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Glyoxal aliphatic

Besides Fe-, other reducing agents that may be used in conjunction with H2O2 are aliphatic amines, Na2S203 thiourea, ascorbic acid, glyoxal, sulfuric acid, NaHSOs, sodium nitrite, ferric nitrate, peroxidase, AgNOs, tartaric acid, hydroxylamine, ethylene sulfate, sodium phosphite, formic acid, ferrous ammonium sulphate, acetic acid, ferrous sulphate, and HNO2, etc,... [Pg.489]

Dinitrophenyl-hydrazine has been successfully employed in the analysis of simple aldehydes, substituted aldehydes, glyoxal and gluteraldehyde (43-45), all the isomers of the C3 to C7 aliphatic ketones (44,45) and in the determination of formaldehyde in tobacco smoke (46). [Pg.244]

Ytterbium triflate [Yb(OTf)3] combined with TMSG1 or TMSOTf are excellent reagents for the conversion of a-methyl styrene and tosyl-imines into homoallylic amides 32 (Equation (19)) (TMS = trimethylsilyl).29 These conditions produce the first examples of intermolecular imino-ene reactions with less reactive imines. Typically, glyoxalate imines are necessary. A comprehensive examination of the lanthanoid metal triflates was done and the activity was shown to directly correlate with the oxophilicity scale. The first report used preformed imines, and subsequently it was found that a three-component coupling reaction could be effected, bypassing the isolation of the intermediate imine.30 Particularly noteworthy was the successful participation of aliphatic aldehydes to yield homoallylic amines. [Pg.564]

The preparative importance of the acyloins depends on the fact that they are intermediate products, from which many 1 2-diketones can be obtained. The simplest aromatic member of this group is benzil (anisil and furil are analogous) like its aliphatic prototype diacetyl CH3.CO.CO.CH3 (and like anhydrous glyoxal) it is yellow in colour. Diacetyl is obtained from methyl-ethyl ketone via the monoxime of the former compound (von Pechmann). It is remarkable that diacetyl condenses to p-xyloquinone. (Formulate). [Pg.224]

The alkoxy radical of Scheme 18.3 (upper reaction) could scission to produce the same carboxyl radical as seen in the Norrish type 1 path (Scheme 18.1, path A) discussed above. As such, it is an additional source of CO2 but not taken into account in the report by Day and Wiles [25], Not reported but still obvious, the other fragment of this scission is an aliphatic aldehyde that could also have been one of the aldehyde carbonyl IR signals reported [11, 25], Hydrolysis of this chain end would yield the reported glyoxal [21],... [Pg.634]

Certain compounds do not show two-stage ignition. These include methane, acetylene, benzene, hydrogen, methanol, formaldehyde, and glyoxal (106, 108). Higher aromatics show the effects of their aliphatic side chains and act like aliphatics. [Pg.195]

The enantioselective addition of allylstannanes to glyoxylates and glyoxals, and also simple aromatic and aliphatic aldehydes, catalysed by chiral (salen)Cr(III) complexes, has been studied.133 The reaction proceeded smoothly for the reactive 2-oxoaldehydes and allyltributy 1 tin in the presence of small amounts (1-2 mol%) of (salen)Cr(III)BF4 under mild, undemanding conditions. The stereochemical results have been rationalized on the basis of the proposed model. [Pg.298]

Several attempts of FruA-catalyzed DHAP additions to simple aliphatic dialdehydes like glyoxal or glutaric dialdehyde have been reported in the literature, but in no case had a product been isolated and characterized [72,85]. Malonic dialdehyde cannot be used because it tends to enolize under protic conditions and engages in polycondensations. Our own extensive studies corroborate that enzymatic assays indicate a consumption of DHAP, but no defined products result according to t.Lc. or NMR analysis. Problematic also is the fact that aliphatic dialdehydes irreversibly destroy enzymatic activity by protein cross-linking [86,87]. [Pg.94]

