ZIB

Hits per page

hits 1 - 4 | 4 hits

Sorting

Electronic Resource

Metabolization of 3,5-dichlorocatechol by Alcaligenes eutrophus JMP 134 (1991)

Pieper, Dietmar Helmut ; Kuhm, Andrea Elisabeth ; Stadler-Fritzsche, Karin ; [et al.]

Springer

Archives of microbiology 156 (1991), S. 218-222

add to mindlist on the mindlist

Details

ISSN: 1432-072X

Keywords: 3,5-Dichlorocatechol ; 2,4-Dichloromuconate ; Dichloromuconate cycloisomerase ; 2-Chloro-4-carboxymethylenebut-2-en-4-olide ; Alcaligenes eutrophus JMP 134 ; Pseudomonas sp. B 13

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract 2,4-Dichloro-cis,cis-muconate is established as ringcleavage product in the degradation of 3,5-dichlorocatechol by Alcaligenes eutrophus JMP 134. The formerly described isomerization of 2-chloro-trans- to 2-chlorocis-4-carboxymethylenebut-2-en-4-olide as an essential catabolic step could not be certified.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00249118

Permalink

Library	Location	Call Number	Volume/Issue/Year	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

Electronic Resource

A standard test mixture for assessing enantioselectivity of chiral phase capillary GC columns - CHIRAL-Test IThis test mixture is intended for routinely determining the enantioselective separation potential of capillary GC columns. In preference to an acronym, derived from the authors' names, we propose CHIRAL,-Test as a self-explicatory label for such routine. The CHlRAL-Test I presented here has been optimized towards probing the “chiral performance” of amide phases. for amide phases (1990)

Aichholz, Reiner ; Bölz, Uwe ; Fischer, Peter

Weinheim : Wiley-Blackwell

Journal of High Resolution Chromatography 13 (1990), S. 234-238

add to mindlist on the mindlist

Details

ISSN: 0935-6304

Keywords: Gas chromatography ; Capillary columns, glass ; Enantioselectivity test procedure ; Cyclodextrin/amide phase comparison ; Enantiomer separation ; Chiral resolution (cR) ; Chemistry ; Analytical Chemistry and Spectroscopy

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: A test mixture is proposed which allows assessment of the enantioselective separation potential of chiral amide phase capillary columns. This CHIRAL-Test I includes a range of chromatographically problematical substrates, covering the temperature range from 100-200°C. One test component, the N-pivaloyl leucine methyl ester enatiomers, may be used exemplarily to calculate chiral resolution (chirale Auflösung, cR). Unlike separation factors α, cR values take account of peak shape as well as of relative retention time of both enantiomers, and thus are a measure of affective chromatographic separation. In combination with the Grob test, the CHIRAL-Test may be used for characterizing the chromatographical properties of columns coated with chiral amide phases.

Additional Material: 2 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/jhrc.1240130404

Permalink

Library	Location	Call Number	Volume/Issue/Year	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

Electronic Resource

Functional group interaction in the fragmentation of protonated 2,7-octanedione (1989)

Mueller, Dieter R. ; Domon, Bruno ; Blum, Wolfgang ; [et al.]

Chichester : Wiley-Blackwell

Biological Mass Spectrometry 24 (1989), S. 157-163

add to mindlist on the mindlist

Details

ISSN: 0030-493X

Keywords: Chemistry ; Analytical Chemistry and Spectroscopy

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: The fragmentation of 2,7-octanedione, induced by chemical ionization with methane as a reagent gas (CI (CH4)), is shown to be extensively governed by the interaction of the two carbonyl groups. Tandem mass spectrometry reveals that a sequential loss of H2O and C2H4O from the [M + H]+ ion competes with sequential loss of H2O and C6H10, and that both processes occur via the same [MH - H2O]+ intermediate. This intermediate is likely to be formed via intramolecular gas-phase aldol condensation and subsequent dehydration. The resulting C(1) protonated 1-acetyl-2-methylcyclopentene structure readily accounts for the observed further decomposition to CH3C≡O+ and 1-methylcyclopentene (C6H10) or, alternatively, to [C6H9]+ (e. g. 1-methylcyclopentenylium) ions and acetaldehyde (C2H4O). Support for this mechanistic rationale is derived from deuterium isotope labelling and low-energy collision-induced dissociation (CID) of the [MH - H2O]+ ion. The common intermediate shows a CID behaviour indistinguishable by these techniques from that of reference ions, which are produced by gas-phase protonation of the authentic cyclic aldol or by gas-phase addition of an acetyl cation to 1-methylcyclopentene in a CI (CH3COOCH3) experiment.

Additional Material: 7 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/oms.1210240304

Permalink

Library	Location	Call Number	Volume/Issue/Year	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

Electronic Resource

13C, 1H long-range coupling constants in configuration assignment of some trisubstituted alkenes (1994)

Fischer, Peter ; Schweizer, Eberhard ; Langner, Jörg ; [et al.]

Chichester : Wiley-Blackwell

Organic Magnetic Resonance 32 (1994), S. 567-568

add to mindlist on the mindlist

Details

ISSN: 0749-1581

Keywords: 13C ; NMR ; 13C,1H ; coupling constants ; 2-Acyloxy-2-alkenoates ; E/Z differentiation ; Chemistry ; Analytical Chemistry and Spectroscopy

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: Chemical shifts and long-range 13C, 1H coupling constants to the two carbonyl C atoms were determined for a series of ethyl 2-acyloxy-2-alkenoates. The 3J(C,H) coupling constant across the double bond is 9.5-10.1 Hz for the E- and 2.9-3.8 Hz for the Z-isomer. 3J(C,H) values, therefore, may be used as a criterion for E/Z differentiation even if only one isomer is available. 13C chemical shift data, in contrast, cannot be employed for a straightforward differentiation.

Additional Material: 2 Tab.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/mrc.1260320918

Permalink

Library	Location	Call Number	Volume/Issue/Year	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

hits 1 - 4 | 4 hits