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  • 1985-1989  (13)
  • 1980-1984  (17)
  • 1965-1969  (21)
  • 1840-1849
  • 1830-1839
  • Alkenes
  • Heterocycles
  • 1
    Electronic Resource
    Electronic Resource
    Perspectives in Photochromism: A Novel System Based on the 1,5-Electrocyclization of Heteroanalogous Pentadienyl AnionsDedicated to Professor Emanuel Vogel and Professor Klaus Hafner on the occasion of their 60th birthdays (1989)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 28 (1989), S. 413-431 
    Details
    ISSN: 0570-0833
    Keywords: Photochromism ; Electrocyclic reactions ; Cyclization ; Pentadienyl anions ; Heterocycles ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The molecular process whereby light induces color changes in certain substances, namely photochromism, is currently a topic of active research. Many reactions - mainly monomolecular - have been reexamined in greater detail from the standpoint of photochromism. Those found to be especially suitable for such studies include cis-trans isomerizations, pericyclic reactions, tautomerizations and dissociations. The most important in this group are undoubtedly the electrocyclization reactions. In this paper we present spiro[fluorene-9,1′-[1,8a]-dihydroindolizine] and its bis- and tris-aza analogues as examples of a promising new system with a wide range of variability. Not only the classical uses, but also those in new fields such as frequency doubling of laser radiation, holography or molecular microcircuit chips can now be considered.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.198904131
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  • 2
    Electronic Resource
    Electronic Resource
    Über enantiomerenreines (R)-2-Methyl-3-oxo-perhydro-1,4-oxazin (1988)
    Springer
    Monatshefte für Chemie 119 (1988), S. 839-844 
    Details
    ISSN: 1434-4475
    Keywords: Alpha haloesters ; Enantioselective synthesis ; Heterocycles ; Morpholinones ; Racemization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The synthesis of enantiomerically pure (R)-2-methyl-3-oxo-perhydro-1,4-oxazine is described for the first time. Stereochemical proofs are given and the formation of byproducts is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00809695
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  • 3
    Electronic Resource
    Electronic Resource
    Influence of structure of alkenes on their retention on different stationary phases (1988)
    Springer
    Chromatographia 25 (1988), S. 655-658 
    Details
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Structure-retention relationships ; Connectivity indices, topological indices ; Alkenes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Retention indices of different alkenes are correlated with connectivity and topological parameters. The appropriate statistically valid relations hips are derived and discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02327667
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  • 4
    Electronic Resource
    Electronic Resource
    Ketenimine Complexes from Carbene Complexes and Isocyanides: Versatile Building Blocks for Carbocycles and N-Heterocycles [New Synthetic Methods (74)]Dedicated to Professor Ernst Otto Fischer on the occasion of his 70th birthday (1988)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 27 (1988), S. 1456-1467 
    Details
    ISSN: 0570-0833
    Keywords: Ketenimines ; Carbene ligands ; Isocyanides ; Carbocycles ; Heterocycles ; Synthetic methods ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ketenimine complexes are readily available in great variety by reaction of isocyanides with carbene complexes. They have proven to be useful building blocks in new synthetic approaches to carbocyclic and N-heterocyclic four-, five-, and six-membered rings. The reactions involve new metal-induced bond formation patterns of the ketenimine ligands, which can be influenced across a wide range by varying the following five parameters: the metal, the ligands, and the three substituents on the N=C=C unit.
    Additional Material: 8 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.198814561
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  • 5
    Electronic Resource
    Electronic Resource
    Phosphaalkynes - Syntheses, Reactions, Coordination Behavior [New Synthetic Methods (73)]Phosphorus Compounds with Unusual Coordination, Part 30. Part 29: [119]. (1988)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 27 (1988), S. 1484-1508 
    Details
    ISSN: 0570-0833
    Keywords: Phosphaalkynes ; Synthetic methods ; Phosphorus-carbon compounds ; Multiple bonds ; Heterocycles ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organophosphorus compounds have been applied in two ways in chemical synthesis. They can either be used as a reagent in a step of the synthesis (for example, in the Wittig reaction) or they can be incorporated directly into the target molecule. This second application, in particular, has expanded greatly in the last few years with the preparation of low-coordination phosphorus compounds. These include the phosphaalkynes, which are of great interest to organic and inorganic chemists. Phosphaalkynes have been employed in the synthesis of heterocyclic compounds, phosphaarenes and their valence isomers, and polycyclic compounds. Further applications have been the use of phosphaalkynes as new ligand systems in complex chemistry and their cyclooligomerization with organometallic reagents. While the chemical properties of phosphaalkynes have little in common with those of nitriles, they are in many ways very similar to those of the isoelectronic acetylenes.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.198814841
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  • 6
    Electronic Resource
    Electronic Resource
    A new convenient synthetic method for 3,4-diaryl-2,6-piperidinediones (1987)
    Springer
    Monatshefte für Chemie 118 (1987), S. 987-991 
    Details
    ISSN: 1434-4475
    Keywords: Heterocycles ; Piperidinediones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Durch saure Hydrolyse der entsprechenden Ethyl-3,4-diaryl-4-cyanobutyrate wurden in einem Schritt (Eintopfreaktion) die 3,4-Diaryl-2,6-piperidindione dargestellt.
