Library

X
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
    α-Methylidene- and α-Alkylidene-β-lactams from Nonproteinogenic Amino Acids (1991)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 74 (1991), S. 1213-1220 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Treatment of methyl 2-(1-hydroxyalkyl)prop-2-enoates 1 with conc. HBr solution afforded methyl (Z)-2-(bromomethyl)alk-2-enoates 2, which were transformed regioselectively into N-substituted methyl (E)-2- (aminomethyl)alk-2-enoates 3 (SN2 reaction) and into N-substituted methyl 2-(1-aminoalkyl)prop-2-enoates 4(SN2′ reaction). Regiocontrol of nucleophilic attack by amine was accomplished simply by choice of solvent, the SN2 reaction occurring in MeCN and the SN2′ reaction in petroleum ether. Hydrolysis and lactamization afforded β-lactams 7 and 8, containing an exocyciic alkylidene and methylidene group at C(3), respectively.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19910740608
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Die Reaktion von 2-Halogenethoxycarbonyl-Verbindungen mit tertiären Phosphanen (1979)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 1908-1914 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaction of 2-Haloethoxycarbonyl Compounds with Tertiary Phosphanes(2-Bromoethoxycarbonyl)amino acids 1 including the sarcosine derivatives 13 and 15 react with methyldiphenylphosphane to give the 2-phosphonioethoxycarbonyl derivatives, which are cleaved under mild basic conditions to yield the corresponding free amino compounds. The same transformation of the protective group was not successful in the case of the 2-bromoethoxycarbonyl protected alcohols 3, phenols 4, secondary amines 11 and 12 and the analogous 2-bromoethyl esters of amino acids and peptides; these compounds furnish the ethylene-1,2-bisphosphonium salt 6.
    Notes: (2-Bromethoxycarbonyl)aminosäuren 1, einschließlich der Sarkosin-Derivate 13 und 15, reagieren mit Methyldiphenylphosphan zu den 2-Phosphonioethoxycarbonyl-Verbindungen, welche unter milden basischen Bedingungen zu den freien Aminoverbindungen gespalten werden. Die gleiche Schutzgruppenumwandlung gelingt an 2-Bromethoxycarbonyl-geschützten Alkoholen 3. Phenolen 4 und den sekundären Aminen 11 und 12 sowie an Aminosäure- und Peptid-(2-bromethylestern) nicht. In diesen Fällen bildet sich das Ethylen-1,2-bisphosphoniumsalz 6.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197919791127
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Synthese von Giycopeptiden: Selektive C-terminale Deblockierung und Peptidkettenverlängerung an Glucosylserin-Derivaten (1983)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1983 (1983), S. 1859-1885 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Glycopeptide Synthesis: Selective C-Terminal Deblocking and Peptide Chain elongation of Glucosylserine DerivativesBenzyloxycarbonyl-(Z-)serine 2-bromoethyl ester (3b) reacts with 2,3,4,6-tetra-O-benzoyl-α-D-glucopyranosyl bromide (14) to give the glucosylserine ester 15. After conversion into the corresponding 2-iodoethyl ester 23 the carboxylic group is deblocked selectively by reductive elimination using zinc. In this procedure the Z and the carbohydrate protective functions as well as the sensitive O-glycoside bond remain unaffected. The glycosylserine 24 is condensed with amino acid 2-bromoethyl esters 2 to form protected glycodipeptide 2-bromoethyl esters 18 which are extended to give glycotripeptide esters 25 after selective carboxyl deblocking. Whereas protected serine dipeptides 5 are glycosylated with 14 to form the conjugates 18, the glycosylation of the serine tripeptides 10 was not successful.
    Notes: Benzyloxycarbonyl-(Z-)serin-2-bromethylester (3b) wird mit 2,3,4,6-Tetra-O-benzoyl-α-D-gluco-pyranosylbromid (14) zum Glucosylserinester 15 verknüpft. Nach Umwandlung in den entsprechenden 2-Iodethylester 23 wird die Carboxygruppe durch Eliminierung mit Zink selektiv deblockiert. Dabei bleiben die Z- und die Kohlenhydrat-Schutzgruppen sowie die empfindliche O-glycosidische Bindung unverändert erhalten. Das Glycosyl-Z-serin 24 reagiert mit Aminosäure-2-bromethylestern 2 zu geschützten Glycodipeptid-2-bromethylestern 18, die nach selektiver Carboxydeblockierung zu Glycotripeptidestern 25 C-terminal verlängert werden. Während geschützte Serin-Dipeptide 5 mit 14 zu Konjugaten 18 glycosyliert werden können, gelingt die Glycosylierung von Serin-Tripeptiden 10 nicht.
    Additional Material: 9 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198319831103
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Organische Photochemie, XXXIV. Thiophenthiocarbonsäure-S-ester, Synthone für Thienothiochromone und Thienoazathiochromone (1979)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 2043-2056 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Organic Photochemistry, XXXIV.  -  S-Esters of Thiophencarbothioic Acids. Synthons for Thienothiochromones and ThienoazathiochromonesOn UV irradiation in benzene S-aryl esters 4c - e, 9a - c of 3-bromothiophen-2- and thiophen-3-carbothioic acid yield thienobenzothiopyranones 7 and 11, respectively. The corresponding S-pyridyl esters 4f, g, 9e, f of these thiophencarbothioic acids give the thienothiopyranopyridinones 8a, b and 14a, b, respectively, which are new heterocyclic ring systems. - The constitutional requirements for the formation of these heterocycles by photocyclization via thiolester-thiopyrone-transformation are discussed. Only 9a photocyclizes in a twofold manner with formation of thienobenzothiopyranone 11a and thienothiocoumarin 12. - Compound 12, thiophen-2-carbaldehyde 5c, and S-ester 6 are products of intra- or intermolecular aromatic photosubstitutions of halogen by phenyl. - The majority of S-esters 4 and 9 also yield thiophenecarbaldehydes 5 or 10, respectively, which can even be main products of the photoreactions.
    Notes: Die S-Arylester 4c - e, 9a - c der 3-Bromthiophen-2-carbonsäuren und Thiophen-3-thiocarbon-säuren liefern bei UV-Bestrahlung in Benzol die Thienobenzothiopyranone 7 bzw. 11. Entsprechend erhält man aus den S-Pyridylestern 4f, g, 9e, f dieser Thiophenthiocarbonsäuren die Thienothiopyranopyridinone 8a, b bzw. 14a, b, die neue heterocyclische Ringsysteme darstellen. - Die konstitutionellen Voraussetzungen für die Bildung dieser Heterocyclen durch Photocyclisierung über Thiolester-Thiopyron-Transformation werden diskutiert. Lediglich 9a photocyclisiert in zweifacher Weise zum Thienobenzothiopyranon 11a und zum Thienothiocumarin 12. - Die Verbindung 12, der Thiophen-2-carbaldehyd 5c und der S-Ester 6 sind Produkte intra- oder inter-molekularer aromatischer Photosubstitutionen von Halogen gegen Phenyl. - Die Mehrzahl der S-Ester 4 und 9 liefern bei UV-Bestrahlung auch die Thiophencarbaldehyde 5 bzw. 10 als Neben-oder Hauptprodukte.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197919791215
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Zur Kenntniss des β-Aminocrotonsäureesters; (1901)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 314 (1901), S. 200-230 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.19013140118
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Structural Aspects of Cyclopropyl Homoconjugation: Experimental Studies and Ab Initio Calculations (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 1429-1435 
    Details
    ISSN: 0947-3440
    Keywords: Cyclopropyl homoconjugation ; Molecular structures ; Electron density determinations ; Ab initio calculations ; Spiro compounds ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Low-temperature crystal structural studies of a series of saturated and unsaturated bicyclo[2.2.1]heptadiene, heptene and heptane compounds with 7-spirocyclopropyl substitution reveal significant differences in the bond lengths of the three-membered rings and in the C—C single bonds of the bicyclic fragment. A complex interplay of strain and different types of conjugation influence the molecular structure of the bicycloheptadiene derivative 1, where the difference in the length of the three-membered ring bonds is 0.040 Å and all C—C single bonds in the bicyclic fragment are lengthened significantly. Ab initio calculations at the HF/6-31G(d) (to a minor extent) and MP2/6-31G(d) levels are in good agreement with the experimental data. Calculated charge distributions and dipole moments further support the relevance of cyclopropyl homoconjugation in the investigated prototype of Walsh and through-space π-orbital interaction. Static difference electron density maps have been derived from the experimental data by multipole refinements which showed exocyclic shifts of electron density in the planes of the three-membered rings and significant bond ellipticities at the C—C single bonds in the unsaturated bicyclic units.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970721
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Innere Komplexsalze von Oxyaldiminen und Oxyketiminen (1931)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 129 (1931), S. 163-177 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19311290112
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Photochemie von Aminoketonen. VII. Eine diastereoselektive Synthese von 3-Hydroxy-prolinen (1985)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 327 (1985), S. 51-62 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photochemistry of Aminoketones. VIII. Diastereoselective Synthesis of 3-Hydroxy-prolinesGlycine esters react in two steps (aminoalkylation and N-acylation) to N-acyl-N-(β-benzoylethyl)-glycine ester 3. In less polar solvents these ketonic compounds are n,π*-excited by 300 nm irradiation. In ether 3* yield mixtures of aminocyclopropanoles 4, hydroxyprolines 5 and products of additions and cleavages. In benzene and cyclohexane/benzene, respectively, the regioselective photocyclization to 5 is favoured. Furthermore this hydroxyproline synthesis has the advantages of high diastereoselectivity yielding the (2,3) E-5 and of high overall-yields in connection with the one pot method. The influence of solvents and substituents on the regio- and diastereoselectivity are explained using a model with stabilization of special conformations of intermediates by dipol-dipol interactions.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19853270108
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Die Inneren Komplexsalze des α-Benziloxims (1930)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 124 (1930), S. 133-143 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19301240112
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Polycyclische Verbindungen, XVI1). Methylsubstituierte 3.4-Benzpyrene (1965)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 688 (1965), S. 40-53 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Michael-Addition von Vinyl-[2-methoxycarbonyl-äthyl]-keton (8) an 1-Oxo-2-hydroxy-methylen-3-methyl-1.2.3.4-tetrahydro-phenanthren (5a) führt zur Verbindung 9a, die mit Natriummethylat in absol. Methanol 9-Oxo-6-methyl-10-carboxymethyl-5.6.6a.7.8.9-hexahydro-chrysen (10a) ergibt. Durch Cyclisierung mit wasserfreier Flußsäure entsteht daraus 5-Hydroxy-3-oxo-12-methyl-1.2.3.11.12.12a-hexahydro-benzo[a]pyren (11a), das bei der Zinkstaub-Destillation 12-Methyl-benzo[a]pyrenIn der vorliegenden Arbeit wurde für 3.4-Benzpyren und seine Derivate die Benennung und Bezifferung nach Ringindex, 2. Aufl. (1959) durchgeführt. (12a) liefert. Analog erhält man aus 8 und 1-Oxo-6.8-dimethyl-2-hydroxymethylen-1.2.3.4-tetrahydro-phenanthren (5b) über die Zwischenprodukte 9b, 10b und 11b 7.9-Dimethyl-benzo[a]pyren (12b). Zur Darstellung des 7.8.10-Trimethyl-benzo[a]pyrens (22) wird das aus γ-Oxo-γ-[pyrenyl-(l)]-hexandiol-(2.5) (20) mit wasserfreier Flußsäure cyclisiert, dem sich eine Pd/Kohle-Dehydrierung anschließt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.19656880105
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...