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  • 11
    Electronic Resource
    Electronic Resource
    Synthese von Aminopyrazolo- und Aminotriazolo[2,3-a]pyridinen (1975)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 317 (1975), S. 561-566 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Substituierte 1,2-Diamino-6-methylmercaptopyridiniumsalze 2 reagieren mit methylenaktiven Nitrilen zu substituierten 2,7-Diaminopyrazolo[2,3-a]pyridinen 3, die auch aus substituierten 2-Amino-5-cyanmethylenthiopyranen 5 und Hydrazin erhältlich sind. Die Umsetzung von 2 mit Cyanamid führt analog zu 2,7-Diamino-s-triazolo[2,3-a]pyridinen 8. In Gegenwart von sek. Aminen kondensiert 2 zu Diaminodipyrido[2,1-a;2,1-d]tetrazinen 9.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19753170407
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  • 12
    Electronic Resource
    Electronic Resource
    Über die absolute Konfiguration der Cantharsäure und des PalasoninsII. Mitt. zur Biosynthese des Cantharidins; I. Mitt. siehe [1a]. (1974)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 57 (1974), S. 32-64 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The absolute configurations of (+)-cantharic acid, a chiral derivative of the achiral insect defensive substance cantharidin (1), and of palasonin, a lower homologue of 1 occurring in the plant Butea frondosa, were shown to be represented by formulas 2 and 3, respectively (scheme 1). These results were obtained by application of the Horeau method (table 1) on the (+)-cantharic acid derivatives (+)-5, (-)-7, and (-) 11 (scheme 2), and the palasonin derivatives (+)-29 and (+)-30 (scheme 4), as well as by comparison of the chiroptical properties (tables 2 and 3) of a number of derivatives, prepared from either cantharic acid or palasonin. - Attempts to incorporate various radioactively labelled precursors into palasonin (3), using young and adult plants, have been so far unsuccessful.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19740570106
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  • 13
    Electronic Resource
    Electronic Resource
    Biosynthesis of juvenile hormone in the cecropia moth. labelling pattern from 1-[14C]-propionate through degradation to single carbon atom derivativesPresented at the 169 ACS National Meeting, Philadelphia, April 6. II. 1975. (1975)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 58 (1975), S. 1037-1048 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In the adult made cecropia moth, 1-[14C]-propionate is incorporated specifically into juvenile hormone I (1). By chemical degradation it was found that only C(7) and C(11) are labelled, each carbon atom bearing 50% of the radioactivity originally present in JH-I. It is concluded that propionate serves as a precursor of homomevalonate, which in turn is a precursor for JH-I. Application of 2-[14C]-propionate and 3-[14C]-propionate leads to extensive randomization of the label. Apparently propionate is metabolized such that C(2) and C(3) can be reused as smaller fragments-probably acetate-while C(1) is either highly diluted or removed from the propionate in a metabolically inactive form.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19750580407
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  • 14
    Electronic Resource
    Electronic Resource
    N-Acylcatecholamine und 3,4-Dihydro-6,7-isochinolindiole aus N-Acyl-3,4-dimethoxyphenethylaminen (1989)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1989 (1989), S. 1189-1193 
    Details
    ISSN: 0170-2041
    Keywords: Catecholamines ; Isoquinolinediols ; Bischler-Napieralski reaction ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: N-Acylcatecholamines and 3,4-Dihydro-6,7-isoquinolinediols from N-Acyl-3,4-dimethoxyphenethylaminesThe N-[2-(3,4-dimethoxyphenyl)ethyl]acetamides 2a and 2e are cleaved with boron tribromide to yield as expected the catechols 3a and 3e whereas, under the same conditions, mixtures of the catechols 3b, 3c, 3f, or 3g and 1-(haloalkyl)dihydroisoquinolines 4b, 4c, 4f, or 4g are formed from the corresponding halogenated acetamides 2b, 2c, 2f, and 2g, respectively. The trifluoracetamide 2d yields exclusively the cyclization product 4d. Since higher halogenated 1-(haloalkyl)-3,4-dihydroisoquinolines are formed in the Bischler-Napieralski reaction - if at all - under quite drastic conditions only, the use of boron tribromide provides a new entry into this series.
