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  • 1965-1969  (3,129)
  • 1890-1899  (2,182)
  • Organic Chemistry  (5,311)
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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 727 (1969), S. 219-221 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions with Diazocarbonyl Compounds, XXXI V I ). o-Quinone Diazides and o-Quinones as Dehydrobenzene InterceptorsSuitably substituted o-quinone diazides can be used to intercept arynes with simultaneous N2-elimination and formation of dibenzofuranes. o-Quinones add arynes in a Diels-Alder synthesis to form cyclic diketo compounds, which react with o-phenylenediamine to give the corresponding quinoxalines.
    Notes: Arine lassen sich mit geeignet substituierten o-Chinondiaziden unter N2-Abspaltung und Bildung von Dibenzofuranen abfangen. o-Chinone addieren nach Diels-Alder Arine zu cyclischen Diketo-Verbindungen, die mit o-Phenylendiamin zu den entsprechenden Chinoxalinen kondensieren.
    Additional Material: 3 Tab.
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 729 (1969), S. 231-233 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Oxidative Degradation of 5,6-DimethylbenzimidazolePrior to carrying out tracer experiments used in the investigation of the biosynthesis of 5,6-dimethylbenzimidazole (1) methods for its degradation had to be worked out. In order to identify all C-atoms, 1 had to be degraded by two procedures: The Kuhn-Roth degradation yields acetic acid and CO2. The acetic acid undergoes Schmidt degradation thus allowing the identification of C-5, C-6, and the methyl groups of 1. - The oxidation of 1 with K2Cr2O7 yields imidazole-4,5-dicarboxylic acid (4) which after decarboxylation gives imidazole and CO2. Thus C-2, C-8, and C-9 on the one hand and C-4 and C-7 on the other hand can be identified.
    Notes: Für Tracerversuche zur Biosynthese von 5.6-Dimethyl-benzimidazol (1) wurde 1 oxydativ abgebaut. Die Identifizierung sämtlicher C-Atome gelingt nur durch Abbau nach zwei Methoden: Der Kuhn-Roth-Abbau führt zu Essigsäure und CO2. Durch anschließenden Schmidt-Abbau der Essigsäure können C-5, C-6 und die Methyl-Gruppen von 1 identifiziert werden. - Die Oxydation mit Kaliumdichromat führt zu Imidazol-dicarbonsäure-(4.5) (4), deren Decarboxylierung zu Imidazol und CO2 die Identifizierung von C-2, C-8 und C-9 bzw. C-4 und C-7 erlaubt.
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 728 (1969), S. 49-55 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Molecular Structure Changes in Chemical Reactions, XXI 1 ). Deamination in the Bicyclo[2.2.l]-heptane SeriesThe deamination of bornyl- and fenchylamines is studied by gas chromatography. In contrast to norbornylamines the exo and endo compounds behave differently. A Wagner-Meerwein rearrangement is the main reaction in both cases. The resulting tertiary alcohol in the fenchane series is stereochemically mixed. Ring opening is considerable with endo amines but only slight with exo amines. The results are compared with those of the solvolysis in methanol of the corresponding tosylates.
    Notes: Die Desaminierung der Bornyl- und Fenchylamine wird gaschromatographisch untersucht; die im Gegensatz zu den Norbornylaminen bestehenden Verschiedenheiten von exo- und endo- Form werden festgelegt. Die Hauptreaktion ist allerdings in beiden Fällen eine Wagner-Meerwein-Umlagerung. Der entstehende tertiäre Alkohol in der Fenchan-Reihe ist sterisch nicht einheitlich. Eine Ringspaltung tritt bei den endo-Aminen erheblich, bei den exo-Aminen minimal ein. Die Ergebnisse werden mit denen der Methanolyse der entsprechenden Tosylate verglichen.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 729 (1969), S. 119-123 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Azobarbituric Acid arid Alloxan AzineAzobarbituric acid (2) is formed as a by-product of the reaction between barbituric acid and carbamoylazide (H2NCON3), the main product being 5-aminocarbonylbarbituric acid. It is easily dehydrogenated by bromine water to give alloxan azine (3) which readily undergoes disproportionation yielding 2, diazobarbituric acid (1), and alloxan (5). 2 can be prepared in good yield by coupling diazobarbituric acid with barbituric acid in alkaline medium.
    Notes: Azobarbitursäure (2) tritt als Nebenprodukt der Reaktion zwischen Barbitursäure und Carbamoylazid (H2NCON3) zu 5-Aminocarbonyl-barbitursäure auf. 2 wird durch Bromwasser zu Aloxanazin (3) oxydiert, das leicht disproportioniert, wobei 2, Diazobarbitursäure (1) und Alloxan (5) entstehen. 2 wird in guter Ausbeute durch Kupplung von Diazobarbitursäure mit Barbitursäure in alkalischem Medium dargestellt.
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 729 (1969), S. 139-145 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyanacetaldehyde Derivatives and Reaction ProductsThe reaction of malondialdehydedioxim (2) with aromatic diazonium salts or nitrous acid leads to derivatives 5 of cyanoacetaldehyde in a quite simple way. The hydrazones of these compounds can be converted into 1-substituted 5-aminopyrazoles 6.
    Notes: Ausgehend vom Malondialdehyddioxim (2) erschließt sich über die Umsetzung mit Aryldiazoniumsalzen oder salpetriger Säure ein einfacher Zugang zu Cyanacetaldehyd-Derivaten 5, von denen sich die Hydrazone in 1-substituierte 5-Amino-pyrazole 6 überführen lassen.
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 729 (1969), S. 124-138 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Triazolylbenzoic Acids and Acylaminoquinazolones from Benzoxazinones and Curbohydrazideso(4-s-Triazolyl)benzoic acids 2 can easily be prepared in good yields from so-called acylanthranils with carbohydrazides in boiling ethanol. In hot benzene, the isomeric 3-acyl-amino-4-quinazolones 1 are formed from the same components. Both reactions proceed via amidrazones 11, which are formed by the reaction of the terminal hydrazide nitrogen atom with the oxazinone nucleus at C-2. - 3,4,5-Trisubstituted s-triazoles can also be made from N-substituted imidoyl chlorides with hydrazides. - s-Triazolo[4,3-a]quinolines of the type 18c are available by intramolecular condensation of certain triazolylbenzoic acids.
    Notes: o-[s-Triazolyl-(4)]-benzoesäuren 2 können präparativ einfach aus [Acylanthranilen] und Carbonsäurehydraziden in siedendem absolutem äthanol gewonnen werden. Aus den gleichen Komponenten bilden sich in Benzol die isomeren 3-Acylamino-chinazolone-(4) 1. Beide Reaktionen verlaufen über Amidrazone 11, gebildet bei der Reaktion des endständigen Hydrazid-Stickstoffs mit dem Kohlenstoff-Atom 2 des Oxazinon-Ringes. - Eine weitere Synthese für den 3.4.5-trisubstituierten s-Triazol-Ring ist mit N-substituierten Imidchloriden 7 und Hydraziden ausführbar. Bestimmte Triazolylbenzosäuren lassen sich zu s-Triazolo[4.3-a]chinolinen vom Typ 18c kondensieren.
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 729 (1969), S. 198-204 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Frog Venoms.Isolation and Structure of Pumiliotoxin CPumiliotoxin C, a base of the composition C13H25N, is isolated as the crystalline hydrochloride from the skin extracts of Dendrobates pumilio, a strikingly colored Panamanian frog. Complete X-ray analysis of this new venom by the so-called symbolic addition procedure establishes the structure as 2-n-propyl-5-methyl-cis-decahydroquinoline, a type of base, though related to coniine, is here reported for the first time as a natural product. The relative configurations of the four asymmetric centers are elucidated. In addition to this venom there are the congeners pumiliotoxins A and B, as well as further homologs and analogs which have also been isolated from the related frog Dendrobates auratus, and characterized by mass spectra.
    Notes: Aus dem Hautextrakt des in Panama vorkommenden, auffallend gefärbten Froschs Dendrobates pumilio läβt sich das gut kristallisierende Hydrochlorid einer Base Pumiliotoxin C der Formel C13H25N isolieren. Durch Röntgen-Strukturanalyse dieser Base nach dem „symbolischen Additionsverfahren“ (symbolic addition procedure) läβt sich zeigen, daβ es sich um einen zum ersten Mal in der Natur beobachteten, dem Coniin weitläufig verwandten Giftstofftyp handelt, nämlich um ein 2-n-Propyl-5-methyl-cis-decahydrochinolin, dessen vier asymmetrische Zentren in ihrer relativen stereochemischen Bezeichnung aufgeklärt werden. Neben Pumiliotoxin C leiten sich auf Grund der Massenspektren die Pumiliotoxine A und B sowie noch weitere aus dem verwandten Frosch Dendrobates auratus isolierte Basen von einem ähnlichen cis-Deca- oder Octahydrochinolin-System ab.
    Additional Material: 5 Ill.
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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: Constituents of the Horse Chestnut, VII 1). O-Isopropylidene Derivatives of Protoescigenin, Barringtogenol C,and their 21-Angelic (Tiglic) Acid and 28-Angelic (Tiglic) Acid EstersThe O-isopropylidene derivatives of protoescigenin barringtogenol C, and their 21-angelic (tiglic) acid and 28-angelic(tiglic) acid esters have been prepared by reaction with acetone/p-toluenesulfonic acid. The substances were isolated by column chromatography and their structures have been determined.
    Notes: O-Isopropyliden-Derivate von Protoäscigenin, Barringtogenol C und von deren 21- bzw. 28-Angelika(Tiglin)säureestern werden durch Umsetzung mit Aceton/p-Toluolsulfonsäure hergestellt, durch Säulenchromatographie isoliert und in ihrer Struktur bestimmt.
    Additional Material: 3 Tab.
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 729 (1969), S. 237-239 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses and Properties of Dithioamino Acid EstersFrom the previously unknown class of dithioamino acid esters three members have been synthesized: N-benzoyl dithioglycine ethyl ester, ∊-amino-dithiocaproic acid ethyl ester p-toluenesulfonate, and N-acetyl dithiophenylalanine ethyl ester. The syntheses have been carried out via the nitriles. The absorption bands of the C=S-group are at approximately 3100 Å and approximately 4500 Å (table 1). The proton magnetic resonance spectrum of the prototypic N-benzoyl dithioglycine ethyl ester (page 238) is consistent with its proposed structure.
    Notes: Aus der bisher unbekannten Gruppe der Dithioaminosäureester werden drei Vertreter dargestellt: N-Benzoyl-dithioglycinäthylester, ∊-Aminodithiocapronsäureäthylester-p-toluolsulfonat und N-Acetyl-dithiophenylalaninäthylester. Die Darstellung erfolgt über die Nitrile. Die Absorptionsbanden der C=S-Gruppe liegen bei ca. 3100 Å und ca. 4500 Å (Tab. 1). Das Protonenresonanzspektrum von N-Benzoyl-dithioglycinäthylester (S. 238) entspricht seiner Struktur.
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 725 (1969), S. 238-240 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 3H-DesmethylphalloinA radioactive desmethylphalloin (2) is obtained by reduction of the CO-group of ketophalloidin (1) with 3H-containing NaBH4. It has almost the same toxicity as phalloidin (LD50=2.2 mg/kg body weight of the white mouse). As a consequence of the relatively high radioactivity (220 μCi/mg) 2 gives during storing a degradation product, which can be separated by chromatography on Sephadex G-25 or LH-20 using water as eluent, and whose UV-spectrum indicates a sulfoxide structure.
    Notes: Durch Reduktion der Ketogruppe des Ketophalloidins (1) mit 3H-haltigen NaBH4 wird ein radioaktives Desmethylphalloin (2) erhalten, das etwa dieselbe Toxizität wie Phalloidin besitzt. Infolge der hohen spezif. Aktivität (220 μCi/mg) entsteht beim Lagern aus 2 ein chromatographisch an Sephadex G-25 oder LH-20 in Wasser abtrennbares Zersetzungsprodukt, dessen UV-Absorptionskurve auf das Vorliegen einer Sulfoxid-Struktur hindeutet.
    Additional Material: 1 Ill.
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  • 11
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 726 (1969), S. 13-18 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Phosphorus Pentafluoride and Boron Trifluoride in Liquid TrifluoromethanePhosphorus pentafluoride and boron trifluoride form conducting solutions in liquid trifluoromethane. The adducts (CH3)3N·PF5 and (CH3)3N·BF3 and also the salts [(CH3)3NH] [PF6] and [(CH3)3NH][BF4], respectively, may be obtained from these solutions by addition of trimethylamine. Complex anions containing trifluoromethyl ligands are not formed.
