolinone synthesis is discussed.
    Notes: Acyl-enhydrazine 2 lassen sich durch Erhitzen mit Natriummethylat in guten Ausbeuten in 5-Oxo-pyrroline 3 überführen. Diese neue Pyrrolinonsynthese ist verallgemeinerungsfähig. - Aus Acyl-hydrazonen 18 entstehen 5-Oxo-pyrroline nur in speziellen Fällen. Der Mechanismus der Pyrrolinonsynthese wird diskutiert.
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  • 28
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 763 (1972), S. 184-197 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A Contribution to the Mechanism of the Polonovski Reaction.N,N-Dimethyl-mesidine-N-oxide (1b) reacts with acetic anhydride to N-acetyl-N-methyl-mesidine (8b). N-Mesityl-N-methyl-methyleneimmonium perchlorate (5b) and N,N-diisopropyl-methyleneimmonium perchlorate (5c) react with tetramethylammonium acetate (TMA) in acetic anhydride with formation of 8b or N,N-diisopropylacetamide (8e), respectively. In chloroform/methylene chloride 5b reacts with TMA, depending on the order of addition, to N-formyl-N-methyl-mesidine (19) and N,N-dimethyl-mesidine (18), or to N-mesityl-N-methyl-aminomethyl acetate (6b). Acylating agents convert 5b to the various N-acyl-N-methyl-mesidines. Under the same reaction conditions 8b does not suffer transacylation when treated with the above used acylating agents.
    Notes: N.N-Dimethyl-mesidin-N-oxid (1b) reagiert mit Acetanhydrid zu N-Acetyl-N-methyl-mesidin (8b). N-Mesityl-N-methyl-methylenimmoniumperchlorat (5b) und N.N-Diisopropyl-methylen-immoniumperchlorat (5c) reagieren mit Tetramethylammoniumacetat (TMA) in Acetanhydrid zu 8b bzw. N.N-Diisopropyl-acetamid (8e). 5b setzt sich mit TMA in Chloroform/Methylenchlorid je nach Zugabefolge einmal zu N-Formyl-N-methyl-mesidin (19) und N.N-Dimethyl-mesidin (18) und zum anderen zu N-Mesityl-N-methyl-aminomethyl-acetat (6b) um. 6b reagiert mit Acylierungsmitteln zu den verschiedenen N-Acyl-N-methyl-mesidinen. 8b erleidet unter den gleichen Reaktionsbedingungen mit den eingesetzten Acylierungsmitteln keine Umacylierung.
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  • 29
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 758 (1972), S. 202-208 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Chemical Bonded Stationary Phase of Silica and Isocyanate for ChromatographyThe mass transfer term of the stationary phase (isocyanate chemically bound to silica gel) is determined to 5 milliseconds by gas chromatographic methods. Its selectivity is high enough to resolve 18 of C1 - C4 hydrocarbons within 25 minutes at both 25 and 57°C.
    Notes: Mit gaschromatographischen Methoden wird der Massentransportterm der stationären Phase aus an Kieselgel chemisch gebundenem Isocyanat zu 5 Millisekunden bestimmt. Die Selektivität der Phase ermöglicht die Trennung von 18 C1- bis C4-Kohlenwasserstoffen innerhalb 25 Minuten bei 25 bzw. bei 57°C.
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  • 30
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Reactions of Isonitriles with Diethyl-(phenylthio)- and Diethyl-(ethylthio)-boranesIn contrast to the reactions of trialkyl- and triarylboranes, diethyl-(phenylthio)- and diethyl-(ethylthio)-boranes do not react with isonitriles to give six-membered BNC-heterocycles of the structure 1 or 2. Via the 1 : 1 addition compounds 8, novel heterocyclic sulfonium compounds 11 are formed by a 1.3-cycloaddition of a second molecule of thioborinate to the very reactive isothioformamidoborane intermediate 9. The compounds 11 are thermally isomerized to give 12 with conservation of the cyclic structure by a change of place of the ethyl and thiophenyl or thioethyl substituents. The structure of these remarkably stable 1-thionia-2.5-diborinata-3-azonia-cyclopent-3-enes is elucidated by chemical degradation and by spectroscopic investigations. In one case 9 was found to react with a second molecule of 8 to form the cyclic 2 : 2 addition product 10.
