Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 340 (1998), S. 430-436 
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The cathodic reduction of dibenzofuran (2), 2-chlorodibenzofuran (4), and 3-chlorodibenzofuran (1) in deuterated methanol is investigated. The Birch-type reduction product 1,4-dibenzofuran (3) is formed from 1 via 2, whereas 2-chloro-1,4-dihydrodibenzofuran (5) is obtained as by-product besides 3 from 4 as starting compound. Deuterium is only incorporated into the reduction products if CH3OD or CD3OD but not if CD3OH are used. This observation is strongly indicative of a polar mechanism involving protonation rather than a radical mechanism with hydrogen atom abstraction to be operative.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1983 (1983), S. 1116-1132 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: α-Oxo- and α-Thioxothioamides from Methyl KetonesMixtures of α-(chloro)sulfenyl chlorides 5 and trisulfides 6 are obtained from the reaction of thionyl chloride with methyl ketones in the presence of pyridine. From these mixtures as well as from the pure trisulfides 6, with amines the α-oxothioamides 1-4 are formed with good yields. Thionation of the thioamides 1 and 2 yields the deeply coloured α-thioxothioamides 16 and 17, the structure of which has been especially characterized by X-ray structure analyses.
    Notes: Bei der Reaktion von Methylketonen mit Thionylchlorid in Gegenwart von Pyridin entstehen Gemische aus α-(Chlor)sulfenylchloriden 5 und Trisulfiden 6, die - ebenso wie die reinen Trisulfide 6 - mit Aminen hohe Ausbeuten an α-Oxothioamiden 1-4 liefern. - Schwefelung der Thioamide 1 und 2 ergibt die tieffarbigen α-Thioxothioamide 16 und 17, deren Struktur insbesondere durch Röntgenstrukturanalysen charakterisiert wird.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1983 (1983), S. 1694-1711 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation of New Vicinal Tricarbonyl Compounds and Some of Their Sulfur AnaloguesMesoxalamides 5, benzoylglyoxylamides 19, and pivaloylglyoxylamides 26 are prepared from the corresponding malonamides 4, benzoylacetamides 17 and pivaloylacetamides 24, respectively, by suitable oxidation reactions. Some of the sulfur analogues of 5, 19, and 26, including the first stable 2-thiomesoxalic acid derivative 11b, are also obtained. The spectroscopic properties of the compounds are discussed.
    Notes: Durch geeignete Oxidationsreaktionen gelingt die Überführung der Malonamide 4 in Mesoxalamide 5, der Benzoylacetamide 17 in Benzoylglyoxylamide 19 und der Pivaloylacetamide 24 in Pivaloylglyoxylamide 26. Auch Schwefelanaloga von 5, 19 und 26, darunter das erste stabile 2-Thiomesoxalsäurederivat 11b sind zugänglich. Die spektroskopischen Eigenschaften der dargestellten Verbindungen werden diskutiert.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 698 (1966), S. 113-121 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Diazomethan überführt 6-Thio-theophyllin (6) in 6-Thio-coffein (7) und Chinazolinthione-(4) (8) in 4-Methylmercapto-chinazoline (9). Aus 6-Thio-theophyllin-S-oxid (12) entsteht intermediär 6-Thio-coffein-S-oxid (13), das sich zu 6-Thio-coffein (7) und Coffein (14) zersetzt.  -  2-tert.-Butyl-chinazolinthion-(4)-S-oxid (2) wird dagegen am Sauerstoffatom methyliert, wobei sich der Sulfensäuremethylester bildet, dessen Struktur chemisch sowie durch sein IR-, Massen- und Protonenresonanzspektrum gesichert wird.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1975 (1975), S. 1808-1821 
    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, XXXVI. - N-(Trimethylsilyl)thioamides, IThe primary thioamides 1 were treated with hexamethyldisilazane (6) to give N-(trimethyl- silyl)thioamides 3. The strong bathochromic shift of the thioamide B band in the IR spectra of these compounds indicates a weakening of the C—N bond due to dπ - pπ interaction of nitrogen and silicon. The secondary thioamides 7 - 11 were silylated via metallation with potassium or n-butyllithium and reaction with chloro(trimethyl)silane (2). IR- and 1H-NMR spectra indicate an equilibrium between the N-(trimethylsilyl)thioamide 12 and the S-(tri- methylsilyl)-thioimidate 13. With small substituents on the nitrogen and thioacyl carbon of the starting compound only the thioamide structure could be found.  - Free enthalpies of activation were calculated for isomerisation via [1.3-N.S] migration of the trimethylsilyl group and for hindered rotation about the C—N bond.
