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CH1012
STRUCTURES II
•
Fischer                             Haworth
  aldose    hemiacetal
•


• The cyclic hemiacetal form is drawn
with the anomeric C & the hemiacetal O
(of the new
C-O bond)
at the RHS.
  hemiacetal O   
         anomeric C
 In solution the monosaccharides exist
mainly in cyclic hemiacetal forms where the
penultimate -OH bonds with the C=O, an
intramolecular nucleophilic addition reaction.