    Notes: Die Umsetzung von Isonitrilen mit Diäthyl-[phenylthio]- bzw. Diäthyl-[äthylthio]-boran führt nicht wie mit Trialkyl- oder Triarylboranen zu sechsgliedrigen BNC-Heterocyclen der Struktur 1 bzw. 2. Vielmehr entstehen über die 1 : 1-Addukte 8 durch 1.3-Cycloaddition eines weiteren Moleküls Thioborinat an die reaktive Isothioformamidoboran-Zwischenstufe 9 neuartige Sulfonium-Heteroringverbindungen 11, die sich thermisch unter Erhaltung der Ringstruktur und Platztausch von Äthyl- und Thiophenyl- bzw. Thioäthyl-Substituenten zu 12 isomerisieren lassen. Die Strukturaufklärung dieser bemerkenswert stabilen 1-Thionia-2.5-diborinata-3-azonia-cyclopent-3-ene erfolgte durch chemischen Abbau und mit Hilfe spektroskopischer Untersuchungen. Die Reaktion von 9 mit einem weiteren Molekül 8 führte in einem Fall zum cyclischen 2 : 2-Addukt 10.
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  • 31
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 1 (1972) 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
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  • 32
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Description / Table of Contents: The equations for primary, secondary and tertiary excitation in XRFA have been modified in order to describe single- and multiple-scattering processes in XRSA. For different hydrocarbons, the corresponding ratios of coherently and incoherently scattered X-rays have been calculated and the reasons for the discrepancy of approximately 15 per cent between theory and experiment discussed.
    Notes: Es werden die Gleichungen fur die Primä, Sekundär- und Tertiäranregung bei der RFA verwendet, um aus Analogiebetrachtungen die Verhältnisse bei der Einfach-, Zweifach- und Dreifachstreuung quantitativ behandeln zu können. Der charakteristische Quotient aus körent und inkohärent gestreuter Intensität wird sodann fur verschiedene Kohlenwasserstoffe berechnet und mit den experimentell gefundenen verglichen. Die Ursachen für den etwa 15 Prozent betragenden Unterschied werden diskutiert.
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  • 33
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    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 1 (1972), S. 23-28 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The usefulness of the analysing crystal is generally governed by its angular dispersion and reflecting power. This is particularly so today where the increasing requirement for more speed and greater accuracy can often only be obtained by the availability of higher net intensities. Although the performance of the conventional X-ray spectrometer is satisfactory in the middle portion of the wavelength range, it lacks dispersion at the short wavelength end and sensitivity at the long wavelength end. For this reason, there is a continuing search for crystals which offer more angular dispersion in the 0.2 to 2 Å range and better reflecting power in the 5 to 20 Å region.This paper discusses results obtained with some of the newer analysing crystals which have become available during the past couple of years. These crystals include pyrolitic graphite, rubidium acid phthalate, sorbitol hexa-acetate, and the (420) and the (422) cuts of lithium fluoride.
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  • 34
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    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 1 (1972), S. 45-45 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
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  • 35
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    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 1 (1972), S. 43-44 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: One of the current problems in the application of the X-ray spectrometer is the training of operators in the use of instrumentation and techniques. One of the usual consequences of rapid expansion in the use of any instrumental procedure is the lack of general experience and expertise, and in this X-ray spectrometry is no exception. As a technique it has only recently been introduced into the syllabus of the appropriate university course of study and, at the present time, this only at a very few universities. Training in X-ray spectrometry has therefore become very much an extra-mural course of study and among the more successful groups to offer courses in the U.S.A. has been the State University of New York at Albany. The following short report by Professor Chessin gives an informal description of the background of his ‘Clinics’ and describes some of his experiences.
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  • 36
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 1 (1972) 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
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  • 37
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    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 1 (1972), S. 49-50 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The calculator is an aid to identification of lines in X-ray emission spectra. It is designed to solve the well-known Bragg equation: nλ=2d sinθ Principal X-ray emission wavelengths (λ) of elements of atomic numbers Z=6 to 95 and lattice spacings (2d) of crystals commonly used in analysis are entered as data. The display of data is so arranged that line overlaps of the first and higher orders (n) of reflection can be seen at a glance for any spectrometer angle (θ or 2θ).
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  • 38
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    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 1 (1972) 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
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  • 39
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    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 1 (1972), S. 107-111 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: New equations have been derived to describe the dependence of characteristic X-ray intensity on particle size in heterogeneous specimens. The formulae include the effects of continuous size distributions, a problem not covered in earlier theoretical work.
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  • 40
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    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 1 (1972), S. 113-117 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The Berry - Furuta - Rhodes model is used to derive formulae for the characteristic X-ray intensity in specimens of ‘non-infinite’ thickness, as a function of particle size both for discrete values and for continuous distributions, including the Junge distribution for aerosols. Significant simplifications in otherwise complex for mulae are obtained for a number of cases of practical importance, namely, thin specimens, monolayers and low or high packing fractions. The simplified working formulae consist of the equation for a thin, homogeneous specimen, multiplied by a grain size dependent factor. This factor is a function of fluorescent grain size only, so eliminating most inter-element effects. Practical applications of these cussed, with special reference to energy dispersive X-ray fluorescence analysis of thin briquetted specimens and of aerosols collected on filters.
