Conversion of Fructose to Glucose and Mannose
Conversion of Ketose to Corresponding Aldose (Fructose to Glucose and Fructose to Mannose)
Ketose is first reduced with Na-Hg in the presence of trace of acid. This process introduce a new assymetric carbon and result in the formation of two different polyhydric alcohols. These alcohols are next oxidized with HNO3 to give the corresponding monobasic aldonic acids which on treatment with dil. HCl give γ-lactones. These lactones are then reduced with LAH or Na-Hg in a weakly acidic solution to yield aldoses which are isomer of corresponding ketose.D-Fructose may be converted into D-Glucose and D-Mannose by the following process-