    Notes: Abstract A one-pot reaction for the preparation of 3,4-diaryl-2,6-piperidinediones through acid hydrolysis of the corresponding ethyl 3,4-diaryl-4-cyanobutyrates is described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00815326
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  • 7
    Electronic Resource
    Electronic Resource
    On-line gas chromatographic analysis of light Fischer-Tropsch synthesis products (1986)
    Springer
    Chromatographia 21 (1986), S. 265-268 
    Details
    ISSN: 1612-1112
    Keywords: Capillary gas chromatography ; Alumina PLOT columns ; C1−C7 hydrocarbons ; Alkenes ; Fischer-Tropsch products
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A simple gas chromatographic system has been developed for the rapid on-line analysis of light Fischer-Tropsch products. This involves a single chromatography fitted with two columns, a porous-layer open-tubular column coated with KCl deactivated alumina and a packed Porapak-Q column. The capillary column separates the 16 most common C1−C4 hydrocarbons and permits a reasonable analysis of the hydrocarbons in the C5−C7 range. The packed column is used for the separation of methane, carbon monoxide, carbon dioxide, water and methanol. Retention characteristics for the analysis on the capillary column are presented. The total analysis cycle is 30 minutes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02311879
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  • 8
    Electronic Resource
    Electronic Resource
    Oxidation of propene and 1-butene byMethylococcus capsulatus andMethylosinus trichosporium (1986)
    Springer
    Journal of industrial microbiology and biotechnology 1 (1986), S. 119-127 
    Details
    ISSN: 1476-5535
    Keywords: Olefins ; Alkenes ; Epoxidation ; Biotransformation ; Methylococcus capsulatus ; Methylosinus trichosporium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary Methane-grown cells ofMethylococcus capsulatus andMethylosinus trichosporium readily oxidized propene and various isomers of butene to their respective epoxides. When examined in a proton NMR spectrum using tris([3-trifluoromethylhydroxymethylene]-d-camphorato), europium III derivative as an optically active chemical shift reagent, the products propylene oxide and 1,2-epoxybutane were found to contain equal amounts of both isomers. Methane-grown cells of both bacteria had considerable levels of reducing equivalents to catalyze the epoxidation of gaseous olefins. Cells depleted of reductants catalyzed the oxidation in the presence of low levels of methanol or formaldehyde with a stoichiometry of about 2:1. The rates of epoxidation of propene and 1-butene in a continuous reactor were 2–3-times that of a batch-wise reaction; the epoxidation activity, however, was lost within 3 h. The inactivation was attributed to the reactivity of the accumulated epoxides in the reactor. Propene and 1-butene oxidation by both bacteria were drastically inhibited by the respective products. Thus, the major problem in the application of microorganisms for production of epoxides from gaseous olefins is the rapid separation of the reactive products.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01569320
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  • 9
    Electronic Resource
    Electronic Resource
    Gas chromatographic retention indices for alkenes on OV-101 and squalane capillary columns (1986)
    Springer
    Chromatographia 21 (1986), S. 149-151 
    Details
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Retention indices ; Comparison of data ; Alkenes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Gas chromatographic retention indices for 47 C5 to C8 alkenes on OV-101 dimethylsilicone at 50 and 70 °C were determined within a standard deviation of 0.3i.u. Data obtained on OV-101 are compared with those measured on squalane. The comparison of the retention index and dl/dT values from both columns is presented as linear regression equations with correlation coefficients greater than 0.98.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02311743
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  • 10
    Electronic Resource
    Electronic Resource
    13C NMR and lanthanide-induced shifts in epoxides of Terpenes and related compounds (1986)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 24 (1986), S. 718-722 
    Details
    ISSN: 0749-1581
    Keywords: Epoxidation induced ; 13C NMR shifts ; Lanthanide induced shifts ; Epoxides ; Alkanes ; Alkenes ; Terpenes ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Based on literature data, and new measurements with both simple and complicated skeletons, it is shown that epoxidation-induced shifts (EIS) usually vary by only 〈4ppm if compared with the corresponding olefins, but by 〈9 ppm if compared with the saturated analogues. Shift differences between stereoisomers (E/Z or trans/cis) are consistent and, again, similar in epoxides and olefins. Larger variations are observed only for cyclic systems in which flexibility and conformational coupling can lead to significant conformational differences between the epoxide and olefin. Yb(fod)3-induced LIS values are regular if normalized by setting the LIS for the α-carbon atoms to 100%; these and the EIS values can be used to confirm or correct13C signal assignments.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1260240818
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  • 11
    Electronic Resource
    Electronic Resource
    185-nm Photochemistry of Olefins, Strained Hydrocarbons, and Azoalkanes in SolutionDedicated to Professor Dietrich Schulte-Frohlinde on the occasion of his 60th birthday (1986)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 25 (1986), S. 661-672 
    Details
    ISSN: 0570-0833
    Keywords: Photochemistry ; Azoalkanes ; Strained molecules ; Alkenes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The possibility to excite directly at 185 nm chromophores that absorb in the vacuum-UV has stimulated increased activity during the last decade in this field of photochemistry. Whereas photochemical reactions at λ〈200 nm have been thoroughly investigated in the gas phase, only recently have intensive studies on the 185-nm photochemistry of organic compounds in solution provided new insights. Despite the high excitation energies, selective photoreactions are promoted in the short-lived singlet excited states (Rydberg photochemistry). In contrast to conventional photochemistry (λ 〉 220 nm), 185-nm irradiation preferentially results in intramolecular rearrangement, fragmentation, and isomerization reactions. Intermolecular radical couplings and abstractions as well as dimerizations (π, π*-excitation) compete minimally. Besides the straightforward denitrogenation of photoresistant (“reluctant”) azoalkanes, important applications of the short-wavelength photolysis are also found in technology (photolithography) and medicine (193-nm laser). Broadening the scope of the synthetic potential of the 185-nm photochemistry, which so far has been limited to direct cis/trans isomerizations, presents a challenge for the chemist.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.198606613
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  • 12
    Electronic Resource
    Electronic Resource
    Study of the effect of N-protonation and N-methylation on the 1H and 13C chemical shifts of the six-membered ring in benzazoles and 2-substituted N,N-dimethylamino derivatives (1986)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 24 (1986), S. 415-420 
    Details
    ISSN: 0749-1581
    Keywords: Heterocycles ; Benzazoles ; Amino Derivatives ; Cation formation ; 1H and 13C ; NMR ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 1H and 13C NMR spectral data of benzimidazole, benzoxazole, benzothiazole and N-methylbenzimida-zole and of their 2-N,N-dimethylamino derivatives are reported. The spectra were recorded in acetone-water solution. The chemical shifts of these molecules are compared with those of the corresponding cations obtained by N-protonation and N-methylation of the neutral molecules. The carbon atoms C-4, C-5, C-6 and C-4a show a qualitatively identical behaviour, moving to higher field when the cations are formed from the benzazoles examined, but a different behaviour is found for C-2, C-7 and C-7a, which depends on the heterocyclic ring, on the presence of the substituent in position 2 and on the type of cation formed (N-protonation and N-methylation cause different effects). The conversion of benzazoles into the corresponding cations causes all 1H chemical shifts to move to lower field.
    Additional Material: 8 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1260240505
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  • 13
    Electronic Resource
    Electronic Resource
    [3+2] Cycloaddition Approaches to Five-Membered Rings via Trimethylenemethane and Its Equivalents [New Synthetic Methods (55)] (1986)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 25 (1986), S. 1-20 
    Details
    ISSN: 0570-0833
    Keywords: Cycloaddition ; Trimethylenemethane ; Synthetic methods ; Cyclopentanes ; Heterocycles ; Natural products ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The power of cycloadditions for ring formation derives from the potential for chemo-, regio-, diastereo-, and enantioselectivity. Trimethylenemethane (TMM) and its equivalents offer the possibility of extending such benefits to the synthesis of five-membered rings. Three types of conjunctive reagents appear to be promising candidates: (1) selected 4-alky-lidene-4,5-dihydro-3H-pyrazoles, (2) 2-[(trimethylsilyl)methyl]allyl esters and halides, and (3) alkylidenecyclopropanes. Thermal reactions, especially intramolecular ones, effect the cycloaddition of the pyrazoles to olefins-especially electron-poor olefins. The latter two precursors require a catalyst, notably a palladium complex, to unlock the synthetic potential. With the 2-[(trimethylsilyl)methyl]allyl esters, a general chemo-, regio-, and diastereoselective cycloaddition with typical Diels-Alder dienophiles forms methylenecyclopentanes in both inter- and intramolecular fashion. A tin analogue allows extension of this cycloaddition to aldehydes, and, in a related sequence, to ketones and imines to form 3-methylenete-trahydrofurans and 3-methylenepyrrolidines with excellent diastereoselectivity. The 2-[(tri-methylsilyl)methyl]allyl esters also serve to effect net methylenecyclopentane annulation to cyclic enols. Such adducts can further undergo three-carbon intercalation or combined ring contraction-spiroannulation simply by the use of either a nucleophilic or electrophilic trigger. Alkylidenecyclopropanes undergo cycloadditions to both electron-rich and electron-poor olefins when stimulated by metal catalysts, especially palladium. A complementary regiochemistry to the approach based upon silicon conjunctive reagents is observed. The availability of these cycloadditions provides new strategies for the synthesis of natural products.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.198600013
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  • 14
    Electronic Resource
    Electronic Resource
    α,β-Unsaturated nitriles in heterocyclic synthesis: Synthesis of some new pyrazolo[1,5-a]pyrimidine derivatives (1984)
    Springer
    Monatshefte für Chemie 115 (1984), S. 1413-1419 
    Details
    ISSN: 1434-4475
    Keywords: Cinnamonitriles ; Cyanoethylations ; Heterocycles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung 3-Antipyrinyl-5-aminopyrazol (1) reagierte mit Acrylnitril zu 5-Amino-1-β-cyanoethyl-3-antipyrinylpyrazol (2).2 konnte ebenfalls aus der Reaktion von β-Cyanethylhydrazin (3) und Verbindung4 erhalten werden.2 wurde mittels Essigsäure-Salzsäure glatt zu 2-Antipyrinyl-4,5,6,7-tetrahydropyrazolo[1,5-a]-pyrimidin-5-on (5) cyclisiert.5 konnte auch aus der Reaktion von1 mit Methylacrylat erhalten werden. Die Reaktion von1 mit Zimtsäurenitrilderivaten7 a–e ergab die Pyrazolo[1,5-a]pyrimidin-Derivate9,11 und12.
