Osazone

Osazone
Ball-and-stick model of glucose osazone

Osazones are a class of carbohydrate derivatives found in organic chemistry formed when sugars are reacted with phenylhydrazine [1]. The famous German chemist Emil Fischer[2] developed and used the reaction to identify sugars whose stereochemistry differed by only one chiral carbon.[3][4] The reaction involves formation of a pair of phenylhydrazone functionalities, concomitant with the oxidation of the hydroxymethylene group adjacent to the formyl center. The reaction can be used to identify monosaccharides. It involves two reactions. Firstly glucose with phenylhydrazine gives us glucosephenylhydrazone by elimination of a water molecule from the functional group.The next step involves reaction of one mole of glucosephenylhydrazone with two moles of phenylhydrazine (excess). First phenylhydrazine is involved in oxidizing the alpha carbon to a carbonyl group, and the second phenylhydrazine involves in removal of one water molecule with the formyl group of that oxidized carbon and forming the similar carbon nitrogen bond.[5] The alpha carbon is attacked here because its more reactive than the others.They are highly coloured and crystalline compounds and can be easily detected. Glucose gives broomstick shaped crystals with this whereas maltose gives sunflower shaped crystals.

A general reaction showing the formation of an osazone. D-glucose reacts with phenylhydrazine to give glucose osazone. The same product is obtained from mannose

References

  1. ^ Mester, L.; El Khadem, H.; Horton, D. (1970). "Structure of saccharide osazones". Journal of the Chemical Society C: Organic (18): 2567. doi:10.1039/J39700002567.  edit
  2. ^ Helferich, B. (1953). "Emil Fischer zum 100. Geburtstag". Angewandte Chemie 65: 45. doi:10.1002/ange.19530650202. 
  3. ^ Fischer, Emil (1908). "Schmelzpunkt des Phenylhydrazins und einiger Osazone". Berichte der deutschen chemischen Gesellschaft 41: 73. doi:10.1002/cber.19080410120. 
  4. ^ Fischer, Emil (1894). "Ueber einige Osazone und Hydrazone der Zuckergruppe". Berichte der deutschen chemischen Gesellschaft 27: 2486. doi:10.1002/cber.189402702249. 
  5. ^ Barry, VINCENT C.; Mitchell, PW (1955). "Mechanism of Osazone Formation". Nature 175 (4448): 220. doi:10.1038/175220a0. PMID 13235861. 

Wikimedia Foundation. 2010.

Игры ⚽ Нужен реферат?

Look at other dictionaries:

  • Osazone —   [Kurzwort], organische Verbindungen, die durch Reaktion von Monosacchariden (Hexosen, Pentosen; allgemein von Verbindungen, die in 1,2 Stellung eine Carbonyl und eine Hydroxylgruppe enthalten) mit überschüssigem Phenylhydrazin entstehen;… …   Universal-Lexikon

  • Osazone — Osazone, s. Phenylhydrazin …   Meyers Großes Konversations-Lexikon

  • osazone — ● osazone nom féminin Nom générique des bisphénylhydrazones obtenues par action de la phénylhydrazine sur les oses …   Encyclopédie Universelle

  • Osazone — Als Osazone bezeichnet man die Phenylhydrazone von Zuckern. Inhaltsverzeichnis 1 Geschichte 2 Darstellung 3 Eigenschaften 4 Chemische Bedeutung …   Deutsch Wikipedia

  • osazone — noun any glycoside of an aldose or 2 ketose formed by reaction with excess of an aryl hydrazine …   Wiktionary

  • osazone — The compound formed by certain sugars ( e.g., glucose, galactose, fructose) with excess hydrazines, possessing two hydrazones on carbons 1 and 2 instead of only one at C 1, as in the ordinary hydrazone, thus, RNH N=CR′ CR″=N NHR″′; osazones… …   Medical dictionary

  • Osazone — Osa|zo|ne die (Plur.) Kunstw.> organische Verbindungen, die durch Reaktion von ↑Monosacchariden mit überschüssigem ↑Phenylhydrazin entstehen u. zur Isolierung u. Identifizierung von Zuckern verwendet werden (Chem.) …   Das große Fremdwörterbuch

  • osazone — osa·zone …   English syllables

  • osazone — ˈōsəˌzōn, ˈäs noun ( s) Etymology: International Scientific Vocabulary ose (II) + az + one; probably originally formed as German osazon : any of a class of basic compounds that contain two adjacent hydrazone groupings and are made from an alpha… …   Useful english dictionary

  • Озазоны — (Osazone) см. Глюкозы …   Энциклопедический словарь Ф.А. Брокгауза и И.А. Ефрона

Share the article and excerpts

Direct link
… Do a right-click on the link above
and select “Copy Link”