    Notes: Phosphor(V)-fluorid bzw. Bor(III)-fluorid zeigen in flüssigem Trifluormethan elektrisches Leitvermögen. Aus den Lösungen lassen sich mit Trimethylamin die Addukte (CH3)3N· PF5 bzw. (CH3)3N·BF3 und die Salze [(CH3)3NH][PF6] bzw. [(CH3)3NH][BF4] gewinnen. Trifluormethylhaltige Komplex-Anionen werden nicht gebildet.
    Additional Material: 3 Ill.
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  • 12
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 726 (1969), S. 36-41 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Carbenes Derived from Bicyclo[3.3.0]octaneBicyclo[3.3.o]octane derivatives with divalent carbon in position 2 show little tendency to undergo intramolecular insertion with formation of tricyclo[3.2.1.02,8]octane derivatives. The tosylhydrazone of 2-bicyclo[3.3.0]octanone (1) yields predominantly 2-bicyclo[3.3.0]octene (2). the tosylhydrazone 7 of 10 bicyclo[3.3.0]octene-4-one prefer intermolecular reactions 9formation of ether) and affords less than 10% fo 4-tricyclo[3.2.1.02,8] octene (8).
    Notes: Carbene der Bicyclo[33.30]octan-Reihe mit zweibindigem Kohlenstoff in 2-Stellung zeigen geringe Neigung zu intramolekularer Einschiebung unter Bildung von Tricyclo[3.2.1.02.8]-octan-Derivaten. Aus Bicyclo[3.3.0]octanon-(2)-tosylhydrazon (1) entsteht bei alkalisch thermischer Spaltung vorwiegend Bicyclo[3.3.0]octen-(2) (2). Bicyclo[3.3.0]octen-(1)-on(4) tosylhydrazon (7) weicht auf intermolekulare Reaktionen (äther-Bildung) aus und liefert maximal 10% Tricyclo[3.2.1.02.8]octen-(4) (8).
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  • 13
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 726 (1969), S. 77-80 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A New Preparation of AziridinesAddition of chlorine and acetonitrile to olefins yields dichloroimines 1. By methanolysis of 1, followed by acid hydrolysis, we obtained via the iminoesters 4 the β-chloroamines 5, which are easily converted into aziridines 3. It is not necessary to isolate the intermediate products.
    Notes: Eie Addition von Chlor und Acetonitril an Olefine ergibt Dichlorimine 1. Durch Methanolyse von 1 und anschließende saure Hydrolyse erhielten wir über die Iminoester 4 die β-Chloramine 5, die sich leicht in Aziridine 3 überführen lassen. Die Isolierung der Zwischenprodukte ist nicht erforderlich.
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  • 14
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 727 (1969), S. 106-109 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses with Quinones in situ, VII 1). Preparation of 7-Dimethylamino-2-hydroxyphenothiazin-3-one7-Dimethylamino-2-hydroxyphenothiazin-3-one (4) is obtained for the first time by using 2-amino-5-dimethylanilin-thiosulfuric acid (1) as starting material. There are two different procedures, the second procedure allows the isolation of the intermediate indophenol.
    Notes: 7-Dimethylamino-2-hydroxy-phenothiazinon-(3) (4) wird auf zwei Wegen aus 2-Amino-5-dimethyl-anilin-thioschwefelsäure (1) erstmalig dargestellt. Bei dem zweiten Reaktionsweg läßt sich die Indophenol-Zwischenstufe isolieren.
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  • 15
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 727 (1969), S. 125-129 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A Novel Synthesis of AntamanidBy cyclization of the linear decapeptide phenylalanyl-phenylalanyl-prolyl -prolyl-phenyl-alanyl-phenylalanyl-valyl-prolyl-prolyl-alanine (position 5 → 4 in formula 1,) with the help of dicyclohexylcarbodiimide/N-hydroxy-succinimide (DCC/HOSu) antamanid (1,) is obtained in a 36.5% yield.
    Notes: Durch Ringschluß des linearen Decapeptids Phe-Phe-Pro-Pro-Phe-Phe-Val-Pro-Pro-Ala (Stellung 5 → 4 in Formel 1) mittels Dicyclohexylcarbodiimid/N-Hydroxy-succinimid wird das cyclische Decapeptid Antamanid in 36.5 proz. Ausbeute erhalten.
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  • 16
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Catalytic Conversion of Olefins, I If'). Synthesis of cis,trans-l.5-Cyclodecadiene and I,trans-4.9-Decatriene. Co-oligomerization of Butadiene with EthyleneButadiene and ethylene can react together in the presence of “naked nickel” or nickel ligand catalytic systems to give cis,trans-1,5-cyclodecadiene (4; in yields of up to 80%). The intermediate 1 rearranges thermally to cis-1,2-divinylcyclohexane (6). 1, trans-4.9-Decatriene (5) is formed preferentially from butadiene and ethylene at 100°. Other unsaturated systems may also be included in the co-oligomerization reaction.
    Notes: Mit Hilfe von “nacktem Nickel” bzw. von Ligand/Ni-Katalysatoren können Butadien und äthylen zum cis.trans-Cyclodecadien-(1.5) (4) zusammengelagert werden (Ausbeute bis zu 80%). 4 lagert sich thermisch in cis-1.2-Divinyl-cyclohexan (6) um. Bei 100° entsteht aus Butadien und äthylen bevorzugt Decatrien-(1.trans-4.9) (5). In die Mischoligomerisation können auch andere ungesättigte Systeme einbezogen werden.
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  • 17
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions with Diazocarbonyl Compounds, XXXIII1). Reaction of o-Quinone Diazides with Ethyl p-Nitrophenylacetate and p-Nitrobenzylcyanideo-Quinone diazides react with p-NO2-C6H4-Ch2-CO2C2H5 and p-NO2-C6H4-CH2-CN to 2-hydroxyphenylhydrazones of the related keto compounds (table 1). The substances 1-9 are indicators. The cyano compound 8 shows solvatochromy reaching over the whole visible spectrum. The colour of the solution is related to the ability of the solvent to solvatise protons.
    Notes: o-Chinondiazide reagieren mit p-Nitrophenyl-essigsäureäthylester sowie mit p-Nitrobenzylcyanid zu 2-Hydroxy-arylhydrazonen der entsprechenden Keto-Verbindungen (Tab. 1). Die Substanzen 1-9 sind Indikatoren. Die Cyan-Verbindung 8 zeigt eine über das ganze sichtbare Spektrum gehende Solvatochromie, wobei ein Zusammenhang zwischen der Lösungsfarbe und der Fähigkeit des Lösungsmittels, Protonen zu solvatisieren, besteht.
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  • 18
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 727 (1969), S. 228-230 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Mesomeric Kations, I. Synthesis of S-Aryl-thiuronium SaltsS-Aryl-tetramethyl-thiuronium perchlorates (3) are synthesized by reaction of tetramethylthiourea with activated aromatic halogen compounds (2) or with substituted diazonium salts. The reaction of tetramethylchloroformamidinium chloride (4) with thiophenols also gives the compounds 3 in high yields.
    Notes: Zur Synthese von S-Aryl-tetramethylthiuroniumperchloraten (3) läßt sich Tetramethylthioharnstoff mit aktivierten Halogenbenzolen (2) oder mit Diazoniumsalzen arylieren. Außerdem führt die Umsetzung von Tetramethyl-chlorformamidiniumchlorid (4) mit Thiophenolen ebenfalls glatt zu den Verbindungen 3.
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  • 19
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 728 (1969), S. 12-16 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaction of Iodosobenzene dichloride with Symmetrical EthersIodosobenzene dichloride (1) reacts with symmetrical ethers 2 under exposure to light, yielding monochloroethers 3. The formation of 1,2-dichloroethers 9, which are formed by interaction of chlorine with ethers 2, is not observed. The reaction of 1 with 2 can be explained by means of a chain reaction of C6H5-I -Cl radicals.
    Notes: Phenyljodidchlorid (1) reagiert mit symmetrischen äthern 2 bei Lichteinwirkung zu Monochloräthern 3. Das Auftreten von 1.2-Dichloräthern 9, die bei der Einwirkung von Chlor auf äther 2 entstehen, wird nicht beobachtet. Mit einer Kettenreaktion über C6H5-J.-Cl-Radikale läßt sich die Umsetzung von 1 mit 2 zu Monochloräthern 3 erklären.
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  • 20
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 728 (1969), S. 36-43 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: I,2-Dithia-cyclopentenes, X V1). 3-Halogeno-I,2-dithiolium-compounds and Compounds with Positive Halogen3, 5, 9, 10 have been prepared from 3-halogeno-1,2-dithiolium-compounds and compounds with positive halogen. The 3-halogeno-5-amino-1,2-dithiolium-compound 13 does not react; that is interpreted by resonance structures of 13.
    Notes: 3-Halogen-1.2-dithiolium-Verbindungen mit Chlor oder dem Phenyl-Rest in 5-Stellung reagieren mit Substanzen, die „positives Halogen“ enthalten, unter Eliminierung von elementarem Halogen zu Verbindungen vom Typ 3, 5, 9, 10. Die 3-Halogen-5-amino-1.2-dithiolium-Verbindung 13 reagiert nicht; Mesomeriebetrachtungen erklären den Befund.
    Additional Material: 3 Tab.
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  • 21
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 728 (1969), S. 64-87 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Studies on Cyclohexenes, I. Synthesis and Reactions of 3-Amino-4-phenyl-cyclohexenes-(l), a Novel Class of AnalgesicsEthyl atropate (1a) and related alkenes (1b-e) undergo diene-(1.4)-cycloaddition reactions with the electron-rich 1-amino-butadienes-(1,3) 2a-e to give the stable, stereoisomeric 3-amino-4-phenyl-cyclohexenes-(1) 3a-i and 4a-i. The ratio of the isomers does not depend on the dielectric constant of the solvent used in case of 3r-dimethylamino-4c-ethoxycarbonyl-4t-phenyl-cyclohexene-(1) (3a) and 3r-dimethylamino-4t-ethoxycarbonyl-4c-phenyl-cyclohexene-(1) (4a). It however depends on the spatial requirements of the substituents of the alkene and diene (table 1). Structure of 3a and 4a have been established by NMR, mass and infrared spectra analysis and by degradation. - Assigned conformational preferences to 3a-i and 4a-i are confirmed by the hydrogenation rate of the cyclohexene double bond, by supra-annular effects and by the basicity constants of the hydrogenated and nonhydrogenated compounds. - All cyclohexenes 3a-i and 4a, e, g, i are active analgesics. The cyclohexanes 7-10, 17, and 22-25 have no or only weak analgesic properties.
    Notes: Atropasäureäthylester (1a) und verwandte Alkene (1b-e) gehen mit den Elektronen-reichen 1-Amino-butadienen-(1.3) 2a-e Dien-(1.4)-Cycloadditionen ein, die zu stabilen, stereoisomeren 4-Phenyl-3-amino-cyclohexenen-(1) 3a-i und 4a-i führen. Das Verhältnis der Isomeren ist beim 3r-Dimethylamino-4t(bzw. 4c)-phenyl-4c(bzw. 4t)-äthoxycarbonyl-cyclohexen-(1) (3a bzw. 4a) unabhängig von der Dielektrizitätskonstanten des bei der Addition verwendeten Lösungsmittels, jedoch abhängig von der Raumerfüllung der Liganden am En und Dien (Tab. 1). Die Struktur von 3a und 4a wird durch Massen-, NMR und IR-spetroskopische Untersuchungen sowie durch Abbau bewiesen. Mittels Konformationsbetrachtungen gewonnene Aussagen über den räumlichen Bau von 3a-i und 4a-i werden bestätigt vom Geschwindigkeitsverlauf der Hydrierung der Ring-Doppelbindung, von supra-annularen Effekten und den Basizitätskonstanten der hydrierten bzw. nicht-hydrierten Verbindungen. - Alle Cyclohexene 3a-i und 4a,e,g,i besitzen analgetische Aktivität; die Cyclohexane 7-10, 17 und 22-25 besitzen keine oder nur schwache analgetische Eigenschaften.
    Additional Material: 11 Tab.
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  • 22
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 728 (1969), S. 115-143 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metal Complexes of PorphyrinsThe preparation of a series of porphyrin metal complexes is described, and the widely varying spectra of porphyrin complexes are interpreted in terms of known and newly discovered facts. The salts of ms-tetrasubstituted porphins have recently been recognized as derivatives of alloporphins (6); similarly, the porphyrins of the hemin and chlorophyll series form olivegreen or brown allo-complexes. The constitution 8 hitherto assigned to all porphin complexes actually only applies to the red-normal complexes including oxyhemoglobin. Valence-tautomeric chromophores such as 11, 15, and others are to be considered for allo-complexes including hemin.