    Notes: Abstract 3-Antipyrinyl-5-aminopyrazole (1) reacted with acrylonitrile to afford 5-amino-1-β-cyanoethyl-3-antipyrinylpyrazole (2). Compound2 could also be obtained from the reaction of β-cyanoethylhydrazine (3) and compound4.2 was readily cyclized into 2-antipyrinyl-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrimidin-5-one (5) by acetic-hydrochloric acid.5 could be also obtained from the reaction of1 and methyl acrylate. The reaction of1 and cinnamonitrile derivatives7 a–e resulted in the formation of pyrazolo[1,5-a]pyrimidine derivatives9,11 and12.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00816340
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  • 15
    Electronic Resource
    Electronic Resource
    Substituted benzimidazo[2,1 -h]pteridine-2,4-diones (1984)
    Springer
    Monatshefte für Chemie 115 (1984), S. 757-763 
    Details
    ISSN: 1434-4475
    Keywords: Heterocycles ; Synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die 5-Alkyl-5,6-dihydrobenzimidazo[2,1 -h]pteridin-2,4(1H,3H)-dione4 a-d wurden mittels Kondensation von 2-(Alkylaminomethyl)benzimidazolidhydrochloriden1 a–d mit 5-Brombarbitursäure (2) dargestellt. In ähnlicher Weise wurden die 5-Alkyl-5,6-dihydro-4a-nitrobenzimidazo[2,1 -h]pteridin-2,4(3H,4aH)-dione10 a–d über die Kondensation von1 a–d mit 5-Brom-5-nitrobarbitursäure (8) und nachfolgender Cyclisierung der intermediären 5-[(Benzimidazol-2-ylmethyl)alkylamino]-5-nitrobarbitursäuren9 a–d mit 5% NaOH dargestellt. Die thermische Cyclisierung der Produkte9 a–d wurde ebenfalls untersucht. Die Verbindungen wurden mittels Elementaranalyse, IR und PMR charakterisiert.
    Notes: Abstract 5-Alkyl-5,6-dihydrobenzimidazo[2,1 -h]pteridine-2,4(1H,3H)-diones (4 a–d) have been synthesised by the condensation of 2-(alkyl-aminomethyl)benzimidazole dihydrochloride (1 a–d) with 5-bromobarbituric acid (2). Similarly, 5-alkyl-5,6-dihydro-4 a-nitrobenzimidazo[2,1 -h] pteridine-2,4(3H,4aH)-diones (10 a–d) have also been synthesised by the condensation of1 a–d with 5-bromo-5-nitrobarbituric acid (8) followed by cyclisation of the intermediate 5-[(benzimidazol-2-ylmethyl)alkylamino]-5-nitrobarbituric acid (9 a–d) with 5% NaOH. Thermal cyclisation of the intermediates9 a–d have also been studied. Methylation of the compound10 a has been carried out with CH3I and K2CO3 usingD M F as solvent to confirm cyclisation. The structures are supported by elemental analyses, IR and PMR spectra.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01120971
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  • 16
    Electronic Resource
    Electronic Resource
    Darstellung und Struktur von Pyrazolyl-Kationen mit Polymethin- und Methan-Gerüst (1983)
    Springer
    Monatshefte für Chemie 114 (1983), S. 219-225 
    Details
    ISSN: 1434-4475
    Keywords: Cyanine dyes ; Dipyrazolylmethanes ; Heterocycles ; N-15-NMR ; O-17-NMR ; Phenazon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The 4-pyrazoline-3-one1 reacts with 4-dimethylaminobenzaldehyde to yield the stable asymmetric cyanine dye2b which reacts with1 to give the colorless (aryl) (dipyrazolyl) methane3b. Using aldehydes with less cationstabilizing groups the polymethines2 are not isolated but only the methanes3. The structures of2b and3 are discussed by1 H,13C and Hetero NMR spectra.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00798325
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  • 17
    Electronic Resource
    Electronic Resource
    Triazolo[4′,3′:4,5] [1,3,4]thiadiazolo[2,3-b]quinazolin-6-one (1983)
    Springer
    Monatshefte für Chemie 114 (1983), S. 339-342 
    Details
    ISSN: 1434-4475
    Keywords: Heterocycles ; Infrared ; 1H-NMR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung 3-Methyl-6H-[1,2,4]triazolo[4′ ,3′ : 4,5] [1,3,4]thiadiazolo[2,3-b]chinazolin-6-on (6) wurde mittels Kondensation von Isatoesäureanhydrid (1) mit 4-Amino-5-mercapto-3-methyl[1,2,4]triazol (2) und anschließender Cyclisierung von Zwischenverbindung3 mit POCl3 und PCl3 dargestellt. Als Alternative konnte6 auch über die Kondensation von 3-Amino-2-mercapto-3H-chinazolin-4-on (7) mitN-Carbethoxyhydrazin in Gegenwart von HCl und anschließender Cyclisierung der Zwischenverbindung8 mit Essigsäure synthetisiert werden. Die Strukturen der Verbindungen wurden mittels IR,1H-NMR und Mikroanalyse nachgewiesen.