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  • 41
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
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  • 42
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 1 (1972) 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
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  • 43
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    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 1 (1972), S. 143-146 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: An X-ray spectrometric technique is described which enables nickel, gallium and germanium to be analysed in iron meteorites. It is important to know the concentration of these elements with sufficient accuracy in order to chemically classify iron meteorites. The spectrometer was calibrated against a set of ‘standard’ meteorites with well-established compositions.To obtain better accuracy, modification to the geometry were made to improve the peak to background ratio and eliminate machine background. This enabled nickel, gallium and germanium to be analysed with accuracies of ±0.05 per cent, ±4 p.p.m. and ±9 p.p.m. respectively for counting periods of 1 min for nickel and 10 min for gallium and germanium at the peak and background positions.
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  • 44
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
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  • 45
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    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 1 (1972), S. 129-141 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Major improvement in energy resolution in the last two years have made the Si(Li) X-ray energy analysis system a significant tool for X-ray spectroscopy. Its high detection efficiency, coupled with ability to analyse for all element simultaneously, has led to the development of several new techniques for X-ray analysis. This article reviews the present state of the technology for this instrument with respect to performance characteristics and operating principles. A brief reference to its more important applications is also included.
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  • 46
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    X-Ray Spectrometry 1 (1972), S. 161-162 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: An explanation is offered for the appearance of parasitic reflections from LiF (220) analysing crystals. The reflections appear to stem from an unrestricted vertical divergence at the primary collimator allowing entry of reflections from planes other than that to which the crystal is cut. Careful orientation of the crystal boule before cutting would seem to offer the most convenient way of avoiding the problem.
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  • 47
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    X-Ray Spectrometry 1 (1972), S. 168-168 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
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  • 48
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 754 (1972) 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 49
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Basic Di- and Tri-hydroxyanthraquinone Derivatives as Model Compounds for Anthracycline AntibioticsAs model compounds for studies of the interaction of different anthracycline antibiotics with deoxyribonucleic acids, several 1,4-di- and 1,4,5-tri-hydroxyanthraquinones with basic groups in 2-, 3- and 6-position were prepared by applying the alkylation procedure for hydroxy-anthraquinones developed by Marschalk et al.1) as well as the Mannich reaction.
    Notes: Als Modellverbindungen zum Studium der Wechselwirkungen verschiedener Anthracyclin-Antibiotika mit Desoxyribonucleinsäure wird eine Reihe von 1.4-Di- und 1.4.5-Tri-hydroxy-anthrachinonen mit basischen Resten in 2-, 3- und 6-Stellung hergestellt. Dabei kommen das von Marschalk und Mitarbeitern1) entwickelte Alkylierungsverfahren für Hydroxyanthrachinone sowie die Mannich-Reaktion zur Anwendung.
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  • 50
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: α-Halo-substituted Amines, XXXVII. α-Chloro-β-dialkylaminoethane-sulfonamides, -sulfones and -sulfoxidesα-Chloroalkyllithio- and α-chloroalkyldilithio-sulfones and -sulfonamides (2, 5) react with one or two equivalents of α-haloamines to the corresponding α-chloro-β-dialkylamino or α-chloro-β.β'-bisdialkylamino derivatives (3, 6). NMR-spectra of 3 and 6 show second order splitting patterns indicating the presence of diastereotopic methylene protons, which is similar in the case of the analogous α-chloroalkylsulfonamides 11 and 13. Treatment of lithio-α-chloromethyl-phenyl sulfoxide (15) with α-haloamines affords the β-dialkylamino derivatives 16.
    Notes: α-Chlor-alkyllithium- und α-Chlor-alkyldilithium-sulfone und -sulfonamide (2, 5) reagieren mit 1 bzw. 2 Moll. α-halogeniertem Amin zu den entsprechenden α-Chlor-β-dialkylamino-3 bzw. α-Chlor-β.β'-bis-dialkylamino-Derivaten 6. Die NMR-Spektren von 3 und 6 weisen Aufspaltungen höherer Ordnungen auf, die für das Vorliegen diastereotoper Methylen-Protonen sprechen; ähnlich liegen die Verhältnisse bei den analogen α-Chlor-alkylsulfonamiden 11 und 13. Aus Lithium-α-chlormethyl-phenyl-sulfoxid (15) und α-Halogen-methylaminen entstehen [α-Chlor-β-dialkylamino-äthyl]-phenyl-sulfoxide (16).
