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Acetophenone , 9, 119 glyoxal

Bei der Reduktion von 4-Brom- cy-diazo-acetophenon, die stufenweise bis zum 4-Brom-l-phenyl-athanol lauft, kann die Zwischenstufe 2-(4-Brom-phenyl)-glyoxal-hy-drazon bei der Reduktion in Mcllvaine-Pufferlosung an Quecksilber (—0,8 V) isoliert werden1 ... [Pg.700]

Ir(cod)Cl]2 reacts with Q-diimines LL (derived from glyoxal and biacetyl) to yield cationic [Ir(cod)LL]+.523 If the reaction is carried out in the presence of SnCl2, then the pentacoordinate Ir(SnCl3)(cod)LL species results. The compounds are active catalysts in the homogeneous hydrogen transfer from isopropanol to cyclohexanone or to acetophenone followed by hydrogenation... [Pg.206]

Another important use of SeOj is in the oxidation of CH3 groups to CHO, but not to COOH group. But such CH3 group must be activated by a carbonyl or other group. Thus phenyl glyoxal has been prepared in about 72% yield by refluxing a solution of acetophenone in the medium of dioxane for about 4 hours. [Pg.281]

A tandem Kornblum ox/daf/on/imidazole formation reaction was used during the preparation of new fluorescent nucleotides by B. Fischer and co-workers.The adenosine monophosphate free acid was mixed with 10 equivalents of 2-bromo-(p-nitro)-acetophenone and dissolved in DMSO. The required pH value was maintained with the addition of DBU which also served as a base. The Kornblum oxidation of the alkyl halide yielded the glyoxal, which reacted in situ with the aromatic amine to form the desired imidazole derivative. [Pg.251]

Oxidation. Use of selenium dioxide for the oxidation of reactive methylene groups to carbonyl groups was introduced by H. L. Riley, Morley, and Friend. A procedure developed by H. A. Riley and Gray for the preparation of phenyl-glyoxal calls for heating a solution of acetophenone in dioxane with either selenious acid, or equivalent amounts of selenium dioxide and water, and stirring the mixture... [Pg.1230]

In this reaction, initially, acetophenone 36 was converted to a-iodo acetophenone 39 by iodine, which was further transformed into phenyl glyoxal 40 by DMSO (dimethyl sulfoxide). The formed aldehyde then reacted with 2-aminothiophenol 37 to provide intermediate 41, which was further converted to 42 through an intramolecular 1,2-addition. Then, 42 underwent iodine-catalyzed oxidative dehydrogenation to afford the desired product 2-acyl benzothiazole 38 (Scheme 9.9). Very recently, the same authors reported the synthesis of 2,5-disubstituted oxazoles using a similar domino process [17]. [Pg.300]

This reaction is based on the formation of a color in a mixture of an aqueous sodium nitroprusside solution with carbonyl compounds in an alkaline medium. A positive test is obtained with aliphatic and certain aromatic aldehydes and aromatic and aliphatic ketones. The literature data on this reaction are conflicting and no general rule can be expressed about which carbonyl compounds give the reaction and which do not. For example, the color is not produced with formaldehyde, glyoxal, benzaldehyde, o-hydroxy-benzaldehyde, chloral, vanillin, benzophenone, naphthyl phenyl ketone, trihydroxybenzophenone, benzil, acetophenones substituted on the aromatic nucleus with hydroxyl, etc. The reaction can therefore be used for the differentiation of certain types of aldehydes and ketones, as, for example, acetaldehyde from formaldehyde, and acetophenone from benzophenone or hydroxyacetophenone, etc. Further, various colors formed in alkaline media or after the subsequent acidification of the reaction mixture can also be used for differentiation. Sodium hydroxide can be replaced by ammonia, piperidine... [Pg.234]


See other pages where Acetophenone , 9, 119 glyoxal is mentioned: [Pg.866]    [Pg.684]    [Pg.143]    [Pg.281]    [Pg.429]    [Pg.44]    [Pg.111]    [Pg.429]    [Pg.111]    [Pg.332]    [Pg.866]    [Pg.341]    [Pg.312]    [Pg.321]    [Pg.275]    [Pg.196]    [Pg.160]   
See also in sourсe #XX -- [ Pg.20 ]




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