    Notes: Abstract 3-Methyl-6H-[1,2,4]triazolo[4′,3′: 4,5] [1,3,4]thiadiazolo[2,3-b]quinazolin-6-one (6) has been synthesized by the condensation of isatoic anhydride (1) with 4-amino-5-mercapto-3-methyl-[1,2,4]triazole (2) and final cyclisation of the intermediate3 with POCl3 and PCl3. Alternatively6 could also be synthesized by the condensation of 3-amino-2-mercapto-3H-quinazolin-4-one (7) withN-carbethoxy hydrazine in presence of hydrochloric acid and final cyclisation of the intermediate8 with acetic acid. The structures have been confirmed on the basis of IR, PMR and analytical results.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00798956
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  • 18
    Electronic Resource
    Electronic Resource
    Bond-Forming Initiation in Spontaneous Addition and Polymerization Reactions of Alkenes (1983)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 22 (1983), S. 440-455 
    Details
    ISSN: 0570-0833
    Keywords: Initiation ; Addition ; Polymerization ; Alkenes ; C-C coupling ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Spontaneous addition and polymerization reactions of alkenes of different electron-densities result in a wide variety of small organic molecules and high polymers. Tetramethylenes are proposed as key intermediates, i.e. resonance hybrids of 1,4-diradical and zwitterionic limiting structures. Their character is determined by the substituents at the terminals: Zwitterionic character is favored by strong donors, such as alkoxy and dialkylamino groups, at the carbenium center and strong acceptor group such as diesters and cyano-esters, at the acceptor end, and aryl and vinyl groups as donors. Zwitterionic tetramethylenes initiate ionic homopolymerization, while diradical tetramethylenes initiate alternating copolymerization, thus providing an extremely sensitive technique for the detection and characterization of these intermediates. The effects of the donor and acceptor substituents can be arranged as an “Organic Chemist's Periodic Table”, wherein the areas of mechanistic change clearly emerge and which provides predictive capability. - This unifying concept of bondforming initiation is extended to spontaneous addition and polymerization reactions of heteroatom acceptor molecules and 7,7,8,8-tetrasubstituted quinodimethanes and of compounds possessing labile σ-bonds, such as halogens and peroxides. Radical-ion pairs, charge-transfer complexes and adventitious impurities are excluded as significant initiators.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.198304401
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  • 19
    Electronic Resource
    Electronic Resource
    The Versatile Chemistry of 1,4-Diazines: Organic, Inorganic and Biochemical Aspects (1983)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 22 (1983), S. 171-190 
    Details
    ISSN: 0570-0833
    Keywords: 1,4-Diazines ; Pyrazine ; Heterocycles ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In chemical research attention is increasingly being focussed on composite “complex” systems with special properties and functions. As components of such systems 1,4-diazines are steadily gaining in popularity. Here, 1,4-diazines means pyrazine and its derivatives as well as compounds with partial pyrazine structure; examples are quinoxaline, phenazine, pteridine, flavin and their derivatives. All these compounds are characterized by a low lying unoccupied π-molecular orbital and by the ability to act as bridging ligand. Due to these two properties 1,4-diazines, and especially their parent compound pyrazine, possess a characteristic reactivity. 1,4-Diazines may be employed to study inter- and intramolecular electron transfer in organic, inorganic and biochemical reactions. In the redox system of 1,4-diazines the paramagnetic 7π-electron intermediate exhibits exceptional stability, whereas the 1,4-dihydro-1,4-diazines with 8π-electrons in a six-membered ring are not generally accessible due to their potential antiaromaticity and their large excess of π electrons. Its inherent bifunctionality and the low lying unoccupied molecular orbital permit pyrazine to form coordination polymers having unusual electrical and magnetic properties. Finally, the phenomena observed for pyrazines may be used in the interpretation of the reactivity of naturally occurring 1,4-diazines, such as flavins and bioluminescent natural products.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.198301713
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  • 20
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    Formation of CC Bonds by Addition of Free Radicals to AlkenesDedicated to Professor Karl Winnacker on the occassion of his 80th birthday (1983)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 22 (1983), S. 753-764 
    Details
    ISSN: 0570-0833
    Keywords: Addition ; Free radicals ; Alkenes ; C-C coupling ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: There are many reactions in which CC bonds are formed by addition of free radicals to alkenes. Information about the mechanism is important for the synthesis of specific target molecules. The rate of addition of alkyl radicals to alkenes is controlled by steric and polar effects. The stabilities of the educts and products are of only limited importance, since the transition states for these exothermic reactions occur very early on the reaction coordinate. Variations in reactivity and selectivity can be described using frontier orbital theory: for nucleophilic radicals the dominant interactions are those between SOMO's and LUMO's, and for electrophilic radicals those between SOMO's and HOMO's. The large differences in the steric effects of α - and β- substituents of alkenes can be explained by postulating an unsymmetrical transition state -  the radical approaches one of the C atoms preferentially. Regioand stereoselectivities can be predicted and are determined, in general, by steric effects.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.198307531
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  • 21
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    Homolytic Cyclizations of N-ChloroalkenylaminesDedicated to Professor Jean-Marie Surzur on the occasion of his 50th birthday. (1983)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 22 (1983), S. 337-350 
    Details
    ISSN: 0570-0833
    Keywords: Cyclization ; Chloroamines ; Alkenylamines ; Synthetic methods ; Heterocycles ; Free radicals ; Natural products ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Many N-chloroalkylamines with double bond(s) dissociate homolytically to give chlorine atoms and aminyl radicals which undergo intramolecular cyclization reactions. Here, the nature of the aminyl radicals (neutral, protonated, or complexed to metal salts) appears to be important. The reactivity varies strongly from one species to another, and their selectivities can be different towards addition, substitution, abstraction, or dimerization reactions. A good synthetic tool appears to be the “complexed radical”, which is generated under mild conditions. A variety of β-functionalized, substituted, fused, or bridged azaheterocycles with alkaloid part structures thus become easily accessible in high yields, in a regio- and, possibly, stereoselective manner. Many examples are discussed illustrating the synthetic possibilities, limitations, and mechanistic features of this cyclization process.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.198303373
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  • 22
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    Synthese des 4-Hydroxy-6,6-dimethyl-5,6-dihydro-2H-thiopyran-2-thions bzw. -ons und der entsprechenden Tautomeren (1982)
    Springer
    Monatshefte für Chemie 113 (1982), S. 1283-1297 
    Details
    ISSN: 1434-4475
    Keywords: Heterocycles ; Keto-enol-tautomerism ; Synthesis ; 2H-Thiopyrane-2-ones and -2-thiones, 4-alkylamino and 4-alkoxy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The tautomers 4-hydroxy-6,6-dimethyl-5,6-dihydro-2H-thiopyran-2-thione (4 a) and 2-mercapto-6,6-dimethyl-5,6-dihydro-4H-thiopyran-4-one (4 b) resp. were synthesized by hydrolysis of 4-amino-5,6-dihydro-2H-thiopyranthiones6,8. On methylation of4 a,b only the S-methyl product7 is formed. Hydrolysis of 4-amino-2-methylthiothiopyranyliden iodides11 leads—depending on the amino group of11—either to the thiopyranone7 or to the 4-imino-thiopyranes12 and to β-amino-α,β,γ,δ-unsaturated-methyldithio carboxylates13. On reaction of4 a,b with hydrogenperoxyd the tautomers 4-hydroxy-5,6-dihydro-2H-thiopyran-2-one5 a and 5,6-dihydro-2H-thiopyran-2,4(3H)diones5 b resp. are formed.4 a,b and5 a,b undergo an aminolysis with prim. and sec. amines to the corresponding 4-amino-2H-thiopyran-2-thiones6,8 and -ones10 resp. On heating in alcohols the 4-alkoxy-thiopyrane-2-thiones and -ones9,14 are formed from4 a,b and5 a,b resp.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00808744
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  • 23
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    3-Methyl[1,3,4]thiadiazino[2,3-b]quinazolin-6-ones (1982)
    Springer
    Monatshefte für Chemie 113 (1982), S. 1145-1150 
    Details
    ISSN: 1434-4475
    Keywords: Heterocycles ; Synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Zur Synthese von 4H,6H-[1,3,4]thiadiazino[2,3-b]chinazolin-6-on (6a) wurde die Kondensation von 3-Amino-2-mercapto-3H-chinazolin-4-on (1) mit Allylbromid mit nachfolgender Behandlung mit Brom und Dehydrohalogenierung des bromierten Produktes4 mit ethanolischer Natronlauge herangezogen. Das zu6a isomere 2H,6H-Produkt6b wurde ebenfalls durch Kondensation von1 mit Bromaceton und nachfolgender Cyclisierung der Zwischenprodukte8 bzw.9 mit HBr oder H2SO4 erhalten. Die Strukturen wurden mittels IR und NMR abgesichert.