Upon treating certain (but not all) aromatic aldehydes or glyoxals (a-keto aldehydes) with cyanide ion (CN ), benzoins (a-hydroxy-ketones or acyloins) are produced in a reaction called the benzoin condensation. The reverse process is called the retro-benzoin condensation, and it is frequently used for the preparation of ketones. The condensation involves the addition of one molecule of aldehyde to the C=0 group of another. One of the aldehydes serves as the donor and the other serves as the acceptor. Some aldehydes can only be donors (e.g. p-dimethylaminobenzaldehyde) or acceptors, so they are not able to self-condense, while other aldehydes (benzaldehyde) can perform both functions and are capable of self-condensation. Certain thiazolium salts can also catalyze the reaction in the presence of a mild base. This version of the benzoin condensation is more synthetically useful than the original procedure because it works with enolizable and non-enolizable aldehydes and asymmetric catalysts may be used. Aliphatic aldehydes can also be used and mixtures of aliphatic and aromatic aldehydes give mixed benzoins. Recently, it was also shown that thiazolium-ion based organic ionic liquids (Oils) promote the benzoin condensation in the presence of small amounts of triethylamine. The stereoselective synthesis of benzoins has been achieved using chiral thiazolium salts as catalysts. [Pg.54]

The prototype reaction is the conversion of glyoxal into glycolic acid (equation 2), and here the benzilic acid rearrangement mechanism coincides with that for an intramolecular Cannizzaro reaction. The reaction is observed with other purely aliphatic a-diketones such as f-butyl 2,3-dioxobutyrate and cyclohexane-1,2-dione (equations 3 and 4), but the scope is limited in the aliphatic series by competing (c.g. aldol) reactions. Suitably constructed heterocyclic systems also rearrange, and the conversion of alloxan (3) into alloxanic acid (4) was among the first of the benzilic acid rearrangements to be discovered (equation 5). ... [Pg.822]

Chlorinated and/or oxidized starches crosslinked with glyoxal were used to produce a high-strength size for paper.573 Coating adhesives were also prepared by crosslinking glycidyl esters.1385 In addition, esters of starch with inorganic acids (such as starch phosphates) were crosslinked with various aliphatic and aromatic aldehydes in the presence of urea, melamine and similar compounds.1322... [Pg.234]

A thixotropic starch was produced in reactions of POCl3-crosslinked starch with unsaturated aliphatic aldehydes.1361 Starch phosphates have been crosslinked by various aliphatic and aromatic aldehydes in the presence of urea, melamine, and similar compounds. Among several aldehydes tested[formaldehyde, propanal (propionaldehyde), glyoxal, glutaraldehyde, 2-hydroxyadipaldehyde (2-hydroxy -1,6-hexanedial), and some aromatic aldehydes], only those products that had reacted with glyoxal were insoluble in water.1322 Significant increases in viscosity occurred after starch phosphates having a low DS were treated with urea.1590... [Pg.245]

Oxidation of bis-hydrazones of aliphatic polyfluorinated a-dicarbonyl compounds with S02C12 or bromine forms isomeric 1-amino-1,2,3-triazoles, one of which was identified by X-ray analysis (96JFC(79)45) (Scheme 86). Oxidation of polyfluoroalkyl-substituted glyoxal dihydrazones gives only one isomer. [Pg.316]

Glyoxal. [HoechstCelanese/Colorants Surf.] Aliphatic dialddiyde hydrogen sulfi scavengers in natural gas and sour crude prod., textiles, paper, adhesives, coatings, disinfectants, deodorants. [Pg.160]


See other pages where Glyoxal aliphatic is mentioned: [Pg.105]    [Pg.17]    [Pg.105]    [Pg.157]    [Pg.353]    [Pg.729]    [Pg.138]    [Pg.326]    [Pg.94]    [Pg.656]    [Pg.144]    [Pg.1224]    [Pg.5]    [Pg.5]    [Pg.2]    [Pg.900]    [Pg.566]    [Pg.74]    [Pg.831]    [Pg.555]    [Pg.20]    [Pg.86]    [Pg.130]    [Pg.606]    [Pg.232]    [Pg.93]    [Pg.234]    [Pg.70]    [Pg.386]    [Pg.979]    [Pg.94]    [Pg.1224]    [Pg.150]    [Pg.154]    [Pg.161]   
See also in sourсe #XX -- [ Pg.330 ]




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