    Notes: Die Darstellung einer Reihe von Porphyrin-Metall-Komplexen wird beschrieben. Unter Berücksichtigung von bekanntem und neuem Tatsachenmaterial wird eine Deutung der unterschiedlichen Elektronenspektren der Porphyrinkomplexe gegeben. Ausgehend von Salzen ms-tetrasubstituierter Porphine, die als Alloporphin-Derivate (6) erkannt wurden, werden olivgrüne bis braune Metallchelate von Porphyrinen der Hämin- und Chlorophyll-Reihe als Allokomplexe aufgefaßt. Die bisher den Porphyrin-Komplexen allgemein zuerteilte Konstitution 8 gilt nur für die roten Normalkomplexe, denen auch Oxyhämoglobin zuzurechnen ist. Für die Allokomplexe, zu denen Hämin gehört, werden Valenz-tautomere Chromophore wie 11, 15 und andere angenommen.
    Additional Material: 4 Ill.
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  • 23
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 728 (1969), S. 184-192 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: N-Substituted Derivatives of Dehydroubietylamine and DehydroabietylguanidineThe following derivatives of dehydroabietylamine have been synthesized in order to investigate their antimicrobial activity: N-monoalkyl- and N.N-dialkyl-dehydroabietylamines; dehydroabietylguanidines, which are substituted at the N- or N′-atom by an alkyl-, substituted alkyl-, acyl-, amino- or nitro-group; dehydroabietylurea, -thiourea, salts of dehydroabietylisourea and -isothiourea, quaternary dehydroabietylammonium salts and 2-dehydroabietylamino-pyrimidine.
    Notes: Zur Untersuchung ihrer antimikrobiellen Wirkung werden aus Dehydroabietylamin dargestellt: N-Monoalkyl- und N.N-Dialkyl-dehydroabietylamine, am N- oder N'-Atom durch eine Alkyl-, substit. Alkyl-, Acyl-, Amino- oder Nitro-Gruppe substituierte Dehydroabietylguanidine, Dehydroabietylharnstoff, -thioharnstoff, Salze des Dehydroabietylisoharnstoffs und -isothioharnstoffs, quaternäre Dehydroabietylammoniumsalze und 2-Dehydroabietyl-amino-pyrimidin.
    Additional Material: 2 Tab.
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  • 24
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 729 (1969), 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: Organometallic Compounds of the Groups IVa and Va, I. Alkoxytriphenylursine- and Alkoxytriphenylantimony HalidesThe reactions of tert.-butylhypohalities (2a and b) with triphenylarsine (1c) and triphenyl-antimony (1a) have been investigated an dht eproperties of the triphenyl-tert.-butoxyarsine-and - antimony halides (3a-d) formed have been examined.
    Notes: Die Umsetzung von tert.-Butylhypohalogeniten (2a und b) mit Triphenylarsin (1c) un d-stibin (1a) und die Eigenschaften der dabei entstehenden Triphenyl-tert.-butyloxy-arsen - und -antimonhalogenide (3a-d) werden untersucht.
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  • 25
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 729 (1969), S. 8-20 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Wagner- Meerwein Rearrangements in the Bicyclo[3.2.2rsqb;nonane Series I )Deamination of the epimeric 6-aminobicyclo[3.2.2]non-8-enes (6 and 7) and 6-aminobicyclo-[3.2.2]nonanes (8, X = NH2 and 9) mainly proceeds via a stereospecific rearrangement to yield exo-alcohols of hte bicyclo[3.3.1]nonane or bicyclo[4.2.1]nonane series with high stereospecifity. In addition, tricyclo[4.2.1.02.8]nonan-7-ol (10) was produced from the endo-amin 7. - In the presence of silver bromide 2-bromobicyclo[3.2.2]nonane (8, X = Br) rearranges to 2-bromobicyclo[3.3.1]nonane (2, Y = Br). - Both the dehydration of bicyclo[3.2.2]nonan-6-ol (1, X = OH) with phosphoric acid and the acid-catalyzed rearrangement of bicyclo-[3.2.2]non-6-ene (12) give rise to bicyclo[3.3.1]non-2-2ne (11, X = H). The reaction of 12 with an excess of monoperphthalic acid yields syn- and anti-bicyclo[3.3.1.13.9]decane (17). -The deamination of 2e-aminomethylbicyclo[3.2.1]octane (18 gives a mixture of alcohols consisting of bicyclo-[4.2.,1]nonan-3-ol (36), bicyclo[4.2.1]nonan-2-ol (3, Y = OH), bicyclo[3.3.1]nonan-2-ol (2, Y = OH), and 2a-and 2e-methylbicyclo[3.2.1]octan-2e- and 2a-ols (20 and 19).
    Notes: Die Desaminierungen der epimeren 6-Amino-bicyclo[3.2.2]nonene-(8) (6 und 7) und 6-Aminobicyclo[3.2.2]nonane (8, X = NH2, und 9) führen stereospezifisch zu exo-Alkoholen der Bicyclo[3.3.1]nonan- oder Bicyclo[4.2.1]nonan-Reihe. Das endo-Amin 7 liefert daneben Tricyclo[4.2.1.02.8]nonanol-(7) (10). - 6-Brom-bicyclo[3.2.2]nonan (8, X = Br) lagert sich in Gegenwart von AgBr in 2-Brom-bicyclo[3.3.1]nonan (2, Y = Br) um. -Die Dehydratisierung von Bicyclo[3.2.2]nonanol-(6) (1, X = OH) mit Phosphorsäure und die säurekatalysierte Umlagerung von Bicyclo[3.2.2]nonanol-(6) (1, X = OH) mit Phosphorsäure und die säurekatalysierte Umlagerung von Bicyclo[3.2.2]nonen-(6) (12) führen zu Bicyclo[3.3.1]nonen-(2) (11, X = H). - Aus 12 bilden sich mit überschüss. Monoperphthalsäure syn- und anti- Bicyclo[3.3.1]nonen-(2)-ol-(9) (14 und 15) sowie vermutlich 10-Oxatricyclo[3.3.1.13.9]decan (17). - Bei der Desaminierung des 2e-Aminomethyl-bicyclo[3.2.1]octans (18) entstehen Bicyclo[4.2.1]nonanol-(3) (36), Bicyclo[4.2.1]nonanol-(2) (3), Y = OH), Bicyclo[3.3.1]nonanol-(2) (2, Y = OH) sowie 2a und 2e-Methyl-bicycol[3.2.1]octanol-2c und 2a) (20 und 19).
    Additional Material: 1 Tab.
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  • 26
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 729 (1969), S. 52-63 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Ally1 Alcohols with Active Methine and Methylene Compoundsγ.δ-Unsaturated ketones 4 are intermediates in several syntheses of natural products. They may be obtained from allyl alcohols and β-keto esters. Novel synthetic approaches to γ.δ-unsaturated ketones 4 and the related compounds 12, 14, 16, and 18 are described (tables 7-10). The investigations lead to a new synthetic route for the preparation of the juvenile hormone (10).
    Notes: γ.δ-Ungesättigte Ketone 4, herstellbar aus Allylalkoholen und β-Ketoestern, sind Zwischenprodukte verschiedener Naturstoff-Synthesen. Es werden neue Synthesemöglichkeiten von 4 und den damit verwandten Verbindungen 12, 14, 16 und 18 (Tabb. 7 - 10) beschrieben. Die Arbeiten führen zu einem Herstellungsverfahren des Juvenilhormons (10).
    Additional Material: 1 Ill.
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  • 27
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 729 (1969), S. 69-72 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions with Cyclopentadienones, XVII).1,4-Cycloaddition of Dibenzoyldiimide to CyclopentadienonesThe cyclopentadienones 2-7 and dibenzoyldiimide (1) give the corresponding 1,4-compounds 8-12. By heating in xylene the product 8 rearranges to the lactone 13. Reaction mechanisms are discussed.
    Notes: Die Cyclopentadienone 2-7 werden mit Dibenzoyldiimid (1) zu den entsprechenden 1.4-Addukten 8-12 umgesetzt. Erhitzen von 8 in Xylol liefert das Lacton 13. Die Reaktionsmechanismen werden diskutiert.
    Additional Material: 1 Tab.
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  • 28
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 729 (1969), S. 106-118 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthese of Phosphinimine CompoundsA number of new phosphinimine compounds of s-triazines is obtained by the reaction of triamino-s-triazine (9) with triphenylphosphine and halogenes (table 1) or of trichloromelamine (17, table 2) or hexachloromelamine (26, table 3) with tertiary phosphines. The components react in the absence of dehydrohalogenating compounds. Only one reaction step is necessary for the formation of the products. All these methods give pure products in good yields.
    Notes: Eine Reihe neuer Phosphinimin-Derivate von s-Triazinen (Tab. 1) wird in einer Stufe mit groβer Reinheit und hohen Ausbeuten aus Triamino-s-triazinen (9), Triphenylphosphin und Halogenen in Abwesenheit von Halogenwasserstoff bindenden Verbindungen sowie aus Trichlormelamin (17, Tab. 2) oder Hexachlormelamin (26, Tab. 3) und tertiären Phosphinen erhalten.
    Additional Material: 3 Tab.
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  • 29
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 729 (1969), S. 146-151 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A New Synthesis of 1,2-BenzisothiazolesA new method has been found for the preparation of 1,2-benzisothiazoles (1). The compounds are formed by reaction of dihalomethyl-2,6-dihalobenzenes with elementary sulfur and ammonia in a solvent.
    Notes: Es wurde eine neue Herstellungsweise für 1.2-Benzisothiazole (1) gefunden. Die Verbindungen entstehen durch Umsetzen von 2.6-Dihalogen-benzylidenhalogeniden mit elementarem Schwefel und Ammoniak in einem Lösungsmittel.
    Additional Material: 3 Tab.
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  • 30
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 729 (1969), S. 184-192 
    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, XV. Photochemical Reaction of Ubiquinone-7trans-Ubiquinone-7 (1) is converted to several compounds by irradiation of its ethanolic solution with sunlight. One of them, 2a, had been reported previously by us to be an isomer in which the β,γ-double bond of 1 has migrated to the α,β-position. 2a is reinvestigated and its correct structure found to be trans-γ-ethoxy-isoubiquinone-7 (chart 1). In methanol 1 gives the γ-methoxy compund 2b in the same manner. The configurations of α,β-double bond in isoubiquinone groups, 2a, 2b, 2c, and 8 were deduced from the n.m.r. spectra of the corresponding hydroquinone diacetates 3a, 3b, 3c, 9 (figure 1). The mechanism of the photochemical reaction is discussed (chart 2).
    Notes: trans-Ubichinon-7 (1) geht in äthanol durch Sonnenbestrahlung in mehrere Substanzen über. Eine davon, 2a, wurde früher von uns als Isomeres von 1 angesehen, in welchem die β-γ-Doppelbindung in die α.β-Position verschoben ist. Die Struktur von 2a lieβ sich jetzt als trans-γ-äthoxy-isoubichinon-7 richtigstellen (Schema 1). 1 ergibt in Methanol analog das Methoxy-Derivat 2b. Die Konfiguration der α.β-Doppelbindung in der Isoubichinon-Gruppe 2a-c und 8 kann durch die NMR-Spektren ihrer Diacetylhydrochinone 3a-c und 9 festgestellt werden (Abb. 1). Der Mechanismus dieser Photoreaktion wird diskutiert (Schema 2).
    Additional Material: 1 Ill.
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  • 31
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 729 (1969), S. 249-250 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On Natural Tannins, XLIII). (-)-Chebulic Acid from AlgarobillaChebulic acid (1, R = H) is prepared by acid hydrolysis of Algarobilla extracts. It has been shown to be the optical antipode of the acid obtained from Myrobalanes.
    Notes: Aus Algarobilla-Extrakten wird durch Hydrolyse Chebulsäure (1, R = H) abgespalten, die sich als das Spiegelbild der aus Myrobalanen erhaltenen Säure erweist.
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  • 32
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 729 (1969), S. 246-248 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Enol Ethers, VIII. Reactions of Aldehydes with Electron-rich Alkenes1-Dimethylamino-1-ethoxyethylene (1) and 1,1-dipiperidinoethylene (2) react with aromatic aldehydes 3 to give cinnamamides. Coumarines are obtained on reaction with salicylic aldehydes.
    Notes: 1-Dimethylamino-1-äthoxy-äthylen (1) und 1.1-Dipiperidino-äthylen (2) reagieren mit aromatischen Aldehyden 3 zu Zimtsäureamiden. Mit Salicylaldehyden erhält man in glatter Reaktion Cumarine.