    Notes: Abstract 4H,6H-[1,3,4]Thiadiazino[2,3-b]quinazolin-6-one with a methyl group in position 3 (6a) has been synthesised by the condensation of 3-amino-2-mercapto-3H-quinazolin-4-one (1) with allyl bromide (2) followed by treatment with bromine and subsequent dehydrohalogenation of the brominated product (4) with ethanolic sodium hydroxide. Its isomeric 3-methyl-2H,6H-[1,3,4]thiadiazino[2,3-b]quinazolin-6-one (6b) has also been obtained by condensation of1 and bromoacetone (7) followed by cyclisation of the intermediates (8 or9) with hydrobromic acid or with concentrated sulphuric acid. The structures have been established on the basis of IR and PMR data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00808629
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  • 24
    Electronic Resource
    Electronic Resource
    Specific interactions of alkenes with different metal ion forms of ion exchangers in gas solid chromatography (1982)
    Springer
    Chromatographia 16 (1982), S. 251-256 
    Details
    ISSN: 1612-1112
    Keywords: Alkenes ; Gas-solid chromatography ; Ion exchangers ; Alkene separation ; Selectivity ; Specific interactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The gas chromatographic selectivity of K+, Zn2+, Ag+, Ni2+, and Cd2+ forms of a cation exchange packing have been determined for a set of 44 C2 to C8 alkenes. The retention characteristics of each ion are broken down into electronic (charge-transfer) and steric effects associated with the alkene sub-populations of each carbon number. Almost every pair of alkenes tested can be separated on at least one of these packings. Retention is much stronger on the ion exchangers than on metal-ion containing packings in gas-liquid chromatography, even with shorter columns and higher temperatures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02258913
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  • 25
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    Knoevenagel Reaction of malononitrile and its “dimer” with β-ketoanilides (1981)
    Springer
    Monatshefte für Chemie 112 (1981), S. 1187-1194 
    Details
    ISSN: 1434-4475
    Keywords: Heterocycles ; Knoevenagel reaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die Reaktion von Malodinitril mit Benzoylacetaniliden wurde untersucht. Die Struktur der dabei erhaltenen Verbindungen (2–4) wurde auf Basis der chemischen und spektroskopischen Eigenschaften zugeordnet.
    Notes: Abstract The reaction of benzoylacetanilides with malononitrile has been investigated. The structure of the compounds obtained (2, 3, 4) have been assigned on the basis of chemical properties and spectral data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00905473
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  • 26
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    Benzothiazolo[3,2-c]-1,3-dioxolo[4,5-g]quinazolines (1981)
    Springer
    Monatshefte für Chemie 112 (1981), S. 1083-1090 
    Details
    ISSN: 1434-4475
    Keywords: Heterocycles ; 1 H-NMR ; Stereochemistry ; Synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Es wurde eine Reihe von 5,12a-Dihydro-6-alkyl/aryl-6H-benzothiazolo [3,2-c]-1,3-dioxolo[4,5-g]chinazoline, sowohl mitcis-als auchtrans-ständigen Wasserstoffatomen an Kohlenstoff 6 und 12a, synthetisiert. Ebenso wurden auch Verbindungen dieses Systems mit Thiazol an Position 6 hergestellt. Die Strukturen wurden mittels IR- und NMR-spektroskopischen Daten abgesichert.
    Notes: Abstract Some 5,12a-dihydro-6-alkyl/aryl-6H-benzothiazolo[3,2-c]-1,3-dioxolo [4,5-g]quinazolines withcis as well astrans stereochemistry of the hydrogens at carbon 6 and 12a have been synthesised. The synthesis of another series of compounds of the above system with thiazole ring at position 6 has also been accomplished. The structures have been established on the basis of IR and PMR data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00905076
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  • 27
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    Application of methoxymercuration-demercuration followed by mass spectrometry as a convenient microanalytical technique for double-bond location in insect-derived alkenes (1980)
    Springer
    Journal of chemical ecology 6 (1980), S. 257-269 
    Details
    ISSN: 1573-1561
    Keywords: Alkenes ; mercuration-demercuration ; methoxyethers ; mass spectrometry ; insect hydrocarbons ; honeybee
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The positions of double bonds in olefins can be readily determined by a sodium borohydride reduction of their methoxymercuration products followed by mass spectrometry. Fragmentation of the methoxy derivative in the mass spectrometer results in cleavage on either side of the methoxy group to give intense fragment ions which are characteristic of each isomer. This simple and convenient microanalytical technique was applied to several synthetic standards and insect derived olefins, including the alkenes from the cuticular lipids of the honeybeeApis mellifera L.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00987544
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  • 28
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    Thermal and Photochemical Transformations of Hetero-1,3,5-hexatrienes into Five-Membered Rings - Possible Pericyclic ReactionsDocument No. NDRL-1955 from the Notre Dame Radition Laboratory. (1980)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 19 (1980), S. 973-983 
    Details
    ISSN: 0570-0833
    Keywords: Hetero-1,3,5-hexatrienes ; Pericyclic reactions ; Photochemistry ; Cyclization ; Heterocycles ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Heterosubstituted 1,3,5-hexatrienes undergo thermal and photochemical cyclizations, most of which can be viewed as pericyclic reactions. Numerous cyclizations of this type have been reported in the literature. This article presents a systematic account of such reactions, classified according to the number and nature of the heteroatoms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.198009731
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  • 29
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    1,5,-Electrocyclizations - An Important Principle of Heterocyclic ChemistryRobert Burns Woodward - In Memoriam (1980)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 19 (1980), S. 947-973 
    Details
    ISSN: 0570-0833
    Keywords: Electrocyclic reactions ; Cyclization ; Heterocycles ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The principle of orbital control of pericyclic reactions has deepened our understanding of reaction phenomena and provided an excellent classification of these one-step processes. The electrocyclic reaction of the pentadienyl anion ⇌ cyclopentenyl anion type is relatively unimportant in all-carbon systems and has not even been verified in the case of the parent compound. In the heterocyclic series, however, where up to five C-atoms of the pentadienyl anion are replaced by heteroatoms, a multitude of ring closures and ring openings find their ordering principle in the mentioned electrocyclic reaction. The replacement of the carbon atoms by heteroatoms can take place isoinically, i. e., with retention of the anionic character, or isoelectronically. An isoelectronic replacement of CR2 in position 1 by NR2 OR, and or CR in position 3 by NR or O leads to a charge-free resonance structure for the open-chain species; the migration of the charge during the electrocyclization results in a correlation with a cyclic zwitterion. Conversely, isoelectronic exchange of CR in position 2 by NR or O produces a conjugated 1,3-dipole, which cyclizes to a charge-free unsaturated five-membered ring. Twofold isoelectronic exchange allows the whole process to take place in a cation. Selected examples are to shed light on the classification and the thermodynamics of this electrocyclic reaction.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.198009473
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  • 30
