Glucose phenylhydrazone

D-Glucose phenylhydrazone [534-97-4] M 358.4, m 208 . Crystd from aqueous EtOH. 

D-Glucose Phenylhydrazone. This was prepared by the procedure of Fischer and Stahel (58), mp 143 °C. 

Attempts have been made to solve the problem by examining the rate of hydrolysis of the two D-glucose phenylhydrazones, and Frere-jacque/ who used oxalic acid and picric acid to remove the phenyl-hydrazine from the sphere of the reaction as an insoluble salt, claimed to show that both of the D-glucose a - and 9 -phenylhydrazones are derived from a-D-glucose on account of the downward trend of the mutarotation observed on making the solutions alkaline. This result is therefore not in conflict Avith the conclusions of Behrend. From similar studies StempeP concluded that "no information of value concerning... 

D-Glucose phenylhydrazone [3713-25-5] M 358.4, m three forms. Crystallise the hydrazone from 70% aqueous EtOH or EtOH/Et20. Three forms have been described a form m 159°, 160° which mutarotates from [a] -87° to -50° (H2O) [Fischer Bcr 20 821 1887, Behrends Justus Liebigs Ann Chem 353 106 1907], p form m 140-141°, 142° which mutarotates from [a] -2° to -50° (H2O) [Behrends LohrLiebigs Ann Chem 362 78 790S], and Skraup s form m 115-116° which mutarotates from [a] -70° to -47° (H2O) [Skraup Monatsh Chem 10 406 1889, Butler Crechter J Am Chem Soc 51 3161 1921]. These mutarotate to the formazan. [Beilstein 1 IV 4322, Mester Major 7 A/n Chem Soc 77 4297 7955, Stanek et al. The Monosaccharides, Academic Press 1963, pp 539-541,543.]... 

Elimination of acetic acid occurs readily from phenylhydrazones of acetylated aldoses. For example, the reaction between 2,3,4,5,6-penta-O-acetyl-aZde%do-D-glucose and phenylhydrazine gives the unsaturated phenylhydrazone, 3,4,5,6-tetra-O-acetyl-l, 2-dideoxy-l -phenylazo-n-ara-6mo-hex-l-enitol (137), which may also be prepared by acetylation of the acyclic phenylhydrazones of n-glucose and D-mannose, or by condensation of 2,3,4,5,6-penta-0-acetyl-aZdeA /do-D-mannose with phenylhydrazine. 2,3,4,5,6-Penta-O-acetyl-D-glucose phenylhydrazone (138) has been... 

The hydrazones of sugars are capable of existing in various cyclic forms, whose presence is apparent from their nuclear magnetic resonance (NMR) spectra and from the complex mutarotation curves they exhibit110,111117118 (which seldom follow first-order kinetics). The principal structures encountered in saccharide hydrazones are the acyclic, Schiff base-type true hydrazones and the cyclic hydrazino forms, namely glycopyranosyl- and gly-cofuranosylhydrazines. For example, three isomeric forms of D-glucose phenylhydrazone have been isolated.119 The Schiff base derivatives can be... 

D-Glucose phenylhydrazone [3713-25-5] M 358.4, m three forms. Crystallise the hydrazone from 70% aqueous EtOH or Et0H/Et20. Three forms have been described a form m 159°, 160° which mutarotates from [a]g> -87° to -50° (H2O) [Fischer 20 821 1887, Justus Liebigs Ann Chem 353 106 1907],... 

An investigation of the structures of the D-pentose phenylhydrazones in water, methanol, and pyridine by chemical, spectroscopic, and chiroptical methods has indicated that the acyclic form is adopted in these solvents. A related study has shown that D-glucose phenylhydrazone also adopts the acyclic form in DMSO, whereas solutions of the corresponding 4-nitro- and 2,4-dinitro-phenylhydrazones in DMSO contain only 40 and 10%, respectively, of the acyclic form. An n.m.r. study of 2,5-anhydro-D-lyxose and -xylose 4-nitrophenylhydrazones is mentioned in Chapter 20. 

Another method of establishing structures depends upon the well-defined reaction of benzenediazonium chloride with acyclic phenylhydrazones to form diphenylformazans (215) no well-defined product is obtained from cyclic isomers. This method has given the same results as the acetylation method, and, in addition, has shown that the third isomer of glucose phenylhydrazone is also cyclic. 

The reaction of D-glucose phenylhydrazone with glacial acetic acid has been examined iV-fructosyl-A -glucosylphenylhydrazine was formed at 30 °C, whereas 1,2-dideoxy-l -phenylimino-2-phenylhydrazono-D-ara6//io-hexose was obtained after brief treatment at 100 2-(D-arfli //jo-Tetrahydroxybutyl)quinoxaline was also formed. The acetolysis of the 2,3,4,6-tetra-0-acetyl-j8-D-glucopyranosyl 2,4-dinitrophenylhydrazine (154) yielded a mixture of acyclic and cyclic hydrazones... 

---