L1 /
11
CH1012
MUTAROTATION
• The a- and b- forms, called anomers, of a saccharide
exist in equilibrium with the open form.
When a pure anomer is placed in
aqueous
solution
the specific
rotation
changes to
an equilibrium value, here +52.7o.
aqueous
solution
the specific
rotation
changes to
an equilibrium value, here +52.7o.
• The majority of the species in solution
are
invariably the hemiacetal forms rather than
the open form. a- 26%, b-64%, open 0.003%
invariably the hemiacetal forms rather than
the open form. a- 26%, b-64%, open 0.003%
• Mutarotation : the change in ar that comes
about from the interconversion of a- and b-
anomers in aqueous solution. It is common
to all sugars which exist in hemiacetal forms.
about from the interconversion of a- and b-
anomers in aqueous solution. It is common
to all sugars which exist in hemiacetal forms.
