Über die Darstellung isomerenfreier verzweigter Carbonsäuren

Reinheckel, H.; Gensike, R.; Falk, F.; Sonnek, Georg

doi:10.1002/lipi.19690710909

Fette, Seifen, Anstrichm.

1969

DOI: 10.1002/lipi.19690710909

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Über die Darstellung isomerenfreier verzweigter Carbonsäuren

H. Reinheckel

R. Gensike

F. Falk

et al.

Abstract: Ein Vcr:alircn zur Darstellung von isomerenfreien, verzweigten gesattigten und ungesattigten Carbonsauren aus tertiaren y-Lactonen mit Hilfe von Alkylaluminiumddoriden wird besdrieben. Mit Xthylaluminiumdiddorid fuhrte die Reaktion in hohen Ausbeuten zu isomerenfreien, verzweigten und gesattigten Carbonsauren, mit Diathylaluminiumchlorid zu ungesattigtcn Carbonsauren. Lactonspaltungen mit Gemishen der beiden Kthylaluminiumddoride ergaben in ubersidtliher Weise Ge. mischc von gesattigten und ungesattigten Saure… Show more

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Cited by 3 publications

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über Reaktionen mit Aluminiumalkylen. XVIII. Reaktionen von Butanoliden mit Methyl‐ und äthylaluminiumdichloriden

Reinheckel¹,

Sonnek²,

Falk³

1974

J. Prakt. Chem.

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Die Butanolide 1a–f mit Alkyl‐ bzw. Arylgruppen in γ‐Stellung reagieren mit Āthyl‐aluminiumdichlorid zu den gesättigten Säuren 3a–f. Mit Hilfe von unterschiedlich deuteriertem C2H5AlBr2 wird der Mechanismus aufgeklärt, Danach wird bei der Reaktion ein β‐ständiges H‐Atom des Äthyl‐aluminiumdihalogenids über einen Sechsring auf das γ‐C‐Atom des Butanolids übertragen. Mit Methyl‐aluminiumdichlorid reagieren 1a–f unter Alkylierung zu Säuren mit quartärem γ‐C‐Atom 7a–f. Als Nebenreaktion läuft bei 1 d eine FRIEDEL‐CRAFTS‐Reaktion, bei 1b, c Isomerisierung ab. Die α,β‐ungesättigten Butanolide 2a, b ergeben mit Āthyl‐ oder Methylaluminiumdichlorid die Säuren 9a, b mit 2 konjugierten Doppelbindungen.

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über Reaktionen mit Aluminiumalkylen. XVIII. Reaktionen von Butanoliden mit Methyl‐ und äthylaluminiumdichloriden

Reinheckel¹,

Sonnek²,

Falk³

1974

J. Prakt. Chem.

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On the syntheses of branched saturated fatty acids

Gronowitz

Klingstedt

Svensson³

et al. 1993

Lipids

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In order to investigate the relation between the structure of mono‐branched saturated fatty acids and their physical properties, a three‐factor central composite design was constructed. For this purpose sixteen different fatty acids were prepared. The synthetic strategy was to use if possible, a few common starting materials for the preparation of most of the acids. Thus alkylation and hydrolysis of oxazolines were used for the preparation of 2‐butylhexanoic acid, 2‐methyloctadecanoic acid, 2‐hexadecyloctadecanoic acid and 2‐pentyloctadecanoic acid. A number of acids were prepared from thiophene derivatives followed by desulfurization with Raney‐Nickel alloy under alkaline conditions. Thus, starting from 3‐ethylthiophene, 4‐ethyl‐2‐thiophenecarboxylic acid and 4‐ethyl‐2‐methyl‐5‐thiophenecarboxylic acid were prepared, which upon desulfurization gave the desired 4‐methylhexanoic acid. From 3‐bromo‐2‐methylthiophene, 3‐ethyl‐2‐methyl‐5‐thiophenecarboxylic acid was preparedvia 3‐acetyl‐2‐methylthiophene and 3‐ethyl‐2‐methylthiophene. Desulfurization gave 4‐ethylhexanoic acid. Another approach started with 2‐acylthiophenes, which were reacted with Grignard reagent to yield the appropriate olefins. By metalation and reaction with carbon dioxide, these were transformed to the corresponding 2‐thiophenecarboxylic acids. Upon desulfurization, the desired fatty acids were obtained. In this way 6‐propyldecanoic acid, 6‐hexyldodecanoic acid, 6‐methyldodecanoic acid and 6‐pentylpentadecanoic acid were prepared. The remaining four acids were prepared from some of the branched acids described above through Kolbe reactions of dioic acids. Thus 16‐methyloctadecanoic acid and 10‐methyl‐dodecanoic acid were obtained from 4‐methylhexanoic acid, 16‐ethyloctadecanoic acid from 4‐ethylhexanoic acid and 9‐pentyloctadecanoic acid from 6‐pentylpentadecanoic acid.

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3‐carboxy‐4‐nitrophenyl‐dithio‐1,1′,2‐trisnorsqualene: A site‐directed inactivator of yeast oxidosqualene cyclase

Balliano¹,

Grosa²,

Milla³

et al. 1993

Lipids

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The role and location of essential thiol groups in 2,3-oxidosqualene cyclase from Saccharomyces cerevisiae was examined (i) by comparing inactivation properties of two known thiol reagents, 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB) and 2-nitro-5-thiocyanobenzoic acid (NTCB), with 3-carboxy-4-nitrophenyl-dithio-1,1',2-trisnorsqualene (CNDT-squalene), a new thiol reagent designed as a site-directed inactivator of oxidosqualene cyclase and (ii) by testing the ability of the substrate to protect the enzyme against inactivation by the reagents. All reagents gave a time-dependent inactivation following pseudo-first order kinetics. DTNB and CNDT-squalene showed comparable inactivation ability (Ki = 0.67 and 1.21 mM), whereas NTCB was less effective (Ki = 15.6 mM). Strong differences between the two most active inhibitors, DTNB and CNDT-squalene, were observed when the enzyme was saturated with substrate prior to incubation with the thiol reagent. While substrate did not protect the enzyme against the inactivation caused by DTNB, a reduction in the inactivation ability of CNDT-squalene was observed under protection conditions. The data suggest that the squalene-like inactivator modifies a thiol group located at the active site of the enzyme.

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Über die Darstellung isomerenfreier verzweigter Carbonsäuren

Cited by 3 publications

References 5 publications

über Reaktionen mit Aluminiumalkylen. XVIII. Reaktionen von Butanoliden mit Methyl‐ und äthylaluminiumdichloriden

über Reaktionen mit Aluminiumalkylen. XVIII. Reaktionen von Butanoliden mit Methyl‐ und äthylaluminiumdichloriden

On the syntheses of branched saturated fatty acids

3‐carboxy‐4‐nitrophenyl‐dithio‐1,1′,2‐trisnorsqualene: A site‐directed inactivator of yeast oxidosqualene cyclase

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