Osazones 2,4-dinitrophenyl

However, in some cases azines can be converted to hydrazones by treatment with excess hydrazine and NaOH. Arylhydrazines, especially phenyl, p-nitrophenyl, and 2,4-dinitrophenyl, are used much more often and give the corresponding hydrazones with most aldehydes and ketones.Since these are usually solids, they make excellent derivatives and are commonly employed for this purpose. Cyclic hydrazones are also known, ° as are conjugated hydrazones. a-Hydroxy aldehydes and ketones and ot-dicarbonyl compounds give osazones, in which two adjacent carbons have carbon-nitrogen double bonds ... 

Aldehydes 2,4-Dinitrophenyl- hydrazine Formation of colored hydrazones or osazones. It is possible to distinguish between saturated and unsaturated hydrazones using potassium hexacyano-ferrate(III) [5]. [3,4]... 

Recently, Kato and coworkers isolated the 3-deoxy-D-eryhexos-ulose as its (2,4-dinitrophenyl)osazone from some soya-bean products, for example. Soy sauce and Miso soup. 

N sodium hydroxide for 3 hr. at 25°, (52) could be isolated in a yield of 3.7%. The isolation procedure involved deionization and chromatography on a cellulose column. Except for characterization by elemental analysis and the preparation of the (2,4-dinitrophenyl)osazone (identical with that synthesized) and its triacetate, the proof of structure depended upon the identification of formic acid and 2-deoxy-n- ribonic acid, obtained after oxidation with hydrogen peroxide at pH 8. 

Later, Machell and Richards and Whistler and BeMiller isolated the compound as a sirup (in yields of about 1%) by treatment of maltose with 0.05 N sodium hydroxide and of cellobiose with 0.05 N potassium hydroxide. There was a divergence in the reported specific optical rotations (in water), namely, —24.1° and -fll°, respectively, which might be attributable to degradation of this labile compound during isolation or storage. The crystalline (2,4-dinitrophenyl)osazone prepared in both investigations was further characterized as its crystalline triacetate. ... 

Formation of Osazones.—Osazones are readily formed from 3-deoxy-o-erythro-hexosuloae in the presence or absence of acid. However, the only crystalline osazones that have been obtained are the (4-nitrophenyl)osa-zone, the (2,4-dinitrophenyl)osazone, and the (2,5-dichlorophenyl)-osazone. The first two are identical with the respective osazones prepared from 3-deoxy-D-n 5o-hexose. The last two derivatives yield crystalline triacetates.The high melting points of many of these derivatives are not satisfactory for characterization, but their high optical rotations are a useful criterion of purity. ... 

The (2,4-dinitrophenyl)osazone (IS) is the most useful derivative, since... 

The (2,4-dinitrophenyl)osazone (15) is oxidized by periodate, consuming 2 moles per mole and liberating formaldehyde and another aldehyde. This second aldehyde cyclizes to give a crystalline compound, probably a pyrazole or dihydropyridazine. Color reactions and the chromatography of the osazone are discussed in Section VI (see p. 199). 

The tram isomer has been detected in only one other reaction, namely, the action of hot, dilute acid on n-fructose. In the early stages, when the proportion of 5-(hydroxymethyl)-2-furaldehyde is small, ten hydrazones or osazones are formed by adding (2,4-dinitrophenyl)hydrazine to the reaction mixture. These include the derivative of 3-deoxy-D-er /i/iro-hexosulose and smaller proportions of that of the glycosulos-Paper-column chromatography of the original reaction mixture yields the tram compound... 

Ingles heated a solution of n-glucose, sodium sulfite, and bisulfite, removed the cations, and steam-distilled the residue. The product, free of carbonyl-bisulfite addition compounds, was chromatographed on an ion-exchange resin, giving a sulfonic acid. This acid yields a crystalline brucine salt and phenyl- and (2,4-dinitrophenyl)-osazones. The osazones consume 1 mole of periodate per mole, liberating 1 mole of formaldehyde but no formic acid. The (2,4-dinitrophenyl)osazone also forms a diacetate. The acid is oxidized by sodium hypoiodite, taking up 1 mole of oxidant per mole. From these reactions and the possible reaction mechanisms for its formation, structure (41), a 3,4-dideoxy-4-sulfo-n-hexosulose, was proposed for the sulfonic acid. ... 

Deoxy-D-well studied as the o-erythro isomer. It has been prepared in two ways from the decomposition of l,l -(carboxymethylamino)bis(l-deoxy-D-tagatose), ( di-D-tagatosegly-cine ), and from iV-butyl-D-galactosylamine. " These two methods and the isolation procedures are similar to the corresponding ones described for the erythro isomer. The 3-deoxy-n-i/ireo-hexosulose (42) was obtained as a colorless, amorphous powder, [ ]d + 10° — + 12.7° (in water), and was characterized as osazones. The (2,5-dichlorophenyl)osazone and the (2,4-dinitrophenyl)osazone are crystalline, the latter yielding a triacetate. " ... 

The (2,4-dinitrophenyl)osazone of 3-deoxy-D-fifl /cero-pentosulose was isolated by Kato from the decomposition of iV-butyl-D-xylosylamine or A -butyl-D-arabinosylamine. Later, " the free pentosulose was isolated in 2% yield as a colorless solid. It shows properties similar to those of the 3-deoxyhexosuloses, no strong absorption in the range 210-400 m t, and a weak mutarotation C ]d —13.4 -+ —17.2° (in water). It readily forms a (2,4-dinitrophenyl)osazone which yields a diacetate. The osazone was... 

Only the (2,4-dinitrophenyl)osazone of 3-deoxy-ii-gfZ2/cero-pentosulose has been isolated. It forms a racemate on admixture with the D-isomer. ... 

Many oxazoles react slowly at room temperature with 2,4-dinitrophenyl-hydrazine in hydrochloric acid to form hydrazones (223) by ring fission.84 160 On the other hand, refluxing results in the formation of osazones (224) of glyoxal derivatives, presumably via 223.877... 

Braude and Forbes found that primary and secondary alcohols contam-ing two or more ethylenic or aromatic substituents conjugated with the carbinol group are oxidized by (2,4-dinitrophenyl)hydrazine salts they suggested that the same kind of reaction occurs during osazone formation. 

Mineral oils (e. g., Shell Ondina 27) 10 Petrol ether Silica gel G Dioxan-water (60 + 40) 2,4-Dinitrophenyl- osazones... 

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