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  • 51
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 755 (1972), S. 58-66 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses and Reactions of 3-[1-Adamantyl]-aziridinonesThe action of potassium tert-butoxide on 1-adamantyl-N-tert-butyl-α-chloroacetamides 1a-d in ether affords predominantly the 1-tert-butyl-3-[1-adamantyl]-aziridinones 2a-d. The isomeric N-tert-butylimido-3-[1-adamantyl]-oxiranes 4a-d, which are formed only to a small extent, decompose rapidly at room temperature to give 1-adamantyl-carbaldehydes 5a-d and tert-butyl isocyanide. In tert-butyl alcohol as solvent the 1-adamantyl-N-alkyl-chloroacetamides 1a-f are transformed by potassium tert-butoxide via 2 into 1-adamantyl-N-alkyl-aminoacetic acids 6a-f and their tert-butyl esters 7. With strong acids the α-lactams 2a-d suffer a quantitative conversion into the corresponding 1-adamantylcarbaldimonium salts (for instance 3a-d) and carbon monoxide.
    Notes: Durch Einwirkung von Kalium-tert.-butylat auf die Adamantyl-(1)-chloressigsäure-N-tert.-butyl-amide 1a-d in Äther entstehen überwiegend N-tert.-Butyl-3-adamantyl-(1)-aziridinone 2a-d und zum geringen Teil die isomeren N-tert.-Butyl-2-imino-3-adamantyl-(1)-oxirane 4a-d. Letztere zerfallen schon bei 20° schnell in Adamantyl-(1)-carbaldehyde 5a-d und tert.-Butyl-isocyanid. In tert-.Butylalkohol reagieren die Adamantyl-(1)-chloressigsäure N-alkylamide 1a-f mit Kalium-tert.-butylat über 2 zu Adamantyl-(1)-N-alkyl-aminoessigsäuren 6a-f und deren tert.-Butylestern 7. Mineralsäuren spalten die α-Lactame 2a-d quantitativ zu den entsprechenden Adamantyl-(1)-carbaldehydimoniumsalzen (z. B. 3a-d) und Kohlenmonoxid.
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  • 52
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Perchlorobutenyne and Synthesis of Further Halogen-substituted ButenynesPerchlorobutenyne (1a) is brominated to 2 and converted into the ketone 3 by sulfuric acid. The Cl atom at the triple bond of 1a can be replaced by Cu or Li. The trichlorobutenynes 1b and 1c, substituted by bromine or iodine at the triple bond, and their bromination as well as their iodination products 8 and 10 are easily available from the copper salt 4. Glaser-coupling of 4 gives the octadienediyne 7, which adds bromine to give the octatetraene derivative 9.  -  Hydrolysis of the lithium compound 6 yields trichlorobutenyne 1d and treatment of 6 with CO2 or carbonyl compounds furnishes the derivatives 1p or 1e-g.  -  The trichlorobutenynes 1h and 1i with phenyl and methyl groups at the triple bond are synthesized from chloral via the intermediates 13 and 14. The compound 1i is obtainable only mixed with the pentatriene 17.  -  A convenient synthesis of butenynes 1k-n, possessing a chlorine atom at the triple bond and differently substituted at the vinyl group, starts from the aldehydes 18k-n and dichloroketene via the lactones 19 and the butadienes 20.  -  Only the butenynes 1b, 1k, 11 and 1n, characterized by halogen atoms at the triple bond, tend to undergo cyclodimerization similarly to perchlorobutenyne (1a).
    Notes: Perchlorbutenin (1a) wird zu 2 bromiert und mit Schwefelsäure in das Keton 3 übergeführt. Das am Acetylen-C gebundene Cl-Atom von 1a ist durch Cu oder Li ersetzbar. Über das Kupfersalz 4 sind die am Acetylen-C Brom- oder Jod-substituierten Trichlorbutenine 1b und 1c sowie deren Bromierungs- bzw. Jodierungsprodukte 8 und 10 leicht zugänglich. Durch Glaser-Kupplung von 4 wird das Octadiendiin 7 erhalten, welches Brom zum Octatetraen-Derivat 9 addiert.  -  Die Lithiumverbindung 6 ergibt durch Hydrolyse das Trichlorbutenin 1d und mit CO2 bzw. Carbonylverbindungen die Derivate 1p bzw. 1e-g.  -  Die am Acetylen-C Phenyl- bzw. Methyl-substituierten Trichlorbutenine 1h und 1i werden aus Chloral über die Zwischenstufen 13 und 14 dargestellt. 1i ist nur im Gemisch mit dem Pentatrien 17 erhältlich.  -  Die Umsetzung der Aldehyde 18k-n mit Dichlorketen ermöglicht über die Lactone 19 und die Butadiene 20 eine glatte Synthese der am Acetylen-C Chlor-substituierten und in der Vinylgruppe verschiedenartig substituierten Butenine 1k-n.  -  Nur die am Acetylen-C Halogen-substituierten Butenine 1b, 1k, 11 und 1n sind, wie das Perchlorbutenin (1a), zur Cyclodimerisierung befähigt.