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  • 33
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of CH-Active Compounds with Azides, XXVII ). Syntheses of a-Diazo-imines und Isomeric 1,2,3-Triazoles and Their Conversion into a-Diazo-immonium Salts1-Anilino-3-oxo-indenes 6a-f are converted into 1-oxo-3-arylimino-2-diazo-indanes 8a-c or 1-oxo-3-aryl-3H,8H-indeno [1,2-d]triazoles 9d-f by diazo group transfer with p-toluenesulfonyl azide in ethanol/potassium ethoxide. Both classes of substances add mineral acids to form 1-oxo-3-arylimmonium-2-diazo-indane-salts 10a-f. Treatment of the immonium salts with potassium hydroxide yields the α-diazo-imines 8a, b, e and f. 8c hydrolyses to give 1,3-dioxo-2-diazo-indane; 8d, which changes largely to 9d by cyclisation, is accessible by thermal ringopening of the latter. 1-Anilino-3-oxo-cyclohexenes-(1) 12a-f are transformed into 4-oxo-1-aryl-4,5,6,7-tetrahydro-benzotriazoles (14a-f) by diazo group transfer with high yields.
    Notes: 1-Anilino-3-oxo-indene 6a-f liefern bei der Diazogruppen-übertragung mit p-Toluolsulfonsäure-azid in äthanol/Kaliumäthylat 1-Oxo-3-arylimino-2-diazo-indane 8a-c bzw. 1-Oxo-3-aryl-3H.8H-indeno[1.2-d]triazole 9d-f. 8 und 9 addieren Mineralsäuren - 9 unter Ringöffnung - zu 1-Oxo-3-arylimmonium-2-diazo-indan-Salzen 10a-f. Mit Kaliumhydroxid erhält man daraus die α-Diazo-imine 8a, b, e und f. 8c hydrolysiert weiter zu 1.3-Dioxo-2-diazo-indan; 8d cyclisiert größtenteils zum Triazol 9d, ist aber durch dessen direkte thermische Isomerisierung zugänglich. 1-Anilino-3-oxo-cyclohexene-(1) 12a-f werden durch Diazogruppen-übertragung mit hohen Ausbeuten in 4-Oxo-1-aryl-4.5.6.7-tetrahydrobenzotriazole 14a-f umgewandelt.
    Additional Material: 8 Tab.
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  • 34
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Absolute Configuration of Optically Active, Naturally Occurring Dihydroisocoumarins, IIIs2).Determination of the Absolute Configuration of Agrimonolide and MelleineBy degradation with ozone and performic acid (S)-3-hydroxy-adipic acid is obtained from both agrimonolide (1) and (-)-β-tetralol (4), which is characterized as di-hydrazide 3. Therefore 1 and 4 have S-configuration at position 3 and 2 respectively. The positive CD at 260 mμ of 1 and phyllodulcine (7) is a proof of configurative identity. In contrast, melleine (8) shows at 257 mμ negative CD and therefore has R-configuration.
    Notes: Durch Abbau mit Ozon und Perameisensäure wird aus Agrimonolid (1) und (-)-β-Tetralol (4) die gleiche (S)-3-Hydroxy-adipinsäure erhalten und als Dihydrazid 3 charakterisiert. Damit geht für 1 und 4 die S-Konfiguration and C-3 bzw. C-2 hervor. Der positive CD von 1 und Phyllodulcin (7) bei 260 mμ beweist deren konfigurative übereinstimmung. Da der CD des Melleins (8) - wie 7 ein Salicylsäure-Derivat - bei 257 mü negativ ist, muß hier auf R-Konfiguration am C-3 geschlossen werden.
    Additional Material: 1 Ill.
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  • 35
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 729 (1969) 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 36
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    Liebigs Annalen 729 (1969), S. 21-26 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Protonated Methylbenzene Tetrachloroaluminate ComplexesWell defined complexes from methyl substituted benzenes and aligated by proton magnetic resonance (figure 1, table 1). A few of these compounds can be characterized as σ-complexes. Under the conditions used σ-protonation requires a benzene ring with at least three methyl substituents and a 1,3,5-type of substitution. In all other cases complexes are formed, in which π-bonding is likely.
    Notes: Definierte Komplexe aus Methyl-substituierten Benzolen und Aluminiumchlorid/Chlorwasserstoff wurden erhalten und auf ihre NMR-Signale untersucht (Abb. 1, Tab. 1) Nur ein Teil dieser Verbindungen kann als σ-Komplex charakterisiert werden. Unter den angewandten Bedingungen ist für die σ-Protonierung Substitution mit wenigstens drei Methyl-Gruppen in 1.3.5-Stellung erforderlich. In allen anderen Fällen ist π-Komplex-Bildung wahrscheinlich.
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  • 37
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    Liebigs Annalen 729 (1969), S. 40-51 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Production and Reactions of N- MonoalkylamidosulfonylchloridesN-Monosubstituted amidosulfonylchlorides (1) may optimally be obtained by reaction between N-monosubstituted ammonium chlorides and sulfuryl chloride in acetonitrile. N-Monosubstituted amidosulfonylchlorides are very active intermediates, which react especially with reactive H containing compounds to give the free acids 2 (R = H), the esters or thioester 2,5, and 6, and the amides 7 and 8. The hydrogen of the amino group can also be substituted. In this way new compounds are accessible and other already known compounds can be produced more easily.
    Notes: Unter den Methoden zur Herstellung N-monosubstituierter Amidosulfonylchloride (1) erweist sich die Umsetzung von N-monosubstituierten Ammoniumchloriden mit Sulfurylchlorid in Acetonitril als am besten geeignet. N-Monosubstituierte Amidosulfonylchloride sind sehr reaktive Zwischenprodukte, die mit reaktionsfähigen, H-enthaltenden Verbindungen zu den freien Säuren 2 (R = H), den Estern bzw. Thioestern 2, 5 und 6 sowie den Amiden 7 und 8 reagieren können; außerdem besitzen sie einen leicht substituierbaren Wasserstoff an der Amino-Gruppe. Mit ihnen sind Verbindungen präparative leicht zugänglich, die bisher nicht oder nur umständlich gewonnen werden konnten.
    Additional Material: 8 Tab.
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  • 38
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 729 (1969), 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: Catalytic Hydrogenation of PurinesHydrogenation of purines over platinum or palladium occurs initially, if at all, in the 1,6 positions (e. g. 1 → 4). The 1,6-dihydropurines, which can still be acetylated in the 7 or 9 position, can be hydrogenated further to hexahydro- and perhydropurines (20 and 13, respectively).
    Notes: Purine werden an Platin oder Palladium, wenn überhaupt, zuerst in 1.6-Stellung hydriert (z. B. 1 → 4); die 1.6-Dihydro-purine, die noch in 7- bzw. 9-Stellung acetylierbar sind, können dann weiter zu Hexahydro- bzw. Perhydro-purinen (20 bzw. 13) hydriert werden.
    Additional Material: 1 Tab.
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  • 39
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 722 (1969) 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 40
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 722 (1969), S. 29-37 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: a-Hydrazonocarboxylic Acid Azides, I. Aliphatic α-Hydrazonocarboxylic Acid AzidesThe title compounds 2, 5a-c, 6a-e are prepared by reaction of the analogous α-hydrazonocarboxylic acid hydrazides (1, 7a-c, 8a-e) with nitrous acid. Both classes form Z- and E-isomers. The α-hydrazonocarboxylic acid hydrazides (1, 8e), that are unsubstituted in the hydrazono group, prefer the Z-form, whereas those (7a-c, 8a- d), that are substituted in the hydrazono group, prefer the E-form. The Z-azides, prepared from the Z-hydrazides, are unstable and lose hydrazoic acid. The E-azides, prepared from the E-hydrazides, are stable, but change into the unstable Z-isomers on standing at room temperature when exposed to light. On boiling in toluene the E-isomers lose nitrogen to form substituted 1,2,4-triazol-5-ones (15a-c, 16a-d).
    Notes: Die Titelverbindungen 2, 5a-c, 6a-e entstehen aus den entsprechenden α-Hydrazonocarbonsäurehydraziden (1, 7a-c, 8a-e) durch Reaktion mit salpetriger Säure. Beide Substanzklassen treten in Z- und E-Form auf. Die in der Hydrazono-Gruppe unsubstituierten α-Hydrazonocarbonsäurehydrazide (1, 8e) liegen bevorzugt in der Z-Form, die entsprechend substituierten Hydrazide (7a-c, 8a-d) überwiegend in der E-Form vor. Die aus den Z-Hydraziden entstehenden Z-Azide sind instabil und spalten Stickstoffwasserstoffsäure ab. Die aus den E-Hydraziden entstehenden E-Azide sind stabil, wandeln sich jedoch bei längerem Stehenlassen und gleichzeitiger Lichteinwirkung in die instabilen Z-Azide um. Beim Kochen der E-Azide in Toluol wird Stickstoff abgespalten und es bilden sich substituierte 1.2.4-Triazolone-(5) (15a-c, 16a- d).
    Additional Material: 3 Tab.
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  • 41
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Intramolecular Rearrangements of Bicyclo[2,2, heptanes, XI1). Rearrangement of 1- Methyl-7,2-norbornanecarbolactone in Sulfuric AcidIn the presence of concentrated sulfuric acid 1-methyl-7,2-norbornanecarbolactone (1) rearranges to 3exo-methyl- and 1-methyl-2,6-norbornanecarbolactones (2 and 5). The structure of the hitherto unknown lactone 5 is established.
    Notes: 1-Methyl-norbornan-carbolacton-(7.2) (1) lagert sich unter dem Einfluß konzentrierter Schwefelsäure in 3 exo-Methyl- und 1-Methyl-norbornan-carbolacton-(2.6) (2 und 5) um. Die Struktur des bislang unbekannten Lactons 5 wird bewiesen.
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  • 42
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 722 (1969), S. 232-233 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cycloaddition of Dichloroketene to 2-ButyneDichloroketene generated in situ, gives with 2-butyne the 1,2-cycloaddition product 2,3-dimethyl-4,4-dichlorocyclo-2-buten-1-on (1).
    Notes: In situ erzeugtes Dichlorketen addiert sich an Butin-(2) zum 2.3-Dimethyl-4.4-dichlor-cyclobuten-(2)-on-(1) (1).
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  • 43
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Studies on the Occurence of Hydrogen Transfer, 191). Specific Reductive Cleavage of Some Acyl Groups from Nitrogen at the Mercury CathodeElectron donators in the aromatic acyl group and in the amine component shift the reduction potentials of sulfonamides and of carbonamides to more negative values, and hinder the cathodic cleavage. Electron acceptors have the opposite effect. Aromatic ligands on the nitrogen atom change the reduction potentials to more positive values. The influence of the substituents on the reduction potentials follows the Hammett relationship. - If a potential difference of at least 0.2 V exists between acyl groups (which may be in the same molecule, or in different molecules), then selective cleavage of the acyl group having the more positive potentials is possible.
    Notes: In Sulfon und Carbonamiden mit aromatischem Acyl-Rest werden die Reduktionspotentiale durch Elektronen-Donatoren im Acyl-Rest und in der Amin-Komponente zu negativeren Werten verschoben; dabei wird die kathodische Spaltung erschwert. Elektronen-Acceptoren wirken umgekehrt. Aromatische Liganden am Stickstoff verlagern das Reduktionspotential zu positiveren Werten. Die Abhängigkeit der Reduktionspotentiale vom Substituenten gehorcht der Hammett-Beziehung. - Besteht zwischen den Acylamino-Gruppen, die im gleichen Molekül oder auch in verschiedenen Molekülen gebunden sein können, ein Potentialunterschied von wenigstens 0.2 V, so ist eine selektive Abspaltung der Acyl-Gruppe mit dem positiveren Potential möglich.
    Additional Material: 1 Ill.
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  • 44
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 723 (1969), S. 41-46 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Tertiary and Quaternary Salts of Hexahydro-pyrimidinesThe mono- and bis-tertiary salts 7, 11, 12 may be obtained by reaction of 1.3-dialkylhexahydro-pyrimidines and hydrogen chloride in suitable solvents. - The mono-quaternary salts 8-10 are formed from 1.3-dialkyl-hexahydro-pyrimidines and alkyl halides in ether. The bis-quaternary salts 5, 6 and 13-17 result by alkylation of 1.3-dialkyl-hexahydro-pyrimidines with methyl bromide, methyl iodide or trialkyloxonium fluoroborates in polar aprotic solvents or by reaction of α-halogen amines with γ-chloropropyl amines.