    Notes: Primäre Thioamide 1 werden mit Hexamethyldisilazan (6) in N-(Trimethylsilyl)thioamide 3 übergeführt. Die starke bathochrome Verschiebung der Thioamid-B-Bande in den IR-Spektren dieser Verbindungen deutet auf eine Schwächung der C—N-Bindung durch dπ - pπ Wechselwirkung zwischen Silizium und Stickstoff hin. Sekundäre Thioamide 7-11 können nach Metallierung mit Kalium oder n-Butyllithium mit Chlorftrimethyl)silan (2) silyliert werden. IR- und 1H-NMR-Spektren weisen auf das Vorliegen eines Gleichgewichtes zwischen N-(Trimethylsilyl)thioamid 12 und S-(Trimethylsilyl)thioimidat 13 hin. Bei sterisch anspruchslosen Substituenten am Stickstoff und am Thioacylkohlenstoff der Ausgangsver- bindung läßt sich jedoch nur die Thioamidform nachweisen. - Freie Aktivierungsenthalpien für die Isomerisierung durch [1.3-N.S]-Wanderung der Trimethylsilylgruppe und für die behinderte Rotation um die C—N-Bindung wurden bestimmt.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 746 (1971), S. 92-101 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Sulfuration of Ureas by P4S10Tetrasubstituted ureas may be converted into the corresponding thioureas (table 1, page 93) by means of P4S10. Trisubstituted ureas give rise to side reactions yielding trans-acylated products and the dithiophosphate 5a (table 2, page 95).
    Notes: Tetrasubstituierte Harnstoffe lassen sich durch Einwirkung von P4S10 in die entsprechenden Thioharnstoffe (Tab. 1, S. 93) überführen. Trisubstituierte Harnstoffe gehen Nebenreaktionen ein, wobei umacylierte Produkte sowie das Dithiophosphat 5a auftreten (Tab. 2, S. 95).
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    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, XXXII1). - Synthesis, IR- and IH-NMR-spectroscopic Studies on 2-Aminobenzamides and -thiobenzamidesDifferent methods for the synthesis of amides and thioamides of 2-aminobenzoic acid, in particular those in which the protons on both amino-groups are successively exchanged by organic substituents in all possible variations, are reported. From the frequencies and the relative intensities of the NH-stretching vibration bands of these substances in tetrachloro-methane solutions and from the 1H-NMR signal assignments conclusions are drawn regarding the electronic, steric and conformational properties. especially the formation of intramolecular hydrogen bonds of the type NH…X (X = 0, S) and NH…N, as well as the occurrence of E/Z isomerism.
    Notes: Es werden Methoden zur Darstellung von Amiden und Thioamiden der 2-Aminobenzoesäure, und zwar aller durch sukzessiven Austausch der Protonen an beiden Aminogruppen gegen organische Reste denkbaren Varianten, angegeben. Aus der Lage und den relativen Intensitaten der NH-Valenzschwingungsbanden dieser Verbindungen in verdünnten Tetrachlorkohlenstofflösungen und der Zuordnung der 1H-NMR-Signale werden Aussagen über elektronische, sterische und konformative Verhältnisse, insbesondere über die Ausbildung intramolekularer NH … X- (X = 0, S) und NH … N-Wasserstoffbrücken sowie über die E/Z-Isomerie gewonnen.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 66 (1983), S. 801-808 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The He(Iα) photoelectron (PE.) spectra of a series of substituted 1,2-dithietes have been recorded and assigned with respect to the orbital sequence derived from an STO-3G model calculation and by correlation with the PE. spectra of related compounds. The results provide additional support for the presence of a closed, four-membered ring moiety in all the 1,2-dithietes investigated. In all cases the two highest occupied molecular orbitals are b2(π)= HOMO, a2(π), with exception of 3,4-bis(trifluoromethyl)-1,2-dithiete where the sequence b2(π), a2(π) or a2(π), b2(π) is uncertain.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 333 (1991), S. 889-893 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Preparation of Benzo[c]thiophenes Using a Modified Hinsberg-ReactionWhereas the tetrahydrobenzo[c]thiophenes 3 and 6 are easily obtained from 1 and 2 or 4 their dehydrogenation (i. e. aromatization) is difficult and the yields are low. However, the method allows to prepare hitherto unknown benzo[c]thiophenes with special substituents in the 1,3-positions.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Im Gegensatz zu offenkettigen Thioamiden lassen sich Thioamid-S-oxyde mit Diazomethan methylieren. Die Methylierung erfolgt am Stickstoff der Thioamidgruppe. Aus Thiobenzanilid- und Thiobenz-p-toluidid-S-oxyd konnten kristalline Methylierungsprodukte erhalten werden. In den anderen Fällen wurden die Methylierungsprodukte durch Papier- und Dünnschichtchromatographie identifiziert. Der Methylierungsverlauf wird unter Berücksichtigung einer beim N-Methyl-thiobenzamid-S-oxyd auftretenden Besonderheit diskutiert.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...