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  • 53
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 755 (1972), S. 163-170 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of N-Acylglycines by Amidomethylation of Carbon MonoxideThe N-acylglycines 5 (table 1) are obtained by amidomethylation of carbon monoxide in sulfuric acid. Carbon monoxide is added under pressure or prepared in situ by addition of formic acid.
    Notes: Durch Amidomethylierung von Kohlenmonoxid in Schwefelsäure werden die N-Acyl-glycine 5 (Tab. 1) dargestellt. Das Kohlenmonoxid kann aufgepreßt oder im Reaktionsmedium durch Zugabe von Ameisensäure erzeugt werden.
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  • 54
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Novel Reactions of Ketene, III.  -  The Insertion Reactions of Ketene with Activated C-O-, C-S- and C-Halogen Bondsα-Substituted thioethers react with ketene (2) analogously to the corresponding oxygen derivatives. The mercaptals or mercaptols 1 give the esters of β-alkylmercapto-thiocarboxylic acids 3. Trithio-orthoformates 8 afford the β.β-dialkylmercapto-thiopropionic acids 9 and/or β-alkylmercapto-dithioglutaric acids 10. By reaction of 2 with monothioacetals 11 the β-alkoxy-thiocarboxylates 13 are obtained; with α-halogenothioethers 14, the β-alkylmercapto-acyl halides 15. Cyclic mercaptals, mercaptols, acetals or ketals 16 as well as the polyacetals and polyketals 20 react analogously. The cyclic lactones, which probably result as intermediates of the ketene insertion reaction, polymerize under the reaction conditions used, leading to the corresponding poly(thio)ether esters 17.
    Notes: 2-Substituierte Thioäther reagieren analog den entsprechenden Sauerstoffverbindungen mit Keten (2). Aus den Merkaptalen bzw. Merkaptolen 1 erhält man β-Alkylmerkapto-thiocarbonsäureester 3, aus den Trithio-orthoameisensäureestern 8 β.β-Dialkylmerkapto-thio-propionsäureester 9 und/oder β-Alkylmerkapto-dithioglutarsäureester 10. Aus den Mono-thioacetalen 11 entstehen β-Alkoxy-thiocarbonsäureester 13, aus den α-Halogen-thioäthern 14 β-Alkylmerkapto-carbonsäurehalogenide 15. Cyclische Merkaptale, Merkaptole, Acetale oder Ketale 16, sowie Polyacetale bzw. Polyketale 20 reagieren entsprechend. Die möglicherweise bei der Keten-Einschiebung in die cyclischen Verbindungen primär gebildeten cyclischen Lacton-Derivate polymerisieren unter den angewandten Reaktionsbedingungen zu den entsprechenden Poly(thio)ätherestern 17.
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  • 55
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Isobutyraldehyde, IV.  -  1- and 3-Isobutyrate of 2,2,4-Trimethylpentane-1,3-diolCondensation of isobutyraldehyde with catalytic amounts of sodium alcoholate gives 37% of the 3-isobutyrate 1b of 2,2,4-trimethylpentane-1,3-diol (1) as well as the expected 1-isobutyrate 1a. Nearly the same ratio of 1a to 1b is formed by esterification of 1 with isobutyric acid. The isobutyrate 2a of 2,2,4-trimethyl-3-penten-1-ol (2), obtained by cracking the diisobutyrate 1c, is free of isomers, while the esterification of 1 leads as a byproduct to a mixture (3 : 2) of 2a and its Δ4-isomer.
    Notes: Bei der Kondensation von Isobutyraldehyd unter der Katalyse durch Na-alkoholat entsteht neben dem bisher aufgefundenen 1-Isobuttersäureester 1a des 2.2.4-Trimethyl-pentandiols-(1.3) (1) zu 37% der isomere 3-Isobuttersäureester 1b. Ein ähnliches Isomerenverhältnis 1a : 1b wird bei der Veresterug von 1 mit Isobuttersäure gefunden. Der durch thermische Spaltung des Diisobuttersäureesters 1c entstehende Isobuttersäureester 2a des 2.2.4-Trimethylpenten-(3)-ols-(1) (2) ist isomerenfrei, während aus der Veresterung von 1 als Nebenprodukt ein 3 : 2-Gemisch von 2a und dem Δ4-Isomeren hervorgeht.
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  • 56
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 757 (1972) 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 57
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 757 (1972), S. 1-8 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Additions to Trifluoromethyl-substituted 2-Aza-1,3-butaddienes, I. - 1,4-AdditionsN-[1,1,1,3,3,3-Hexafluoroisopropylidene]-2-alkyl(or 2,2-dialkyl)-vinyl amines 1 react with bromine and nucleophilic compounds (primary, secondary amines or mercaptans) yielding the 1,4-addition products 2, 3 and 6-8, respectively.