    Notes: Aus 1.3-Dialkyl-hexahydro-pyrimidinen und Chlorwasserstoff sind in geeigneten Lösungsmitteln die mono-sowie bis-tertiären Salze 7, 11, 12 zu gewinnen. - Die monoquartären Salze 8-10 entstehen aus 1.3-Dialkyl-hexahydro-pyrimidinen und Alkylhalogeniden in Äther. Die bis-quartären Salze 5, 6 und 13-17 sind durch Alkylierung von 1.3-Dialkyl-hexahydropyrimidinen mit Methylbromid oder -jodid sowie Trialkyl-oxoniumfluoroboraten in polaren, aprotischen Lösungsmitteln oder durch Umsetzung α-halogenierter Amine mit γ-Chlorpropylaminen zugänglich.
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  • 45
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 723 (1969), S. 201-204 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Concerning the Mechanism of Catalytic Proton-Transfer by Diazomethane, IIMethyl 3-hydroxy-2-naphthoate (8) gives with 1 mole phenyl isocyanate in the presence of 1 mole deuterodiazomethane (1.6 g-atom D/mole) an adduct 9-d0 free from deuterium; the same reaction carried out with deuterated 8 and non-deuterated diazomethane gives 9-d1. These results are in accordance with a proton-transfer by proton-bridge complexes, whereas they exclude the proton-transfer by methyldiazonium cations.
    Notes: 3-Hydroxy-naphthoesäure-(2)-methylester (8) bildet mit 1 Mol. Phenylisocyanat in Gegenwart von 1 Mol. Deuterodiazomethan (1.6 g-Atom D/Mol) das D-freie Addukt 9-d0; bei der Reaktion mit deuteriertem 8 und undeuteriertem Diazomethan entsteht dagegen 9-d1. Die Befunde lassen sich durch Protonen-Übertragung über Protonbrückenkomplexe erklären und schließen die Protonen-Übertragung durch Methyldiazonium-Kationen aus.
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  • 46
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 724 (1969), S. 24-29 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Conjugation in Macrocyclic Bond Systems, XIII1). Further Compounds of the Hexa-m-phenylene TypeThe preparation of the sterically overcrowded hexamethyl hexa-m-phenylene 2 is reported. Spectroscopic properties (u. v., 1H-n.m.r.) and mass spectra of 2 are discussed with regard to the strong deviation from coplanarity present in this system. Synthesis and properties of 8,2′;8′,2″;8″,2-tris(dibenzothiophenylene) (10), a coplanar a coplanar derivative of 1, are reported.
    Notes: Das sterisch stark behinderte Hexamethyl-hexa-m-phenylen 2 wird hergestellt. Die spektroskopischen Eigenschaften (UV, 1H-NMR) und das Massenspektrum von 2 werden unter dem Gesichtspunkt der hier vorliegenden starken Abweichung von der Komplanarität diskutiert. Über Synthese und Eigenschaften des 8.2′;8′.2″;8″.2-Tris-dibenzothiophenylens (10), eines ebenen Derivats von 1, wird berichtet.
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  • 47
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 724 (1969), S. 66-70 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Photochemical and Thermal 1,4-Cycloaddition of Enamides to 1,2- Dicarbonyl CompoundsThe enamides 2 and 6 can be added to benzil and o-chinones photochemically and thermally to give the 1,4-dioxen derivatives 3 and 7. The thermal addition follows a two-step mechanism, as is shown by the formation of the same 1,4-dioxen compound 7b from the addition of cis- and trans-enamide to 5.
    Notes: Die Enamide 2 und 6 addieren sich photochemisch wie thermisch an Benzil und o-Chinone zu den 1.4-Dioxen-Derivaten 3 und 7. Der Verlauf der thermischen Addition ist zweistufig, wie bei der Reaktion von cis- und trans-Enamid (6b bzw. 2b) mit 5 gezeigt wird, die zu demselben 1.4-Dioxen-Derivat 7b führt.
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  • 48
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Nitromethane Condensation with Dialdehydes, XVI1) S-Benzyl Substituted Nitrodithiols by cyclizing Bismercaptoalkylation of Nitromethane2-Nitrocyclohexanedithiols with trans-, chiro-, and cis-configuration (5-7) are formed by nitromethane-cyclization of glutaraldehyde in the presence of α-toluenethiol or by reaction of 2-nitrocyclohexane-1,3-diol (11) with α-toluenethiol, the product distribution being dependent on the reaction conditions. - Analogously, a 1,4-dinitrocyclohexanetetrathiol (15) is formed from 1,4-dinitro-1,4-dideoxy-neo-inositol (13), whereas its tetraacetate 16 gives 2-nitro-5-benzylmercaptophenol (17), as a result of aromatization followed by nucleophilic displacement of one nitro group by a mercapto moiety. - Configuration and conformation of the nitro dithiols and of the sulfones 8-10 obtained on oxidation are deduced from n.m.r. spectra.
    Notes: Nitromethan-Cyclisierung von Glutardialdehyd in Gegenwart von Benzylmercaptan oder Umsetzung von 2-Nitro-cyclohexandiol-(1.3) (11) mit Benzylmercaptan führt zu 2-Nitro-cyclohexan-dithiolen mit trans-, chiro- und cis-Konfiguration (5-7), deren Mengenverhältnis von den Reaktionsbedingungen abhängt. - Aus 1.4-Dinitro-1.4-Dinitro-1.4-didesoxy-neo-inosit (13) erhält man analog ein 1.4-Dinitro-cyclohexantetrathiol (15), aus dem Dinitrotetraacetat 16 dagegen, infolge Aromatisierung und nucleophiler Verdrängung einer Nitro- durch eine Mercapto-Gruppe, 2-Nitro-5-benzylmercapto-phenol (17). - Konfiguration und Konformation der Nitrodithiole sowie der durch Oxydation erhaltenen Sulfone 8-10 ergeben sich aus den NMR-Spektren.
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  • 49
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 724 (1969), S. 128-136 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation und Hydrolysis of 4- Halogenomethylen-1.3-dioxolanes4-Halogenomethylen-1,3-dioxolanes (4a-o) are obtained by base-catalyzed addition of formaldehyde to 1-halogen-1-propyn-3-ols (3). Acid hydrolysis of the dioxolane derivatives 4 yields 1-halopropan-3-ol-2-ones (5a-f, i-o), which split off hydrogen halide to give 2,3-diketones 6 and 7a-c, if the hydroxyl group is attached to a primary or secondary carbon atom.
    Notes: Durch basenkatalysierte Addition von Formaldehyd an 1-Halogen-propin-(1)-ole-(3) (3) werden 4-Halogenmethylen-1.3-dioxolane (4a-o) erhalten. Die saure Hydrolyse von 4 führt zu 1-Halogen-propanol-(3)-onen-(2) (5a-f, i-o). Soweit diese eine primäre oder sekundäre Hydroxy-Gruppe enthalten (5a-f), werden sie beim Erwärmen in die 2.3-Diketone 6 bzw. 7a-c und Halogenwasserstoff gespalten.
    Additional Material: 2 Tab.
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  • 50
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 724 (1969), S. 155-158 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1-(2- Hydroxyphenyl)-3,5-diphenyl-Δ2-pyrazolines2-Hydroxyphenylhydrazine hydrochlorides 1a-g and chalcone form 1-(2-hydroxyphenyl)-3,5-diphenyl-Δ2-pyrazolines (2a-g). The isolation of chalcone 2-hydroxyphenylhydrazones 3a and 3b depends on the substituents of the compounds 1a-g. - 1,3,5-Triphenyl-Δ2-pyrazolines show fluorescence, 1-(2-hydroxyphenyl)-3,5-diphenyl-Δ2-pyrazolines do not. Acetylation of the phenyl group leads to fluorescent compounds 4a-e.
    Notes: Aus den 2-Hydroxy-phenylhydrazin-hydrochloriden 1a-g, und Benzylidenacetophenon werden 1-[2-Hydroxy-phenyl]-3.5-diphenyl-Δ2-pyrazoline (2a-g) hergestellt. In Abhängigkeit von der Substitution der Verbindungen 1a-g, können bei gleichen Reaktionsbedingungen die Benzylidenacetophenon-2-hydroxy-phenylhydrazone 3a und 3b als Zwischenstufen isoliert werden. - Im Gegensatz zu 1.3.5-Triphenyl-Δ2-pyrazolinen fluoreszieren 1-[2-Hydroxyphenyl]-3.5-diphenyl-Δ2-pyrazoline nicht. Acetylierung der Hydroxyl-Gruppe führt zu fluoreszierenden Verbindungen 4a-e.
    Additional Material: 2 Tab.
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  • 51
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 724 (1969), S. 183-193 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Triterpenes, XXVII1). The Structure of Musennin and DeglucomusenninThe bark of the roots of Albizzia anthelmintica (Brongn.) contains a mixture of saponins, the main components of which, musennin and deglucomusennin, have now been isolated. The sugar chains are attached to the 3-hydroxy group of the aglycon echinocystic acid. Deglucomusennin contains three molecules of l-arabino-pyranose in an unbranched chain. They are connected in α-1,2-position. Musennin has an additional molecule of D-glucose, in β-1,3-linkage to the last molecule of l-arabinose of the chain.
    Notes: Als Hauptkomponenten des Saponingemisches der Wurzelrinde von Albizzia anthelmintica (Brongn.) werden Musennin und Desglucomusennin erkannt, in denen jeweils eine Zuckerkette an die 3-Hydroxyl-Gruppe des Aglykons Echinocystsäure gebunden ist. Desglucomusennin enthält 3 Moll. l-Arabinose in Pyranoseform, die in unverzweigter α-1.2-Verknüpfung vorliegen. Musennin besitzt zusätzlich 1 Mol. D-Glucose, die in β-1.3-Form mit der endständigen Arabinose verbunden ist.
    Additional Material: 3 Tab.
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  • 52
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 725 (1969), S. 196-202 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: NMR-Spectroscopic Studies of Acyl GlycosesA NMR spectroscopical study of the p-cumaroyl-D-glucoses (1a-e), p-hydroxybenzoyl-D-glucose (2a-e), as well as of the p-cumaroyl-L-rhamnoses (3 and 4) and 5-p-cumaroyl-D-xylofuranose (5) was carried out (table 1). The configuration and conformation, and in the case of the 1-, 2-and 6-acyl-glucoses as well as of 4-p-cumaroyl-α-methyl-L-rhamnopyranoside (4) also the position of the acyl group, have been established. With the aid of synthetic sugar esters the structure of neobignonoside, neopetunoside, and negretein could be determined.
    Notes: Aus den NMR-Spektren von p-Cumaroyl- (1a-e), p-Hydroxy-benzoyl-D-glucosen (2a-e) sowie p-Cumaroyl-L-rhamnosen (3 und 4) und 5-p-Cumaroyl-D-xylofuranose (5) (Tab. 1) werden die Konformation, Konfiguration und im Falle der 1-, 2- und 6-Acylglucosen- sowie des 4-p-Cumaroyl-α-methyl-L-rhamnopyranosids (4) die Stellung des jeweiligen Acyl-Restes ermittelt. Mit Hilfe der synthetischen Zuckerester konnte die Struktur von Neobignonosid, Neopetunosid und Negretein geklärt werden.
    Additional Material: 1 Tab.
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  • 53
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 722 (1969), S. 80-97 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Oxidation Products of Thioamides, XX1). Thiourea S-dioxidesThe thiourea S-dioxides 8, 15, and 16 are prepared by oxidation of N-mono- and N.N′-disubstituted thioureas with hydrogen peroxide. Treatment of N.N′-disubstituted thiourea S-dioxides with acids affords formamidines. When N.N′-dineopentylthiourea is oxidized only N.N′-dineopentylformamidine (19) can be isolated. The properties and reactions of the thiourea S-dioxides are compared with those of pyridinesulfinic acids.
    Notes: Bei der Oxydation N-mono- und N.N′-disubstituierter Thioharnstoffe mit H2O2 lassen sich die Thioharnstoff-S-dioxide 8, 15 und 16 isolieren. Durch Behandlung mit Säuren entstehen aus N.N′-disubstituierten Thioharnstoff-S-dioxiden Amidine; bei der Oxydation des N.N′-Di-neopentyl-thioharnstoffs wird einzig N.N′-Di-neopentyl-formamidin (19) erhalten. Eigenschaften und Reaktionen der Thioharnstoff-S-dioxide werden mit denen der Pyridinsulfinsäuren verglichen.
    Additional Material: 1 Ill.
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  • 54
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 722 (1969), S. 132-141 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cycloaddition Reactions with α,β-Diheterosubstituted Olefins, I. Reactions with Sulfonyl IsocyanatesThe reaction of sulfonyl isocyanates with α,β-dialkoxy substituted olefins yields N-sulfonyl-3,4-dialkoxy-2-azetidinon compounds 3 as main products and N-sulfonylcarboxylamide compounds 4. Kinetic studies on the formation of β-lactams 3 are reported and the reactions of these compounds with methanol are described. The formation of β-lactams from α,β-sulfur and nitrogen substituted olefins can be detected by i.r.spectroscopy.