    Notes: Die N-[2-(3,4-Dimethoxyphenyl)ethyl]acetamide 2a und 2e liefern mit Bortribromid erwartungsgemäß die Catechole 3a bzw. 3e, während aus den halogenierten Acetamiden 2b, 2c, 2f und 2g Mischungen aus den korrespondierenden Catecholen 3b, 3c, 3f bzw. 3g und den 1-(Halogenalkyl)dihydroisochinolinen 4b, 4c, 4f, bzw. 4g entstehen. Das Trifluoracetamid 2d liefert ausschließlich das Dihydro-1-(trifluormethyl)isochinolin 4d. Da höher halogenierte 1-(Halogenalkyl)-3,4-dihydroisochinoline mit der Bischler-Napieralski-Reaktion - wenn überhaupt - nur unter drastischen Reaktionsbedingungen zugänglich sind, bietet die Verwendung von BBr3 eine neue Möglichkeit zur Herstellung dieser Verbindungen.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198919890290
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  • 15
    Electronic Resource
    Electronic Resource
    Synthesen von Galactose-Cluster-haltigen Steroid-DerivatenAuszugweise vorgetragen auf der Chemiedozenten-Tagung, Bielefeld, 7, März 1989. (1990)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1990 (1990), S. 863-869 
    Details
    ISSN: 0170-2041
    Keywords: Glycoconjugates ; Galactosides ; Steroid esters ; Amphiphiles ; Glycopeptides ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of Galactose-Cluster-Containing Steroid DerivativesThe synthesis of galactose clusters that are linked to a steroid moiety by a peptide-like spacer unit is described. The galactose cluster is obtained by Koenigs-Knorr glycosylation of TRIS-Gly-Fmoc (2b) under Helferich conditions. Peptide and ester bonds are formed after activation of carboxylic acids as diphenylthiophene dioxide (TDO) esters. 6a is synthesized in a convergent way by coupling of (Ac4Gal)3-TRIS-Gly (3e) with cholesteryl TDO succinate (5b). Coupling of (Ac4Gal)3-TRIS-Gly hydrogen succinate (3f) with Gly-O-Chol (5d) by means of EEDQ yields 6d. Reaction of (Ac4Gal)3-TRIS-Gly-SUCC-O-TDO (3g) with 25-hydroxycholesterol leads in a linear sequence to the oxysterol derivative 6f. Selective cleavage of the acetyl groups from galactose units yields the known compound 6b and the new derivatives 6e and 6g.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.1990199001162
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  • 16
    Electronic Resource
    Electronic Resource
    Synthesis of Aryl Azide Analogues of Insect Juvenile Hormones as Reagents for the Photoaffinity Labeling of Juvenile Hormone Binding Proteins (1987)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1987 (1987), S. 327-331 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthese von Arylazid-Analogen der Juvenilhormone von Insekten als Reagenzien für die Photoaffinitätsmarkierung von Juvenilhormon-bindenden Proteinen.Es werden Synthesen der Azidophenyl-6,7-epoxygeranylether rac-4c und rac-4d sowie des Azidobenzoates rac-6 beschrieben. p-Azidophenyl-6,7-epoxygeranylether (rac-4c) zeigt eine hohe Bindungsaffinität zu dem in der Wanderheuschrecke Locusta migratoria vorkommenden Juvenilhormon-Bindungsprotein. Bestrahlung bei 254 nm oder bei 300 nm führt zu rascher Photolyse. rac-4c wird als neues Reagenz zur Untersuchung von Juvenilhormon-bindenden Proteinen aus solchen Insektenspezies, deren natürliches Hormon 1a ist, vorgeschlagen. Weiterhin werden Synthesen und Bindungseigenschaften des Arylketons rac-4e und des Vinylketons rac-7 beschrieben.
    Notes: The azidophenyl 6,7-epoxygeranyl ethers rac-4c and rac-4d and the azidobenzoate rac-6 were synthesized. p-Azidophenyl 6,7-epoxygeranyl ether (rac-4c) shows a high affinity to the juvenile hormone binding protein of the migratory locust, Locusta migratoria. Fast photolysis is observed upon irradiation at 254 nm and at 300 nm. It is proposed that rac-4c is useful as a new reagent for the study of juvenile hormone binding proteins of insects in which the natural hormone is 1a. The synthesis and binding properties of the aryl ketone rac-4e and the vinyl ketone rac-7 are described also.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198719870329
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  • 17
    Electronic Resource
    Electronic Resource
    Asymmetric Induction in the Epoxidation of Alkenyl Glycosides of Tri-O-acetyl-N-acetyl-β-D-glucosamine (1992)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1992 (1992), S. 1275-1279 
    Details
    ISSN: 0170-2041
    Keywords: Asymmetric induction ; Carbohydrates ; Epoxidation ; Glycosides ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of alkenyl glycosides 2a-2c with MCPBA gives diasteroisomeric mixtures of epoxides 3 and 4. The asymmetric induction decreases in the order 2a ≫ 2b 〉 2c. The absolute configuration of epoxyalkyl glycosides is determined by correlation with (R)-glycerinaldehyde in an independent synthesis of 3a and 3c.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.1992199201211
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  • 18
    Electronic Resource
    Electronic Resource