    Notes: N-[1.1.1.3.3.3-Hexafluor-isopropyliden]-2-alkyl(bzw.2.2-dialkyl)-vinylamine 1 reagieren unter 1.4-Addition mit Brom zu 2 und mit Nucleophilen (primäre, sekundäre Amine oder Mercaptane) zu 3 bzw. 6-8.
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  • 58
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Resolution of Racemic Carbonyl Compounds by Means of Bifunctional Reagents with Optically Active Basesdl-Hydratropaaldehyde(I), dl-3-methylcyclohexanone (II) and dl-carvone (III) are converted with the bifunctional reagents 4-hydrazinobenzoic acid (1), 3-hydrazinobenzoic acid (2), phenylhydrazine-4-sulfonic acid (3) and oxalic acid monohydrazide (4) to hydrazonecarboxylic or sulfonic acids and then resolved by means of optically active bases (brucine, α-phenylethylamine, N-benzyl-α-phenylethylamine). 4 has the most marked anisotropic properties. - The conditions of crystallisation must be quoted with melting point data for characterization of the optically active N,N′-disubstituted hydrazones, since the values, like the specific rotations, are dependent on the temperature of solution and the solvent employed.
    Notes: dl-Hydratropaaldehyd (I), dl-3-Methyl-cyclohexanon (II) und dl-Carvon (III) werden mit den bifunktionellen Reagenzien 4-Hydrazino-benzoesäure (1), 3-Hydrazino-benzoesäure (2), Phenylhydrazin-4-sulfonsäure (3) und Oxalsäuremonohydrazid (4) in Hydrazoncarbonsäuren bzw. -sulfonsäuren umgewandelt und dann mittels optisch aktiver Basen (Brucin, α-Phenyl-äthylamin, N-Benzyl-α-phenyl-äthylamin) gespalten. 4 vermittelt hierbei die stärksten anisotropen Eigenschaften. - Bei der Angabe von Schmelzpunkten und spezifischen Drehwerten der optisch aktiven, kristallinen N.N′-disubstituierten Hydrazone müssen die Kristallisations-bedingungen mitgeteilt werden, da beide Werte von der Temperatur und vom Lösungsmittel beim Umkristallisieren abhängen.
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  • 59
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    Liebigs Annalen 757 (1972), S. 79-86 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Chemistry and Biochemistry of Plant Constituents, XXXII. - Synthesis of Flavanol Derivatives3-Flavanyl methyl ether (12) and 4-methoxy-3-flavanyl methyl ether (18) are synthesized by cyclization of the corresponding 1,3-diphenyl-2-methoxy-3-propanols (7 and 10), obtained by catalytic hydrogenation of the corresponding chalcones (8 and 11). The reaction of 7 and 10 with diphosphoric pentoxide, containing polyphosphoric acid, furnishes the benzalcoumaranes 14 and 17.
    Notes: Flavanyl-(3)-methyläther (12) und 7-Methoxy-flavanyl-(3)-methyläther (18) entstehen bei Cyclisierung der entsprechenden 1.3-Diphenyl-2-methoxy-propanole-(3) (7 und 10), die durch katalytische Hydrierung der entsprechenden Chalkone (8 und 11) erhalten werden. Die Umsetzung von 7 und 10 mit Polyphosphorsäure-haltigem Diphosphorpentoxid führt zu den Benzalcumaranen 14 und 17.
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  • 60
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Catalysis by Phthalocyanines, XII. - Autoxidation of Diphenylcyclopentanes and Diphenylcyclohexanes in Presence of Copper-phthalocyanineIn the autoxidation of cis- and trans-1,2-diphenylcyclopentane (1 and 2), 1,3-diphenylcyclopentane (isomer mixture 3), cis-1,2-diphenylcyclohexane (4) and trans-1,3-diphenylcyclohexane (5) at 86-99° in presence of copper-phthalocyanine (Cu-pc), the reaction rate in the period of increasing rate is dependent on the square of the oxidation degree. The initiation reaction in the presence of hydroperoxide is thus a bimolecular reaction of a hydroperoxide dimer, whereby the long induction periods are accounted for. - The relative reactivities are discussed on the basis of an extended I-strain theory; accordingly special effects are to be considered beside the differences of the torsion strain and the ortho-β-interaction.
    Notes: Die Geschwindigkeit der Autoxidation von cis- und trans-1.2-Diphenyl-cyclopentan (1 bzw. 2), 1.3-Diphenyl-cyclopentan (Isomerengemisch 3), cis-1.2-Diphenyl-cyclohexan (4) und trans-1.3-Diphenyl-cyclohexan (5) bei 86-99° in Gegenwart von Kupfer-phthalocyanin (Cu-pc) ist im ansteigenden Bereich vom Quadrat des Oxidationsgrades abhängig. Als Kettenstartreaktion bei Anwesenheit von Hydroperoxid ist daher eine bimolekulare Reaktion eines Hydroperoxid-Dimeren anzunehmen, woraus sich auch die langen Induktionsperioden erklären lassen. - Die relativen Reaktivitäten werden auf der Basis einer erweiterten I-strain-Theorie diskutiert, wobei neben den Differenzen der Torsionsspannungen und der ortho-β-Wechselwirkung weitere spezielle Wechselwirkungen zu berücksichtigen sind.
