Gabriel-Synthese

Die Alkylierungen konnen mit oder ohne Isolierung der Zwischenstufen durchgefuhrt werden. Insgesamt stellt diese Methode eine Alternative zur Gabriel-Synthese dar und eignet sich dariiber hinaus auch zur Herstellung sekundarer Amine. 

Neuere Beispiele fur die Anwendung der Gabriel-Synthese in ihrer urspriinglichen Form sind u.a. die Herstellung von 4-Chlor-l-phthalimido-2-buten aus l,4-Dichlor-2-buten (65%)1 sowie die erste Stufe der folgenden Synthese von zwei allenischen Amino-alko-holen, 5-Amino-4-ethyl-l-hydroxy-2-methyl-2,3-hexadien (I R =H, R2=R3 = CH3 ... 

Eine weitere Alternative zur Gabriel-Synthese von primaren aliphatischen Aminen ist die Reaktion von Alkyl-bromiden mit den N-Lithium-Derivaten von Bis-[benzolsulfensaure]-oder Bis-[4-chlor-benzolsulfensaure]-imid, gefolgt von Spaltung der N-Alkylierungspro-dukte mit 3N-Salzsaure in Ether5,6. Man erhalt auf diese Weise z. B. Benzylamin bzw. (4-Nitro-benzyl)-amin aus den entsprechenden Brom-Verbindungen in 86% Ausbeute. 

Sulfonsaure-alkylester konnen auch mittels Gabriel-Synthese in primare Amine iiber-gefuhrt werden. So lassen sich z, B. fluorierte Alkylamine wie 2-Amino-l,1,1-trifluor-ethan, 3-Amino-1,1,2,2-tetrafluor-propan und hohere Homologe durch Reaktion der entsprechen-den 2-Nitro-benzolsulfonsaure-fluoralkylester mit Kalium-phthalimid und anschliefiende Spaltung mit Hydrazin in guten Ausbeuten herstellen1. 

M.S. Gibson u. R. W. Bradshaw, Angew. Chem. 80, 986-996 (1968) engl. 7, 919 Gabriel-Synthese pri-miirer Amine". 

Show how Gabriel syntheses might be used to prepare the following amines, (a) benzylamine (b) hexan-1-amine (c) y-aminobutyric acid... 

The Wenker and Gabriel syntheses have great scope and usually give good yields, however the routes via triazolines (e.g. 19) are not good for V-unsubstituted aziridines or for V-alkylaziridines. The Gabriel... 

Show how Gabriel syntheses might be used to prepare the following amines. 

Propose Gabriel syntheses of methionine, aspartic acid, and glutamic acid. 

Quinazoline (1,3-diazanaphthalene) was prepared by Gabriel in 1903 although the first derivative tvas synthesized by Griess 34 years earlier. The name was proposed by Widdege. Other names such as phenmiazine, benzo-l,3-diazine, and 5,6-benzopyrimidine have occasionally been used. The numbering suggested by Paal and Busch (1) is still in use. ... 

An early claim by Gabriel and Neumann to have synthesized 1-methylisoindolenine (59) from the diazanaphthalene (60) has been shown to he in error, the actual product being 1-methylisoindoline (61). Several synthetic routes to 1,3,3-trisubstituted isoindolenines... 

The reaction with ammonia or amines, which undoubtedly proceeds by the SnAt mechanism, is catalyzed by copper and nickel salts, though these are normally used only with rather unreactive halides. This reaction, with phase-transfer catalysis, has been used to synthesize triarylamines. Copper ion catalysts (especially cuprous oxide or iodide) also permit the Gabriel synthesis (10-61) to be... 

Prof. Claude Mo ise Laboratoire de Synthese et d Electrosynthese Organometalliques associe au CNRS Faculte des Sciences 6, Bd Gabriel 21000 Dijon France Prof. Fumie Sato Department of Biomolecular Engineering Tokyo Institute of Technology 4259 Nagatsuta-cho, Midori-ku Yokohama Kanagawa 226-8501 Japan... 

Gabriele Centi and Siglinda Perathoner (University of Messina, Italy) look at how quasi-one-dimensional catalyst morphologies can be synthesized. Though they focus on titania as an example, they also show how this technique can be used for more general types of supports and catalysts. 

Problem 21.2 Synthesize leucine, (CH,),CHCH,CH(NH,)COO, by (a) Hell-Volhard-Zelinsky reaction (Section 16.3) followed by ammonolysis. (b) Gabriel synthesis, (c) phthalimidomalonic ester synthesis, (d) reductive amination of a keto acid, (e) Strecker synthesis (addition of NH, HCN to RCH=0), (/) acetylaminomalonic ester. 

Current address Laboratoire de Synthese et d Electrosynthese Organometallique, Faculte de Sciences Gabriel, 6 Boulevard Gabriel, 21100 Dijon, France. 

C. EtkyUnimine Ketones and Related Syntheses Closely related to the Gabriel synthesis is the reaction of /9-dihaloketones or cc-hslo-a -unsaturated ketones with primary amines... 

Chapters 17 through 21 deal with carbohydrate-enzyme systems. Hehre presents some new ideas on the action of amylases. Kabat presents some new immunochemical studies on the carbohydrate moiety of certain water-soluble blood-group substances and their precursor antigens. Hassid reviews the role of sugar phosphates in the biosynthesis of complex saccharides. Pazur and co-workers present information obtained by isotopic techniques on the nature of enzyme-substrate complexes in the hydrolysis of polysaccharides. Gabriel presents a common mechanism for the production of 6-deoxyhexoses. An intermediate nucleoside-5 -(6-deoxyhexose-4-ulose pyrophosphate) is formed in each of the syntheses. 

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