    Notes: Sulfonylisocyanate reagieren mit α.β-disauerstoffsubstituierten Olefinen unter 1.2-Addition zu 1-Sulfonyl-3.4-dialkoxy-azetidinon-(2)-Verbindungen 3. Daneben bilden sich durch Substitution α.β-ungesättigte N-Sulfonyl-carbonsäureamid-Verbindungen 4. Mit Schwefel-und Stickstoff-substituierten Olefinen wird eine Azetidinon-Bildung IR-spektroskopisch nachgewiesen. Reaktionsweisen sowie kinetische Untersuchungen zur Bildung der β-Lactam-Derivate 3 werden beschrieben.
    Additional Material: 7 Tab.
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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 with Organophosphorus Compounds, XXIII1). A New Synthesis of Tetrazoles and Iminonitriles from N- Substituted IminophosphoranesA generally applicable synthesis of 1-R1-5-R2-substituted tetrazoles by reaction of the corresponding triphenyliminophosphoranes (C6H5)P=NR1 with acid chlorides R2COCl and NaN3 is reported. The same phosphoranes react with acyl cyanides R2COCN to form the iminonitriles R2C(CN)=NR1.
    Notes: Es wird über eine allgemein anwendbare Synthese von 1-R1-5-R2-substituierten Tetrazolen durch Umsetzung von Triphenyliminophosphoranen (C6H5)3P=NR1 (R1=Alkyl, Aryl) mit Säurechloriden R2COCl (R2=Alkyl, Alkenyl) und NaN3 berichtet. Triphenyliminophosphorane lassen sich mit Säurecyaniden R2COCN zu Iminonitrilen R2C(CN)=NR1 umsetzen.
    Additional Material: 1 Tab.
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  • 56
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 725 (1969), S. 73-86 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Ketene Derivatives, XVI1). Electrophilic Substitution of Simple Ketene S,N-AcetalsSimple ketene S,N-acetals [R-CH=C(SCH3)NR′ 2; R=Horalkyl] react with electrophiles such as acid chlorides, activated vinyl chlorides, ketene mercaptals, ethoxymethylene sulfonic acid amides, dinitrofluorobenzene, trichloro-s-triazine and o-nitrobenzenesulfenyl chloride to give β-substituted ketene S,N-acetals. In some cases products of secondary reactions are isolated; acid chlorides, for instance, sometimes give substituted β-acyloxyacrylic acid thioamides.
    Notes: Einfache Keten-S.N-acetale [R-CH=C(SCH3)NR′2; R=H oder Alkyl] reagieren mit Elektrophilen - z. B. mit Säurechloriden (zu 4), aktivierten Vinylchloriden (zu 12), Ketenmercaptalen (zu 14), Äthoxymethylensulfonamiden (zu 22, 23), Dinitrofluorbenzol (zu 19), Cyanurchlorid (zu 18) und o-Nitro-benzolsulfensäurechlorid (zu 20, 21) - zu β-substituierten Keten-S.N-acetalen. In einigen Fällen isoliert man Produkte von Folgereaktionen; mit Säurechloriden erhält man z. T. substituierte β-Acyloxy-acrylsäurethioamide (z. B. 8).
    Additional Material: 13 Tab.
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  • 57
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Fragmentation Reactions of Carbonyl Compounds with Electronegative β-Substituents, XV1). On the Reaction of Electronegatively β-Substituted Pivalic Acid EstersReaction of triiodo- (2) and tritosyloxy pivalic acid ester 3a, with sodium ethanolate affords 3-ethoxy-2-ethoxymethyl-1-propene (5) and diethyl carbonate (6) by a fragmentation reaction; on the other hand yields the tribromo pivalic acid ester 1b by neopentyl substitution 7a and b. Substitution of the monosubstituted pivalic acid esters 4a-d leads to the formation of 9, by products being formed at the same time. - Reaction of ethyl tosyloxypivalate (4b) with lithium organic compounds gives tetrasubstituted oxetanes 14.
    Notes: Trijod- (2) und Tritosyloxy-pivalinsäureester 3a liefern mit Na-äthylat 3-Äthoxy-2-äthoxymethyl-propen-(1) (5) und Kohlensäurediäthylester (6). Der Tribrom-pivalinsäureester 1b ergibt durch Neopentyl-Substitution 7a und b. Die monosubstituierten Pivalinsäureester 4a-d werden zu Methoxy-pivalinsäure-methylester (9) substituiert, wobei Nebenprodukte entstehen. - Umsetzung von Tosyloxy-privalinsäure-äthylester (4b) mit Lithiumorganylen ergibt die tetrasubstituierten Oxetane 14.
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  • 58
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 725 (1969), S. 154-166 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation of Analogs of Dehydroabietylamine and Dehydroabietylguanidine by Total SynthesisAnalogs of racemic dehydroabietylamine and homodehydroabietylamine have been synthesized. The isopropyl group is replaced by hydrogen, or by a methyl or methoxy group. The guanidinium salts are prepared from the corresponding amines. Further variations include the additional introduction of a hydroxy group and substitution of the amino or guanidinium group by a quaternary ammonium or isothiouronium group.
    Notes: Es werden Analoge 2 des racemischen Dehydroabietylamins und Homodehydroabietylamins dargestellt. Dabei wird die Isopropyl-Gruppe durch Wasserstoff, eine Methyl- oder eine Methoxy-Gruppe ersetzt. Aus den Aminen werden die entsprechenden Guanidinium-Salze dargestellt. Weitere Variationen erstrecken sich auf die zusätzliche Einführung einer Hydroxy-Gruppe und Ersatz der Amino- bzw. Guanidinium-Gruppe durch eine quartäre Ammonium-oder Isothiuronium-Gruppe.
    Additional Material: 7 Tab.
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  • 59
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions with Diazocarbonyl Compounds, XXXII1). Synthesis of 2-Carboxy-5-hydroxytryptamine and Pyridazine Derivatives. Japp-Klingemann-Synthesis with p-Hydroxy-phenyl-diazonium Salts or p-Chinon-diazides, respectivelyp-Hydroxybenzenediazoniumchloride (1) and 2,6-dichloro-1,4-benzoquinone-4-diazide (2) react with 3-ethoxycarbonyl-2-piperidone (3) and with ethyl 2-acetyl-4-cyanobutyrate (10) (Japp-Klingemann synthesis) to give 4-hydroxyphenylhydrazones 6, 7 nad 11, 12 respectively. The hydrazones 6 and 7 are converted into the 5-hydroxyindole dervatives 8 and 9 (E. Fischer indole synthesis), while the hydrazone 12 is cyclized to the tetrahydropyridazine derivatives 13 and 14.
    Notes: p-Hydroxy-benzoldiaziniumchlorid (1) und 2.6-Dichlor-benzochinon-(1.4)-diazid-(4) (2) werden mit 3-Äthoxycarbonyl-piperidon-(2) (3) und mit 2-Acetyl-4-cyan-buttersäureäthylester (10) nach Japp und Klingemann zu den 4-Hydroxy-phenylhydrazonen 6 und 7 bzw. 11 und 12 umgesetzt. Die Hydrazone 6 und 7 lassen sich nach E. Fischer in die 5-Hydroxy-indol-Derivate 8 und 9 überführen, während das Hydrazon 12 zu den Tetrahydropyridazin Derivaten 13 und 14 cyclisiert.
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  • 60
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    Liebigs Annalen 726 (1969), S. 125-135 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Triterpenes XXVIII1). The Saponins of Spinach (Spinacia oleracea L.)Two saponins, spinasaponin A and B, have been isolated from the roots of spinach. The structures are elucidated by acid and enzymatic hydrolysis and by methylation, fission of the resulting methyl derivatives, and identification of the methyl sugars. Accordingly, spinasaponin A is 3O-[β-D-Glucopyranosyl(1 → 3)-β-D-glucuronopyranosyl]-3β-hydroxy-Δ12-oleanen-28-acid (1a), whereas B is the corresponding derivative 2a of hederagenin.
    Notes: Aus den Wurzeln des Spinats werden zwei Saponine, Spinasaponin A und B, isoliert, deren Struktur durch saure und enzymatische Hydrolyse sowie durch Methylierung, Spaltung der Methyl-Derivate und Identifizierung der methylierten Zucker ermittelt wird. Spinasaponin A ist demnach eine 3O-[β-D-Glucopyranosyl(1 → 3)-β-D-glucuronopyranosyl-(1)]-3β-hydroxy-Δ12-oleanen-28-säure (1a), während B das entsprechende Hederagenin-Derivat 2a ist.
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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: Preparation of 6α-Fluoro-11β, 21 -dihydroxy-l6α-methyl-l,4-pregnadiene-3,20-dione (Fluocortolone) via Substrate-Structure- Directed Specific 11β- Hydroxylation by Curvularia lunataThe formation of the by-products 14 and 13, with 9α- and 14α-hydroxy groups, in the 11β-hydroxylation of 6α-fluoro-21-hydroxy-16α-methyl-4-pregnene-3,20-dione (9b) with Curvularia lunata is inhibited by using a similar substrate with 5α-bromo-substituent by sterical shielding of the α-side. A subsequent route for the synthesis of 6α-fluoro-11β,21-dihydroxy-16α-methyl-1,4-pregnadiene-3,20-dione (15) is described.
    Notes: Die bei der 11β-Hydroxylierung von 6α-Fluor-21-hydroxy-16α-methyl-4-pregnen-3.20-dion (9b) mit Curvularia lunata entstehenden Nebenprodukte 14 und 13 mit 9α- und 14α-Hydroxy-Funktion treten bei Einsatz der 5α-Brom-substituierten Vorstufe 5 durch sterische Abschirmung der α-Seite nicht auf. Der weitere Synthesegang zu 6α-Fluor-11β.21-dihydroxy-16α-methyl-1.4-pregnadien-3.20-dion (15, Fluocortolon) wird beschrieben.
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  • 62
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    Liebigs Annalen 726 (1969), S. 216-218 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses and Properties of the Nine Isomeric Tolyl ToluatesThe title compounds 5-7 (a-c) are prepared and analyzed for their chemical and spectroscopical properties.
    Notes: Die Titelverbindungen 5-7 (a-c) werden hergestellt und ihre chemischen und spektroskopischen Eigenschaften untersucht.
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  • 63
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    Liebigs Annalen 727 (1969), S. 22-34 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaction of Thioamides with Sulfenyl ChloridesSulfenyl chlorides react with secondary thioamides to give iminomethyl disulfides 2. The sulfur atom is attacked by the sulfenyl chloride, even when the thioamide system is substituted by electron-withdrawing groups. Asymmetric iminomethyl disulfides obtained from the reaction of primary thioamides and sulfenyl chlorides decompose very easily, and in general they have been isolated as salts. In only one case has a neutral iminomethyl disulfide (23) been isolated. Thiobenzamide condenses with chlorocarbonyl sulfur chloride (21) to give 5-phenyl-1,2,4-dithiazol-3-one (28), whereas condensation with phenylimino-chloromethane sulfenyl chloride (20) leads to the corresponding dithiazole derivative 25, but only in small amounts.
    Notes: Durch Umsetzung von sekundären Thioamiden mit Sulfenylchloriden entstehen Iminomethyldisulfide 2. Der elektrophile Angriff des Sulfenylchlorids erfolgt auch dann am Thion-Schwefel, wenn das Thioamid-System elektronenziehende Substituenten trägt. Asymmetrische Iminomethyldisulfide aus primären Thioamiden und Sulfenylchloriden sind besonders leicht zersetzlich und nur als Salze isoliert worden. Nur in einem speziellen Fall wird ein neutrales Iminomethyldisulfid (23) aus einem primären Thioamid erhalten. Thiobenzamid reagiert mit Chlorcabonylschwefelchlorid (21) unter Ringschluß zu 5-Phenyl-1.2.4-dithiazolon-(3) (28). Bei Umsetzung mit Phenylimino-chlormethansulfenylchlorid (20) weicht die Reaktion aus, und das entsprechende Dithiazol-Derivat 25 wird nur in geringem Maße gebildet.
    Additional Material: 4 Tab.
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  • 64
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 727 (1969), S. 61-70 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Structure of Thioamides and their Derivatives, Vl 1). Magnetic Anisotropy of the Thio-amide GroupModels of the magnetic anisotropy of the thioformamide and the thioacetamide system are developed with the aid of sterically fixed 1-thioacyl piperidines. In this way the different assignment of the signals of the cis- and trans-N-methyl groups in dimethylthioacetamide and dimethylthioformamide (2a) can be explained. The steric effects of the acid residue on the shielding conditions are discussed on the basis of the n.m.r. spectra of 1-thioisobutyryl- and 1-thiopivalyl-4-methylpiperidine (1c and d). In 1d and in N.N-dimethylthiopivalinamide (2d) rotation around the C-N bond is fast at room temperature. The 2-methyl group in 1-thioacetyl-2-methylpiperidine (1f) is axial.
    Notes: Mit Hilfe von sterisch fixierten 1-Thioacyl-piperidinen werden Modelle für die magnetische Anisotropie-Wirkung des Thioformamid- und Thioacetamid-Systems entwickelt, die die unterschiedliche Zuordnung der Signale der cis- und trans-N-Methyl-Gruppe beim Dimethylthioacetamid und Dimethylthioformamid (2a) erklären. Anhand der NMR-Spektren von 1-Thioisobutyryl- und 1-Thiopivalyl-4-methyl-piperidin (1c und d) wird der sterische Einfluß des Säurerestes auf die Abschirmverhältnisse diskutiert. 1d sowie das N.N-Dimethyl-thiopivalinsäureamid (2d) zeigen bei Raumtemperatur schnelle Rotation um die C-N-Bindung. - Die 2-Methyl-Gruppe des 1-Thioacetyl-2-methyl-piperidins (1f) ist axial angeordnet.
    Additional Material: 1 Ill.
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  • 65
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The absolute oil of cassie (Acacia farnesiana WILLD.) has been thoroughly investigated by using several combined chromatographic techniques. Among the 38 new constituents which were thus identified in this oil, four deserve a particular mention, namely, the cis-3-methyldec-3-en-1-ol (I), the related acid III, the trans-3-methyl-dec-4-enoic acid (IV), and the homoterpene lactone dihydroactinidiolide (II). With the exception of the last one, these unusual C11 compounds play a prominent role in the characteristic fragrance of cassie oil.
    Additional Material: 2 Ill.
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  • 66
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    Helvetica Chimica Acta 52 (1969), S. 69-76 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The three ternary limiting isotherms of the system KCI-RbCI-CsCI-H2O are given for 25°. The system KCI-RbCI-H2O, with only one solid phase present, belongs to the type I of the ROOZEBOOM classification. A large miscibility gap is present in the systems RbCI-CsCI-H2O and KCI-CsCI-H2O; in the latter the incorporation is almost negligible; they belong to ROOZEBOOM's type IV.
    Additional Material: 5 Ill.
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  • 67
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new chemical degradation of (-)-kopsine is described which completely confirms the structure of this alkaloid. Correlation of (-)-aspidofractinine, (-)-pleiocarpine and (-)-kopsine with (-)-minovincine establishes the absolute stereochemistry of these bases. It appears that, in contrast to the aspidospermine group, all alkaloids containing the aspidofractinine skeleton possess the same absolute stereochemistry.
    Additional Material: 2 Ill.
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  • 68
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 13C NMR. spectra of seventeen m- and p- subsituted benzonitriles were examined and partially anlayzed. The C-1 carbon shieldings can be expressed in terms of a linear correlation with the LCAO-MO-π-electron density at C-1. No such correlation was found for the cyanocarbon, whose electron density shows only slight varriations for the different substitutents. This fact is consistent with the relatively small range of the chemical shifts at this center.
    Additional Material: 1 Ill.
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  • 69
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    Helvetica Chimica Acta 52 (1969), S. 107-121 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Es wird über Darstellung und spektroskopische Untersuchungen von Kupfer (II)-Komplexen CuL2X2 und CuL4X2 mit grösstenteils unidentaten Stickstoffbasen berichtet. Durch Ausnützung der Einflüsse von Substitutenten am Pyridin- bzw. Piperidinring der Liganden L wurden Komplexe verschiedener Stereometrie erhalten, an denen sich der Zusammenhang zwischen Mikrosymmetrie und Elektronenspektren studieren liess. Insbesondere konnte die Stauchung eines pseudotetraedrischen Teilchens über eine Reihe von Zwischenstufen bis zur planaren Anordnung der 4 Ligandatome anhand einer Anzahl von Verbindungen des Type CuL2X2 verfolgt werden. Die Arbeit befasst sich dabei im wesentlichen mit den Ligandenfeldspektren (über die Elektronentransfer-Übergange sol1 später berichtet werden). Der letzte Ligandenfeldübergang tritt bei den planaren Komplexen - offenbar wegen. Abschirmung des Zentral-Ions vor Störungen längs der z-achse bei unerwartet hoher Energie auf.
    Additional Material: 4 Ill.
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  • 70
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of the di- and trimerization of ethylen in organic solvents under the influence of a homogeneous catalyst containing π-tetramethylcyclobutadiene-nickeldichloride and a prereacted mixture of ethylaluminiumdichloride and tri-n-butylphosphine are reported. The primary reaction product is 1-butene, which is isomerized to 2-butene (cis/trans) during the reaction. The C6-Olefins are formed by the reaction of ethylene with 1-butene and with the 2-butenes. The following primary reaction products are obtained: 3-hexene (cis/trans), 1-hexene, 2-ethyl-1-butene, 3-methyl-1-pentene and 3-methyl-2-pentene (cis/trans).The effect of other phosphines on the reaction was also studied. The relative composition of the reaction product is strongly dependent upon the amount and the LEWIS base strength of the phosphine present. The results are in accordance with a coordinative mechanism on nickel.
    Additional Material: 5 Ill.
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  • 71
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of the condimerization of ethylene and propene in organic solvents under the influence of a homogeneous catalyst containing π-tetramethylcyclobutadiene-nickeldichloride and a prereacted mixture of ethylaluminiumdichloride and tri-n-butylphosphine are reported. The primary reaction products are: 1-pentene, 2-pentene (cis/trans), 2-methyl-1-butene and 3-methyl-1-butene.The effect of other phosphines was also studied. The activity as well as the selectivity of the catalyst are strongly dependent upon the amount and the LEWIS base strength of the phosphine present.The results are in accordance with a coordinative mechanism on nickel.
    Additional Material: 3 Ill.
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  • 72
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Hydrazinoethyl phosphoric monoester has been prepared by reacting hydrazinoethanol with polyphosphoric acid, and isolated as di-sodium salt.Sodium hydrazinoethyl phosphate reacts with phenylisothiocyanate (in H2O+ethanol) to yield mainly the derivative thiocarbamoylated at the substituted nitrogen atom. This derivative, heated for one night at 100° in 0.5 N HCl, is cyclized to 3-amino-2-phenylimino-thiazolidine in 62% yield. Sodium hydrazinoethyl phosphate reacts with o-methoxycarbonylphenyl isothiocyanate (in H2O+dioxane) at the unsubstituted nitrogen atom to yield mainly the corresponding quinazoline derivative (IV, X = OPO3Na2). This derivative, heated for one night at 100° in 0.5 N HCl, is cyclized to 2-o-carboxyphenylamino-dihydro-δ2-1, 3, 4-thiadiazine (Va) in 55% yield (hydrolysis of the lactamic function as well).Aminoethyl phosphorous monoester (colaminephosphorous acid) reacted with phenylisocyanate (in H20+dioxane) in slightly alkaline medium (one equivalent of NaOH) yields sodium N-phenylcarbamoylaminoethyl phosphite. Refluxed for 20 minutes in 1N NaOH, this carbamoyl derivative is not cyclized but only hydrolyzed to the open-chained N-phenyl-N′-hydroxyethylurea (VII).
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  • 73
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new ring-closure reaction is described, consisting in the treatment of basic carbinols of types 2, 8, 13, 16, with sodamide or sodium hydride, and adding to the sodium salts formed an alkyl halide. Oxolanes of types 5, 9, 14, 17, 20, are formed.
    Additional Material: 3 Ill.
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  • 74
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The total vapor pressures and the heats of mixing of the system cyclohexane-tetrahydrofuran were measured at 25°C. The density was used to determine concentrations for the total pressure measurements. The partial pressures, activity coefficients, excess free energies, entropy functions, and excess volumes were calculated.
    Additional Material: 3 Ill.
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  • 75
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    Helvetica Chimica Acta 52 (1969), S. 282-291 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The N-(p-nitrophenoxy-carbonyl) and N-(phenylthio-carbonyl) derivatives of α-amino-acyl-hydrazides cyclize in presence of diazomethane, yielding hexahydro-1, 2, 4-triazines with simultaneous formation of p-nitro-anisole or thio-anisole respectively. The molecules with a phenoxycarbonyl function such as N-(phenoxycarbonyl)-glycyl-(N, N′-diphenylhydrazide) give the corresponding ring products and anisole only in solvents with high dielectric constant (e.g. nitromethane). The phenylthio-carbonyl derivatives give the same ring products in presence of lead acetate by the intervention of HO-. The p-nitrophenoxycarbonyl derivatives give rise to the same cyclisations in the presence of pyridine by the intermediate of carbamyle-pyridinium ion acting as electrophile.These different types of intramolecular reactions are illustrated by the formation of 1, 2-diphenyl-5-alcoyl-3, 6-dioxo-1, 2, 4-hexahydro-triazines.
    Additional Material: 1 Tab.
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  • 76
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    Helvetica Chimica Acta 52 (1969), S. 408-418 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2-Dimethylaminoethanol reacts with 1,2-epoxyoctane presumably via a hydrogen-bonded complex to form a quaternary ammonium compound which exhibits a fair stability at lower temperatures. At higher temperatures the quaternary structure decomposes with the resulting formation of a wide variety of products. Most of the products have been identified and a reasonable mechanistic picture for their formation is presented. The main products of the reaction are 1-(ß-dimethylaminoethoxy)-2-octanol (IIIa) and 1-dimethylamino-2-octanol (IV), the latter being formed according to several pathways concurrently with ethylene oxide, 2-methyl-4-hexyl-1, 3-dioxolane (VI), and 2-hexyl-1, 4-dioxane (VII). Some of the higher molecular weight products are secondary products resulting from the action of epoxide on the primary reaction products IIIa and IV. The relative amount of each product formed depends on the ratio of starting materials and reaction temperature. In the presence of an additional hydroxylic solvent such as ethanol, the solvent enters also into the reaction.
    Additional Material: 1 Tab.
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  • 77
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    Helvetica Chimica Acta 52 (1969), S. 418-431 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The enthalpies of formation of 1.6-methano-[10] annulene (IV) (ΔHf298 (IV, g) = 75.2 ± 0.6 kcal mol-1), 1.6-imino-[10] annulene (V) (ΔHf298(V, g) = 87.8 ± 0.7 kcal mol-1) and of 1.6-oxido-[10] annulene (VI) (ΔHf298(VI, g) = 47.8 ± 1.2 kcal mol-1) have been determined by combustion calorimetry. The difficulties connected with an attempt to derive meaningfull «resonance energies» are discussed.
    Additional Material: 6 Tab.
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  • 78
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of the reduction of substituted azobenzenes by dihydroquinoxalines have been measured. Azo-compounds with electron-donating substituents in o- or p-position are reduced to the amines in neutral or acid solution, whereby two molecules of the reducing agent are consumed. If such substituents are absent, the reaction stops at the hydrazo stage. This is also the case with cleaveable azo-compounds in strongly alcaline solution.Our kinetic measurements of the reductive cleavage reaction of methylorange are in agreement with only one mechanism, which is discussed in detail. The very high reactivity of protonated methylorange may be attributed to the formation of a mesomeric quinoid structure. Knowing the pH-dependence of the reaction rate allows the determination of the pK-value of the extremely unstable hydrazo stage of methylorange. The structure of the dihydroquinoxaline has a strong influence on ΔH
    Additional Material: 2 Ill.
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  • 79
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Treatment of 3-oxo-4, 5-oxido steroids with lead tetraacetate results in acetoxylation in the 2α-position as could be shown by independent synthesis of the acetoxylated compounds. The products of this reaction rearrange even under very mild conditions (chromatography on silicagel or alumina) to the corresponding 2,3-dioxo-Δ4 compounds. The influence of structure and conformation of the various intermediates on their NMR.-spectra is discussed. A mechanism for this new transformation is proposed.
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  • 80
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    Helvetica Chimica Acta 52 (1969), S. 501-515 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The preparation of a non-stoichiometric basic carbonate of iron (III) is described. The amounts of carbon dioxide and water can vary in large limits, depending on the way the samples are dried. The ratio of Fe2O3:CO2 in a fresh product is nearly one, but decomposition takes place already at room temperature and ambient humidity. When heated slowly, the carbon dioxide is given of in two clear steps, an intermediate product being formed at about 200°C. The basic iron (III) carbonate decomposes between 400° and 500°C to an α-Fe2O3 with still a small amount of carbon dioxide. The infrared spectra show that in the freshly prepared products the greater part of the CO32- ions are linked by two oxygen atoms to two iron atoms, and a smaller part probably only by one oxygen to one iron atom. In the intermediate product, part of the CO2_3 ions are linked by two oxygen atoms to one iron atom, or a hydrogenocarbonate group may be formed. The X-ray diagrams taken with Mo Kα rays show only two broad lines.
    Additional Material: 8 Ill.
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  • 81
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    Helvetica Chimica Acta 52 (1969), S. 522-527 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The obtention of the crystalline basic carbonate of iron (III) and ammonium, (NH4)4Fe2(OH)4(CO3)3 · 3 H2O, is described, and its formula is established by chemical analysis and infrared spectroscopy. The compound is probably monoclinic, but it was not possible to index with certainty all X-ray reflections. The compound is similar to (NH4)2Fe2(OH)4(CO3)2 · H2O and its infrared spectrum leads to the assumption that in both the CO32- group is linked in the same fashion.
    Additional Material: 3 Ill.
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  • 82
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pseudostrophanthidin (2) can be easily prepared by treating strophanthidin (1) with concentrated hydrochloric acid in the cold [1]. 2 has served as the initial product for the preparation of a number of analogues and homologues of steroid hormones [2] [3]. 17α-Pseudostrophanthidin (4) is considered a suitable starting material for an extension of these investigations.It was logical to attempt the preparation of 4 from 17α-strophanthidin (3) under conditions identical with those used in the conversion of 1 into 2. However, these experiments did not lead to 4 but, instead, by way of the unstable 14ξ-chloro-14-deoxy-17α-strophanthidin (5) to 14-anhydro-17α-strophanthidin (6). This result is essentially in agreement with findings reported in the literature [5]. To support the structure assigned to 6, this compound was also prepared by a different, unambiguous, route. Treatment of 3 with thionyl chloride in pyridine gave mainly 3β, 5β-O, Osulfinyl-14-anhydro-17α-strophanthidin (8), which was converted into 6 by mild hydrolysis. In turn 6, as obtained via the unstable chloro compound 5, gave on treatment with thionyl chloride in pyridine a product identical with 8. - 6 was characterized as the 3-acetate 7.As extension of these experiments, 17α-strophanthidol (10) [6] was treated with concentrated hydrochloric acid in the cold under conditions similar to those used in the conversion of 3 into 6 by way of 5. This led to the isolation of 14-anhydro-17α-strophanthidol (11), which could also be obtained by the reduction of 6 with aluminium amalgam.As is known [1] [8], strophanthidinic acid (13) can be converted into strophanthidinic acid 19,8-lactone (14) by treatment with concentrated hydrochloric acid in the cold. In view of the negative results obtained in the attempt to transform 3 into 4 under these conditions, the question arose as to whether the conversion of 17α-strophanthidinic acid (15) into 17α-strophanthidinic acid 19,8-lactone (16) by the same procedure is also impossible. 15 was prepared by treating 3 with hydrogen peroxide and was characterized as the methyl ester 17 and the methyl ester of the 3-benzoate (18). 15 and 17 have been mentioned in the literature [5], but the physical constants reported differ from those obtained in this laboratory. It was demonstrated that after treating 15 with concentrated hydrochloric acid in the cold, no 16 could be isolated but, instead, an unstable chloro compound 19 which was converted into 14-anhydro-17α-strophanthidinic acid (20). 20 was characterized as the methyl ester 21 and the 3-acetate 22.
    Additional Material: 2 Tab.
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  • 83
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    Helvetica Chimica Acta 52 (1969), S. 543-549 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of kaolinite with potassium hydroxide (1 to 9N) was investigated between 70 and 90°C. During a first period of the reaction the content of Si and Al in solution increased and reached a maximum in 100 to 240 minutes, depending on KOH concentration and temperature; then an amorphous aluminosilicate gel formed. After an induction period, again depending on KOH concentration and temperature, the concentrations of Si and Al decreased rapidly, due to the formation of a crystalline potassium aluminosilicate.
    Additional Material: 6 Ill.
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  • 84
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: La triméthyl-2, 6, 6-hydroxy-2-cyclohexanone et l'époxy-5, 6-ionone ont été identifiées dans l'arǒme de thé noir.
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  • 85
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    Helvetica Chimica Acta 52 (1969), S. 568A 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 86
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    Helvetica Chimica Acta 52 (1969), S. 569-576 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Benzhydroxamsäure und im Phenylkern substituierte Analoge bilden mit α-Halogencarbonsäureestern Benzhydroxamsäureester (IV in Tab.1). Diese reagierten mit Diazomethan stereospezifisch zu den entsprechenden syn-Methyl-benzhydroximsäureestern (V in Tab.1.). Die Zuordnung der Stereochemie basiert auf dem Aufbau von XIV und XVIII aus den beiden 3-O-Methyl-benzhydroxamsäuren XII und XIII, deren Stereochemie gesichert ist.
    Additional Material: 2 Tab.
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  • 87
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: By electrolysis of cryolitic solutions of P2O5, elementary pure phosphorus is obtained on carbon cathode and Ni phosphides on Ni cathode. The most probable mechanism of phosphorus formation in these conditions seems to be the final dissociation of P2O5 in P5+ and O2- and the primary electrodic discharge of these ions.
    Additional Material: 2 Ill.
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  • 88
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New data concerning the tryptophan content, the stability, and the specificity of goose egg-white lysozyme are reported. This enzyme occupies a special place among the mammelian lysozymes already studied and the general definition of a lysozyme had to be modified. The mechanism of action is discussed.
    Additional Material: 3 Ill.
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  • 89
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    Helvetica Chimica Acta 52 (1969), S. 622-628 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The syntheses of dibenzo [b, f]-1, 4-oxazepin-11 (10 H)-ones (I) with electron-attracting substituents in position 2 by ring closure of the sodium salts of 2-halogeno-2′-hydroxy-benzanilides (II) are described. The reaction of II (R = SO2·N(CH3)2) in N-methylpyrrolidone also led, by SMILES rearrangement, to the isomeric minor product dibenzo [b, e]-1, 4-oxazepin-11 (5 H)-one (III; R = SO2·N(CH3)2), whose constitution was proven by synthesis from VI. In the case of II (R = SO2·CH3), the 5-methylsulfonyl-2-(2-hydroxyanilino)-benzoic acid (VI; R = SO2·CH3) was obtained directly after hydrolysis. The lactam I (R = NO2) was rearranged to the corresponding acid VI by heating with dilute caustic soda.
    Additional Material: 3 Tab.
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  • 90
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The results of the ultraviolet irradiation of the saturated β-ketosulfide 2 are discussed. The photochemistry of 2 is characterized by the occurrence of two primary photoprocesses. Their efficiences depend markedly on the excited transition, (charge-transfer)- or (n → π*)-excitation, respectively. In methanol solution (charge-transfer)-excitation leads almost exclusively to product 7, due to (Cα - S)-fission, and (n → π*)-excitation to nearly equal amounts of 7 and of products 4 and 6 which result from α-cleavage. On solvent sensibilization in benzene products 4, 6, 7 and the still unidentified product 52 are formed.Compounds 4 and 6 have been described earlier [2]. The structure elucidation of 7 is reported in this paper. Acid-induced transformation of 7 yields the dihetero-isotwistane 15.
    Additional Material: 4 Tab.
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  • 91
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    Helvetica Chimica Acta 52 (1969), S. 737-743 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The structure of the products of the pyrolysis gas chromatography of some azobenzenes has been determined. The thermal fragmentation is compared with the fragmentation induced by electron impact.The pyrolysis technique described gives information on the aromatic substitution not obtainable by mass spectrometry.
    Additional Material: 2 Ill.
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  • 92
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    Helvetica Chimica Acta 52 (1969), S. 743-763 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Proton NMR. spectra of 18 pteridines have been measured in strongly acidic solutions. In trifluoroacidic acid mono-cations are formed whereas in fluorosulfonic acid double protonation occurs. For the first time di-cations of pteridines are described, and the structures of these species are determined by NMR. and UV. data. The chemical shifts of the NH2 protons in the mono-cations and of the methyl protons in the mono- and di-cations follow linear correlations with the basic pKa values. From NMR. variable temperature measurements the energy barrier to internal rotation in the amidinium system has been ddtermined for both cations. The results are discussed with particular regard to the structure of the mono-and di-cations.
    Additional Material: 9 Ill.
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  • 93
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    Helvetica Chimica Acta 52 (1969), S. 764-776 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The behaviour of benzene and its mixtures with naphthalene, anthracene, cyclohexene and cyclohexadienes under the influence of γ-irradiation is examined. A mechanism of the product formation in pure benzene is proposed and discussed, that is mainly based on radical reactions between cyclohexadienyl and phenylcyclohexadienyl radicals. The existence of phenyl radicals is shown by the formation of phenylnaphthalenes with naphthalene as additive. The inhibiting effect of cyclohexene and cyclohexadiene on the biphenyl and phenylcyclohexadiene formation can be explained by hydrogen abstraction by the phenyl radicals.
    Additional Material: 2 Ill.
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  • 94
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bis-chloromethyl-alkyl-and - aryl-phosphine oxides, (CICH2)2P(O)R, which are obtained by reaction of (CICH2)2P(O)Cl with GRIGNARD reagents, undergo a MICHAELIS-ARBUSOV reaction when heated for several hours with trivalent phosphorus esters (phosphites, phosphonites, or phosphinites) at 170-180°C. The reaction affords bis-(dialkyloxyphosphonyl-methyl)-, bis (alkyloxyphosphinyl-methyl)-, and bis-(oxophosphoranyl-methyl)-, -alkyl- or -aryl-phosphine oxides, R(O)P[CH2P(O)R′R″]2 R = CH3, C2H5, n-C8H17, n-C12H25, C6H5; R′ and R″ = C2H5O, C4H9O, C6H5, CH3 in good yields.Conversion of the compounds containing alkyloxy groups to the free acids is achieved by refluxing with conc. HCl. Bis-(dihydroxyphosphonyl-methyl)-dodecylphosphine oxide, n-C12H25(O)P[CH2P(O) (OH)2]2, obtained by hydrolysis of the all-ethyl ester, titrates in aqueous solution as a tetrabasic acid with breaks at pH = 4 (two equivalents), pH = 6,9 (one equivalent) and pH = 9,6 (one equivalent). This acid, its disodium salt (m. p. 405-410°) and its tetrasodium salt (m.p. 〉 460°) are surface active and are excellent chelating agents.The 1H- and 31P-NMR. spectra of all the compounds prepared are discussed.
    Additional Material: 2 Ill.
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  • 95
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    Helvetica Chimica Acta 52 (1969), S. 872-872 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 96
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    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 52 (1969) 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 97
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    Helvetica Chimica Acta 52 (1969), S. 887-891 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A gas-chromatographic investigation of tomato aroma has revealed 46 components of which 32 are new. The isolation and identification of 2-isobutyl-thiazole, substance for the first time found in a natural aroma, are given in detail.
    Additional Material: 5 Ill.
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  • 98
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: rac-threo-α-(2, 2-Dichloroacetamido)-β-hydroxy-p-nitrohydrocinnamaldehyde (3) and rac-erythro-α-(2, 2-dichloroacetamido)-β-hydroxy-p-nitrohydrocinnamaldehyde (4) were synthesized starting from α-acetamido-p-nitroacetophenone (7), and their structures were proved bn- reduction to rac-chloramphenicol (19) and rac-erythro-2-(2, 2-dichloroacetamido)-1-(p-nitrophenyl)v 1, 3-propanediol (14) respectively. 3 exhibited only low antibacterial activity compared to rac-chloramphenicol (19).
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  • 99
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    Helvetica Chimica Acta 52 (1969), S. 913-933 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The rates of the BECKMANN-CHAPMAN rearrangement of the ketoximpicryl-ethers 1a-1k in 1, 4-dichlorobutane are correlated with parameters describing the bulk of the substituted groups R and R′. From regression analyses it is concluded that the relative rate constants are mainly controlled by steric contributions in the ground state, such as geminal interactions of R with R′ and vicinal interactions of R′ with O—X, and less by inductive effects.Conformational equilibria between (Z)- and (E)-isomers of N-alkyl-N-picryl-amids have been studied by NMR. in several solvents.
    Additional Material: 5 Ill.
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  • 100
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    Helvetica Chimica Acta 52 (1969), S. 944-947 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 4′-Demethylepipodophyllotoxin (III) has been synthesized by epimerisation of 4′-demethylpodophyllotoxin (I) via the corresponding chloride II. An improved method for the preparation of III has been developed by selective ether cleavage of the easily available podophyllotoxin (V) using the bromoderivatives VI and VII as intermediates.
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