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  • 61
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Catalysis by Phthalocyanines, XI. - Autoxidation of Phenylcycloalkanes in the Presence of Copper-phthalocyanineThe autoxidation of phenylcycloheptane (1) at 86-96° in presence of copper-phthalocyanine ([Cu-pc] 0.75 mmole/mole) yields (Δ Ei 20.7 kcal/mole) 1-phenylcycloheptylhydroperoxide (1a). Phenylcyclopropane (3) and phenylcyclooctane (2) do not react under the conditions used. The relative reactivity of 1 in comparison to the formerly studied phenylcyclopentane and phenylcyclohexane is explained by the I-strain-theory, both the differences of the torsion strain and ortho-β-hydrogen interactions being discussed. The stability of 2 is explained by the o-β-interaction and a chain effect. The difference in the angle strain and the quasi-olefinic character of the hydrocarbon 3 are responsible for the stability.
    Notes: Die Autoxidation von Phenylcycloheptan (1) bei 86-96° mit Kupferphthalocyanin ([Cu-pc] 0.75 mMol/Mol) liefert (ΔEi = 20.7 kcal/Mol) 1-Phenyl-cycloheptylhydroperoxid (1a). Phenylcyclopropan (3) und Phenylcyclooctan (2) reagieren unter den angewandten Bedingungen nicht. Die relative Reaktivität von 1 im Vergleich zum früher studierten Phenylcyclopentan und Phenylcyclohexan wird aufgrund der I-strain-Theorie erklärt, wobei, neben den Differenzen der Torsionsspannungen, ortho-β-Wasserstoffwechselwirkungen diskutiert werden. Die Stabilität von 2 wird durch die o-β-Wechselwirkung sowie einen Ketteneffekt erklärt. Beim Kohlenwasserstoff 3 sind die Differenz in der Winkelspannung sowie der quasiolefinische Charakter für die Stabilität verantwortlich.
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  • 62
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaction of Aryl Alkyl Ketones with Dimorpholinodisulfide. - Contribution to the Willgerodt-Kindler-SynthesisSubstitution of the normally used sulfur-amine mixtures by dimorpholinodisulfide 1 in a modified Willgerodt-Kindler-reaction with the ketones 2a-d affords the products 5, 6 and 7. The fragmentation reaction of 1, occurring as a side reaction in the modified Willgerodt-Kindler-reaction affords the compounds 3 and 4.
    Notes: Ersetzt man die bisher üblichen Schwefel-Amin-Gemische durch Dimorpholinodisulfid 1 und wendet dieses in einer modifizierten Willgerodt-Kindler-Reaktion auf die Ketone 2a-d an, so können die Produkte 5, 6 und 7 isoliert werden. Die Fragmentierungsreaktion von 1, die als Konkurrenzreaktion bei den obengenannten Umsetzungen auftritt, führt zu den Verbindungen 3 und 4.
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  • 63
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Antamanide, XI. - Merrifield Synthesis of Tyrosine-containing Analogues of AntamanideAnalogues of antamanide (AA) in which the phenylalanines in positions 5, 6, 9 and 10 are replaced by tyrosine are synthesized by punched tape programmed automatic synthesis on polystyrene resins. Tyrosine is used as its O-benzyl derivative: Tyr5-AA (1), Tyr6-AA (2), Tyr9-AA (3), Tyr10-AA (4), Ile1. Tyr6-AA (5), Ile1. Tyr5. Tyr10-AA (6), Gly1. Gly4. Tyr5-AA (7), Gly1. Gly4. Tyr6-AA (8), and Tyr9. de-Ala-AA (9). The cyclopeptides 1, 2 and 5 like AA protect in a dose of 0.5-1 mg per kg the white mouse from being killed by 5 mg phalloidine per kg, the analogue 3 with 2 mg per kg; 4 and 6 have the same effect with 5 mg per kg and the glycine-containing tyrosine-antamanides 7 and 8 are ineffective even with 20 mg per kg. The cyclononapeptide 9 without Ala4 of the antamanide sequence is found to be the first effective shortened analogues of AA with a protecting dose of 5-10 mg per kg.