    Synthesis of Dopamines Labelled with 13C in the α- or β-Side Chain Position and Their Application to Structural Studies on Melanins by Solid-State NMR SpectroscopyDedicated to Professor Peter Karlson on the occasion of his 75th birthday. (1994)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1994 (1994), S. 563-567 
    Details
    ISSN: 0170-2041
    Keywords: CP-MAS NMR Spectroscopy ; Melanin ; Oxidative phenolic coupling ; Quinone methides ; Labelled compounds, 13C ; Dopamines ; Enzymes ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Solid-state NMR spectroscopy was applied to the analysis of melanins prepared by peroxidase-H2O2 oxidation of dopamines specifically 13C labelled in the α- or β-side chain positions. A surprisingly diverse pattern of signals indicated the presence of uncyclized dopamine and noradrenaline-derived units, in addition to indole and carbonyl carbon atoms. These structural features, coupled with the results obtained from elemental analysis of dopamine melanin samples prepared under different conditions, point to a pigment formation process more complex than previously believed.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199419940606
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  • 19
    Electronic Resource
    Electronic Resource
    Recovery of all species from photolytic degradation of tributyltin compounds TBTX (X = Cl, OSn Bu3) (1987)
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 1 (1987), S. 133-142 
    Details
    ISSN: 0268-2605
    Keywords: Photolytic degradation ; Kinetics ; Bis(tributyltin)oxide ; Tributyltin chloride ; Antifouling paints ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Malformations in shellfish have been reported by many authors. They attributed the cause of the deformity to the presence in water of organotin compounds used in the formulation of antifouling paints, for example bis(tributyltin) oxide (TBTO) and tributyltin chloride (TBTC). The behaviour of these compounds has been examined under abiotic laboratory conditions. The influence of many parameters such as sunlight, pH, oxygen, salinity have been examined. The degradation compounds obtained have been identified: (1) In the gas phase two major products, butene-1 and buetene-2, are observed with consumption of oxygen; (2) In the liquid phase, three main products are obtained, butanol-1, butanol-2 and butanone 2. The identified products represent a small part of the total concentration, suggesting a competing process such as formation of butyltin polymers; (3) In fresh water an amorphous solid phase is observed while in seawater a white cristalline precipitate appears.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aoc.590010205
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  • 20
    Electronic Resource
    Electronic Resource
    Preparation of the N-Acetylglucosaminidase Inhibitor 1-Acetamido-1,2,5-trideoxy-2,5-imino-D-glucitol from Methyl α-D-Mannopyranoside (1994)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1994 (1994), S. 555-561 
    Details
    ISSN: 0170-2041
    Keywords: Aza sugars ; Glycosidase inhibitors ; Piperidine ring contraction ; Pyrrolidines ; Enzymes ; Carbohydrates ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Fragmentation of methyl 3-O-benzyl-6-bromo-2-O-(tert-butyldimethylsilyl)-6-deoxy-4-O-(4-methoxybenzyl)-α-D-mannopyranoside (2) and in situ reductive amination give (3R,4S,5R)-6-benzylamino-4-benzyloxy-5-(tert-butyldimethylsilyloxy)-3-(4-methoxybenzyloxy)hexene (3) which is converted by intramolecular aminomercuration into an epimeric mixture of the bromomercuriopiperidine derivatives 4 and 5. The minor D-manno epimer 4 is transformed into mesylate 10 which, upon reaction with LiN3 in DMF, suffers a piperidine-pyrrolidine ring contraction to give azidomethylpyrrolidine 11. Reductive acetylation by means of thioacetic acid affords the fully protected pyrrolidine aza sugar derivative 12. The major L-gulo epimer 5 is transformed into the mesylate 15 which, again, upon reaction with LiN3 in DMF undergoes piperidine-pyrrolidine ring contraction to give the 1-azido-3-O-benzyl-2,5-benzylimino-6-bromomercurio-1,2,5,6-tetradeoxy-4-O-(4-methoxybenzyl)-L-iditol (16). Eliminative dehalomercuration by means of Zn powder is accompanied by in situ reduction of the azido group to give amino alkene 17. Intramolecular aminomercuration of 17 followed by N-acetylation yields the protected 1,2,5,6-tetradeoxy-2,5-imino-D-glucitol derivative 20 as the major epimer. Reductive oxygenation of 20 leads to pyrrolidine 22 which is deprotected to give title compound 1. Selective cleavage of the PMB group of 22 leads to 24. Benzylation of 22 affords again 12 from which the OH group at C-4 is liberated by selective cleavage of the PMB ether to give pyrrolidine 13. Compound 1 inhibits NAGase from bovine kidney.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199419940605
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