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    Heterocyclic Analogues of Methylenecyclopropanes (1980)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 19 (1980), S. 276-289 
    Details
    ISSN: 0570-0833
    Keywords: Methylenecyclopropanes ; Heterocycles ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Heterocyclic three-membered rings with an exocyclic double bond merit special interest in view of their ring strain and their fascinating chemistry. Their synthesis, thermal decomposition, ring opening, and cycloaddition reactions will be discussed in this review. α-Lactams, alkylideneaziridines, diaziridinones, and diaziridinimines belong to the best known classes, but the chemistry of alkylideneoxiranes and -thiiranes, α-lactones, α-thiolactones, thiiranimines, and aziridinimines has also been studied to some extent. Two elusive three-membered rings are oxiranimines and thiaziridinimines; the former were postulated as reactive intermediates in the thermal decomposition of α-lactams, whereas the latter were trapped efficiently with double and triple bonds during thermolysis of N-sulfonyliminothiatriazolines. In spite of many attempts to prepare thione derivatives of the title compounds, they are still unknown. Included in this review are also some open-chain dipolar species which are isomeric with the heterocyclic three-membered rings.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.198002761
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  • 31
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    Hetero Analogs of SesquifulvaleneFrom the Habilitation Thesis by G. Seitz, Universität Marburg 1968, also Part 4 of Cyclopentadienylidenes. - Part 3: Tetrahedron Letters 1968, 2305. (1969)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 8 (1969), S. 478-482 
    Details
    ISSN: 0570-0833
    Keywords: Sesquifulvalenes ; Fulvalene ; Heterocycles ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Heterosesquifulvalenes containing sulfur or oxygen as hetero atom may be prepared, e.g., by condensation of cyclopentadienes with thiopyrones or pyrones in acetic anhydride. Heterosesquifulvalenes containing nitrogen can be obtained from the oxygen compounds by O,N-exchange. The ground state of all these compounds is determined mainly by the nonpolar resonance formula.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.196904781
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  • 32
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    The Ene Reaction (1969)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 8 (1969), S. 556-577 
    Details
    ISSN: 0570-0833
    Keywords: Ene reaction ; Addition ; Alkenes ; C-C coupling ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The ene reaction is defined as the indirect substituting addition of a compound with a double bond (enophile) to an olefin with an allylic hydrogen (ene). For a long time the reaction has been neglected and has remained overshadowed by the related Diels-Alder addition. It is shown that the ene reaction possesses wide scope and applicability ranging from industrial to biosynthetic processes. Preparative aspects are summarized and current views on the mechanism are discussed.
    Additional Material: 8 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.196905561
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  • 33
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    Small Charged Heterocycles (1969)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 8 (1969), S. 962-974 
    Details
    ISSN: 0570-0833
    Keywords: Heterocycles ; Aziridinium salts ; Azetidinium salts ; Cycloaddition ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis and important reactions of stable aziridinium salts are described in this article. The more stable azetidinium salts, which undergo similar reactions, have also been studied. Polar and dipolar cycloadditions produce heterocycles by ring expansions that can be represented as .
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.196909621
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  • 34
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    The Reduction of Organic Compounds with Chromium(II) Salts (1968)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 7 (1968), S. 247-252 
    Details
    ISSN: 0570-0833
    Keywords: Reduction ; Chromium ; Alkyl halides ; Alkenes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chromium(II) salts can be used for a variety of reductions in organic chemistry; for example, alkyl halides and suitably substituted olefins may both be reduced to alkanes, and alkynes may be converted into trans-olefins. Several epoxyketones are reduced to α,β-unsaturated ketones or β-hydroxyketones, and a nitro steroid was found to give a hydroxy(hydroxyimino) compound. The reduction of alkyl halides is reported to proceed by a free-radical mechanism; the halogen atom that is set free forms a bridge between two chromium atoms.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.196802471
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    Carbonylation of Olefins under Mild Temperature Conditions in the Presence of Palladium ComplexesDedicated to Professor A. Steinhofer on the occasion of his 60th birthday (1968)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 7 (1968), S. 329-335 
    Details
    ISSN: 0570-0833
    Keywords: Carbonylation ; Alkenes ; Palladium ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: During a search for catalysts that allow carbonylation reactions on olefins to proceed below 100 °C, complex palladium(II) compounds having the formula LmPdXn were found to be catalytically active. L denotes a ligand such as a phosphine, nitrile, amine, or olefin, X is an acid residue, and m+n is 3 or 4. The catalysts permit the carbonylation of heat-sensitive compounds, as well as selective carbonylation of polyunsaturated olefins. The new process can also be carried out on the industrial scale, as is shown by the carbonylation of cyclododecatriene
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.196803291
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  • 36
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    Reactions of Electron-Rich Olefins (1968)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 7 (1968), S. 754-765 
    Details
    ISSN: 0570-0833
    Keywords: Electron-rich alkenes ; Tetraaminoethylen ; Alkenes ; Tetramethoxyethylene ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Olefins are normally preferentially attacked by electrophiles. This trend is strengthened in enol ethers and enamines, and is particularly pronounced in tetramethoxyethylene and in tetraaminoethylenes. These electron-rich olefins are accordingly also excellent reducing agents. In their reactivity, therefore, they behave as counterparts of tetracyanoethylene. This compound shares with the electron-rich olefins a strong tendency to undergo cycloadditions, the electron-rich olefins adding particularly readily to electrophiles.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.196807541
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    Sulfonyl Hydrazones of Cyclic Amides and Quaternary Azo Sulfones of Heterocycles as Reagents in Azo ChemistryPart XXIX of the series “Azo dyes by oxidative coupling”. For Part XXVIII, see [26].Dedicated to Professor A. Steinhofer on the occasion of his 60th birthday (1968)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 7 (1968), S. 335-344 
    Details
    ISSN: 0570-0833
    Keywords: Sulfonyl hydrazones ; Amides ; Azo sulfones ; Heterocycles ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Sulfonyl hydrazones of cyclic amides undergo oxidative coupling with phenols and reactive methylene components. The reaction proceeds via the azo sulfones, which may be used as such, and which, as ambident cations, enter into many reactions with nucleophiles and extend the scope of oxidative coupling. The reaction with phenols is a two-step process, in which the limiting cases k1 ≪ k2, k1 ≈ k2, and k1 ≫ k2 can be realized by slight variation of the reactants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.196803351