    Notes: Analoge des Antamanids (AA), in denen die Phenylalanine der Positionen 5, 6, 9 und 10 durch Tyrosin ersetzt sind, werden durch Lochstreifen-programmierte, automatische Synthese der linearen Decapeptide-Vorstufen an Polystyrolharzen unter Verwendung von O-Benzyl-tyrosin aufgebaut und zwar: Tyr5-AA (1), Tyr6-AA (2), Tyr9-AA (3), Tyr10-AA (4), Ile1. Tyr6-AA (5), Ile1. Tyr5. Tyr10-AA (6), Gly1. Gly4. Tyr5-AA (7), Gly1. Gly4. Tyr6-AA (8), und Tyr9. des-Ala-AA (9). Die Cyclopeptide 1, 2 und 5 schützen wie Antamanid mit ca. 1 mg pro kg die weiße Maus vor dem Tod durch 5 mg Phalloidin pro kg, die Variante 3 mit 2 mg pro kg; 4 und 6 wirken mit 5 mg pro kg, während die Glycin-haltigen Tyrosin-Antamanide 7 und 8 noch mit 20 mg pro kg unwirksam sind. Im Cyclononapeptid 9, dem das Ala4 der Antamanidsequenz fehlt, liegt das erste wirksame, verkürzte Antamanid-Analog vor; es schützt die Maus bei einer Dosis von 5-10 mg pro kg.
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  • 64
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    Liebigs Annalen 757 (1972), S. 181-186 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Halogenoethers, IX. - Chlorination of Enol Ethers with Iodosobenzene DichlorideThe enol ethers 1 react with iodosobenzene dichloride (6) to 1.2-dichloroethers 3. Secondary products formed from enol ethers 1 and chlorine are not obtained. The interaction between 3.4-dihydropyran (1d) and 6 shows that a trans-addition takes place. The chlorination of 1 with 6 is described by a radical-chain-reaction.
    Notes: Die Enoläther 1 reagieren mit [Dichlorjod]-benzol (6) zu den 1.2-Dichlor-alkyläthern 3. Folgeprodukte, wie sie bei der Chlorierung von 1 mit Cl2 entstehen, treten dabei nicht auf. Die Reaktion von 3.4-Dihydro-pyran (1d) mit 6 zeigt, daß es sich hierbei um eine trans-Addition handelt. Die Chlorierung von 1 mit 6 läßt sich mit einem Radikalmechanismus beschreiben.
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  • 65
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 757 (1972), S. 153-169 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyclisation Reactions of Alkynones with Double CH-Acid Compounds to PhenolsAlkynones 1 and CH-acid compounds like dibenzyl ketone react to substituted phenols 4 in the presence of K-tert-butylate. Depending on the substituents, 2,3,5,6-tetrasubstituted phenols are oxidized by CrO3/acetic acid to benzoquinones 11a-f or fluorene quinones 9 and 10 In a solution of HBr/acetic acid phenols of the type of 4a or 4f form fluorenols like 12 or phthalanes like 13.
    Notes: Acetylenketone 1 und CH-acide Verbindungen von der Art des Dibenzylketons reagieren in Gegenwart von K-tert.-butylat zu substituierten Phenolen 4. 2.3.5.6-Tetrasubstituierte Phenole werden mit CrO3/Eisessig je nach Substitution zu Benzochinonen 11a-f bzw. zu Fluorenchinonen 9 und 10 oxydiert. In HBr/Eisessig reagieren Phenole vom Typ 4a bzw. 4f zu Fluorenolen, wie 12, bzw. zu Phthalanen, wie 13.
    Additional Material: 3 Tab.
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    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 757 (1972), S. 170-180 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Halogenoethers, VIII. - The Mechanism of Ether Chlorination with Chlorinating ReagentsThe reaction of iodosobenzene dichloride (2) with the unsymmetrical ethers 6 is investigated. Distribution of the chlorinated products 7 and 8 proves the participation of a C6H5-l-Cl radical in ether chlorination with 2. An explanation is given for the formation of only the monochloroethers 3 from the ethers 1 and 2. The monochloroethers 3 alone also are obtained from sulfuryl chloride and dialkyl ethers 1, which are used as solvents. The mechanism of this reaction is studied.
    Notes: Die Umsetzung von [Dichlorjod]-benzol (2) mit den unsymmetrischen Äthern 6 wird untersucht. Aus der Verteilung der Chlorierungsprodukte 7 und 8 läßt sich die Beteiligung eines C6H5-j-Cl-Radikals bei der Ätherchlorierung mit 2 beweisen. Es wird versucht, das ausschließliche Auftreten der Monochloräther 3 bei der Reaktion der Äther 1 mit 2 zu erklären. Sulfurylchlorid gibt mit den Dialkyläthern 1, die dabei zugleich als Lösungsmittel dienen, ebenfalls nur die monochlorierten Äther 3. Der Mechanismus dieser Reaktion wird durch Chlorieren von unsymmetrischen Äthern verfolgt.
    Additional Material: 1 Ill.
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    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology