Osazone are a class of carbohydrate derivatives found in organic chemistry formed when reducing sugars are reacted with excess of phenylhydrazine at boiling temperatures.[1][2]

Formation

Osazone formation was developed by Emil Fischer,[3] who used the reaction as a test to identify monosaccharides.

The formation of a pair of hydrazone functionalities involves both oxidation and condensation reactions.[4] Since the reaction requires a free carbonyl group, only "reducing sugars" participate. Sucrose, which is nonreducing, does not form an osazone.

Appearance

Osazones are highly coloured and crystalline compounds. Osazones are readily distinguished.[5]

  • Maltosazone (from maltose) forms petal-shaped crystals.
  • Lactosazone (from lactose) forms powder puff-shaped crystals.
  • Galactosazone (from galactose) forms rhombic-plate shaped crystals.
  • Glucosazone (from glucose, fructose or mannose) forms broomstick or needle-shaped crystals.

Historic references

References

  1. ^ El Khadem, Hassan S. & Fatiadi, Alexander J. (2000). "Hydrazine derivatives of carbohydrates and related compounds". Advances in Carbohydrate Chemistry and Biochemistry. 55: 175-263. doi:10.1016/S0065-2318(00)55006-9. ISBN 9780120072552. Retrieved 31 March 2021.
  2. ^ 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
  3. ^ Helferich, B. (1953). "Emil Fischer zum 100. Geburtstag". Angewandte Chemie. 65 (2): 45–52. Bibcode:1953AngCh..65...45H. doi:10.1002/ange.19530650202
  4. ^ Ramakrishnan, S. (2004). Textbook of Medical Biochemistry. Orient Blackswan. ISBN 9788125020714.
  5. ^ Gupta, Anil (2019). "Carbohydrates". Comprehensive Biochemistry for Dentistry. Singapore: Springer. pp. 108–110. ISBN 978-981-13-1035-5.