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  • 38
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    Olefin Alkylation in Biosynthesis (1968)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 7 (1968), S. 903-911 
    Details
    ISSN: 0570-0833
    Keywords: Alkylation ; Squalene epoxide ; Polyisoprenoid synthesis ; Biosynthesis ; Alkenes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Stereochemical studies, made possible by asymmetric labeling with hydrogen isotopes, have led to the hypothesis that enzymic association of C5 units in polysoprenoid synthesis is not a concerted process but proceeds in two steps: a trans 1,2-addition to an olefin followed by a trans 1,2-elimination. It is shown that similar mechanisms can also explain the cyclization of squalene epoxide to tetracyclic and pentacyclic triterpenoids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.196809031
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    Hydration of c=n bonds in heteroaromatic substancesSubstance of a plenary lecture given at the First German Heterocyclic Symposium, Stuttgart, October 5th, 1966. (1967)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 6 (1967), S. 919-928 
    Details
    ISSN: 0570-0833
    Keywords: Heteroaromatic compounds ; Hydration ; Heterocycles ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Many aromatic N-heterocycles add water across the C=N double bond. Methods are described for recognizing this phenomenon and for diagnosis of the site of attack. These methods are extended to the determination of (a) the ionization constants of unstable states (whether hydrated or anhydrous), (b) the ratio of hydrated to anhydrous forms at equilibrium, and (c) the rate constants of hydration. The features that stabilize hydration in a molecule are discussed. The literature through 1965 and 1966 is reviewed with special reference to the emergence of new principles, such as di-hydration and the shifting of hydration within a molecule.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.196709191
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    Syntheses with ketones, sulfur, and ammonia or amines at room temperatureSimple syntheses and chemical behavior of new heterocyclic ring systems, part 2. Part 1: F. Asinger and M. Thiel, Angew. Chem. 70, 667 (1958). Cf. also F. Asinger, W. Schäfer, K. Halcour, A. Saus, and H. Triem, Angew. Chem. 75, 1050 (1963); Angew. Chem. internat. Edit. 3, 19 (1964). (1967)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 6 (1967), S. 907-919 
    Details
    ISSN: 0570-0833
    Keywords: Ketones ; Sulfur ; Amines ; Heterocycles ; Synthetic methods ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A large number of preparatively interesting compounds have become readily available by the simultaneous action of sulfur and ammonia or amines on ketones. Direct syntheses of Δ3-thiazolines, Δ3-imidazoline-5-thiones, 5,6-dihydro-4H-1,4-thiazines, and the 1,2,3,4,5,6-hexathiocane system from ketones, sulfur, and ammonia or amines, and further possibilities for the synthesis of these heterocyclic systems have been proposed. Other heterocycles containing N or N and S (thiazoles, thiophenes, thiazolidines, tetrahydrothiazolo[2,3-c]-1,4-thiazines, thiomorpholines, 4-amino-2H-imidazoles, etc.) are readily obtainable by further reactions of these compounds. Hydrolysis of the Δ3-thiazolines yields α-mercapto ketones, which are the starting materials for other syntheses. Most of the syntheses described proceed at room temperature and at normal pressure.
    Additional Material: 10 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.196709071
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    Additions to the Activated CC Triple Bond (1967)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 6 (1967), S. 423-434 
    Details
    ISSN: 0570-0833
    Keywords: Addition ; Alkenes ; Alkynes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The possibilities of additions to the activated CC triple bond are discussed with the aid of a number of examples. The additions of donors that contain no active hydrogen are generally initiated via a dipolar primary complex, which can undergo stabilization by rearrangement, cyclization, or addition reactions. Preparative aspects of these reactions are also discussed. They offer routes for the preparation of heterocycles, particularly pyrrole and thiophene derivatives.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.196704231
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    Allyl-Transition Metal SystemsDedicated to Prof. K. Freudenberg on the occasion of his 80th birthday (1966)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 5 (1966), S. 151-164 
    Details
    ISSN: 0570-0833
    Keywords: Allyl transition metal systems ; Bis(allyl)nickel ; Nickel ; Polymerization ; Alkenes ; Allylic ligands ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: As a continuation of a report published in 1963, recent results in the field of allyl-transition metal complexes are describedThe term “allyl compounds” in the present paper refers not only to compounds containing the simple allyl group (CH2=CH—CH2—), but also to those that contain substituted allyl groups or allyl groups forming part of a ring system.. Syntheses and reactions of these compounds, as well as the bonding between metal and allyl group, are discussed. Allyl-transition metal complexes form the basis of extremely selective catalysts for homogeneous reactions of 1, 3-diolefins and of olefins; the metal atoms in these “matrix” catalysts are either “bare”The description “bare” is applied to complexed metal atoms from which the ligands can be quantitatively displaced by the substances taking part in catalytic reactions. or are bound to only a few ligands.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.196601511
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    Novel Approaches to the Synthesis of Some Heterocycles Containing Nitrogen (1966)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 5 (1966), S. 35-39 
    Details
    ISSN: 0570-0833
    Keywords: Heterocycles ; Pyrimidines ; Quinazolines ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Some syntheses of heretofore unknown pyrimidines, tetrahydroquinazolines, and quinazolines are described. These methods are uniquely simple one- or two-step reactions, general and versatile in scope, and give high yields. Some interesting chemistry associated with these heterocyclic systems is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.196600351
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    Silicon-Nitrogen Heterocycles (1966)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 5 (1966), S. 760-776 
    Details
    ISSN: 0570-0833
    Keywords: Silicon-nitrogen heterocycles ; Heterocycles ; Cyclosilazanes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Great progress has recently been made in the chemistry of the silicon-nitrogen bondC. Eaborn: Organosilicon Compounds. Butterworths, London 1960, p. 339.R. Fessenden and J. S. Fessenden, Chem. Reviews 61, 361 (1961).K. A. Andrianov, I. Haiduc, and L. M. Khananashvili, Uspekhi Khim. 32, 563 (1963); Chem. Abstr. 59, 8782 (1963).U. Wannagat, Advances inorg. Chem. Radiochem. 6, 265 (1964).I. Haiduc: Westep do Chemii Nieorganicznych Zwiazkow Pierscieniowyrh. WPN, Warsaw 1964, Chap. 10 (in Polish).. Whereas attention was formerly concentrated on open-chain silazanes and silylamines, growing interest is now being shown in the cyclic SiN compounds. A major factor which has contributed to the rapid development in this field is the need for better polymers and liquids for use above 350 °CCf. E. G. Rochow, Chim. et Ind. 85, 897 (1961).. The present article deals with monomeric cyclic compounds containing at least one silicon-nitrogen bond in the ring, as well as the polycyclic compounds derived from these.
