Osazones oxidation

The unsaturated diamine, CgHgoNj, from the hydrolysis of sphero-physine, on oxidation with permanganate yields the ketoaldehyde, McgCH. CO. CHO fdioxime, m.p. 95-6°, and osazone, m.p. 113-4°) and putrescine, NH2[CH2]4NH2, which indicates that this unsaturated diamine is Me2CH. CH CH. NH[CH2]4. NH2. 

Fischer projections and, 977-978 glycosides of, 989-990 hemiacetals of, 984-986 osazones from, 1013 oxidation of, 992-994 phosphorylation of, 991 reaction with acetic anhydride, 988... 

The 2-keto acids such as 2-keto-D-galactonic acid (XXIV) can be derived from the corresponding osone (XXIII) by oxidation with bromine.10 Oxidation of L-gulosone by the same method has provided 2-keto-L-gulonic acid. The success of this oxidation depends to a large extent upon the purity of the osone subjected to oxidation and this, as previously stated, is controlled by the purity of the osazone. 

The reaction of these aldehydes, derived from periodate oxidation, with carbonyl reagents has also been investigated. Studies 147 148 were made on oxidized laminarin, a (1 —> 3)-linked polysaccharide, in which only the terminal residues had been oxidized. The addition of phenylhydrazine acetate detached the remainder of the terminal residue as glyoxal phenyl-osazone. When the aldehydic compounds derived from the periodate oxidation of raffinose and trehalose818a were reacted with p-nitrophenylhydrazine, the authors were surprised to find that one molecule of oxidized raffinose, containing six aldehydic functions, reacts with only three molecules of the reagent, and that the four aldehydic functions of the oxidized trehalose molecule react with only two. The reactions of periodate-oxidized carbo-... 

Like all hydrazones, osazones lose phenylhydrazine when heated with hydrochloric acid. Naturally, it is not the sugar originally taken which is thus recovered, but an oxidation product, a so-called osone. In the example chosen the osone is ... 

Many oxidizing agents have been used, especially copper sulfate and other cupric salts. Potassium dichromate in acetic acid and manganese dioxide are good oxidants for benzil bis(phenylhydrazone). Nitrous acid has been used for the osazones of acetylated sugars and for phenylglyoxal bis(phenylhydrazone). ... 

The carbonyl group (and adjacent alcohol) oxidizes with excess phenyl hydrazine (PhNHNH2) to form an osazone (see Figure 16-15). Osazone formation is very important in determining the relationship between various monosaccharides. For example, both D-glucose and D-mannose produce the same osazone, so they re epimers. Epimers differ by only one chiral center, which osazone formation destroys. 

Hydrolysis of the diacetamides is effected by acids. Dilute hydrochloric, sulfuric and nitric acid have been used. An aldose with one carbon atom less than the original nitrile is then liberated from the combination. Only exceptionally can this aldose be isolated in pure condition without transforming it into an insoluble derivative in these instances, the method has been employed for preparative work. In most cases the sugar has been characterized as an osazone. The aldose, without great purification, has been employed successfully for reduction - or oxidation experiments. ... 

N sulfuric acid produced D-lyxose as a sirup, characterized by its phenyl-osazone and by oxidation to D-lyxonic acid. 

Another 2,3-bis(phenylhydrazone), namely, l,5 4,6-dianhydro-2,3-hexodiulose bis(phenylhydrazone) (62a), was also found to cyclize to a pyrazoline (63a) by the action of copper(II) sulfate or benzalde-hyde, which usually convert osazones into aldosuloses or osotria-zoles.65 Reduction of this bicyclic compound (63a) led to the pyrazo-lidine 64, and periodate oxidation of 63a gave the expected aldehyde 65. 

Another type of substituted pyrazole is obtained by refluxing osazones with acetic anhydride during the acetylation, two molecules of water per molecule are removed. The structure of the resulting 5-(D-g/ycero-diacetoxyethyl)-3-formyl-l-phenylpyrazole 2-acetyl-2-phenylhydrazone (71) was determined by deacetylation followed by oxidation with (a) periodate to a pyrazolaldehyde (72), and (b) permanganate to the known l-phenyl-pyrazole-3,5-dicarboxylic acid (73), as well as by a study of its n.m.r. spectrum, which confirmed the pres-... 

The bishydrazones of the 1,2-diketones from inositols have also been converted into triazoles.222,223 The conversion of arylosazones into the corresponding osotriazoles requires the presence of an oxidant, and it is obvious that simple removal of aniline from the osazone, as suggested by the equation, is not involved. In addition to copper(II) sulfate, the reagent most commonly used, other oxidizing heavy-metal salts, such as ferric sulfate and chloride,224 and mercuric acetate,223 have been used, as well as halogens225 and nitro-sulfonates.226 The osazone acetates are converted into osotriazoles by nitrous acid,227 which decomposes the unacetylated osazones to the aldosuloses228 and the osazone formazans are cyclized with warm... 

Since mannose and glucose are C epimers, they are identical at the C, C. C, and C" portions of the molecule, which are unaltered during osazone formation. The chiral C , which differs in each hexose, loses chirality in the osazone and becomes identical for both mannose and glucose. 2-Ketohexoses give osazones in which the C CH,OH is oxidized. Since C, C, C and C of fructose and glucose are identical (Problem 22.8), fructose also gives the same osazone. Identical portions are in the boxes below. 

Problsm 22.26 The pentoses o-xylose and o-lyxose give the same osazone. Xylose and lyxose are oxidized to an optically inactive and optically active dicarboxylic acid, respectively. Give their shorthand structural formulas. <... 

Problem 22.57 (a) Write shorthand open structures for a ketohexose (I) and an aldohexose (II) which form the same osazone as D-(-)-altrose (III), the C epimer of o-mannose, and for the aric acid (IV) formed by HNOj oxidation of the o-aldohexoses (III) and o-talose (V). (b) Write shorthand and conformational structures for -D-altropyranose (VI). ... 

The fourth student in this group, Stanford Moore, began his doctoral thesis research with Link in 1935. His work involved the development of a new, and still useful, procedure for oxidizing aldoses to the aldonic acids by potassium hypoiodite in methanol solution the resulting aldonic acids were then converted into nicely crystalline benzimidazole derivatives that proved more suitable for the characterization of carbohydrates than the classical osazones. This method, developed by Moore and Link (1940), was extended to the characterization of hexuronic acids, as their bis(benzimidazole)s, after oxidation to the glycaric acid (R. Lohmar, Dimler, Moore, and Link, 1942), of lactic acid (Moore, Dimler, and Link, 1941 Dimler and Link, 1942), and of ribose, fucose, and digitoxose (Dimler and Link, 1943). During these... 

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