    Additional Material: 8 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.196607601
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    Eliminations from Olefins (1965)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 4 (1965), S. 49-68 
    Details
    ISSN: 0570-0833
    Keywords: Elimination ; Alkenes ; Alkynes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Eliminations from olefins are very often initiated by bases, and usually lead to formation of acetylene derivatives. In view of the numerous side-reactions and subsequent additions or rearrangments observed, the nature of the base used is of considerable significance. Organometallic bases are very versatile. In addition to dehydrohalogenation, dehalogenation by metals, and also thermolytic and photolytic eliminations. (e.g. the retrodiene reaction with exchange of substituents) are discussed. Elimination from low-membered cyclic olefins yields cycloalkynes having strained ring-systems, and the existence of these can be demonstrated by trapping them. The mechanisms known for β-elimination (E2, E1 and E1cB) occur also in the case of olefins; however - due to the sp2-hybridization of the carbon atoms taking part - they are realized with different rates of reaction relative to saturated compounds. α-Eliminations from olefines having aryl residues in the β-position lead to formation of arylacetylenes by rearrangement of the carbon skeleton. The mechanism of this reaction, which is known as the Fritsch-Buttenberg-Wiechell rearrangement, is discussed in considerable detail, and several variations of the reaction are considered. According to present-day knowledge carbenes are involved in α-eliminations only when both β-positions of the olefin are occupied by aliphatic substituents, or when they are occupied by aromatic residues where rearrangement to acetylenes is impossible for steric reasons (as for example with 9-chloromethylenefluorene). With organolithium compounds a number of dehydrohalogenations, which are formally β-eliminations, actually proceed via deprotonation on the halogenbearing carbon atom (α-metallation). α-Metallations are the rate-determining steps when ether is used as solvent, but proceed quickly in tetrahydrofuran even at low temperatures. Compounds of the type \documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}$\raise1pt\hbox{$〉$}{\rm C}\raise1pt\hbox{=\kern-3.45pt=}{\rm C(Li)Cl}$\end{document} may be prepared by this method and are recognized as intermediates in α-eliminations.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.196500491
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    New Reactions of Alkylidenephosphoranes and their Preparative Uses. Part I: The Acid-Base Character of Phosphonium Salts and AlkylidenephosphoranesParts II and III will appear shortly in this journal. (1965)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 4 (1965), S. 583-587 
    Details
    ISSN: 0570-0833
    Keywords: Alkylidenephosphoranes ; Phosphonium salts ; Synthetic methods ; Phosphoranes ; Ylides ; Alkenes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Phosphonium salts may be regarded as Bronsted acids, and alkylidenephosphoranes as the conjugate bases. Compounds of the two classes exist in equilibrium with each other. Phosphonium salts and alkylidenephosphoranes can be obtained by this “transylidation”. Other methods are also given for the preparation of members of both classes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.196505831
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    New Reactions of Alkylidenephosphoranes and their Preparative Uses. Part II. Alkylidenephosphoranes and Halogen CompoundsFor Part I see Angew. Chem. 77,609 (1965), Angew. Chem. internat. Edit. 4, 583 (1965). Part III will appear shortly in this journal. (1965)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 4 (1965), S. 645-660 
    Details
    ISSN: 0570-0833
    Keywords: Alkylidenephosphoranes ; Phosphonium salts ; Synthetic methods ; Phosphoranes ; Ylides ; Alkenes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of alkylidenephosphoranes with compounds containing halogens can be used to prepare ylides, which can be converted in to useful products, e.g. by hydrolysis, by thermal decomposition, or by other reactions. Examples of such products are ketones including cyclic, unsaturated, and branched-chain ketones (including cyclic, unsaturated, and branched-chain ketones), carboxlic esters (including those of unsaturated, branched- chain, polyenecarboxylic, acetylenecarboxylic, and allenecarboxylic acids), and aldehydes.
    Additional Material: 10 Tab.
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    URL: http://dx.doi.org/10.1002/anie.196506451
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    The Hetarynes (1965)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 4 (1965), S. 543-557 
    Details
    ISSN: 0570-0833
    Keywords: Hetarynes ; Heterocycles ; Alkynes ; Arynes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Investigations carried out during the last six years have shown that, as in the case of benzene, an extra bond can be introduced into heteroaromatic rings. Since this possibility does not appear to be confined to exceptional cases, the heterocyclic arynes (hetarynes) promise a much wider variety than the carbocyclic arynes. Hetarynes occur mainly as intermediates in nucleophilic substitutions on halogenated heterocyclic compounds. Since the replacement of a CH group in dehydrobenzene by a nitrogen atom and the condensation of benzene rings have stabilizing effects, the stability of hetarynes is expected to increase with the number of N atoms and with the number of condensed aromatic rings.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.196505431
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    New Reactions of Alkylidenephosphoranes and their Preparative Uses IIIFor Part I, see Angew. Chem. 77, 609 (1965) Angew. Chem. internat. Edit. 4, 583 (1965); for Part II, see Angew. Chem. 77, 651 (1965); Angew. Chem. internat. Edit. 4, 645 (1965).. Alkylidenephosphoranes and Reagents Containing Multiple Bonds (1965)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 4 (1965), S. 830-838 
    Details
    ISSN: 0570-0833
    Keywords: Alkylidenephosphoranes ; Phosphonium salts ; Synthetic methods ; Phosphoranes ; Ylides ; Alkenes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A few examples of preparatively useful syntheses using alkylidenephosphoranes and substances containing a C—N or C—C double bond are the preparations of olefins, allenes, pyran derivatives, and cyclopropane derivatives. Olefins, ketones, and monocyclic compounds can be obtained by autoxidation of alkylidenephosphoranes; α, β-dioxo compounds (including cyclicones) can be prepared by oxidation with peroxy-acids. Alkylidenephosphoranes can also be used for the synthesis of azines and Schiff bases. Of the many possibilities offered by the Wittig reaction, only the preparation of tritiated aldehydes and olefins will be considered.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/anie.196508301
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    New Methods in the Chemistry PyridazonesPublished on the occasion of the 100th anniversary of the establishment of Badische Anilin- & Soda-Fabrik AG., on April 6th, 1965. (1965)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 4 (1965), S. 292-300 
    Details
    ISSN: 0570-0833
    Keywords: Pyridazones ; Heterocycles ; Mucochloric acid ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new synthesis of mucochloric acid by chlorination of butynediol has facilitated the preparation of a series of 4,5-dichoropyridazones. The high reactivity of these compounds has been investigated and applied in several ways. New classes of compounds, some with biological activity, were obtained by displacement of the chlorine atoms. New heterocyclic systems were prepared by condensation and rearrangement reactions.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.196502921
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    Heterocycles Containing Phosphorus (1965)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 4 (1965), S. 1023-1038 
    Details
    ISSN: 0570-0833
    Keywords: Heterocycles ; Phosphorus ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The preparation of heterocycles containing phosphorus is described. The chemical behavior of ring systems containing trivalent phosphorus is mainly determined by their phosphine character; heterocyclic behavior in the ordinary sense is shown by rings containing functional groups. Syntheses and reactions of cyclic compounds of pentavalent and hexavalent phosphorus are particularly interesting.
    Additional Material: 3 Tab.
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    URL: http://dx.doi.org/10.1002/anie.196510231
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